Merge branch 'spi-next' from git://git.kernel.org/pub/scm/linux/kernel/git/broonie/misc.git

Pull in the changes Mark has queued up for SPI

10 files changed, 2158 insertions, 77 deletions

diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig
index 2a13e63..5065842 100644
--- a/drivers/spi/Kconfig
+++ b/drivers/spi/Kconfig
@@ -392,6 +392,20 @@ config SPI_MXS
 	help
 	  SPI driver for Freescale MXS devices.
 
+config SPI_TEGRA20_SFLASH
+	tristate "Nvidia Tegra20 Serial flash Controller"
+	depends on ARCH_TEGRA
+	help
+	  SPI driver for Nvidia Tegra20 Serial flash Controller interface.
+	  The main usecase of this controller is to use spi flash as boot
+	  device.
+
+config SPI_TEGRA20_SLINK
+	tristate "Nvidia Tegra20/Tegra30 SLINK Controller"
+	depends on ARCH_TEGRA && TEGRA20_APB_DMA
+	help
+	  SPI driver for Nvidia Tegra20/Tegra30 SLINK Controller interface.
+
 config SPI_TI_SSP
 	tristate "TI Sequencer Serial Port - SPI Support"
 	depends on MFD_TI_SSP
diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile
index 25ab4a1..e0fca55 100644
--- a/drivers/spi/Makefile
+++ b/drivers/spi/Makefile
@@ -61,10 +61,11 @@ obj-$(CONFIG_SPI_SH_MSIOF)		+= spi-sh-msiof.o
 obj-$(CONFIG_SPI_SH_SCI)		+= spi-sh-sci.o
 obj-$(CONFIG_SPI_SIRF)		+= spi-sirf.o
 obj-$(CONFIG_SPI_STMP3XXX)		+= spi-stmp.o
+obj-$(CONFIG_SPI_TEGRA20_SFLASH)	+= spi-tegra20-sflash.o
+obj-$(CONFIG_SPI_TEGRA20_SLINK)		+= spi-tegra20-slink.o
 obj-$(CONFIG_SPI_TI_SSP)		+= spi-ti-ssp.o
 obj-$(CONFIG_SPI_TLE62X0)		+= spi-tle62x0.o
 obj-$(CONFIG_SPI_TOPCLIFF_PCH)		+= spi-topcliff-pch.o
 obj-$(CONFIG_SPI_TXX9)			+= spi-txx9.o
 obj-$(CONFIG_SPI_XCOMM)		+= spi-xcomm.o
 obj-$(CONFIG_SPI_XILINX)		+= spi-xilinx.o
-
diff --git a/drivers/spi/spi-bcm63xx.c b/drivers/spi/spi-bcm63xx.c
index a9f4049..6d97047 100644
--- a/drivers/spi/spi-bcm63xx.c
+++ b/drivers/spi/spi-bcm63xx.c
@@ -36,7 +36,6 @@
 #include <bcm63xx_dev_spi.h>
 
 #define PFX		KBUILD_MODNAME
-#define DRV_VER		"0.1.2"
 
 struct bcm63xx_spi {
 	struct completion	done;
@@ -170,13 +169,6 @@ static int bcm63xx_spi_setup(struct spi_device *spi)
 		return -EINVAL;
 	}
 
-	ret = bcm63xx_spi_check_transfer(spi, NULL);
-	if (ret < 0) {
-		dev_err(&spi->dev, "setup: unsupported mode bits %x\n",
-			spi->mode & ~MODEBITS);
-		return ret;
-	}
-
 	dev_dbg(&spi->dev, "%s, mode %d, %u bits/w, %u nsec/bit\n",
 		__func__, spi->mode & MODEBITS, spi->bits_per_word, 0);
 
@@ -441,8 +433,8 @@ static int __devinit bcm63xx_spi_probe(struct platform_device *pdev)
 		goto out_clk_disable;
 	}
 
-	dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d) v%s\n",
-		 r->start, irq, bs->fifo_size, DRV_VER);
+	dev_info(dev, "at 0x%08x (irq %d, FIFOs size %d)\n",
+		 r->start, irq, bs->fifo_size);
 
 	return 0;
 
@@ -485,6 +477,8 @@ static int bcm63xx_spi_suspend(struct device *dev)
 			platform_get_drvdata(to_platform_device(dev));
 	struct bcm63xx_spi *bs = spi_master_get_devdata(master);
 
+	spi_master_suspend(master);
+
 	clk_disable(bs->clk);
 
 	return 0;
@@ -498,6 +492,8 @@ static int bcm63xx_spi_resume(struct device *dev)
 
 	clk_enable(bs->clk);
 
+	spi_master_resume(master);
+
 	return 0;
 }
 
diff --git a/drivers/spi/spi-omap2-mcspi.c b/drivers/spi/spi-omap2-mcspi.c
index 08a7670..8501384 100644
--- a/drivers/spi/spi-omap2-mcspi.c
+++ b/drivers/spi/spi-omap2-mcspi.c
@@ -129,6 +129,7 @@ struct omap2_mcspi {
 	struct omap2_mcspi_dma	*dma_channels;
 	struct device		*dev;
 	struct omap2_mcspi_regs ctx;
+	unsigned int		pin_dir:1;
 };
 
 struct omap2_mcspi_cs {
@@ -322,19 +323,11 @@ static void omap2_mcspi_tx_dma(struct spi_device *spi,
 	struct omap2_mcspi	*mcspi;
 	struct omap2_mcspi_dma  *mcspi_dma;
 	unsigned int		count;
-	u8			* rx;
-	const u8		* tx;
-	void __iomem		*chstat_reg;
-	struct omap2_mcspi_cs	*cs = spi->controller_state;
 
 	mcspi = spi_master_get_devdata(spi->master);
 	mcspi_dma = &mcspi->dma_channels[spi->chip_select];
 	count = xfer->len;
 
-	rx = xfer->rx_buf;
-	tx = xfer->tx_buf;
-	chstat_reg = cs->base + OMAP2_MCSPI_CHSTAT0;
-
 	if (mcspi_dma->dma_tx) {
 		struct dma_async_tx_descriptor *tx;
 		struct scatterlist sg;
@@ -358,19 +351,6 @@ static void omap2_mcspi_tx_dma(struct spi_device *spi,
 	dma_async_issue_pending(mcspi_dma->dma_tx);
 	omap2_mcspi_set_dma_req(spi, 0, 1);
 
-	wait_for_completion(&mcspi_dma->dma_tx_completion);
-	dma_unmap_single(mcspi->dev, xfer->tx_dma, count,
-			 DMA_TO_DEVICE);
-
-	/* for TX_ONLY mode, be sure all words have shifted out */
-	if (rx == NULL) {
-		if (mcspi_wait_for_reg_bit(chstat_reg,
-					OMAP2_MCSPI_CHSTAT_TXS) < 0)
-			dev_err(&spi->dev, "TXS timed out\n");
-		else if (mcspi_wait_for_reg_bit(chstat_reg,
-					OMAP2_MCSPI_CHSTAT_EOT) < 0)
-			dev_err(&spi->dev, "EOT timed out\n");
-	}
 }
 
 static unsigned
@@ -491,6 +471,7 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
 	struct dma_slave_config	cfg;
 	enum dma_slave_buswidth width;
 	unsigned es;
+	void __iomem		*chstat_reg;
 
 	mcspi = spi_master_get_devdata(spi->master);
 	mcspi_dma = &mcspi->dma_channels[spi->chip_select];
@@ -525,8 +506,24 @@ omap2_mcspi_txrx_dma(struct spi_device *spi, struct spi_transfer *xfer)
 		omap2_mcspi_tx_dma(spi, xfer, cfg);
 
 	if (rx != NULL)
-		return omap2_mcspi_rx_dma(spi, xfer, cfg, es);
-
+		count = omap2_mcspi_rx_dma(spi, xfer, cfg, es);
+
+	if (tx != NULL) {
+		chstat_reg = cs->base + OMAP2_MCSPI_CHSTAT0;
+		wait_for_completion(&mcspi_dma->dma_tx_completion);
+		dma_unmap_single(mcspi->dev, xfer->tx_dma, xfer->len,
+				 DMA_TO_DEVICE);
+
+		/* for TX_ONLY mode, be sure all words have shifted out */
+		if (rx == NULL) {
+			if (mcspi_wait_for_reg_bit(chstat_reg,
+						OMAP2_MCSPI_CHSTAT_TXS) < 0)
+				dev_err(&spi->dev, "TXS timed out\n");
+			else if (mcspi_wait_for_reg_bit(chstat_reg,
+						OMAP2_MCSPI_CHSTAT_EOT) < 0)
+				dev_err(&spi->dev, "EOT timed out\n");
+		}
+	}
 	return count;
 }
 
@@ -764,8 +761,15 @@ static int omap2_mcspi_setup_transfer(struct spi_device *spi,
 	/* standard 4-wire master mode:  SCK, MOSI/out, MISO/in, nCS
 	 * REVISIT: this controller could support SPI_3WIRE mode.
 	 */
-	l &= ~(OMAP2_MCSPI_CHCONF_IS|OMAP2_MCSPI_CHCONF_DPE1);
-	l |= OMAP2_MCSPI_CHCONF_DPE0;
+	if (mcspi->pin_dir == MCSPI_PINDIR_D0_IN_D1_OUT) {
+		l &= ~OMAP2_MCSPI_CHCONF_IS;
+		l &= ~OMAP2_MCSPI_CHCONF_DPE1;
+		l |= OMAP2_MCSPI_CHCONF_DPE0;
+	} else {
+		l |= OMAP2_MCSPI_CHCONF_IS;
+		l |= OMAP2_MCSPI_CHCONF_DPE1;
+		l &= ~OMAP2_MCSPI_CHCONF_DPE0;
+	}
 
 	/* wordlength */
 	l &= ~OMAP2_MCSPI_CHCONF_WL_MASK;
@@ -1166,6 +1170,11 @@ static int __devinit omap2_mcspi_probe(struct platform_device *pdev)
 	master->cleanup = omap2_mcspi_cleanup;
 	master->dev.of_node = node;
 
+	dev_set_drvdata(&pdev->dev, master);
+
+	mcspi = spi_master_get_devdata(master);
+	mcspi->master = master;
+
 	match = of_match_device(omap_mcspi_of_match, &pdev->dev);
 	if (match) {
 		u32 num_cs = 1; /* default number of chipselect */
@@ -1174,19 +1183,17 @@ static int __devinit omap2_mcspi_probe(struct platform_device *pdev)
 		of_property_read_u32(node, "ti,spi-num-cs", &num_cs);
 		master->num_chipselect = num_cs;
 		master->bus_num = bus_num++;
+		if (of_get_property(node, "ti,pindir-d0-out-d1-in", NULL))
+			mcspi->pin_dir = MCSPI_PINDIR_D0_OUT_D1_IN;
 	} else {
 		pdata = pdev->dev.platform_data;
 		master->num_chipselect = pdata->num_cs;
 		if (pdev->id != -1)
 			master->bus_num = pdev->id;
+		mcspi->pin_dir = pdata->pin_dir;
 	}
 	regs_offset = pdata->regs_offset;
 
-	dev_set_drvdata(&pdev->dev, master);
-
-	mcspi = spi_master_get_devdata(master);
-	mcspi->master = master;
-
 	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 	if (r == NULL) {
 		status = -ENODEV;
diff --git a/drivers/spi/spi-pl022.c b/drivers/spi/spi-pl022.c
index a1db91a..1361868 100644
--- a/drivers/spi/spi-pl022.c
+++ b/drivers/spi/spi-pl022.c
@@ -371,6 +371,7 @@ struct pl022 {
 	/* Two optional pin states - default & sleep */
 	struct pinctrl			*pinctrl;
 	struct pinctrl_state		*pins_default;
+	struct pinctrl_state		*pins_idle;
 	struct pinctrl_state		*pins_sleep;
 	struct spi_master		*master;
 	struct pl022_ssp_controller	*master_info;
@@ -2116,6 +2117,11 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id)
 	} else
 		dev_err(dev, "could not get default pinstate\n");
 
