spi: add support for SuperH SPI

The SH7757 has SPI0 module. This patch supports it.

Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
[grant.likely@secretlab.ca: fixed Makefile ordering, added
    __dev{init,exit} annotations, removed DRIVER_VERSION (this is
    mainline, the version == the kernel version) and tidied some
    indentation & style stuff]
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

1 files changed, 543 insertions, 0 deletions

diff --git a/drivers/spi/spi_sh.c b/drivers/spi/spi_sh.c
new file mode 100644
index 0000000..869a07d
--- /dev/null
+++ b/drivers/spi/spi_sh.c
@@ -0,0 +1,543 @@
+/*
+ * SH SPI bus driver
+ *
+ * Copyright (C) 2011  Renesas Solutions Corp.
+ *
+ * Based on pxa2xx_spi.c:
+ * Copyright (C) 2005 Stephen Street / StreetFire Sound Labs
+ *
+ * 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; version 2 of the License.
+ *
+ * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
+ *
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/timer.h>
+#include <linux/delay.h>
+#include <linux/list.h>
+#include <linux/workqueue.h>
+#include <linux/interrupt.h>
+#include <linux/platform_device.h>
+#include <linux/io.h>
+#include <linux/spi/spi.h>
+
+#define SPI_SH_TBR		0x00
+#define SPI_SH_RBR		0x00
+#define SPI_SH_CR1		0x08
+#define SPI_SH_CR2		0x10
+#define SPI_SH_CR3		0x18
+#define SPI_SH_CR4		0x20
+#define SPI_SH_CR5		0x28
+
+/* CR1 */
+#define SPI_SH_TBE		0x80
+#define SPI_SH_TBF		0x40
+#define SPI_SH_RBE		0x20
+#define SPI_SH_RBF		0x10
+#define SPI_SH_PFONRD		0x08
+#define SPI_SH_SSDB		0x04
+#define SPI_SH_SSD		0x02
+#define SPI_SH_SSA		0x01
+
+/* CR2 */
+#define SPI_SH_RSTF		0x80
+#define SPI_SH_LOOPBK		0x40
+#define SPI_SH_CPOL		0x20
+#define SPI_SH_CPHA		0x10
+#define SPI_SH_L1M0		0x08
+
+/* CR3 */
+#define SPI_SH_MAX_BYTE		0xFF
+
+/* CR4 */
+#define SPI_SH_TBEI		0x80
+#define SPI_SH_TBFI		0x40
+#define SPI_SH_RBEI		0x20
+#define SPI_SH_RBFI		0x10
+#define SPI_SH_WPABRT		0x04
+#define SPI_SH_SSS		0x01
+
+/* CR8 */
+#define SPI_SH_P1L0		0x80
+#define SPI_SH_PP1L0		0x40
+#define SPI_SH_MUXI		0x20
+#define SPI_SH_MUXIRQ		0x10
+
+#define SPI_SH_FIFO_SIZE	32
+#define SPI_SH_SEND_TIMEOUT	(3 * HZ)
+#define SPI_SH_RECEIVE_TIMEOUT	(HZ >> 3)
+
+#undef DEBUG
+
+struct spi_sh_data {
+	void __iomem *addr;
+	int irq;
+	struct spi_master *master;
+	struct list_head queue;
+	struct workqueue_struct *workqueue;
+	struct work_struct ws;
+	unsigned long cr1;
+	wait_queue_head_t wait;
+	spinlock_t lock;
+};
+
+static void spi_sh_write(struct spi_sh_data *ss, unsigned long data,
+			     unsigned long offset)
+{
+	writel(data, ss->addr + offset);
+}
+
+static unsigned long spi_sh_read(struct spi_sh_data *ss, unsigned long offset)
+{
+	return readl(ss->addr + offset);
+}
+
+static void spi_sh_set_bit(struct spi_sh_data *ss, unsigned long val,
+				unsigned long offset)
+{
+	unsigned long tmp;
+
+	tmp = spi_sh_read(ss, offset);
+	tmp |= val;
+	spi_sh_write(ss, tmp, offset);
+}
+
+static void spi_sh_clear_bit(struct spi_sh_data *ss, unsigned long val,
+				unsigned long offset)
+{
+	unsigned long tmp;
+
+	tmp = spi_sh_read(ss, offset);
+	tmp &= ~val;
+	spi_sh_write(ss, tmp, offset);
+}
+
+static void clear_fifo(struct spi_sh_data *ss)
+{
+	spi_sh_set_bit(ss, SPI_SH_RSTF, SPI_SH_CR2);
