diff options
Diffstat (limited to 'drivers/spi')
| -rw-r--r-- | drivers/spi/Kconfig | 10 | ||||
| -rw-r--r-- | drivers/spi/Makefile | 1 | ||||
| -rw-r--r-- | drivers/spi/ti-ssp-spi.c | 402 |
3 files changed, 413 insertions, 0 deletions
diff --git a/drivers/spi/Kconfig b/drivers/spi/Kconfig index bb233a9c..42f5a8d 100644 --- a/drivers/spi/Kconfig +++ b/drivers/spi/Kconfig @@ -350,6 +350,16 @@ config SPI_TEGRA help SPI driver for NVidia Tegra SoCs +config SPI_TI_SSP + tristate "TI Sequencer Serial Port - SPI Support" + depends on MFD_TI_SSP + help + This selects an SPI master implementation using a TI sequencer + serial port. + + To compile this driver as a module, choose M here: the + module will be called ti-ssp-spi. + config SPI_TOPCLIFF_PCH tristate "Topcliff PCH SPI Controller" depends on PCI diff --git a/drivers/spi/Makefile b/drivers/spi/Makefile index 86d1b5f..f3f31d9 100644 --- a/drivers/spi/Makefile +++ b/drivers/spi/Makefile @@ -43,6 +43,7 @@ obj-$(CONFIG_SPI_S3C24XX_GPIO) += spi_s3c24xx_gpio.o obj-$(CONFIG_SPI_S3C24XX) += spi_s3c24xx_hw.o obj-$(CONFIG_SPI_S3C64XX) += spi_s3c64xx.o obj-$(CONFIG_SPI_TEGRA) += spi_tegra.o +obj-$(CONFIG_SPI_TI_SSP) += ti-ssp-spi.o obj-$(CONFIG_SPI_TOPCLIFF_PCH) += spi_topcliff_pch.o obj-$(CONFIG_SPI_TXX9) += spi_txx9.o obj-$(CONFIG_SPI_XILINX) += xilinx_spi.o diff --git a/drivers/spi/ti-ssp-spi.c b/drivers/spi/ti-ssp-spi.c new file mode 100644 index 0000000..ee22795 --- /dev/null +++ b/drivers/spi/ti-ssp-spi.c @@ -0,0 +1,402 @@ +/* + * Sequencer Serial Port (SSP) based SPI master driver + * + * Copyright (C) 2010 Texas Instruments Inc + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that 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, write to the Free Software + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA + */ + +#include <linux/kernel.h> +#include <linux/err.h> +#include <linux/completion.h> +#include <linux/delay.h> +#include <linux/platform_device.h> +#include <linux/spi/spi.h> +#include <linux/mfd/ti_ssp.h> + +#define MODE_BITS (SPI_CPHA | SPI_CPOL | SPI_CS_HIGH) + +struct ti_ssp_spi { + struct spi_master *master; + struct device *dev; + spinlock_t lock; + struct list_head msg_queue; + struct completion complete; + bool shutdown; + struct workqueue_struct *workqueue; + struct work_struct work; + u8 mode, bpw; + int cs_active; + u32 pc_en, pc_dis, pc_wr, pc_rd; + void (*select)(int cs); +}; + +static u32 ti_ssp_spi_rx(struct ti_ssp_spi *hw) +{ + u32 ret; + + ti_ssp_run(hw->dev, hw->pc_rd, 0, &ret); + return ret; +} + +static void ti_ssp_spi_tx(struct ti_ssp_spi *hw, u32 data) +{ + ti_ssp_run(hw->dev, hw->pc_wr, data << (32 - hw->bpw), NULL); +} + +static int ti_ssp_spi_txrx(struct ti_ssp_spi *hw, struct spi_message *msg, + struct spi_transfer *t) +{ + int count; + + if (hw->bpw <= 8) { + u8 *rx = t->rx_buf; + const u8 *tx = t->tx_buf; + + for (count = 0; count < t->len; count += 1) { + if (t->tx_buf) + ti_ssp_spi_tx(hw, *tx++); + if (t->rx_buf) + *rx++ = ti_ssp_spi_rx(hw); + } + } else if (hw->bpw <= 16) { + u16 *rx = t->rx_buf; + const u16 *tx = t->tx_buf; + + for (count = 0; count < t->len; count += 2) { + if (t->tx_buf) + ti_ssp_spi_tx(hw, *tx++); + if (t->rx_buf) + *rx++ = ti_ssp_spi_rx(hw); + } + } else { + u32 *rx = t->rx_buf; + const u32 *tx = t->tx_buf; + + for (count = 0; count < t->len; count += 4) { + if (t->tx_buf) + ti_ssp_spi_tx(hw, *tx++); + if (t->rx_buf) + *rx++ = ti_ssp_spi_rx(hw); + } + } + + msg->actual_length += count; /* bytes transferred */ + + dev_dbg(&msg->spi->dev, "xfer %s%s, %d bytes, %d bpw, count %d%s\n", + t->tx_buf ? "tx" : "", t->rx_buf ? "rx" : "", t->len, + hw->bpw, count, (count < t->len) ? " (under)" : ""); + + return (count < t->len) ? -EIO : 0; /* left over data */ +} + +static void ti_ssp_spi_chip_select(struct ti_ssp_spi *hw, int cs_active) +{ + cs_active = !!cs_active; + if (cs_active == hw->cs_active) + return; + ti_ssp_run(hw->dev, cs_active ? hw->pc_en : hw->pc_dis, 0, NULL); + hw->cs_active = cs_active; +} + +#define __SHIFT_OUT(bits) (SSP_OPCODE_SHIFT | SSP_OUT_MODE | \ + cs_en | clk | SSP_COUNT((bits) * 2 - 1)) +#define __SHIFT_IN(bits) (SSP_OPCODE_SHIFT | SSP_IN_MODE | \ + cs_en | clk | SSP_COUNT((bits) * 2 - 1)) + +static int ti_ssp_spi_setup_transfer(struct ti_ssp_spi *hw, u8 bpw, u8 mode) +{ + int error, idx = 0; + u32 seqram[16]; + u32 cs_en, cs_dis, clk; + u32 topbits, botbits; + + mode &= MODE_BITS; + if (mode == hw->mode && bpw == hw->bpw) + return 0; + + cs_en = (mode & SPI_CS_HIGH) ? SSP_CS_HIGH : SSP_CS_LOW; + cs_dis = (mode & SPI_CS_HIGH) ? SSP_CS_LOW : SSP_CS_HIGH; + clk = (mode & SPI_CPOL) ? SSP_CLK_HIGH : SSP_CLK_LOW; + + /* Construct instructions */ + + /* Disable Chip Select */ + hw->pc_dis = idx; + seqram[idx++] = SSP_OPCODE_DIRECT | SSP_OUT_MODE | cs_dis | clk; + seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_dis | clk; + + /* Enable Chip Select */ + hw->pc_en = idx; + seqram[idx++] = SSP_OPCODE_DIRECT | SSP_OUT_MODE | cs_en | clk; + seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk; + + /* Reads and writes need to be split for bpw > 16 */ + topbits = (bpw > 16) ? 16 : bpw; + botbits = bpw - topbits; + + /* Write */ + hw->pc_wr = idx; + seqram[idx++] = __SHIFT_OUT(topbits) | SSP_ADDR_REG; + if (botbits) + seqram[idx++] = __SHIFT_OUT(botbits) | SSP_DATA_REG; + seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk; + + /* Read */ + hw->pc_rd = idx; + if (botbits) + seqram[idx++] = __SHIFT_IN(botbits) | SSP_ADDR_REG; + seqram[idx++] = __SHIFT_IN(topbits) | SSP_DATA_REG; + seqram[idx++] = SSP_OPCODE_STOP | SSP_OUT_MODE | cs_en | clk; + + error = ti_ssp_load(hw->dev, 0, seqram, idx); + if (error < 0) + return error; + + error = ti_ssp_set_mode(hw->dev, ((mode & SPI_CPHA) ? + 0 : SSP_EARLY_DIN)); + if (error < 0) + return error; + + hw->bpw = bpw; + hw->mode = mode; + + return error; +} + +static void ti_ssp_spi_work(struct work_struct *work) +{ + struct ti_ssp_spi *hw = container_of(work, struct ti_ssp_spi, work); + + spin_lock(&hw->lock); + + while (!list_empty(&hw->msg_queue)) { + struct spi_message *m; + struct spi_device *spi; + struct spi_transfer *t = NULL; + int status = 0; + + m = container_of(hw->msg_queue.next, struct spi_message, + queue); + + list_del_init(&m->queue); + + spin_unlock(&hw->lock); + + spi = m->spi; + + if (hw->select) + hw->select(spi->chip_select); + + list_for_each_entry(t, &m->transfers, transfer_list) { + int bpw = spi->bits_per_word; + int xfer_status; + + if (t->bits_per_word) + bpw = t->bits_per_word; + + if (ti_ssp_spi_setup_transfer(hw, bpw, spi->mode) < 0) + break; + + ti_ssp_spi_chip_select(hw, 1); + + xfer_status = ti_ssp_spi_txrx(hw, m, t); + if (xfer_status < 0) + status = xfer_status; + + if (t->delay_usecs) + udelay(t->delay_usecs); + + if (t->cs_change) + ti_ssp_spi_chip_select(hw, 0); + } + + ti_ssp_spi_chip_select(hw, 0); + m->status = status; + m->complete(m->context); + + spin_lock(&hw->lock); + } + + if (hw->shutdown) + complete(&hw->complete); + + spin_unlock(&hw->lock); +} + +static int ti_ssp_spi_setup(struct spi_device *spi) +{ + if (spi->bits_per_word > 32) + return -EINVAL; + + return 0; +} + +static int ti_ssp_spi_transfer(struct spi_device *spi, struct spi_message *m) +{ + struct ti_ssp_spi *hw; + struct spi_transfer *t; + int error = 0; + + m->actual_length = 0; + m->status = -EINPROGRESS; + + hw = spi_master_get_devdata(spi->master); + + if (list_empty(&m->transfers) || !m->complete) + return -EINVAL; + + list_for_each_entry(t, &m->transfers, transfer_list) { + if (t->len && !