+	pl022->pins_idle = pinctrl_lookup_state(pl022->pinctrl,
+					      PINCTRL_STATE_IDLE);
+	if (IS_ERR(pl022->pins_idle))
+		dev_dbg(dev, "could not get idle pinstate\n");
+
 	pl022->pins_sleep = pinctrl_lookup_state(pl022->pinctrl,
 					       PINCTRL_STATE_SLEEP);
 	if (IS_ERR(pl022->pins_sleep))
@@ -2246,10 +2252,9 @@ pl022_probe(struct amba_device *adev, const struct amba_id *id)
 		pm_runtime_set_autosuspend_delay(dev,
 			platform_info->autosuspend_delay);
 		pm_runtime_use_autosuspend(dev);
-		pm_runtime_put_autosuspend(dev);
-	} else {
-		pm_runtime_put(dev);
 	}
+	pm_runtime_put(dev);
+
 	return 0;
 
  err_spi_register:
@@ -2303,35 +2308,47 @@ pl022_remove(struct amba_device *adev)
  * the runtime counterparts to handle external resources like
  * clocks, pins and regulators when going to sleep.
  */
-static void pl022_suspend_resources(struct pl022 *pl022)
+static void pl022_suspend_resources(struct pl022 *pl022, bool runtime)
 {
 	int ret;
+	struct pinctrl_state *pins_state;
 
 	clk_disable(pl022->clk);
 
+	pins_state = runtime ? pl022->pins_idle : pl022->pins_sleep;
 	/* Optionally let pins go into sleep states */
-	if (!IS_ERR(pl022->pins_sleep)) {
-		ret = pinctrl_select_state(pl022->pinctrl,
-					   pl022->pins_sleep);
+	if (!IS_ERR(pins_state)) {
+		ret = pinctrl_select_state(pl022->pinctrl, pins_state);
 		if (ret)
-			dev_err(&pl022->adev->dev,
-				"could not set pins to sleep state\n");
+			dev_err(&pl022->adev->dev, "could not set %s pins\n",
+				runtime ? "idle" : "sleep");
 	}
 }
 
-static void pl022_resume_resources(struct pl022 *pl022)
+static void pl022_resume_resources(struct pl022 *pl022, bool runtime)
 {
 	int ret;
 
 	/* Optionaly enable pins to be muxed in and configured */
+	/* First go to the default state */
 	if (!IS_ERR(pl022->pins_default)) {
-		ret = pinctrl_select_state(pl022->pinctrl,
-					   pl022->pins_default);
+		ret = pinctrl_select_state(pl022->pinctrl, pl022->pins_default);
 		if (ret)
 			dev_err(&pl022->adev->dev,
 				"could not set default pins\n");
 	}
 
+	if (!runtime) {
+		/* Then let's idle the pins until the next transfer happens */
+		if (!IS_ERR(pl022->pins_idle)) {
+			ret = pinctrl_select_state(pl022->pinctrl,
+					pl022->pins_idle);
+		if (ret)
+			dev_err(&pl022->adev->dev,
+				"could not set idle pins\n");
+		}
+	}
+
 	clk_enable(pl022->clk);
 }
 #endif
@@ -2347,7 +2364,9 @@ static int pl022_suspend(struct device *dev)
 		dev_warn(dev, "cannot suspend master\n");
 		return ret;
 	}
-	pl022_suspend_resources(pl022);
+
+	pm_runtime_get_sync(dev);
+	pl022_suspend_resources(pl022, false);
 
 	dev_dbg(dev, "suspended\n");
 	return 0;
@@ -2358,7 +2377,8 @@ static int pl022_resume(struct device *dev)
 	struct pl022 *pl022 = dev_get_drvdata(dev);
 	int ret;
 
-	pl022_resume_resources(pl022);
+	pl022_resume_resources(pl022, false);
+	pm_runtime_put(dev);
 
 	/* Start the queue running */
 	ret = spi_master_resume(pl022->master);
@@ -2376,7 +2396,7 @@ static int pl022_runtime_suspend(struct device *dev)
 {
 	struct pl022 *pl022 = dev_get_drvdata(dev);
 
-	pl022_suspend_resources(pl022);
+	pl022_suspend_resources(pl022, true);
 	return 0;
 }
 
@@ -2384,7 +2404,7 @@ static int pl022_runtime_resume(struct device *dev)
 {
 	struct pl022 *pl022 = dev_get_drvdata(dev);
 
-	pl022_resume_resources(pl022);
+	pl022_resume_resources(pl022, true);
 	return 0;
 }
 #endif
diff --git a/drivers/spi/spi-s3c64xx.c b/drivers/spi/spi-s3c64xx.c
index 6e7a805..57900a8 100644
--- a/drivers/spi/spi-s3c64xx.c
+++ b/drivers/spi/spi-s3c64xx.c
@@ -516,7 +516,7 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
 
 	/* Disable Clock */
 	if (sdd->port_conf->clk_from_cmu) {
-		clk_disable(sdd->src_clk);
+		clk_disable_unprepare(sdd->src_clk);
 	} else {
 		val = readl(regs + S3C64XX_SPI_CLK_CFG);
 		val &= ~S3C64XX_SPI_ENCLK_ENABLE;
@@ -564,7 +564,7 @@ static void s3c64xx_spi_config(struct s3c64xx_spi_driver_data *sdd)
 		/* There is half-multiplier before the SPI */
 		clk_set_rate(sdd->src_clk, sdd->cur_speed * 2);
 		/* Enable Clock */
-		clk_enable(sdd->src_clk);
+		clk_prepare_enable(sdd->src_clk);
 	} else {
 		/* Configure Clock */
 		val = readl(regs + S3C64XX_SPI_CLK_CFG);
@@ -1112,7 +1112,7 @@ static int s3c64xx_spi_parse_dt_gpio(struct s3c64xx_spi_driver_data *sdd)
 			dev_err(dev, "invalid gpio[%d]: %d\n", idx, gpio);
 			goto free_gpio;
 		}
-
+		sdd->gpios[idx] = gpio;
 		ret = gpio_request(gpio, "spi-bus");
 		if (ret) {
 			dev_err(dev, "gpio [%d] request failed: %d\n",
@@ -1302,7 +1302,7 @@ static int __init s3c64xx_spi_probe(struct platform_device *pdev)
 		goto err3;
 	}
 
-	if (clk_enable(sdd->clk)) {
+	if (clk_prepare_enable(sdd->clk)) {
 		dev_err(&pdev->dev, "Couldn't enable clock 'spi'\n");
 		ret = -EBUSY;
 		goto err4;
@@ -1317,7 +1317,7 @@ static int __init s3c64xx_spi_probe(struct platform_device *pdev)
 		goto err5;
 	}
 
-	if (clk_enable(sdd->src_clk)) {
+	if (clk_prepare_enable(sdd->src_clk)) {
 		dev_err(&pdev->dev, "Couldn't enable clock '%s'\n", clk_name);
 		ret = -EBUSY;
 		goto err6;
@@ -1361,11 +1361,11 @@ static int __init s3c64xx_spi_probe(struct platform_device *pdev)
 err8:
 	free_irq(irq, sdd);
 err7:
-	clk_disable(sdd->src_clk);
+	clk_disable_unprepare(sdd->src_clk);
 err6:
 	clk_put(sdd->src_clk);
 err5:
-	clk_disable(sdd->clk);
+	clk_disable_unprepare(sdd->clk);
 err4:
 	clk_put(sdd->clk);
 err3:
@@ -1393,10 +1393,10 @@ static int s3c64xx_spi_remove(struct platform_device *pdev)
 
 	free_irq(platform_get_irq(pdev, 0), sdd);
 
-	clk_disable(sdd->src_clk);
+	clk_disable_unprepare(sdd->src_clk);
 	clk_put(sdd->src_clk);
 
-	clk_disable(sdd->clk);
+	clk_disable_unprepare(sdd->clk);
 	clk_put(sdd->clk);
 
 	if (!sdd->cntrlr_info->cfg_gpio && pdev->dev.of_node)
@@ -1417,8 +1417,8 @@ static int s3c64xx_spi_suspend(struct device *dev)
 	spi_master_suspend(master);
 
 	/* Disable the clock */
-	clk_disable(sdd->src_clk);
-	clk_disable(sdd->clk);
+	clk_disable_unprepare(sdd->src_clk);
+	clk_disable_unprepare(sdd->clk);
 
 	if (!sdd->cntrlr_info->cfg_gpio && dev->of_node)
 		s3c64xx_spi_dt_gpio_free(sdd);
@@ -1440,8 +1440,8 @@ static int s3c64xx_spi_resume(struct device *dev)
 		sci->cfg_gpio();
 
 	/* Enable the clock */
-	clk_enable(sdd->src_clk);
-	clk_enable(sdd->clk);
+	clk_prepare_enable(sdd->src_clk);
+	clk_prepare_enable(sdd->clk);
 
 	s3c64xx_spi_hwinit(sdd, sdd->port_id);
 
@@ -1457,8 +1457,8 @@ static int s3c64xx_spi_runtime_suspend(struct device *dev)
 	struct spi_master *master = dev_get_drvdata(dev);
 	struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
 
-	clk_disable(sdd->clk);
-	clk_disable(sdd->src_clk);
+	clk_disable_unprepare(sdd->clk);
+	clk_disable_unprepare(sdd->src_clk);
 
 	return 0;
 }
@@ -1468,8 +1468,8 @@ static int s3c64xx_spi_runtime_resume(struct device *dev)
 	struct spi_master *master = dev_get_drvdata(dev);
 	struct s3c64xx_spi_driver_data *sdd = spi_master_get_devdata(master);
 
-	clk_enable(sdd->src_clk);
-	clk_enable(sdd->clk);
+	clk_prepare_enable(sdd->src_clk);
+	clk_prepare_enable(sdd->clk);
 
