spi_txx9 controller driver

This is a driver for SPI controller built into TXx9 MIPS SoCs.
This driver is derived from arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c.

Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 474 insertions, 0 deletions

diff --git a/drivers/spi/spi_txx9.c b/drivers/spi/spi_txx9.c
new file mode 100644
index 0000000..08e981c
--- /dev/null
+++ b/drivers/spi/spi_txx9.c
@@ -0,0 +1,474 @@
+/*
+ * spi_txx9.c - TXx9 SPI controller driver.
+ *
+ * Based on linux/arch/mips/tx4938/toshiba_rbtx4938/spi_txx9.c
+ * Copyright (C) 2000-2001 Toshiba Corporation
+ *
+ * 2003-2005 (c) MontaVista Software, Inc. This file is licensed under the
+ * terms of the GNU General Public License version 2. This program is
+ * licensed "as is" without any warranty of any kind, whether express
+ * or implied.
+ *
+ * Support for TX4938 in 2.6 - Manish Lachwani (mlachwani@mvista.com)
+ *
+ * Convert to generic SPI framework - Atsushi Nemoto (anemo@mba.ocn.ne.jp)
+ */
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/errno.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/sched.h>
+#include <linux/spinlock.h>
+#include <linux/workqueue.h>
+#include <linux/spi/spi.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <asm/gpio.h>
+
+
+#define SPI_FIFO_SIZE 4
+
+#define TXx9_SPMCR		0x00
+#define TXx9_SPCR0		0x04
+#define TXx9_SPCR1		0x08
+#define TXx9_SPFS		0x0c
+#define TXx9_SPSR		0x14
+#define TXx9_SPDR		0x18
+
+/* SPMCR : SPI Master Control */
+#define TXx9_SPMCR_OPMODE	0xc0
+#define TXx9_SPMCR_CONFIG	0x40
+#define TXx9_SPMCR_ACTIVE	0x80
+#define TXx9_SPMCR_SPSTP	0x02
+#define TXx9_SPMCR_BCLR		0x01
+
+/* SPCR0 : SPI Control 0 */
+#define TXx9_SPCR0_TXIFL_MASK	0xc000
+#define TXx9_SPCR0_RXIFL_MASK	0x3000
+#define TXx9_SPCR0_SIDIE	0x0800
+#define TXx9_SPCR0_SOEIE	0x0400
+#define TXx9_SPCR0_RBSIE	0x0200
+#define TXx9_SPCR0_TBSIE	0x0100
+#define TXx9_SPCR0_IFSPSE	0x0010
+#define TXx9_SPCR0_SBOS		0x0004
+#define TXx9_SPCR0_SPHA		0x0002
+#define TXx9_SPCR0_SPOL		0x0001
+
+/* SPSR : SPI Status */
+#define TXx9_SPSR_TBSI		0x8000
+#define TXx9_SPSR_RBSI		0x4000
+#define TXx9_SPSR_TBS_MASK	0x3800
+#define TXx9_SPSR_RBS_MASK	0x0700
+#define TXx9_SPSR_SPOE		0x0080
+#define TXx9_SPSR_IFSD		0x0008
+#define TXx9_SPSR_SIDLE		0x0004
+#define TXx9_SPSR_STRDY		0x0002
+#define TXx9_SPSR_SRRDY		0x0001
+
+
+struct txx9spi {
+	struct workqueue_struct	*workqueue;
+	struct work_struct work;
+	spinlock_t lock;	/* protect 'queue' */
+	struct list_head queue;
+	wait_queue_head_t waitq;
+	void __iomem *membase;
+	int irq;
+	int baseclk;
+	struct clk *clk;
+	u32 max_speed_hz, min_speed_hz;
+	int last_chipselect;
+	int last_chipselect_val;
+};
+
+static u32 txx9spi_rd(struct txx9spi *c, int reg)
+{
+	return __raw_readl(c->membase + reg);
+}
+static void txx9spi_wr(struct txx9spi *c, u32 val, int reg)
+{
+	__raw_writel(val, c->membase + reg);
+}
+
+static void txx9spi_cs_func(struct spi_device *spi, struct txx9spi *c,
+		int on, unsigned int cs_delay)
+{
+	int val = (spi->mode & SPI_CS_HIGH) ? on : !on;
+	if (on) {
+		/* deselect the chip with cs_change hint in last transfer */
+		if (c->last_chipselect >= 0)
+			gpio_set_value(c->last_chipselect,
+					!c->last_chipselect_val);