(t->rx_buf || t->tx_buf)) { + dev_err(&spi->dev, "invalid xfer, no buffer\n"); + return -EINVAL; + } + + if (t->len && t->rx_buf && t->tx_buf) { + dev_err(&spi->dev, "invalid xfer, full duplex\n"); + return -EINVAL; + } + + if (t->bits_per_word > 32) { + dev_err(&spi->dev, "invalid xfer width %d\n", + t->bits_per_word); + return -EINVAL; + } + } + + spin_lock(&hw->lock); + if (hw->shutdown) { + error = -ESHUTDOWN; + goto error_unlock; + } + list_add_tail(&m->queue, &hw->msg_queue); + queue_work(hw->workqueue, &hw->work); +error_unlock: + spin_unlock(&hw->lock); + return error; +} + +static int __devinit ti_ssp_spi_probe(struct platform_device *pdev) +{ + const struct ti_ssp_spi_data *pdata; + struct ti_ssp_spi *hw; + struct spi_master *master; + struct device *dev = &pdev->dev; + int error = 0; + + pdata = dev->platform_data; + if (!pdata) { + dev_err(dev, "platform data not found\n"); + return -EINVAL; + } + + master = spi_alloc_master(dev, sizeof(struct ti_ssp_spi)); + if (!master) { + dev_err(dev, "cannot allocate SPI master\n"); + return -ENOMEM; + } + + hw = spi_master_get_devdata(master); + platform_set_drvdata(pdev, hw); + + hw->master = master; + hw->dev = dev; + hw->select = pdata->select; + + spin_lock_init(&hw->lock); + init_completion(&hw->complete); + INIT_LIST_HEAD(&hw->msg_queue); + INIT_WORK(&hw->work, ti_ssp_spi_work); + + hw->workqueue = create_singlethread_workqueue(dev_name(dev)); + if (!hw->workqueue) { + error = -ENOMEM; + dev_err(dev, "work queue creation failed\n"); + goto error_wq; + } + + error = ti_ssp_set_iosel(hw->dev, pdata->iosel); + if (error < 0) { + dev_err(dev, "io setup failed\n"); + goto error_iosel; + } + + master->bus_num = pdev->id; + master->num_chipselect = pdata->num_cs; + master->mode_bits = MODE_BITS; + master->flags = SPI_MASTER_HALF_DUPLEX; + master->setup = ti_ssp_spi_setup; + master->transfer = ti_ssp_spi_transfer; + + error = spi_register_master(master); + if (error) { + dev_err(dev, "master registration failed\n"); + goto error_reg; + } + + return 0; + +error_reg: +error_iosel: + destroy_workqueue(hw->workqueue); +error_wq: + spi_master_put(master); + return error; +} + +static int __devexit ti_ssp_spi_remove(struct platform_device *pdev) +{ + struct ti_ssp_spi *hw = platform_get_drvdata(pdev); + int error; + + hw->shutdown = 1; + while (!list_empty(&hw->msg_queue)) { + error = wait_for_completion_interruptible(&hw->complete); + if (error < 0) { + hw->shutdown = 0; + return error; + } + } + destroy_workqueue(hw->workqueue); + spi_unregister_master(hw->master); + + return 0; +} + +static struct platform_driver ti_ssp_spi_driver = { + .probe = ti_ssp_spi_probe, + .remove = __devexit_p(ti_ssp_spi_remove), + .driver = { + .name = "ti-ssp-spi", + .owner = THIS_MODULE, + }, +}; + +static int __init ti_ssp_spi_init(void) +{ + return platform_driver_register(&ti_ssp_spi_driver); +} +module_init(ti_ssp_spi_init); + +static void __exit ti_ssp_spi_exit(void) +{ + platform_driver_unregister(&ti_ssp_spi_driver); +} +module_exit(ti_ssp_spi_exit); + +MODULE_DESCRIPTION("SSP SPI Master"); +MODULE_AUTHOR("Cyril Chemparathy"); +MODULE_LICENSE("GPL"); +MODULE_ALIAS("platform:ti-ssp-spi"); |