+	spi_sh_clear_bit(ss, SPI_SH_RSTF, SPI_SH_CR2);
+}
+
+static int spi_sh_wait_receive_buffer(struct spi_sh_data *ss)
+{
+	int timeout = 100000;
+
+	while (spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_RBE) {
+		udelay(10);
+		if (timeout-- < 0)
+			return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static int spi_sh_wait_write_buffer_empty(struct spi_sh_data *ss)
+{
+	int timeout = 100000;
+
+	while (!(spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_TBE)) {
+		udelay(10);
+		if (timeout-- < 0)
+			return -ETIMEDOUT;
+	}
+	return 0;
+}
+
+static int spi_sh_send(struct spi_sh_data *ss, struct spi_message *mesg,
+			struct spi_transfer *t)
+{
+	int i, retval = 0;
+	int remain = t->len;
+	int cur_len;
+	unsigned char *data;
+	unsigned long tmp;
+	long ret;
+
+	if (t->len)
+		spi_sh_set_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
+
+	data = (unsigned char *)t->tx_buf;
+	while (remain > 0) {
+		cur_len = min(SPI_SH_FIFO_SIZE, remain);
+		for (i = 0; i < cur_len &&
+				!(spi_sh_read(ss, SPI_SH_CR4) &
+							SPI_SH_WPABRT) &&
+				!(spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_TBF);
+				i++)
+			spi_sh_write(ss, (unsigned long)data[i], SPI_SH_TBR);
+
+		if (spi_sh_read(ss, SPI_SH_CR4) & SPI_SH_WPABRT) {
+			/* Abort SPI operation */
+			spi_sh_set_bit(ss, SPI_SH_WPABRT, SPI_SH_CR4);
+			retval = -EIO;
+			break;
+		}
+
+		cur_len = i;
+
+		remain -= cur_len;
+		data += cur_len;
+
+		if (remain > 0) {
+			ss->cr1 &= ~SPI_SH_TBE;
+			spi_sh_set_bit(ss, SPI_SH_TBE, SPI_SH_CR4);
+			ret = wait_event_interruptible_timeout(ss->wait,
+						 ss->cr1 & SPI_SH_TBE,
+						 SPI_SH_SEND_TIMEOUT);
+			if (ret == 0 && !(ss->cr1 & SPI_SH_TBE)) {
+				printk(KERN_ERR "%s: timeout\n", __func__);
+				return -ETIMEDOUT;
+			}
+		}
+	}
+
+	if (list_is_last(&t->transfer_list, &mesg->transfers)) {
+		tmp = spi_sh_read(ss, SPI_SH_CR1);
+		tmp = tmp & ~(SPI_SH_SSD | SPI_SH_SSDB);
+		spi_sh_write(ss, tmp, SPI_SH_CR1);
+		spi_sh_set_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
+
+		ss->cr1 &= ~SPI_SH_TBE;
+		spi_sh_set_bit(ss, SPI_SH_TBE, SPI_SH_CR4);
+		ret = wait_event_interruptible_timeout(ss->wait,
+					 ss->cr1 & SPI_SH_TBE,
+					 SPI_SH_SEND_TIMEOUT);
+		if (ret == 0 && (ss->cr1 & SPI_SH_TBE)) {
+			printk(KERN_ERR "%s: timeout\n", __func__);
+			return -ETIMEDOUT;
+		}
+	}
+
+	return retval;
+}
+
+static int spi_sh_receive(struct spi_sh_data *ss, struct spi_message *mesg,
+			  struct spi_transfer *t)
+{
+	int i;
+	int remain = t->len;
+	int cur_len;
+	unsigned char *data;
+	unsigned long tmp;
+	long ret;
+
+	if (t->len > SPI_SH_MAX_BYTE)
+		spi_sh_write(ss, SPI_SH_MAX_BYTE, SPI_SH_CR3);
+	else
+		spi_sh_write(ss, t->len, SPI_SH_CR3);
+
+	tmp = spi_sh_read(ss, SPI_SH_CR1);
+	tmp = tmp & ~(SPI_SH_SSD | SPI_SH_SSDB);
+	spi_sh_write(ss, tmp, SPI_SH_CR1);
+	spi_sh_set_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
+
+	spi_sh_wait_write_buffer_empty(ss);
+
+	data = (unsigned char *)t->rx_buf;
+	while (remain > 0) {
+		if (remain >= SPI_SH_FIFO_SIZE) {
+			ss->cr1 &= ~SPI_SH_RBF;
+			spi_sh_set_bit(ss, SPI_SH_RBF, SPI_SH_CR4);
+			ret = wait_event_interruptible_timeout(ss->wait,
+						 ss->cr1 & SPI_SH_RBF,
+						 SPI_SH_RECEIVE_TIMEOUT);
+			if (ret == 0 &&