+		c->last_chipselect = spi->chip_select;
+		c->last_chipselect_val = val;
+	} else {
+		c->last_chipselect = -1;
+		ndelay(cs_delay);	/* CS Hold Time */
+	}
+	gpio_set_value(spi->chip_select, val);
+	ndelay(cs_delay);	/* CS Setup Time / CS Recovery Time */
+}
+
+/* the spi->mode bits understood by this driver: */
+#define MODEBITS	(SPI_CS_HIGH|SPI_CPOL|SPI_CPHA)
+
+static int txx9spi_setup(struct spi_device *spi)
+{
+	struct txx9spi *c = spi_master_get_devdata(spi->master);
+	u8 bits_per_word;
+
+	if (spi->mode & ~MODEBITS)
+		return -EINVAL;
+
+	if (!spi->max_speed_hz
+			|| spi->max_speed_hz > c->max_speed_hz
+			|| spi->max_speed_hz < c->min_speed_hz)
+		return -EINVAL;
+
+	bits_per_word = spi->bits_per_word ? : 8;
+	if (bits_per_word != 8 && bits_per_word != 16)
+		return -EINVAL;
+
+	if (gpio_direction_output(spi->chip_select,
+			!(spi->mode & SPI_CS_HIGH))) {
+		dev_err(&spi->dev, "Cannot setup GPIO for chipselect.\n");
+		return -EINVAL;
+	}
+
+	/* deselect chip */
+	spin_lock(&c->lock);
+	txx9spi_cs_func(spi, c, 0, (NSEC_PER_SEC / 2) / spi->max_speed_hz);
+	spin_unlock(&c->lock);
+
+	return 0;
+}
+
+static irqreturn_t txx9spi_interrupt(int irq, void *dev_id)
+{
+	struct txx9spi *c = dev_id;
+
+	/* disable rx intr */
+	txx9spi_wr(c, txx9spi_rd(c, TXx9_SPCR0) & ~TXx9_SPCR0_RBSIE,
+			TXx9_SPCR0);
+	wake_up(&c->waitq);
+	return IRQ_HANDLED;
+}
+
+static void txx9spi_work_one(struct txx9spi *c, struct spi_message *m)
+{
+	struct spi_device *spi = m->spi;
+	struct spi_transfer *t;
+	unsigned int cs_delay;
+	unsigned int cs_change = 1;
+	int status = 0;
+	u32 mcr;
+	u32 prev_speed_hz = 0;
+	u8 prev_bits_per_word = 0;
+
+	/* CS setup/hold/recovery time in nsec */
+	cs_delay = 100 + (NSEC_PER_SEC / 2) / spi->max_speed_hz;
+
+	mcr = txx9spi_rd(c, TXx9_SPMCR);
+	if (unlikely((mcr & TXx9_SPMCR_OPMODE) == TXx9_SPMCR_ACTIVE)) {
+		dev_err(&spi->dev, "Bad mode.\n");
+		status = -EIO;
+		goto exit;
+	}
+	mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
+
+	/* enter config mode */
+	txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
+	txx9spi_wr(c, TXx9_SPCR0_SBOS
+			| ((spi->mode & SPI_CPOL) ? TXx9_SPCR0_SPOL : 0)
+			| ((spi->mode & SPI_CPHA) ? TXx9_SPCR0_SPHA : 0)
+			| 0x08,
+			TXx9_SPCR0);
+
+	list_for_each_entry (t, &m->transfers, transfer_list) {
+		const void *txbuf = t->tx_buf;
+		void *rxbuf = t->rx_buf;
+		u32 data;
+		unsigned int len = t->len;
+		unsigned int wsize;
+		u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
+		u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
+
+		bits_per_word = bits_per_word ? : 8;
+		wsize = bits_per_word >> 3; /* in bytes */
+
+		if (prev_speed_hz != speed_hz
+				|| prev_bits_per_word != bits_per_word) {
+			u32 n = (c->baseclk + speed_hz - 1) / speed_hz;
+			if (n < 1)
+				n = 1;
+			else if (n > 0xff)
+				n = 0xff;
+			/* enter config mode */
+			txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR,
+					TXx9_SPMCR);
+			txx9spi_wr(c, (n << 8) | bits_per_word, TXx9_SPCR1);
+			/* enter active mode */
+			txx9spi_wr(c, mcr | TXx9_SPMCR_ACTIVE, TXx9_SPMCR);
+
+			prev_speed_hz = speed_hz;
+			prev_bits_per_word = bits_per_word;
+		}
+
+		if (cs_change)
+			txx9spi_cs_func(spi, c, 1, cs_delay);