 	return 0;
 }
diff --git a/drivers/spi/spi-tegra20-sflash.c b/drivers/spi/spi-tegra20-sflash.c
new file mode 100644
index 0000000..54eb948
--- /dev/null
+++ b/drivers/spi/spi-tegra20-sflash.c
@@ -0,0 +1,665 @@
+/*
+ * SPI driver for Nvidia's Tegra20 Serial Flash Controller.
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * Author: Laxman Dewangan <ldewangan@nvidia.com>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-tegra.h>
+#include <mach/clk.h>
+
+#define SPI_COMMAND				0x000
+#define SPI_GO					BIT(30)
+#define SPI_M_S					BIT(28)
+#define SPI_ACTIVE_SCLK_MASK			(0x3 << 26)
+#define SPI_ACTIVE_SCLK_DRIVE_LOW		(0 << 26)
+#define SPI_ACTIVE_SCLK_DRIVE_HIGH		(1 << 26)
+#define SPI_ACTIVE_SCLK_PULL_LOW		(2 << 26)
+#define SPI_ACTIVE_SCLK_PULL_HIGH		(3 << 26)
+
+#define SPI_CK_SDA_FALLING			(1 << 21)
+#define SPI_CK_SDA_RISING			(0 << 21)
+#define SPI_CK_SDA_MASK				(1 << 21)
+#define SPI_ACTIVE_SDA				(0x3 << 18)
+#define SPI_ACTIVE_SDA_DRIVE_LOW		(0 << 18)
+#define SPI_ACTIVE_SDA_DRIVE_HIGH		(1 << 18)
+#define SPI_ACTIVE_SDA_PULL_LOW			(2 << 18)
+#define SPI_ACTIVE_SDA_PULL_HIGH		(3 << 18)
+
+#define SPI_CS_POL_INVERT			BIT(16)
+#define SPI_TX_EN				BIT(15)
+#define SPI_RX_EN				BIT(14)
+#define SPI_CS_VAL_HIGH				BIT(13)
+#define SPI_CS_VAL_LOW				0x0
+#define SPI_CS_SW				BIT(12)
+#define SPI_CS_HW				0x0
+#define SPI_CS_DELAY_MASK			(7 << 9)
+#define SPI_CS3_EN				BIT(8)
+#define SPI_CS2_EN				BIT(7)
+#define SPI_CS1_EN				BIT(6)
+#define SPI_CS0_EN				BIT(5)
+
+#define SPI_CS_MASK			(SPI_CS3_EN | SPI_CS2_EN |	\
+					SPI_CS1_EN | SPI_CS0_EN)
+#define SPI_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
+
+#define SPI_MODES			(SPI_ACTIVE_SCLK_MASK | SPI_CK_SDA_MASK)
+
+#define SPI_STATUS			0x004
+#define SPI_BSY				BIT(31)
+#define SPI_RDY				BIT(30)
+#define SPI_TXF_FLUSH			BIT(29)
+#define SPI_RXF_FLUSH			BIT(28)
+#define SPI_RX_UNF			BIT(27)
+#define SPI_TX_OVF			BIT(26)
+#define SPI_RXF_EMPTY			BIT(25)
+#define SPI_RXF_FULL			BIT(24)
+#define SPI_TXF_EMPTY			BIT(23)
+#define SPI_TXF_FULL			BIT(22)
+#define SPI_BLK_CNT(count)		(((count) & 0xffff) + 1)
+
+#define SPI_FIFO_ERROR			(SPI_RX_UNF | SPI_TX_OVF)
+#define SPI_FIFO_EMPTY			(SPI_TX_EMPTY | SPI_RX_EMPTY)
+
+#define SPI_RX_CMP			0x8
+#define SPI_DMA_CTL			0x0C
+#define SPI_DMA_EN			BIT(31)
+#define SPI_IE_RXC			BIT(27)
+#define SPI_IE_TXC			BIT(26)
+#define SPI_PACKED			BIT(20)
+#define SPI_RX_TRIG_MASK		(0x3 << 18)
+#define SPI_RX_TRIG_1W			(0x0 << 18)
+#define SPI_RX_TRIG_4W			(0x1 << 18)
+#define SPI_TX_TRIG_MASK		(0x3 << 16)
+#define SPI_TX_TRIG_1W			(0x0 << 16)
+#define SPI_TX_TRIG_4W			(0x1 << 16)
+#define SPI_DMA_BLK_COUNT(count)	(((count) - 1) & 0xFFFF);
+
+#define SPI_TX_FIFO			0x10
+#define SPI_RX_FIFO			0x20
+
+#define DATA_DIR_TX			(1 << 0)
+#define DATA_DIR_RX			(1 << 1)
+
+#define MAX_CHIP_SELECT			4
+#define SPI_FIFO_DEPTH			4
+#define SPI_DMA_TIMEOUT               (msecs_to_jiffies(1000))
+
+struct tegra_sflash_data {
+	struct device				*dev;
+	struct spi_master			*master;
+	spinlock_t				lock;
+
+	struct clk				*clk;
+	void __iomem				*base;
+	unsigned				irq;
+	u32					spi_max_frequency;
+	u32					cur_speed;
+
+	struct spi_device			*cur_spi;
+	unsigned				cur_pos;
+	unsigned				cur_len;
+	unsigned				bytes_per_word;
+	unsigned				cur_direction;
+	unsigned				curr_xfer_words;
+
+	unsigned				cur_rx_pos;
+	unsigned				cur_tx_pos;
+
+	u32					tx_status;
+	u32					rx_status;
+	u32					status_reg;
+
+	u32					def_command_reg;
+	u32					command_reg;
+	u32					dma_control_reg;
+
+	struct completion			xfer_completion;
+	struct spi_transfer			*curr_xfer;
+};
+
+static int tegra_sflash_runtime_suspend(struct device *dev);
+static int tegra_sflash_runtime_resume(struct device *dev);
+
+static inline unsigned long tegra_sflash_readl(struct tegra_sflash_data *tsd,
+		unsigned long reg)
+{
+	return readl(tsd->base + reg);
+}
+
+static inline void tegra_sflash_writel(struct tegra_sflash_data *tsd,
+		unsigned long val, unsigned long reg)
+{
+	writel(val, tsd->base + reg);
+}
+
+static void tegra_sflash_clear_status(struct tegra_sflash_data *tsd)
+{
+	/* Write 1 to clear status register */
+	tegra_sflash_writel(tsd, SPI_RDY | SPI_FIFO_ERROR, SPI_STATUS);
+}
+
+static unsigned tegra_sflash_calculate_curr_xfer_param(
+	struct spi_device *spi, struct tegra_sflash_data *tsd,
+	struct spi_transfer *t)
+{
+	unsigned remain_len = t->len - tsd->cur_pos;
+	unsigned max_word;
+
+	tsd->bytes_per_word = (t->bits_per_word - 1) / 8 + 1;
+	max_word = remain_len / tsd->bytes_per_word;
+	if (max_word > SPI_FIFO_DEPTH)
+		max_word = SPI_FIFO_DEPTH;
+	tsd->curr_xfer_words = max_word;
+	return max_word;
+}
+
+static unsigned tegra_sflash_fill_tx_fifo_from_client_txbuf(
+	struct tegra_sflash_data *tsd, struct spi_transfer *t)
+{
+	unsigned nbytes;
+	unsigned long status;
+	unsigned max_n_32bit = tsd->curr_xfer_words;
+	u8 *tx_buf = (u8 *)t->tx_buf + tsd->cur_tx_pos;
+
+	if (max_n_32bit > SPI_FIFO_DEPTH)
+		max_n_32bit = SPI_FIFO_DEPTH;
+	nbytes = max_n_32bit * tsd->bytes_per_word;
+
+	status = tegra_sflash_readl(tsd, SPI_STATUS);
+	while (!(status & SPI_TXF_FULL)) {
+		int i;
+		unsigned int x = 0;
+
+		for (i = 0; nbytes && (i < tsd->bytes_per_word);
+							i++, nbytes--)
+				x |= ((*tx_buf++) << i*8);
+		tegra_sflash_writel(tsd, x, SPI_TX_FIFO);
+		if (!nbytes)
+			break;
+
+		status = tegra_sflash_readl(tsd, SPI_STATUS);
+	}
+	tsd->cur_tx_pos += max_n_32bit * tsd->bytes_per_word;
+	return max_n_32bit;
+}
+
+static int tegra_sflash_read_rx_fifo_to_client_rxbuf(
+		struct tegra_sflash_data *tsd, struct spi_transfer *t)
+{
+	unsigned long status;
+	unsigned int read_words = 0;
+	u8 *rx_buf = (u8 *)t->rx_buf + tsd->cur_rx_pos;
+
+	status = tegra_sflash_readl(tsd, SPI_STATUS);
+	while (!(status & SPI_RXF_EMPTY)) {
+		int i;
+		unsigned long x;
+
+		x = tegra_sflash_readl(tsd, SPI_RX_FIFO);
+		for (i = 0; (i < tsd->bytes_per_word); i++)
+			*rx_buf++ = (x >> (i*8)) & 0xFF;
+		read_words++;
+		status = tegra_sflash_readl(tsd, SPI_STATUS);
+	}
+	tsd->cur_rx_pos += read_words * tsd->bytes_per_word;
+	return 0;
+}
+
+static int tegra_sflash_start_cpu_based_transfer(
+		struct tegra_sflash_data *tsd, struct spi_transfer *t)
+{
+	unsigned long val = 0;
+	unsigned cur_words;
+
+	if (tsd->cur_direction & DATA_DIR_TX)
+		val |= SPI_IE_TXC;
+
+	if (tsd->cur_direction & DATA_DIR_RX)
+		val |= SPI_IE_RXC;
+
+	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
+	tsd->dma_control_reg = val;
+
+	if (tsd->cur_direction & DATA_DIR_TX)
+		cur_words = tegra_sflash_fill_tx_fifo_from_client_txbuf(tsd, t);
+	else
+		cur_words = tsd->curr_xfer_words;
+	val |= SPI_DMA_BLK_COUNT(cur_words);
+	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
+	tsd->dma_control_reg = val;
+	val |= SPI_DMA_EN;
+	tegra_sflash_writel(tsd, val, SPI_DMA_CTL);
+	return 0;
+}
+
+static int tegra_sflash_start_transfer_one(struct spi_device *spi,
+		struct spi_transfer *t, bool is_first_of_msg,
+		bool is_single_xfer)
+{
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(spi->master);
+	u32 speed;
+	unsigned long command;
+
+	speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
+	if (!speed)
+		speed = tsd->spi_max_frequency;
+	if (speed != tsd->cur_speed) {
+		clk_set_rate(tsd->clk, speed);
+		tsd->cur_speed = speed;
+	}
+
+	tsd->cur_spi = spi;
+	tsd->cur_pos = 0;
+	tsd->cur_rx_pos = 0;
+	tsd->cur_tx_pos = 0;
+	tsd->curr_xfer = t;
+	tegra_sflash_calculate_curr_xfer_param(spi, tsd, t);
+	if (is_first_of_msg) {
+		command = tsd->def_command_reg;
+		command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
+		command |= SPI_CS_VAL_HIGH;
+
+		command &= ~SPI_MODES;
+		if (spi->mode & SPI_CPHA)
+			command |= SPI_CK_SDA_FALLING;
+
+		if (spi->mode & SPI_CPOL)
+			command |= SPI_ACTIVE_SCLK_DRIVE_HIGH;
+		else
+			command |= SPI_ACTIVE_SCLK_DRIVE_LOW;
+		command |= SPI_CS0_EN << spi->chip_select;
+	} else {
+		command = tsd->command_reg;
+		command &= ~SPI_BIT_LENGTH(~0);
+		command |= SPI_BIT_LENGTH(t->bits_per_word - 1);
+		command &= ~(SPI_RX_EN | SPI_TX_EN);
+	}
+
+	tsd->cur_direction = 0;
+	if (t->rx_buf) {
+		command |= SPI_RX_EN;
+		tsd->cur_direction |= DATA_DIR_RX;
+	}
+	if (t->tx_buf) {
+		command |= SPI_TX_EN;
+		tsd->cur_direction |= DATA_DIR_TX;
+	}
+	tegra_sflash_writel(tsd, command, SPI_COMMAND);
+	tsd->command_reg = command;
+
+	return  tegra_sflash_start_cpu_based_transfer(tsd, t);
+}
+
+static int tegra_sflash_transfer_one_message(struct spi_master *master,
+			struct spi_message *msg)
+{
+	bool is_first_msg = true;
+	int single_xfer;
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+	struct spi_transfer *xfer;
+	struct spi_device *spi = msg->spi;
+	int ret;
+
+	ret = pm_runtime_get_sync(tsd->dev);
+	if (ret < 0) {
+		dev_err(tsd->dev, "pm_runtime_get() failed, err = %d\n", ret);
+		return ret;
+	}
+
+	msg->status = 0;
+	msg->actual_length = 0;
+	single_xfer = list_is_singular(&msg->transfers);
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		INIT_COMPLETION(tsd->xfer_completion);
+		ret = tegra_sflash_start_transfer_one(spi, xfer,
+					is_first_msg, single_xfer);
+		if (ret < 0) {
+			dev_err(tsd->dev,
+				"spi can not start transfer, err %d\n", ret);
+			goto exit;
+		}
+		is_first_msg = false;
+		ret = wait_for_completion_timeout(&tsd->xfer_completion,
+						SPI_DMA_TIMEOUT);
+		if (WARN_ON(ret == 0)) {
+			dev_err(tsd->dev,
+				"spi trasfer timeout, err %d\n", ret);
+			ret = -EIO;
+			goto exit;
+		}
+
+		if (tsd->tx_status ||  tsd->rx_status) {
+			dev_err(tsd->dev, "Error in Transfer\n");
+			ret = -EIO;
+			goto exit;
+		}
+		msg->actual_length += xfer->len;
+		if (xfer->cs_change && xfer->delay_usecs) {
+			tegra_sflash_writel(tsd, tsd->def_command_reg,
+					SPI_COMMAND);
+			udelay(xfer->delay_usecs);
+		}
+	}
+	ret = 0;
+exit:
+	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
+	msg->status = ret;
+	spi_finalize_current_message(master);
+	pm_runtime_put(tsd->dev);
+	return ret;
+}
+
+static irqreturn_t handle_cpu_based_xfer(struct tegra_sflash_data *tsd)
+{
+	struct spi_transfer *t = tsd->curr_xfer;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tsd->lock, flags);
+	if (tsd->tx_status || tsd->rx_status || (tsd->status_reg & SPI_BSY)) {
+		dev_err(tsd->dev,
+			"CpuXfer ERROR bit set 0x%x\n", tsd->status_reg);
+		dev_err(tsd->dev,
+			"CpuXfer 0x%08x:0x%08x\n", tsd->command_reg,
+				tsd->dma_control_reg);
+		tegra_periph_reset_assert(tsd->clk);
+		udelay(2);
+		tegra_periph_reset_deassert(tsd->clk);
+		complete(&tsd->xfer_completion);
+		goto exit;
+	}
+
+	if (tsd->cur_direction & DATA_DIR_RX)
+		tegra_sflash_read_rx_fifo_to_client_rxbuf(tsd, t);
+
+	if (tsd->cur_direction & DATA_DIR_TX)
+		tsd->cur_pos = tsd->cur_tx_pos;
+	else
+		tsd->cur_pos = tsd->cur_rx_pos;
+
+	if (tsd->cur_pos == t->len) {
+		complete(&tsd->xfer_completion);
+		goto exit;
+	}
+
+	tegra_sflash_calculate_curr_xfer_param(tsd->cur_spi, tsd, t);
+	tegra_sflash_start_cpu_based_transfer(tsd, t);
+exit:
+	spin_unlock_irqrestore(&tsd->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t tegra_sflash_isr(int irq, void *context_data)
+{
+	struct tegra_sflash_data *tsd = context_data;
+
+	tsd->status_reg = tegra_sflash_readl(tsd, SPI_STATUS);