+			    spi_sh_read(ss, SPI_SH_CR1) & SPI_SH_RBE) {
+				printk(KERN_ERR "%s: timeout\n", __func__);
+				return -ETIMEDOUT;
+			}
+		}
+
+		cur_len = min(SPI_SH_FIFO_SIZE, remain);
+		for (i = 0; i < cur_len; i++) {
+			if (spi_sh_wait_receive_buffer(ss))
+				break;
+			data[i] = (unsigned char)spi_sh_read(ss, SPI_SH_RBR);
+		}
+
+		remain -= cur_len;
+		data += cur_len;
+	}
+
+	/* deassert CS when SPI is receiving. */
+	if (t->len > SPI_SH_MAX_BYTE) {
+		clear_fifo(ss);
+		spi_sh_write(ss, 1, SPI_SH_CR3);
+	} else {
+		spi_sh_write(ss, 0, SPI_SH_CR3);
+	}
+
+	return 0;
+}
+
+static void spi_sh_work(struct work_struct *work)
+{
+	struct spi_sh_data *ss = container_of(work, struct spi_sh_data, ws);
+	struct spi_message *mesg;
+	struct spi_transfer *t;
+	unsigned long flags;
+	int ret;
+
+	pr_debug("%s: enter\n", __func__);
+
+	spin_lock_irqsave(&ss->lock, flags);
+	while (!list_empty(&ss->queue)) {
+		mesg = list_entry(ss->queue.next, struct spi_message, queue);
+		list_del_init(&mesg->queue);
+
+		spin_unlock_irqrestore(&ss->lock, flags);
+		list_for_each_entry(t, &mesg->transfers, transfer_list) {
+			pr_debug("tx_buf = %p, rx_buf = %p\n",
+					t->tx_buf, t->rx_buf);
+			pr_debug("len = %d, delay_usecs = %d\n",
+					t->len, t->delay_usecs);
+
+			if (t->tx_buf) {
+				ret = spi_sh_send(ss, mesg, t);
+				if (ret < 0)
+					goto error;
+			}
+			if (t->rx_buf) {
+				ret = spi_sh_receive(ss, mesg, t);
+				if (ret < 0)
+					goto error;
+			}
+			mesg->actual_length += t->len;
+		}
+		spin_lock_irqsave(&ss->lock, flags);
+
+		mesg->status = 0;
+		mesg->complete(mesg->context);
+	}
+
+	clear_fifo(ss);
+	spi_sh_set_bit(ss, SPI_SH_SSD, SPI_SH_CR1);
+	udelay(100);
+
+	spi_sh_clear_bit(ss, SPI_SH_SSA | SPI_SH_SSDB | SPI_SH_SSD,
+			 SPI_SH_CR1);
+
+	clear_fifo(ss);
+
+	spin_unlock_irqrestore(&ss->lock, flags);
+
+	return;
+
+ error:
+	mesg->status = ret;
+	mesg->complete(mesg->context);
+
+	spi_sh_clear_bit(ss, SPI_SH_SSA | SPI_SH_SSDB | SPI_SH_SSD,
+			 SPI_SH_CR1);
+	clear_fifo(ss);
+
+}
+
+static int spi_sh_setup(struct spi_device *spi)
+{
+	struct spi_sh_data *ss = spi_master_get_devdata(spi->master);
+
+	if (!spi->bits_per_word)
+		spi->bits_per_word = 8;
+
+	pr_debug("%s: enter\n", __func__);
+
+	spi_sh_write(ss, 0xfe, SPI_SH_CR1);	/* SPI sycle stop */
+	spi_sh_write(ss, 0x00, SPI_SH_CR1);	/* CR1 init */
+	spi_sh_write(ss, 0x00, SPI_SH_CR3);	/* CR3 init */
+
+	clear_fifo(ss);
+
+	/* 1/8 clock */
+	spi_sh_write(ss, spi_sh_read(ss, SPI_SH_CR2) | 0x07, SPI_SH_CR2);
+	udelay(10);
+
+	return 0;
+}
+
+static int spi_sh_transfer(struct spi_device *spi, struct spi_message *mesg)
+{
+	struct spi_sh_data *ss = spi_master_get_devdata(spi->master);
+	unsigned long flags;
+
+	pr_debug("%s: enter\n", __func__);
+	pr_debug("\tmode = %02x\n", spi->mode);
+
+	spin_lock_irqsave(&ss->lock, flags);
+
+	mesg->actual_length = 0;
+	mesg->status = -EINPROGRESS;
+
+	spi_sh_clear_bit(ss, SPI_SH_SSA, SPI_SH_CR1);
+
+	list_add_tail(&mesg->queue, &ss->queue);
+	queue_work(ss->workqueue, &ss->ws);
+
+	spin_unlock_irqrestore(&ss->lock, flags);
+
+	return 0;
+}
+
+static void spi_sh_cleanup(struct spi_device *spi)
+{
+	struct spi_sh_data *ss = spi_master_get_devdata(spi->master);
+
+	pr_debug("%s: enter\n", __func__);
+