+		cs_change = t->cs_change;
+		while (len) {
+			unsigned int count = SPI_FIFO_SIZE;
+			int i;
+			u32 cr0;
+
+			if (len < count * wsize)
+				count = len / wsize;
+			/* now tx must be idle... */
+			while (!(txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_SIDLE))
+				cpu_relax();
+			cr0 = txx9spi_rd(c, TXx9_SPCR0);
+			cr0 &= ~TXx9_SPCR0_RXIFL_MASK;
+			cr0 |= (count - 1) << 12;
+			/* enable rx intr */
+			cr0 |= TXx9_SPCR0_RBSIE;
+			txx9spi_wr(c, cr0, TXx9_SPCR0);
+			/* send */
+			for (i = 0; i < count; i++) {
+				if (txbuf) {
+					data = (wsize == 1)
+						? *(const u8 *)txbuf
+						: *(const u16 *)txbuf;
+					txx9spi_wr(c, data, TXx9_SPDR);
+					txbuf += wsize;
+				} else
+					txx9spi_wr(c, 0, TXx9_SPDR);
+			}
+			/* wait all rx data */
+			wait_event(c->waitq,
+				txx9spi_rd(c, TXx9_SPSR) & TXx9_SPSR_RBSI);
+			/* receive */
+			for (i = 0; i < count; i++) {
+				data = txx9spi_rd(c, TXx9_SPDR);
+				if (rxbuf) {
+					if (wsize == 1)
+						*(u8 *)rxbuf = data;
+					else
+						*(u16 *)rxbuf = data;
+					rxbuf += wsize;
+				}
+			}
+			len -= count * wsize;
+		}
+		m->actual_length += t->len;
+		if (t->delay_usecs)
+			udelay(t->delay_usecs);
+
+		if (!cs_change)
+			continue;
+		if (t->transfer_list.next == &m->transfers)
+			break;
+		/* sometimes a short mid-message deselect of the chip
+		 * may be needed to terminate a mode or command
+		 */
+		txx9spi_cs_func(spi, c, 0, cs_delay);
+	}
+
+exit:
+	m->status = status;
+	m->complete(m->context);
+
+	/* normally deactivate chipselect ... unless no error and
+	 * cs_change has hinted that the next message will probably
+	 * be for this chip too.
+	 */
+	if (!(status == 0 && cs_change))
+		txx9spi_cs_func(spi, c, 0, cs_delay);
+
+	/* enter config mode */
+	txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
+}
+
+static void txx9spi_work(struct work_struct *work)
+{
+	struct txx9spi *c = container_of(work, struct txx9spi, work);
+	unsigned long flags;
+
+	spin_lock_irqsave(&c->lock, flags);
+	while (!list_empty(&c->queue)) {
+		struct spi_message *m;
+
+		m = container_of(c->queue.next, struct spi_message, queue);
+		list_del_init(&m->queue);
+		spin_unlock_irqrestore(&c->lock, flags);
+
+		txx9spi_work_one(c, m);
+
+		spin_lock_irqsave(&c->lock, flags);
+	}
+	spin_unlock_irqrestore(&c->lock, flags);
+}
+
+static int txx9spi_transfer(struct spi_device *spi, struct spi_message *m)
+{
+	struct spi_master *master = spi->master;
+	struct txx9spi *c = spi_master_get_devdata(master);
+	struct spi_transfer *t;
+	unsigned long flags;
+
+	m->actual_length = 0;
+
+	/* check each transfer's parameters */
+	list_for_each_entry (t, &m->transfers, transfer_list) {
+		u32 speed_hz = t->speed_hz ? : spi->max_speed_hz;
+		u8 bits_per_word = t->bits_per_word ? : spi->bits_per_word;
+
+		bits_per_word = bits_per_word ? : 8;
+		if (!t->tx_buf && !t->rx_buf && t->len)
+			return -EINVAL;
+		if (bits_per_word != 8 && bits_per_word != 16)
+			return -EINVAL;
+		if (t->len & ((bits_per_word >> 3) - 1))
+			return -EINVAL;
+		if (speed_hz < c->min_speed_hz || speed_hz > c->max_speed_hz)
+			return -EINVAL;
+	}
+
+	spin_lock_irqsave(&c->lock, flags);
+	list_add_tail(&m->queue, &c->queue);