+	if (tsd->cur_direction & DATA_DIR_TX)
+		tsd->tx_status = tsd->status_reg & SPI_TX_OVF;
+
+	if (tsd->cur_direction & DATA_DIR_RX)
+		tsd->rx_status = tsd->status_reg & SPI_RX_UNF;
+	tegra_sflash_clear_status(tsd);
+
+	return handle_cpu_based_xfer(tsd);
+}
+
+static struct tegra_spi_platform_data *tegra_sflash_parse_dt(
+		struct platform_device *pdev)
+{
+	struct tegra_spi_platform_data *pdata;
+	struct device_node *np = pdev->dev.of_node;
+	u32 max_freq;
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata) {
+		dev_err(&pdev->dev, "Memory alloc for pdata failed\n");
+		return NULL;
+	}
+
+	if (!of_property_read_u32(np, "spi-max-frequency", &max_freq))
+		pdata->spi_max_frequency = max_freq;
+
+	return pdata;
+}
+
+static struct of_device_id tegra_sflash_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,tegra20-sflash", },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tegra_sflash_of_match);
+
+static int __devinit tegra_sflash_probe(struct platform_device *pdev)
+{
+	struct spi_master	*master;
+	struct tegra_sflash_data	*tsd;
+	struct resource		*r;
+	struct tegra_spi_platform_data *pdata = pdev->dev.platform_data;
+	int ret;
+	const struct of_device_id *match;
+
+	match = of_match_device(of_match_ptr(tegra_sflash_of_match),
+					&pdev->dev);
+	if (!match) {
+		dev_err(&pdev->dev, "Error: No device match found\n");
+		return -ENODEV;
+	}
+
+	if (!pdata && pdev->dev.of_node)
+		pdata = tegra_sflash_parse_dt(pdev);
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "No platform data, exiting\n");
+		return -ENODEV;
+	}
+
+	if (!pdata->spi_max_frequency)
+		pdata->spi_max_frequency = 25000000; /* 25MHz */
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*tsd));
+	if (!master) {
+		dev_err(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA;
+	master->transfer_one_message = tegra_sflash_transfer_one_message;
+	master->num_chipselect = MAX_CHIP_SELECT;
+	master->bus_num = -1;
+
+	dev_set_drvdata(&pdev->dev, master);
+	tsd = spi_master_get_devdata(master);
+	tsd->master = master;
+	tsd->dev = &pdev->dev;
+	spin_lock_init(&tsd->lock);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r) {
+		dev_err(&pdev->dev, "No IO memory resource\n");
+		ret = -ENODEV;
+		goto exit_free_master;
+	}
+	tsd->base = devm_request_and_ioremap(&pdev->dev, r);
+	if (!tsd->base) {
+		dev_err(&pdev->dev,
+			"Cannot request memregion/iomap dma address\n");
+		ret = -EADDRNOTAVAIL;
+		goto exit_free_master;
+	}
+
+	tsd->irq = platform_get_irq(pdev, 0);
+	ret = request_irq(tsd->irq, tegra_sflash_isr, 0,
+			dev_name(&pdev->dev), tsd);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
+					tsd->irq);
+		goto exit_free_master;
+	}
+
+	tsd->clk = devm_clk_get(&pdev->dev, "spi");
+	if (IS_ERR(tsd->clk)) {
+		dev_err(&pdev->dev, "can not get clock\n");
+		ret = PTR_ERR(tsd->clk);
+		goto exit_free_irq;
+	}
+
+	tsd->spi_max_frequency = pdata->spi_max_frequency;
+	init_completion(&tsd->xfer_completion);
+	pm_runtime_enable(&pdev->dev);
+	if (!pm_runtime_enabled(&pdev->dev)) {
+		ret = tegra_sflash_runtime_resume(&pdev->dev);
+		if (ret)
+			goto exit_pm_disable;
+	}
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
+		goto exit_pm_disable;
+	}
+
+	/* Reset controller */
+	tegra_periph_reset_assert(tsd->clk);
+	udelay(2);
+	tegra_periph_reset_deassert(tsd->clk);
+
+	tsd->def_command_reg  = SPI_M_S | SPI_CS_SW;
+	tegra_sflash_writel(tsd, tsd->def_command_reg, SPI_COMMAND);
+	pm_runtime_put(&pdev->dev);
+
+	master->dev.of_node = pdev->dev.of_node;
+	ret = spi_register_master(master);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can not register to master err %d\n", ret);
+		goto exit_pm_disable;
+	}
+	return ret;
+
+exit_pm_disable:
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_sflash_runtime_suspend(&pdev->dev);
+exit_free_irq:
+	free_irq(tsd->irq, tsd);
+exit_free_master:
+	spi_master_put(master);
+	return ret;
+}
+
+static int __devexit tegra_sflash_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = dev_get_drvdata(&pdev->dev);
+	struct tegra_sflash_data	*tsd = spi_master_get_devdata(master);
+
+	free_irq(tsd->irq, tsd);
+	spi_unregister_master(master);
+
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_sflash_runtime_suspend(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_sflash_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+
+	return spi_master_suspend(master);
+}
+
+static int tegra_sflash_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm runtime failed, e = %d\n", ret);
+		return ret;
+	}
+	tegra_sflash_writel(tsd, tsd->command_reg, SPI_COMMAND);
+	pm_runtime_put(dev);
+
+	return spi_master_resume(master);
+}
+#endif
+
+static int tegra_sflash_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+
+	/* Flush all write which are in PPSB queue by reading back */
+	tegra_sflash_readl(tsd, SPI_COMMAND);
+
+	clk_disable_unprepare(tsd->clk);
+	return 0;
+}
+
+static int tegra_sflash_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_sflash_data *tsd = spi_master_get_devdata(master);
+	int ret;
+
+	ret = clk_prepare_enable(tsd->clk);
+	if (ret < 0) {
+		dev_err(tsd->dev, "clk_prepare failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static const struct dev_pm_ops slink_pm_ops = {
+	SET_RUNTIME_PM_OPS(tegra_sflash_runtime_suspend,
+		tegra_sflash_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(tegra_sflash_suspend, tegra_sflash_resume)
+};
+static struct platform_driver tegra_sflash_driver = {
+	.driver = {
+		.name		= "spi-tegra-sflash",
+		.owner		= THIS_MODULE,
+		.pm		= &slink_pm_ops,
+		.of_match_table	= of_match_ptr(tegra_sflash_of_match),
+	},
+	.probe =	tegra_sflash_probe,
+	.remove =	__devexit_p(tegra_sflash_remove),
+};
+module_platform_driver(tegra_sflash_driver);
+
+MODULE_ALIAS("platform:spi-tegra-sflash");
+MODULE_DESCRIPTION("NVIDIA Tegra20 Serial Flash Controller Driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/spi/spi-tegra20-slink.c b/drivers/spi/spi-tegra20-slink.c
new file mode 100644
index 0000000..7882b50
--- /dev/null
+++ b/drivers/spi/spi-tegra20-slink.c
@@ -0,0 +1,1358 @@
+/*
+ * SPI driver for Nvidia's Tegra20/Tegra30 SLINK Controller.
+ *
+ * Copyright (c) 2012, NVIDIA CORPORATION.  All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include <linux/clk.h>
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/dmaengine.h>
+#include <linux/dma-mapping.h>
+#include <linux/dmapool.h>
+#include <linux/err.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/io.h>
+#include <linux/kernel.h>
+#include <linux/kthread.h>
+#include <linux/module.h>
+#include <linux/platform_device.h>
+#include <linux/pm_runtime.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/spi-tegra.h>
+#include <mach/clk.h>
+
+#define SLINK_COMMAND			0x000
+#define SLINK_BIT_LENGTH(x)		(((x) & 0x1f) << 0)
+#define SLINK_WORD_SIZE(x)		(((x) & 0x1f) << 5)
+#define SLINK_BOTH_EN			(1 << 10)
+#define SLINK_CS_SW			(1 << 11)
+#define SLINK_CS_VALUE			(1 << 12)
+#define SLINK_CS_POLARITY		(1 << 13)
+#define SLINK_IDLE_SDA_DRIVE_LOW	(0 << 16)
+#define SLINK_IDLE_SDA_DRIVE_HIGH	(1 << 16)
+#define SLINK_IDLE_SDA_PULL_LOW		(2 << 16)
+#define SLINK_IDLE_SDA_PULL_HIGH	(3 << 16)
+#define SLINK_IDLE_SDA_MASK		(3 << 16)
+#define SLINK_CS_POLARITY1		(1 << 20)
+#define SLINK_CK_SDA			(1 << 21)
+#define SLINK_CS_POLARITY2		(1 << 22)
+#define SLINK_CS_POLARITY3		(1 << 23)
+#define SLINK_IDLE_SCLK_DRIVE_LOW	(0 << 24)
+#define SLINK_IDLE_SCLK_DRIVE_HIGH	(1 << 24)
+#define SLINK_IDLE_SCLK_PULL_LOW	(2 << 24)
+#define SLINK_IDLE_SCLK_PULL_HIGH	(3 << 24)
+#define SLINK_IDLE_SCLK_MASK		(3 << 24)
+#define SLINK_M_S			(1 << 28)
+#define SLINK_WAIT			(1 << 29)
+#define SLINK_GO			(1 << 30)
+#define SLINK_ENB			(1 << 31)
+
+#define SLINK_MODES			(SLINK_IDLE_SCLK_MASK | SLINK_CK_SDA)
+
+#define SLINK_COMMAND2			0x004
+#define SLINK_LSBFE			(1 << 0)
+#define SLINK_SSOE			(1 << 1)
+#define SLINK_SPIE			(1 << 4)
+#define SLINK_BIDIROE			(1 << 6)
+#define SLINK_MODFEN			(1 << 7)
+#define SLINK_INT_SIZE(x)		(((x) & 0x1f) << 8)
+#define SLINK_CS_ACTIVE_BETWEEN		(1 << 17)
+#define SLINK_SS_EN_CS(x)		(((x) & 0x3) << 18)
+#define SLINK_SS_SETUP(x)		(((x) & 0x3) << 20)
+#define SLINK_FIFO_REFILLS_0		(0 << 22)
+#define SLINK_FIFO_REFILLS_1		(1 << 22)
+#define SLINK_FIFO_REFILLS_2		(2 << 22)
+#define SLINK_FIFO_REFILLS_3		(3 << 22)
+#define SLINK_FIFO_REFILLS_MASK		(3 << 22)
+#define SLINK_WAIT_PACK_INT(x)		(((x) & 0x7) << 26)
+#define SLINK_SPC0			(1 << 29)
+#define SLINK_TXEN			(1 << 30)
+#define SLINK_RXEN			(1 << 31)
+
+#define SLINK_STATUS			0x008
+#define SLINK_COUNT(val)		(((val) >> 0) & 0x1f)
+#define SLINK_WORD(val)			(((val) >> 5) & 0x1f)
+#define SLINK_BLK_CNT(val)		(((val) >> 0) & 0xffff)
+#define SLINK_MODF			(1 << 16)
+#define SLINK_RX_UNF			(1 << 18)
+#define SLINK_TX_OVF			(1 << 19)
+#define SLINK_TX_FULL			(1 << 20)
+#define SLINK_TX_EMPTY			(1 << 21)
+#define SLINK_RX_FULL			(1 << 22)
+#define SLINK_RX_EMPTY			(1 << 23)
+#define SLINK_TX_UNF			(1 << 24)
+#define SLINK_RX_OVF			(1 << 25)
+#define SLINK_TX_FLUSH			(1 << 26)
+#define SLINK_RX_FLUSH			(1 << 27)
+#define SLINK_SCLK			(1 << 28)
+#define SLINK_ERR			(1 << 29)
+#define SLINK_RDY			(1 << 30)
+#define SLINK_BSY			(1 << 31)
+#define SLINK_FIFO_ERROR		(SLINK_TX_OVF | SLINK_RX_UNF |	\
+					SLINK_TX_UNF | SLINK_RX_OVF)
+
+#define SLINK_FIFO_EMPTY		(SLINK_TX_EMPTY | SLINK_RX_EMPTY)
+
+#define SLINK_MAS_DATA			0x010
+#define SLINK_SLAVE_DATA		0x014
+
+#define SLINK_DMA_CTL			0x018
+#define SLINK_DMA_BLOCK_SIZE(x)		(((x) & 0xffff) << 0)
+#define SLINK_TX_TRIG_1			(0 << 16)
+#define SLINK_TX_TRIG_4			(1 << 16)
+#define SLINK_TX_TRIG_8			(2 << 16)
+#define SLINK_TX_TRIG_16		(3 << 16)
+#define SLINK_TX_TRIG_MASK		(3 << 16)
+#define SLINK_RX_TRIG_1			(0 << 18)
+#define SLINK_RX_TRIG_4			(1 << 18)
+#define SLINK_RX_TRIG_8			(2 << 18)
+#define SLINK_RX_TRIG_16		(3 << 18)
+#define SLINK_RX_TRIG_MASK		(3 << 18)
+#define SLINK_PACKED			(1 << 20)
+#define SLINK_PACK_SIZE_4		(0 << 21)
+#define SLINK_PACK_SIZE_8		(1 << 21)
+#define SLINK_PACK_SIZE_16		(2 << 21)
+#define SLINK_PACK_SIZE_32		(3 << 21)
+#define SLINK_PACK_SIZE_MASK		(3 << 21)
+#define SLINK_IE_TXC			(1 << 26)
+#define SLINK_IE_RXC			(1 << 27)
+#define SLINK_DMA_EN			(1 << 31)
+
+#define SLINK_STATUS2			0x01c
+#define SLINK_TX_FIFO_EMPTY_COUNT(val)	(((val) & 0x3f) >> 0)
+#define SLINK_RX_FIFO_FULL_COUNT(val)	(((val) & 0x3f0000) >> 16)
+#define SLINK_SS_HOLD_TIME(val)		(((val) & 0xF) << 6)
+
+#define SLINK_TX_FIFO			0x100
+#define SLINK_RX_FIFO			0x180
+
+#define DATA_DIR_TX			(1 << 0)
+#define DATA_DIR_RX			(1 << 1)
+
+#define SLINK_DMA_TIMEOUT		(msecs_to_jiffies(1000))
+
+#define DEFAULT_SPI_DMA_BUF_LEN		(16*1024)
+#define TX_FIFO_EMPTY_COUNT_MAX		SLINK_TX_FIFO_EMPTY_COUNT(0x20)
+#define RX_FIFO_FULL_COUNT_ZERO		SLINK_RX_FIFO_FULL_COUNT(0)
+
+#define SLINK_STATUS2_RESET \
+	(TX_FIFO_EMPTY_COUNT_MAX | RX_FIFO_FULL_COUNT_ZERO << 16)
+
+#define MAX_CHIP_SELECT			4
+#define SLINK_FIFO_DEPTH		32
+
+struct tegra_slink_chip_data {
+	bool cs_hold_time;
+};
+
+struct tegra_slink_data {
+	struct device				*dev;
+	struct spi_master			*master;
+	const struct tegra_slink_chip_data	*chip_data;
+	spinlock_t				lock;
+
+	struct clk				*clk;
+	void __iomem				*base;