+	spi_sh_clear_bit(ss, SPI_SH_SSA | SPI_SH_SSDB | SPI_SH_SSD,
+			 SPI_SH_CR1);
+}
+
+static irqreturn_t spi_sh_irq(int irq, void *_ss)
+{
+	struct spi_sh_data *ss = (struct spi_sh_data *)_ss;
+	unsigned long cr1;
+
+	cr1 = spi_sh_read(ss, SPI_SH_CR1);
+	if (cr1 & SPI_SH_TBE)
+		ss->cr1 |= SPI_SH_TBE;
+	if (cr1 & SPI_SH_TBF)
+		ss->cr1 |= SPI_SH_TBF;
+	if (cr1 & SPI_SH_RBE)
+		ss->cr1 |= SPI_SH_RBE;
+	if (cr1 & SPI_SH_RBF)
+		ss->cr1 |= SPI_SH_RBF;
+
+	if (ss->cr1) {
+		spi_sh_clear_bit(ss, ss->cr1, SPI_SH_CR4);
+		wake_up(&ss->wait);
+	}
+
+	return IRQ_HANDLED;
+}
+
+static int __devexit spi_sh_remove(struct platform_device *pdev)
+{
+	struct spi_sh_data *ss = dev_get_drvdata(&pdev->dev);
+
+	destroy_workqueue(ss->workqueue);
+	free_irq(ss->irq, ss);
+	iounmap(ss->addr);
+	spi_master_put(ss->master);
+
+	return 0;
+}
+
+static int __devinit spi_sh_probe(struct platform_device *pdev)
+{
+	struct resource *res;
+	struct spi_master *master;
+	struct spi_sh_data *ss;
+	int ret, irq;
+
+	/* get base addr */
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (unlikely(res == NULL)) {
+		dev_err(&pdev->dev, "invalid resource\n");
+		return -EINVAL;
+	}
+
+	irq = platform_get_irq(pdev, 0);
+	if (irq < 0) {
+		dev_err(&pdev->dev, "platform_get_irq error\n");
+		return -ENODEV;
+	}
+
+	master = spi_alloc_master(&pdev->dev, sizeof(struct spi_sh_data));
+	if (master == NULL) {
+		dev_err(&pdev->dev, "spi_alloc_master error.\n");
+		return -ENOMEM;
+	}
+
+	ss = spi_master_get_devdata(master);
+	dev_set_drvdata(&pdev->dev, ss);
+
+	ss->irq = irq;
+	ss->master = master;
+	ss->addr = ioremap(res->start, resource_size(res));
+	if (ss->addr == NULL) {
+		dev_err(&pdev->dev, "ioremap error.\n");
+		ret = -ENOMEM;
+		goto error1;
+	}
+	INIT_LIST_HEAD(&ss->queue);
+	spin_lock_init(&ss->lock);
+	INIT_WORK(&ss->ws, spi_sh_work);
+	init_waitqueue_head(&ss->wait);
+	ss->workqueue = create_singlethread_workqueue(
+					dev_name(master->dev.parent));
+	if (ss->workqueue == NULL) {
+		dev_err(&pdev->dev, "create workqueue error\n");
+		ret = -EBUSY;
+		goto error2;
+	}
+
+	ret = request_irq(irq, spi_sh_irq, IRQF_DISABLED, "spi_sh", ss);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "request_irq error\n");
+		goto error3;
+	}
+
+	master->num_chipselect = 2;
+	master->bus_num = pdev->id;
+	master->setup = spi_sh_setup;
+	master->transfer = spi_sh_transfer;
+	master->cleanup = spi_sh_cleanup;
+
+	ret = spi_register_master(master);
+	if (ret < 0) {
+		printk(KERN_ERR "spi_register_master error.\n");
+		goto error4;
+	}
+
+	return 0;
+
+ error4:
+	free_irq(irq, ss);
+ error3:
+	destroy_workqueue(ss->workqueue);
+ error2:
+	iounmap(ss->addr);
+ error1:
+	spi_master_put(master);
+
+	return ret;
+}
+
+static struct platform_driver spi_sh_driver = {
+	.probe = spi_sh_probe,
+	.remove = __devexit_p(spi_sh_remove),
+	.driver = {
+		.name = "sh_spi",
+		.owner = THIS_MODULE,
+	},
+};
+
+static int __init spi_sh_init(void)
+{
+	return platform_driver_register(&spi_sh_driver);
+}
+module_init(spi_sh_init);
+
+static void __exit spi_sh_exit(void)
+{
+	platform_driver_unregister(&spi_sh_driver);
+}
+module_exit(spi_sh_exit);
+
+MODULE_DESCRIPTION("SH SPI bus driver");
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Yoshihiro Shimoda");
+MODULE_ALIAS("platform:sh_spi");