+	queue_work(c->workqueue, &c->work);
+	spin_unlock_irqrestore(&c->lock, flags);
+
+	return 0;
+}
+
+static int __init txx9spi_probe(struct platform_device *dev)
+{
+	struct spi_master *master;
+	struct txx9spi *c;
+	struct resource *res;
+	int ret = -ENODEV;
+	u32 mcr;
+
+	master = spi_alloc_master(&dev->dev, sizeof(*c));
+	if (!master)
+		return ret;
+	c = spi_master_get_devdata(master);
+	c->irq = -1;
+	platform_set_drvdata(dev, master);
+
+	INIT_WORK(&c->work, txx9spi_work);
+	spin_lock_init(&c->lock);
+	INIT_LIST_HEAD(&c->queue);
+	init_waitqueue_head(&c->waitq);
+
+	c->clk = clk_get(&dev->dev, "spi-baseclk");
+	if (IS_ERR(c->clk)) {
+		ret = PTR_ERR(c->clk);
+		c->clk = NULL;
+		goto exit;
+	}
+	ret = clk_enable(c->clk);
+	if (ret) {
+		clk_put(c->clk);
+		c->clk = NULL;
+		goto exit;
+	}
+	c->baseclk = clk_get_rate(c->clk);
+	c->min_speed_hz = (c->baseclk + 0xff - 1) / 0xff;
+	c->max_speed_hz = c->baseclk;
+
+	res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+	if (!res)
+		goto exit;
+	c->membase = ioremap(res->start, res->end - res->start + 1);
+	if (!c->membase)
+		goto exit;
+
+	/* enter config mode */
+	mcr = txx9spi_rd(c, TXx9_SPMCR);
+	mcr &= ~(TXx9_SPMCR_OPMODE | TXx9_SPMCR_SPSTP | TXx9_SPMCR_BCLR);
+	txx9spi_wr(c, mcr | TXx9_SPMCR_CONFIG | TXx9_SPMCR_BCLR, TXx9_SPMCR);
+
+	c->irq = platform_get_irq(dev, 0);
+	if (c->irq < 0)
+		goto exit;
+	ret = request_irq(c->irq, txx9spi_interrupt, 0, dev->name, c);
+	if (ret) {
+		c->irq = -1;
+		goto exit;
+	}
+
+	c->workqueue = create_singlethread_workqueue(master->cdev.dev->bus_id);
+	if (!c->workqueue)
+		goto exit;
+	c->last_chipselect = -1;
+
+	dev_info(&dev->dev, "at %#llx, irq %d, %dMHz\n",
+		 (unsigned long long)res->start, c->irq,
+		 (c->baseclk + 500000) / 1000000);
+
+	master->bus_num = dev->id;
+	master->setup = txx9spi_setup;
+	master->transfer = txx9spi_transfer;
+	master->num_chipselect = (u16)UINT_MAX; /* any GPIO numbers */
+
+	ret = spi_register_master(master);
+	if (ret)
+		goto exit;
+	return 0;
+exit:
+	if (c->workqueue)
+		destroy_workqueue(c->workqueue);
+	if (c->irq >= 0)
+		free_irq(c->irq, c);
+	if (c->membase)
+		iounmap(c->membase);
+	if (c->clk) {
+		clk_disable(c->clk);
+		clk_put(c->clk);
+	}
+	platform_set_drvdata(dev, NULL);
+	spi_master_put(master);
+	return ret;
+}
+
+static int __exit txx9spi_remove(struct platform_device *dev)
+{
+	struct spi_master *master = spi_master_get(platform_get_drvdata(dev));
+	struct txx9spi *c = spi_master_get_devdata(master);
+
+	spi_unregister_master(master);
+	platform_set_drvdata(dev, NULL);
+	destroy_workqueue(c->workqueue);
+	free_irq(c->irq, c);
+	iounmap(c->membase);
+	clk_disable(c->clk);
+	clk_put(c->clk);
+	spi_master_put(master);
+	return 0;
+}
+
+static struct platform_driver txx9spi_driver = {
+	.remove = __exit_p(txx9spi_remove),
+	.driver = {
+		.name = "txx9spi",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init txx9spi_init(void)
+{
+	return platform_driver_probe(&txx9spi_driver, txx9spi_probe);
+}
+subsys_initcall(txx9spi_init);
+
+static void __exit txx9spi_exit(void)
+{
+	platform_driver_unregister(&txx9spi_driver);
+}
+module_exit(txx9spi_exit);
+
+MODULE_DESCRIPTION("TXx9 SPI Driver");
+MODULE_LICENSE("GPL");