+	phys_addr_t				phys;
+	unsigned				irq;
+	int					dma_req_sel;
+	u32					spi_max_frequency;
+	u32					cur_speed;
+
+	struct spi_device			*cur_spi;
+	unsigned				cur_pos;
+	unsigned				cur_len;
+	unsigned				words_per_32bit;
+	unsigned				bytes_per_word;
+	unsigned				curr_dma_words;
+	unsigned				cur_direction;
+
+	unsigned				cur_rx_pos;
+	unsigned				cur_tx_pos;
+
+	unsigned				dma_buf_size;
+	unsigned				max_buf_size;
+	bool					is_curr_dma_xfer;
+	bool					is_hw_based_cs;
+
+	struct completion			rx_dma_complete;
+	struct completion			tx_dma_complete;
+
+	u32					tx_status;
+	u32					rx_status;
+	u32					status_reg;
+	bool					is_packed;
+	unsigned long				packed_size;
+
+	u32					command_reg;
+	u32					command2_reg;
+	u32					dma_control_reg;
+	u32					def_command_reg;
+	u32					def_command2_reg;
+
+	struct completion			xfer_completion;
+	struct spi_transfer			*curr_xfer;
+	struct dma_chan				*rx_dma_chan;
+	u32					*rx_dma_buf;
+	dma_addr_t				rx_dma_phys;
+	struct dma_async_tx_descriptor		*rx_dma_desc;
+
+	struct dma_chan				*tx_dma_chan;
+	u32					*tx_dma_buf;
+	dma_addr_t				tx_dma_phys;
+	struct dma_async_tx_descriptor		*tx_dma_desc;
+};
+
+static int tegra_slink_runtime_suspend(struct device *dev);
+static int tegra_slink_runtime_resume(struct device *dev);
+
+static inline unsigned long tegra_slink_readl(struct tegra_slink_data *tspi,
+		unsigned long reg)
+{
+	return readl(tspi->base + reg);
+}
+
+static inline void tegra_slink_writel(struct tegra_slink_data *tspi,
+		unsigned long val, unsigned long reg)
+{
+	writel(val, tspi->base + reg);
+
+	/* Read back register to make sure that register writes completed */
+	if (reg != SLINK_TX_FIFO)
+		readl(tspi->base + SLINK_MAS_DATA);
+}
+
+static void tegra_slink_clear_status(struct tegra_slink_data *tspi)
+{
+	unsigned long val;
+	unsigned long val_write = 0;
+
+	val = tegra_slink_readl(tspi, SLINK_STATUS);
+
+	/* Write 1 to clear status register */
+	val_write = SLINK_RDY | SLINK_FIFO_ERROR;
+	tegra_slink_writel(tspi, val_write, SLINK_STATUS);
+}
+
+static unsigned long tegra_slink_get_packed_size(struct tegra_slink_data *tspi,
+				  struct spi_transfer *t)
+{
+	unsigned long val;
+
+	switch (tspi->bytes_per_word) {
+	case 0:
+		val = SLINK_PACK_SIZE_4;
+		break;
+	case 1:
+		val = SLINK_PACK_SIZE_8;
+		break;
+	case 2:
+		val = SLINK_PACK_SIZE_16;
+		break;
+	case 4:
+		val = SLINK_PACK_SIZE_32;
+		break;
+	default:
+		val = 0;
+	}
+	return val;
+}
+
+static unsigned tegra_slink_calculate_curr_xfer_param(
+	struct spi_device *spi, struct tegra_slink_data *tspi,
+	struct spi_transfer *t)
+{
+	unsigned remain_len = t->len - tspi->cur_pos;
+	unsigned max_word;
+	unsigned bits_per_word ;
+	unsigned max_len;
+	unsigned total_fifo_words;
+
+	bits_per_word = t->bits_per_word ? t->bits_per_word :
+						spi->bits_per_word;
+	tspi->bytes_per_word = (bits_per_word - 1) / 8 + 1;
+
+	if (bits_per_word == 8 || bits_per_word == 16) {
+		tspi->is_packed = 1;
+		tspi->words_per_32bit = 32/bits_per_word;
+	} else {
+		tspi->is_packed = 0;
+		tspi->words_per_32bit = 1;
+	}
+	tspi->packed_size = tegra_slink_get_packed_size(tspi, t);
+
+	if (tspi->is_packed) {
+		max_len = min(remain_len, tspi->max_buf_size);
+		tspi->curr_dma_words = max_len/tspi->bytes_per_word;
+		total_fifo_words = max_len/4;
+	} else {
+		max_word = (remain_len - 1) / tspi->bytes_per_word + 1;
+		max_word = min(max_word, tspi->max_buf_size/4);
+		tspi->curr_dma_words = max_word;
+		total_fifo_words = max_word;
+	}
+	return total_fifo_words;
+}
+
+static unsigned tegra_slink_fill_tx_fifo_from_client_txbuf(
+	struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+	unsigned nbytes;
+	unsigned tx_empty_count;
+	unsigned long fifo_status;
+	unsigned max_n_32bit;
+	unsigned i, count;
+	unsigned long x;
+	unsigned int written_words;
+	unsigned fifo_words_left;
+	u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
+
+	fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
+	tx_empty_count = SLINK_TX_FIFO_EMPTY_COUNT(fifo_status);
+
+	if (tspi->is_packed) {
+		fifo_words_left = tx_empty_count * tspi->words_per_32bit;
+		written_words = min(fifo_words_left, tspi->curr_dma_words);
+		nbytes = written_words * tspi->bytes_per_word;
+		max_n_32bit = DIV_ROUND_UP(nbytes, 4);
+		for (count = 0; count < max_n_32bit; count++) {
+			x = 0;
+			for (i = 0; (i < 4) && nbytes; i++, nbytes--)
+				x |= (*tx_buf++) << (i*8);
+			tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
+		}
+	} else {
+		max_n_32bit = min(tspi->curr_dma_words,  tx_empty_count);
+		written_words = max_n_32bit;
+		nbytes = written_words * tspi->bytes_per_word;
+		for (count = 0; count < max_n_32bit; count++) {
+			x = 0;
+			for (i = 0; nbytes && (i < tspi->bytes_per_word);
+							i++, nbytes--)
+				x |= ((*tx_buf++) << i*8);
+			tegra_slink_writel(tspi, x, SLINK_TX_FIFO);
+		}
+	}
+	tspi->cur_tx_pos += written_words * tspi->bytes_per_word;
+	return written_words;
+}
+
+static unsigned int tegra_slink_read_rx_fifo_to_client_rxbuf(
+		struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+	unsigned rx_full_count;
+	unsigned long fifo_status;
+	unsigned i, count;
+	unsigned long x;
+	unsigned int read_words = 0;
+	unsigned len;
+	u8 *rx_buf = (u8 *)t->rx_buf + tspi->cur_rx_pos;
+
+	fifo_status = tegra_slink_readl(tspi, SLINK_STATUS2);
+	rx_full_count = SLINK_RX_FIFO_FULL_COUNT(fifo_status);
+	if (tspi->is_packed) {
+		len = tspi->curr_dma_words * tspi->bytes_per_word;
+		for (count = 0; count < rx_full_count; count++) {
+			x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
+			for (i = 0; len && (i < 4); i++, len--)
+				*rx_buf++ = (x >> i*8) & 0xFF;
+		}
+		tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
+		read_words += tspi->curr_dma_words;
+	} else {
+		unsigned int bits_per_word;
+
+		bits_per_word = t->bits_per_word ? t->bits_per_word :
+						tspi->cur_spi->bits_per_word;
+		for (count = 0; count < rx_full_count; count++) {
+			x = tegra_slink_readl(tspi, SLINK_RX_FIFO);
+			for (i = 0; (i < tspi->bytes_per_word); i++)
+				*rx_buf++ = (x >> (i*8)) & 0xFF;
+		}
+		tspi->cur_rx_pos += rx_full_count * tspi->bytes_per_word;
+		read_words += rx_full_count;
+	}
+	return read_words;
+}
+
+static void tegra_slink_copy_client_txbuf_to_spi_txbuf(
+		struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+	unsigned len;
+
+	/* Make the dma buffer to read by cpu */
+	dma_sync_single_for_cpu(tspi->dev, tspi->tx_dma_phys,
+				tspi->dma_buf_size, DMA_TO_DEVICE);
+
+	if (tspi->is_packed) {
+		len = tspi->curr_dma_words * tspi->bytes_per_word;
+		memcpy(tspi->tx_dma_buf, t->tx_buf + tspi->cur_pos, len);
+	} else {
+		unsigned int i;
+		unsigned int count;
+		u8 *tx_buf = (u8 *)t->tx_buf + tspi->cur_tx_pos;
+		unsigned consume = tspi->curr_dma_words * tspi->bytes_per_word;
+		unsigned int x;
+
+		for (count = 0; count < tspi->curr_dma_words; count++) {
+			x = 0;
+			for (i = 0; consume && (i < tspi->bytes_per_word);
+							i++, consume--)
+				x |= ((*tx_buf++) << i * 8);
+			tspi->tx_dma_buf[count] = x;
+		}
+	}
+	tspi->cur_tx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
+
+	/* Make the dma buffer to read by dma */
+	dma_sync_single_for_device(tspi->dev, tspi->tx_dma_phys,
+				tspi->dma_buf_size, DMA_TO_DEVICE);
+}
+
+static void tegra_slink_copy_spi_rxbuf_to_client_rxbuf(
+		struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+	unsigned len;
+
+	/* Make the dma buffer to read by cpu */
+	dma_sync_single_for_cpu(tspi->dev, tspi->rx_dma_phys,
+		tspi->dma_buf_size, DMA_FROM_DEVICE);
+
+	if (tspi->is_packed) {
+		len = tspi->curr_dma_words * tspi->bytes_per_word;
+		memcpy(t->rx_buf + tspi->cur_rx_pos, tspi->rx_dma_buf, len);
+	} else {
+		unsigned int i;
+		unsigned int count;
+		unsigned char *rx_buf = t->rx_buf + tspi->cur_rx_pos;
+		unsigned int x;
+		unsigned int rx_mask, bits_per_word;
+
+		bits_per_word = t->bits_per_word ? t->bits_per_word :
+						tspi->cur_spi->bits_per_word;
+		rx_mask = (1 << bits_per_word) - 1;
+		for (count = 0; count < tspi->curr_dma_words; count++) {
+			x = tspi->rx_dma_buf[count];
+			x &= rx_mask;
+			for (i = 0; (i < tspi->bytes_per_word); i++)
+				*rx_buf++ = (x >> (i*8)) & 0xFF;
+		}
+	}
+	tspi->cur_rx_pos += tspi->curr_dma_words * tspi->bytes_per_word;
+
+	/* Make the dma buffer to read by dma */
+	dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
+		tspi->dma_buf_size, DMA_FROM_DEVICE);
+}
+
+static void tegra_slink_dma_complete(void *args)
+{
+	struct completion *dma_complete = args;
+
+	complete(dma_complete);
+}
+
+static int tegra_slink_start_tx_dma(struct tegra_slink_data *tspi, int len)
+{
+	INIT_COMPLETION(tspi->tx_dma_complete);
+	tspi->tx_dma_desc = dmaengine_prep_slave_single(tspi->tx_dma_chan,
+				tspi->tx_dma_phys, len, DMA_MEM_TO_DEV,
+				DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
+	if (!tspi->tx_dma_desc) {
+		dev_err(tspi->dev, "Not able to get desc for Tx\n");
+		return -EIO;
+	}
+
+	tspi->tx_dma_desc->callback = tegra_slink_dma_complete;
+	tspi->tx_dma_desc->callback_param = &tspi->tx_dma_complete;
+
+	dmaengine_submit(tspi->tx_dma_desc);
+	dma_async_issue_pending(tspi->tx_dma_chan);
+	return 0;
+}
+
+static int tegra_slink_start_rx_dma(struct tegra_slink_data *tspi, int len)
+{
+	INIT_COMPLETION(tspi->rx_dma_complete);
+	tspi->rx_dma_desc = dmaengine_prep_slave_single(tspi->rx_dma_chan,
+				tspi->rx_dma_phys, len, DMA_DEV_TO_MEM,
+				DMA_PREP_INTERRUPT |  DMA_CTRL_ACK);
+	if (!tspi->rx_dma_desc) {
+		dev_err(tspi->dev, "Not able to get desc for Rx\n");
+		return -EIO;
+	}
+
+	tspi->rx_dma_desc->callback = tegra_slink_dma_complete;
+	tspi->rx_dma_desc->callback_param = &tspi->rx_dma_complete;
+
+	dmaengine_submit(tspi->rx_dma_desc);
+	dma_async_issue_pending(tspi->rx_dma_chan);
+	return 0;
+}
+
+static int tegra_slink_start_dma_based_transfer(
+		struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+	unsigned long val;
+	unsigned long test_val;
+	unsigned int len;
+	int ret = 0;
+	unsigned long status;
+
+	/* Make sure that Rx and Tx fifo are empty */
+	status = tegra_slink_readl(tspi, SLINK_STATUS);
+	if ((status & SLINK_FIFO_EMPTY) != SLINK_FIFO_EMPTY) {
+		dev_err(tspi->dev,
+			"Rx/Tx fifo are not empty status 0x%08lx\n", status);
+		return -EIO;
+	}
+
+	val = SLINK_DMA_BLOCK_SIZE(tspi->curr_dma_words - 1);
+	val |= tspi->packed_size;
+	if (tspi->is_packed)
+		len = DIV_ROUND_UP(tspi->curr_dma_words * tspi->bytes_per_word,
+					4) * 4;
+	else
+		len = tspi->curr_dma_words * 4;
+
+	/* Set attention level based on length of transfer */
+	if (len & 0xF)
+		val |= SLINK_TX_TRIG_1 | SLINK_RX_TRIG_1;
+	else if (((len) >> 4) & 0x1)
+		val |= SLINK_TX_TRIG_4 | SLINK_RX_TRIG_4;
+	else
+		val |= SLINK_TX_TRIG_8 | SLINK_RX_TRIG_8;
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		val |= SLINK_IE_TXC;
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		val |= SLINK_IE_RXC;
+
+	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+	tspi->dma_control_reg = val;
+
+	if (tspi->cur_direction & DATA_DIR_TX) {
+		tegra_slink_copy_client_txbuf_to_spi_txbuf(tspi, t);
+		wmb();
+		ret = tegra_slink_start_tx_dma(tspi, len);
+		if (ret < 0) {
+			dev_err(tspi->dev,
+				"Starting tx dma failed, err %d\n", ret);
+			return ret;
+		}
+
+		/* Wait for tx fifo to be fill before starting slink */
+		test_val = tegra_slink_readl(tspi, SLINK_STATUS);
+		while (!(test_val & SLINK_TX_FULL))
+			test_val = tegra_slink_readl(tspi, SLINK_STATUS);
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX) {
+		/* Make the dma buffer to read by dma */
+		dma_sync_single_for_device(tspi->dev, tspi->rx_dma_phys,
+				tspi->dma_buf_size, DMA_FROM_DEVICE);
+
+		ret = tegra_slink_start_rx_dma(tspi, len);
+		if (ret < 0) {
+			dev_err(tspi->dev,
+				"Starting rx dma failed, err %d\n", ret);
+			if (tspi->cur_direction & DATA_DIR_TX)
+				dmaengine_terminate_all(tspi->tx_dma_chan);
+			return ret;
+		}
+	}
+	tspi->is_curr_dma_xfer = true;
+	if (tspi->is_packed) {
+		val |= SLINK_PACKED;
+		tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+		/* HW need small delay after settign Packed mode */
+		udelay(1);
+	}
+	tspi->dma_control_reg = val;
+
+	val |= SLINK_DMA_EN;
+	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+	return ret;
+}
+
+static int tegra_slink_start_cpu_based_transfer(
+		struct tegra_slink_data *tspi, struct spi_transfer *t)
+{
+	unsigned long val;
+	unsigned cur_words;
+
+	val = tspi->packed_size;
+	if (tspi->cur_direction & DATA_DIR_TX)
+		val |= SLINK_IE_TXC;
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		val |= SLINK_IE_RXC;
+
+	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+	tspi->dma_control_reg = val;
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		cur_words = tegra_slink_fill_tx_fifo_from_client_txbuf(tspi, t);
+	else
+		cur_words = tspi->curr_dma_words;
+	val |= SLINK_DMA_BLOCK_SIZE(cur_words - 1);
+	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+	tspi->dma_control_reg = val;
+
+	tspi->is_curr_dma_xfer = false;
+	if (tspi->is_packed) {
+		val |= SLINK_PACKED;
+		tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+		udelay(1);
+		wmb();
+	}
+	tspi->dma_control_reg = val;
+	val |= SLINK_DMA_EN;
+	tegra_slink_writel(tspi, val, SLINK_DMA_CTL);
+	return 0;
+}
+
+static int tegra_slink_init_dma_param(struct tegra_slink_data *tspi,
+			bool dma_to_memory)
+{
+	struct dma_chan *dma_chan;
+	u32 *dma_buf;
+	dma_addr_t dma_phys;
+	int ret;
+	struct dma_slave_config dma_sconfig;
+	dma_cap_mask_t mask;
+
+	dma_cap_zero(mask);
+	dma_cap_set(DMA_SLAVE, mask);
+	dma_chan = dma_request_channel(mask, NULL, NULL);
+	if (!dma_chan) {
+		dev_err(tspi->dev,
+			"Dma channel is not available, will try later\n");
+		return -EPROBE_DEFER;
+	}
+
+	dma_buf = dma_alloc_coherent(tspi->dev, tspi->dma_buf_size,
+				&dma_phys, GFP_KERNEL);
+	if (!dma_buf) {
+		dev_err(tspi->dev, " Not able to allocate the dma buffer\n");
+		dma_release_channel(dma_chan);
+		return -ENOMEM;
+	}
+
+	dma_sconfig.slave_id = tspi->dma_req_sel;
+	if (dma_to_memory) {
+		dma_sconfig.src_addr = tspi->phys + SLINK_RX_FIFO;
+		dma_sconfig.src_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		dma_sconfig.src_maxburst = 0;
+	} else {
+		dma_sconfig.dst_addr = tspi->phys + SLINK_TX_FIFO;
+		dma_sconfig.dst_addr_width = DMA_SLAVE_BUSWIDTH_4_BYTES;
+		dma_sconfig.dst_maxburst = 0;
+	}
+
+	ret = dmaengine_slave_config(dma_chan, &dma_sconfig);
+	if (ret)
+		goto scrub;
+	if (dma_to_memory) {
+		tspi->rx_dma_chan = dma_chan;
+		tspi->rx_dma_buf = dma_buf;
+		tspi->rx_dma_phys = dma_phys;
+	} else {
+		tspi->tx_dma_chan = dma_chan;
+		tspi->tx_dma_buf = dma_buf;
+		tspi->tx_dma_phys = dma_phys;
+	}
+	return 0;
+
+scrub:
+	dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
+	dma_release_channel(dma_chan);
+	return ret;
+}
+
+static void tegra_slink_deinit_dma_param(struct tegra_slink_data *tspi,
+	bool dma_to_memory)
+{
+	u32 *dma_buf;
+	dma_addr_t dma_phys;
+	struct dma_chan *dma_chan;
+
+	if (dma_to_memory) {
+		dma_buf = tspi->rx_dma_buf;
+		dma_chan = tspi->rx_dma_chan;
+		dma_phys = tspi->rx_dma_phys;
+		tspi->rx_dma_chan = NULL;
+		tspi->rx_dma_buf = NULL;
+	} else {
+		dma_buf = tspi->tx_dma_buf;
+		dma_chan = tspi->tx_dma_chan;
+		dma_phys = tspi->tx_dma_phys;
+		tspi->tx_dma_buf = NULL;
+		tspi->tx_dma_chan = NULL;
+	}
+	if (!dma_chan)
+		return;
+
+	dma_free_coherent(tspi->dev, tspi->dma_buf_size, dma_buf, dma_phys);
+	dma_release_channel(dma_chan);
+}
+
+static int tegra_slink_start_transfer_one(struct spi_device *spi,
+		struct spi_transfer *t, bool is_first_of_msg,
+		bool is_single_xfer)
+{
+	struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
+	u32 speed;
+	u8 bits_per_word;
+	unsigned total_fifo_words;
+	int ret;
+	struct tegra_spi_device_controller_data *cdata = spi->controller_data;
+	unsigned long command;
+	unsigned long command2;
+
+	bits_per_word = t->bits_per_word;
+	speed = t->speed_hz ? t->speed_hz : spi->max_speed_hz;
+	if (!speed)
+		speed = tspi->spi_max_frequency;
+	if (speed != tspi->cur_speed) {
+		clk_set_rate(tspi->clk, speed * 4);
+		tspi->cur_speed = speed;
+	}
+
+	tspi->cur_spi = spi;
+	tspi->cur_pos = 0;
+	tspi->cur_rx_pos = 0;
+	tspi->cur_tx_pos = 0;
+	tspi->curr_xfer = t;
+	total_fifo_words = tegra_slink_calculate_curr_xfer_param(spi, tspi, t);
+
+	if (is_first_of_msg) {
+		tegra_slink_clear_status(tspi);
+
+		command = tspi->def_command_reg;
+		command |= SLINK_BIT_LENGTH(bits_per_word - 1);
+
+		command2 = tspi->def_command2_reg;
+		command2 |= SLINK_SS_EN_CS(spi->chip_select);
+
+		/* possibly use the hw based chip select */
+		tspi->is_hw_based_cs = false;
+		if (cdata && cdata->is_hw_based_cs && is_single_xfer &&
+			((tspi->curr_dma_words * tspi->bytes_per_word) ==
+						(t->len - tspi->cur_pos))) {
+			int setup_count;
+			int sts2;
+
+			setup_count = cdata->cs_setup_clk_count >> 1;
+			setup_count = max(setup_count, 3);
+			command2 |= SLINK_SS_SETUP(setup_count);
+			if (tspi->chip_data->cs_hold_time) {
+				int hold_count;
+
+				hold_count = cdata->cs_hold_clk_count;
+				hold_count = max(hold_count, 0xF);
+				sts2 = tegra_slink_readl(tspi, SLINK_STATUS2);
+				sts2 &= ~SLINK_SS_HOLD_TIME(0xF);
+				sts2 |= SLINK_SS_HOLD_TIME(hold_count);
+				tegra_slink_writel(tspi, sts2, SLINK_STATUS2);
+			}
+			tspi->is_hw_based_cs = true;
+		}
+
+		if (tspi->is_hw_based_cs)
+			command &= ~SLINK_CS_SW;
+		else
+			command |= SLINK_CS_SW | SLINK_CS_VALUE;
+
+		command &= ~SLINK_MODES;
+		if (spi->mode & SPI_CPHA)
+			command |= SLINK_CK_SDA;
+
+		if (spi->mode & SPI_CPOL)
+			command |= SLINK_IDLE_SCLK_DRIVE_HIGH;
+		else
+			command |= SLINK_IDLE_SCLK_DRIVE_LOW;
+	} else {
+		command = tspi->command_reg;
+		command &= ~SLINK_BIT_LENGTH(~0);
+		command |= SLINK_BIT_LENGTH(bits_per_word - 1);
+
+		command2 = tspi->command2_reg;
+		command2 &= ~(SLINK_RXEN | SLINK_TXEN);
+	}
+
+	tegra_slink_writel(tspi, command, SLINK_COMMAND);
+	tspi->command_reg = command;
+
+	tspi->cur_direction = 0;
+	if (t->rx_buf) {
+		command2 |= SLINK_RXEN;
+		tspi->cur_direction |= DATA_DIR_RX;
+	}
+	if (t->tx_buf) {
+		command2 |= SLINK_TXEN;
+		tspi->cur_direction |= DATA_DIR_TX;
+	}
+	tegra_slink_writel(tspi, command2, SLINK_COMMAND2);
+	tspi->command2_reg = command2;
+
+	if (total_fifo_words > SLINK_FIFO_DEPTH)
+		ret = tegra_slink_start_dma_based_transfer(tspi, t);
+	else
+		ret = tegra_slink_start_cpu_based_transfer(tspi, t);
+	return ret;
+}
+
+static int tegra_slink_setup(struct spi_device *spi)
+{
+	struct tegra_slink_data *tspi = spi_master_get_devdata(spi->master);
+	unsigned long val;
+	unsigned long flags;
+	int ret;
+	unsigned int cs_pol_bit[MAX_CHIP_SELECT] = {
+			SLINK_CS_POLARITY,
+			SLINK_CS_POLARITY1,
+			SLINK_CS_POLARITY2,
+			SLINK_CS_POLARITY3,
+	};
+
+	dev_dbg(&spi->dev, "setup %d bpw, %scpol, %scpha, %dHz\n",
+		spi->bits_per_word,
+		spi->mode & SPI_CPOL ? "" : "~",
+		spi->mode & SPI_CPHA ? "" : "~",
+		spi->max_speed_hz);
+
+	BUG_ON(spi->chip_select >= MAX_CHIP_SELECT);
+
+	ret = pm_runtime_get_sync(tspi->dev);
+	if (ret < 0) {
+		dev_err(tspi->dev, "pm runtime failed, e = %d\n", ret);
+		return ret;
+	}
+
+	spin_lock_irqsave(&tspi->lock, flags);
+	val = tspi->def_command_reg;
+	if (spi->mode & SPI_CS_HIGH)
+		val |= cs_pol_bit[spi->chip_select];
+	else
+		val &= ~cs_pol_bit[spi->chip_select];
+	tspi->def_command_reg = val;
+	tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
+	spin_unlock_irqrestore(&tspi->lock, flags);
+
+	pm_runtime_put(tspi->dev);
+	return 0;
+}
+
+static int tegra_slink_prepare_transfer(struct spi_master *master)
+{
+	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+
+	return pm_runtime_get_sync(tspi->dev);
+}
+
+static int tegra_slink_unprepare_transfer(struct spi_master *master)
+{
+	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+
+	pm_runtime_put(tspi->dev);
+	return 0;
+}
+
+static int tegra_slink_transfer_one_message(struct spi_master *master,
+			struct spi_message *msg)
+{
+	bool is_first_msg = true;
+	int single_xfer;
+	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+	struct spi_transfer *xfer;
+	struct spi_device *spi = msg->spi;
+	int ret;
+
+	msg->status = 0;
+	msg->actual_length = 0;
+	single_xfer = list_is_singular(&msg->transfers);
+	list_for_each_entry(xfer, &msg->transfers, transfer_list) {
+		INIT_COMPLETION(tspi->xfer_completion);
+		ret = tegra_slink_start_transfer_one(spi, xfer,
+					is_first_msg, single_xfer);
+		if (ret < 0) {
+			dev_err(tspi->dev,
+				"spi can not start transfer, err %d\n", ret);
+			goto exit;
+		}
+		is_first_msg = false;
+		ret = wait_for_completion_timeout(&tspi->xfer_completion,
+						SLINK_DMA_TIMEOUT);
+		if (WARN_ON(ret == 0)) {
+			dev_err(tspi->dev,
+				"spi trasfer timeout, err %d\n", ret);
+			ret = -EIO;
+			goto exit;
+		}
+
+		if (tspi->tx_status ||  tspi->rx_status) {
+			dev_err(tspi->dev, "Error in Transfer\n");
+			ret = -EIO;
+			goto exit;
+		}
+		msg->actual_length += xfer->len;
+		if (xfer->cs_change && xfer->delay_usecs) {
+			tegra_slink_writel(tspi, tspi->def_command_reg,
+					SLINK_COMMAND);
+			udelay(xfer->delay_usecs);
+		}
+	}
+	ret = 0;
+exit:
+	tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
+	tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
+	msg->status = ret;
+	spi_finalize_current_message(master);
+	return ret;
+}
+
+static irqreturn_t handle_cpu_based_xfer(struct tegra_slink_data *tspi)
+{
+	struct spi_transfer *t = tspi->curr_xfer;
+	unsigned long flags;
+
+	spin_lock_irqsave(&tspi->lock, flags);
+	if (tspi->tx_status ||  tspi->rx_status ||
+				(tspi->status_reg & SLINK_BSY)) {
+		dev_err(tspi->dev,
+			"CpuXfer ERROR bit set 0x%x\n", tspi->status_reg);
+		dev_err(tspi->dev,
+			"CpuXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
+				tspi->command2_reg, tspi->dma_control_reg);
+		tegra_periph_reset_assert(tspi->clk);
+		udelay(2);
+		tegra_periph_reset_deassert(tspi->clk);
+		complete(&tspi->xfer_completion);
+		goto exit;
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		tegra_slink_read_rx_fifo_to_client_rxbuf(tspi, t);
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		tspi->cur_pos = tspi->cur_tx_pos;
+	else
+		tspi->cur_pos = tspi->cur_rx_pos;
+
+	if (tspi->cur_pos == t->len) {
+		complete(&tspi->xfer_completion);
+		goto exit;
+	}
+
+	tegra_slink_calculate_curr_xfer_param(tspi->cur_spi, tspi, t);
+	tegra_slink_start_cpu_based_transfer(tspi, t);
+exit:
+	spin_unlock_irqrestore(&tspi->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t handle_dma_based_xfer(struct tegra_slink_data *tspi)
+{
+	struct spi_transfer *t = tspi->curr_xfer;
+	long wait_status;
+	int err = 0;
+	unsigned total_fifo_words;
+	unsigned long flags;
+
+	/* Abort dmas if any error */
+	if (tspi->cur_direction & DATA_DIR_TX) {
+		if (tspi->tx_status) {
+			dmaengine_terminate_all(tspi->tx_dma_chan);
+			err += 1;
+		} else {
+			wait_status = wait_for_completion_interruptible_timeout(
+				&tspi->tx_dma_complete, SLINK_DMA_TIMEOUT);
+			if (wait_status <= 0) {
+				dmaengine_terminate_all(tspi->tx_dma_chan);
+				dev_err(tspi->dev, "TxDma Xfer failed\n");
+				err += 1;
+			}
+		}
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX) {
+		if (tspi->rx_status) {
+			dmaengine_terminate_all(tspi->rx_dma_chan);
+			err += 2;
+		} else {
+			wait_status = wait_for_completion_interruptible_timeout(
+				&tspi->rx_dma_complete, SLINK_DMA_TIMEOUT);
+			if (wait_status <= 0) {
+				dmaengine_terminate_all(tspi->rx_dma_chan);
+				dev_err(tspi->dev, "RxDma Xfer failed\n");
+				err += 2;
+			}
+		}
+	}
+
+	spin_lock_irqsave(&tspi->lock, flags);
+	if (err) {
+		dev_err(tspi->dev,
+			"DmaXfer: ERROR bit set 0x%x\n", tspi->status_reg);
+		dev_err(tspi->dev,
+			"DmaXfer 0x%08x:0x%08x:0x%08x\n", tspi->command_reg,
+				tspi->command2_reg, tspi->dma_control_reg);
+		tegra_periph_reset_assert(tspi->clk);
+		udelay(2);
+		tegra_periph_reset_deassert(tspi->clk);
+		complete(&tspi->xfer_completion);
+		spin_unlock_irqrestore(&tspi->lock, flags);
+		return IRQ_HANDLED;
+	}
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		tegra_slink_copy_spi_rxbuf_to_client_rxbuf(tspi, t);
+
+	if (tspi->cur_direction & DATA_DIR_TX)
+		tspi->cur_pos = tspi->cur_tx_pos;
+	else
+		tspi->cur_pos = tspi->cur_rx_pos;
+
+	if (tspi->cur_pos == t->len) {
+		complete(&tspi->xfer_completion);
+		goto exit;
+	}
+
+	/* Continue transfer in current message */
+	total_fifo_words = tegra_slink_calculate_curr_xfer_param(tspi->cur_spi,
+							tspi, t);
+	if (total_fifo_words > SLINK_FIFO_DEPTH)
+		err = tegra_slink_start_dma_based_transfer(tspi, t);
+	else
+		err = tegra_slink_start_cpu_based_transfer(tspi, t);
+
+exit:
+	spin_unlock_irqrestore(&tspi->lock, flags);
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t tegra_slink_isr_thread(int irq, void *context_data)
+{
+	struct tegra_slink_data *tspi = context_data;
+
+	if (!tspi->is_curr_dma_xfer)
+		return handle_cpu_based_xfer(tspi);
+	return handle_dma_based_xfer(tspi);
+}
+
+static irqreturn_t tegra_slink_isr(int irq, void *context_data)
+{
+	struct tegra_slink_data *tspi = context_data;
+
+	tspi->status_reg = tegra_slink_readl(tspi, SLINK_STATUS);
+	if (tspi->cur_direction & DATA_DIR_TX)
+		tspi->tx_status = tspi->status_reg &
+					(SLINK_TX_OVF | SLINK_TX_UNF);
+
+	if (tspi->cur_direction & DATA_DIR_RX)
+		tspi->rx_status = tspi->status_reg &
+					(SLINK_RX_OVF | SLINK_RX_UNF);
+	tegra_slink_clear_status(tspi);
+
+	return IRQ_WAKE_THREAD;
+}
+
+static struct tegra_spi_platform_data *tegra_slink_parse_dt(
+		struct platform_device *pdev)
+{
+	struct tegra_spi_platform_data *pdata;
+	const unsigned int *prop;
+	struct device_node *np = pdev->dev.of_node;
+	u32 of_dma[2];
+
+	pdata = devm_kzalloc(&pdev->dev, sizeof(*pdata), GFP_KERNEL);
+	if (!pdata) {
+		dev_err(&pdev->dev, "Memory alloc for pdata failed\n");
+		return NULL;
+	}
+
+	if (of_property_read_u32_array(np, "nvidia,dma-request-selector",
+				of_dma, 2) >= 0)
+		pdata->dma_req_sel = of_dma[1];
+
+	prop = of_get_property(np, "spi-max-frequency", NULL);
+	if (prop)
+		pdata->spi_max_frequency = be32_to_cpup(prop);
+
+	return pdata;
+}
+
+const struct tegra_slink_chip_data tegra30_spi_cdata = {
+	.cs_hold_time = true,
+};
+
+const struct tegra_slink_chip_data tegra20_spi_cdata = {
+	.cs_hold_time = false,
+};
+
+static struct of_device_id tegra_slink_of_match[] __devinitconst = {
+	{ .compatible = "nvidia,tegra30-slink", .data = &tegra30_spi_cdata, },
+	{ .compatible = "nvidia,tegra20-slink", .data = &tegra20_spi_cdata, },
+	{}
+};
+MODULE_DEVICE_TABLE(of, tegra_slink_of_match);
+
+static int __devinit tegra_slink_probe(struct platform_device *pdev)
+{
+	struct spi_master	*master;
+	struct tegra_slink_data	*tspi;
+	struct resource		*r;
+	struct tegra_spi_platform_data *pdata = pdev->dev.platform_data;
+	int ret, spi_irq;
+	const struct tegra_slink_chip_data *cdata = NULL;
+	const struct of_device_id *match;
+
+	match = of_match_device(of_match_ptr(tegra_slink_of_match), &pdev->dev);
+	if (!match) {
+		dev_err(&pdev->dev, "Error: No device match found\n");
+		return -ENODEV;
+	}
+	cdata = match->data;
+	if (!pdata && pdev->dev.of_node)
+		pdata = tegra_slink_parse_dt(pdev);
+
+	if (!pdata) {
+		dev_err(&pdev->dev, "No platform data, exiting\n");
+		return -ENODEV;
+	}
+
+	if (!pdata->spi_max_frequency)
+		pdata->spi_max_frequency = 25000000; /* 25MHz */
+
+	master = spi_alloc_master(&pdev->dev, sizeof(*tspi));
+	if (!master) {
+		dev_err(&pdev->dev, "master allocation failed\n");
+		return -ENOMEM;
+	}
+
+	/* the spi->mode bits understood by this driver: */
+	master->mode_bits = SPI_CPOL | SPI_CPHA | SPI_CS_HIGH;
+	master->setup = tegra_slink_setup;
+	master->prepare_transfer_hardware = tegra_slink_prepare_transfer;
+	master->transfer_one_message = tegra_slink_transfer_one_message;
+	master->unprepare_transfer_hardware = tegra_slink_unprepare_transfer;
+	master->num_chipselect = MAX_CHIP_SELECT;
+	master->bus_num = -1;
+
+	dev_set_drvdata(&pdev->dev, master);
+	tspi = spi_master_get_devdata(master);
+	tspi->master = master;
+	tspi->dma_req_sel = pdata->dma_req_sel;
+	tspi->dev = &pdev->dev;
+	tspi->chip_data = cdata;
+	spin_lock_init(&tspi->lock);
+
+	r = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!r) {
+		dev_err(&pdev->dev, "No IO memory resource\n");
+		ret = -ENODEV;
+		goto exit_free_master;
+	}
+	tspi->phys = r->start;
+	tspi->base = devm_request_and_ioremap(&pdev->dev, r);
+	if (!tspi->base) {
+		dev_err(&pdev->dev,
+			"Cannot request memregion/iomap dma address\n");
+		ret = -EADDRNOTAVAIL;
+		goto exit_free_master;
+	}
+
+	spi_irq = platform_get_irq(pdev, 0);
+	tspi->irq = spi_irq;
+	ret = request_threaded_irq(tspi->irq, tegra_slink_isr,
+			tegra_slink_isr_thread, IRQF_ONESHOT,
+			dev_name(&pdev->dev), tspi);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "Failed to register ISR for IRQ %d\n",
+					tspi->irq);
+		goto exit_free_master;
+	}
+
+	tspi->clk = devm_clk_get(&pdev->dev, "slink");
+	if (IS_ERR(tspi->clk)) {
+		dev_err(&pdev->dev, "can not get clock\n");
+		ret = PTR_ERR(tspi->clk);
+		goto exit_free_irq;
+	}
+
+	tspi->max_buf_size = SLINK_FIFO_DEPTH << 2;
+	tspi->dma_buf_size = DEFAULT_SPI_DMA_BUF_LEN;
+	tspi->spi_max_frequency = pdata->spi_max_frequency;
+
+	if (pdata->dma_req_sel) {
+		ret = tegra_slink_init_dma_param(tspi, true);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "RxDma Init failed, err %d\n", ret);
+			goto exit_free_irq;
+		}
+
+		ret = tegra_slink_init_dma_param(tspi, false);
+		if (ret < 0) {
+			dev_err(&pdev->dev, "TxDma Init failed, err %d\n", ret);
+			goto exit_rx_dma_free;
+		}
+		tspi->max_buf_size = tspi->dma_buf_size;
+		init_completion(&tspi->tx_dma_complete);
+		init_completion(&tspi->rx_dma_complete);
+	}
+
+	init_completion(&tspi->xfer_completion);
+
+	pm_runtime_enable(&pdev->dev);
+	if (!pm_runtime_enabled(&pdev->dev)) {
+		ret = tegra_slink_runtime_resume(&pdev->dev);
+		if (ret)
+			goto exit_pm_disable;
+	}
+
+	ret = pm_runtime_get_sync(&pdev->dev);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "pm runtime get failed, e = %d\n", ret);
+		goto exit_pm_disable;
+	}
+	tspi->def_command_reg  = SLINK_M_S;
+	tspi->def_command2_reg = SLINK_CS_ACTIVE_BETWEEN;
+	tegra_slink_writel(tspi, tspi->def_command_reg, SLINK_COMMAND);
+	tegra_slink_writel(tspi, tspi->def_command2_reg, SLINK_COMMAND2);
+	pm_runtime_put(&pdev->dev);
+
+	master->dev.of_node = pdev->dev.of_node;
+	ret = spi_register_master(master);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "can not register to master err %d\n", ret);
+		goto exit_pm_disable;
+	}
+	return ret;
+
+exit_pm_disable:
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_slink_runtime_suspend(&pdev->dev);
+	tegra_slink_deinit_dma_param(tspi, false);
+exit_rx_dma_free:
+	tegra_slink_deinit_dma_param(tspi, true);
+exit_free_irq:
+	free_irq(spi_irq, tspi);
+exit_free_master:
+	spi_master_put(master);
+	return ret;
+}
+
+static int __devexit tegra_slink_remove(struct platform_device *pdev)
+{
+	struct spi_master *master = dev_get_drvdata(&pdev->dev);
+	struct tegra_slink_data	*tspi = spi_master_get_devdata(master);
+
+	free_irq(tspi->irq, tspi);
+	spi_unregister_master(master);
+
+	if (tspi->tx_dma_chan)
+		tegra_slink_deinit_dma_param(tspi, false);
+
+	if (tspi->rx_dma_chan)
+		tegra_slink_deinit_dma_param(tspi, true);
+
+	pm_runtime_disable(&pdev->dev);
+	if (!pm_runtime_status_suspended(&pdev->dev))
+		tegra_slink_runtime_suspend(&pdev->dev);
+
+	return 0;
+}
+
+#ifdef CONFIG_PM_SLEEP
+static int tegra_slink_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+
+	return spi_master_suspend(master);
+}
+
+static int tegra_slink_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+	int ret;
+
+	ret = pm_runtime_get_sync(dev);
+	if (ret < 0) {
+		dev_err(dev, "pm runtime failed, e = %d\n", ret);
+		return ret;
+	}
+	tegra_slink_writel(tspi, tspi->command_reg, SLINK_COMMAND);
+	tegra_slink_writel(tspi, tspi->command2_reg, SLINK_COMMAND2);
+	pm_runtime_put(dev);
+
+	return spi_master_resume(master);
+}
+#endif
+
+static int tegra_slink_runtime_suspend(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+
+	/* Flush all write which are in PPSB queue by reading back */
+	tegra_slink_readl(tspi, SLINK_MAS_DATA);
+
+	clk_disable_unprepare(tspi->clk);
+	return 0;
+}
+
+static int tegra_slink_runtime_resume(struct device *dev)
+{
+	struct spi_master *master = dev_get_drvdata(dev);
+	struct tegra_slink_data *tspi = spi_master_get_devdata(master);
+	int ret;
+
+	ret = clk_prepare_enable(tspi->clk);
+	if (ret < 0) {
+		dev_err(tspi->dev, "clk_prepare failed: %d\n", ret);
+		return ret;
+	}
+	return 0;
+}
+
+static const struct dev_pm_ops slink_pm_ops = {
+	SET_RUNTIME_PM_OPS(tegra_slink_runtime_suspend,
+		tegra_slink_runtime_resume, NULL)
+	SET_SYSTEM_SLEEP_PM_OPS(tegra_slink_suspend, tegra_slink_resume)
+};
+static struct platform_driver tegra_slink_driver = {
+	.driver = {
+		.name		= "spi-tegra-slink",
+		.owner		= THIS_MODULE,
+		.pm		= &slink_pm_ops,
+		.of_match_table	= of_match_ptr(tegra_slink_of_match),
+	},
+	.probe =	tegra_slink_probe,
+	.remove =	__devexit_p(tegra_slink_remove),
+};
+module_platform_driver(tegra_slink_driver);
+
+MODULE_ALIAS("platform:spi-tegra-slink");
+MODULE_DESCRIPTION("NVIDIA Tegra20/Tegra30 SLINK Controller Driver");
+MODULE_AUTHOR("Laxman Dewangan <ldewangan@nvidia.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/drivers/spi/spi.c b/drivers/spi/spi.c
index 1587a4a..f1217ae 100644
--- a/drivers/spi/spi.c
+++ b/drivers/spi/spi.c
@@ -1204,7 +1204,7 @@ EXPORT_SYMBOL_GPL(spi_busnum_to_master);
 int spi_setup(struct spi_device *spi)
 {
 	unsigned	bad_bits;
-	int		status;
+	int		status = 0;
 
 	/* help drivers fail *cleanly* when they need options
 	 * that aren't supported with their current master
@@ -1219,7 +1219,8 @@ int spi_setup(struct spi_device *spi)
 	if (!spi->bits_per_word)
 		spi->bits_per_word = 8;
 
-	status = spi->master->setup(spi);
+	if (spi->master->setup)
+		status = spi->master->setup(spi);
 
 	dev_dbg(&spi->dev, "setup mode %d, %s%s%s%s"
 				"%u bits/w, %u Hz max --> %d\n",
@@ -1238,6 +1239,7 @@ EXPORT_SYMBOL_GPL(spi_setup);
 static int __spi_async(struct spi_device *spi, struct spi_message *message)
 {
 	struct spi_master *master = spi->master;
+	struct spi_transfer *xfer;
 
 	/* Half-duplex links include original MicroWire, and ones with
 	 * only one data pin like SPI_3WIRE (switches direction) or where
@@ -1246,7 +1248,6 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
 	 */
 	if ((master->flags & SPI_MASTER_HALF_DUPLEX)
 			|| (spi->mode & SPI_3WIRE)) {
-		struct spi_transfer *xfer;
 		unsigned flags = master->flags;
 
 		list_for_each_entry(xfer, &message->transfers, transfer_list) {
@@ -1259,6 +1260,15 @@ static int __spi_async(struct spi_device *spi, struct spi_message *message)
 		}
 	}
 
+	/**
+	 * Set transfer bits_per_word as spi device default if it is not
+	 * set for this transfer.
+	 */
+	list_for_each_entry(xfer, &message->transfers, transfer_list) {
+		if (!xfer->bits_per_word)
+			xfer->bits_per_word = spi->bits_per_word;
+	}
+
 	message->spi = spi;
 	message->status = -EINPROGRESS;
 	return master->transfer(spi, message);
diff --git a/drivers/spi/spidev.c b/drivers/spi/spidev.c
index 830adbe..e44abc9 100644
--- a/drivers/spi/spidev.c
+++ b/drivers/spi/spidev.c
@@ -31,6 +31,8 @@
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/compat.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
 
 #include <linux/spi/spi.h>
 #include <linux/spi/spidev.h>
@@ -642,10 +644,18 @@ static int __devexit spidev_remove(struct spi_device *spi)
 	return 0;
 }
 
+static const struct of_device_id spidev_dt_ids[] = {
+	{ .compatible = "rohm,dh2228fv" },
+	{},
+};
+
+MODULE_DEVICE_TABLE(of, spidev_dt_ids);
+
 static struct spi_driver spidev_spi_driver = {
 	.driver = {
 		.name =		"spidev",
 		.owner =	THIS_MODULE,
+		.of_match_table = of_match_ptr(spidev_dt_ids),
 	},
 	.probe =	spidev_probe,
 	.remove =	__devexit_p(spidev_remove),