i2c: Renesas SH7760 I2C master driver

Driver for I2C interfaces in master mode on SH7760.

Signed-off-by: Manuel Lauss <mano@roarinelk.homelinux.net>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 577 insertions, 0 deletions

diff --git a/drivers/i2c/busses/i2c-sh7760.c b/drivers/i2c/busses/i2c-sh7760.c
new file mode 100644
index 000000000000..5e0e254976de
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sh7760.c
@@ -0,0 +1,577 @@
+/*
+ * I2C bus driver for the SH7760 I2C Interfaces.
+ *
+ * (c) 2005-2008 MSC Vertriebsges.m.b.H, Manuel Lauss <mlau@msc-ge.com>
+ *
+ * licensed under the terms outlined in the file COPYING.
+ *
+ */
+
+#include <linux/completion.h>
+#include <linux/delay.h>
+#include <linux/err.h>
+#include <linux/i2c.h>
+#include <linux/init.h>
+#include <linux/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+
+#include <asm/clock.h>
+#include <asm/i2c-sh7760.h>
+#include <asm/io.h>
+
+/* register offsets */
+#define I2CSCR		0x0		/* slave ctrl		*/
+#define I2CMCR		0x4		/* master ctrl		*/
+#define I2CSSR		0x8		/* slave status		*/
+#define I2CMSR		0xC		/* master status	*/
+#define I2CSIER		0x10		/* slave irq enable	*/
+#define I2CMIER		0x14		/* master irq enable	*/
+#define I2CCCR		0x18		/* clock dividers	*/
+#define I2CSAR		0x1c		/* slave address	*/
+#define I2CMAR		0x20		/* master address	*/
+#define I2CRXTX		0x24		/* data port		*/
+#define I2CFCR		0x28		/* fifo control		*/
+#define I2CFSR		0x2C		/* fifo status		*/
+#define I2CFIER		0x30		/* fifo irq enable	*/
+#define I2CRFDR		0x34		/* rx fifo count	*/
+#define I2CTFDR		0x38		/* tx fifo count	*/
+
+#define REGSIZE		0x3C
+
+#define MCR_MDBS	0x80		/* non-fifo mode switch	*/
+#define MCR_FSCL	0x40		/* override SCL pin	*/
+#define MCR_FSDA	0x20		/* override SDA pin	*/
+#define MCR_OBPC	0x10		/* override pins	*/
+#define MCR_MIE		0x08		/* master if enable	*/
+#define MCR_TSBE	0x04
+#define MCR_FSB		0x02		/* force stop bit	*/
+#define MCR_ESG		0x01		/* en startbit gen.	*/
+
+#define MSR_MNR		0x40		/* nack received	*/
+#define MSR_MAL		0x20		/* arbitration lost	*/
+#define MSR_MST		0x10		/* sent a stop		*/
+#define MSR_MDE		0x08
+#define MSR_MDT		0x04
+#define MSR_MDR		0x02
+#define MSR_MAT		0x01		/* slave addr xfer done	*/
+
+#define MIE_MNRE	0x40		/* nack irq en		*/
+#define MIE_MALE	0x20		/* arblos irq en	*/
+#define MIE_MSTE	0x10		/* stop irq en		*/
+#define MIE_MDEE	0x08
+#define MIE_MDTE	0x04
+#define MIE_MDRE	0x02
+#define MIE_MATE	0x01		/* address sent irq en	*/
+
+#define FCR_RFRST	0x02		/* reset rx fifo	*/
+#define FCR_TFRST	0x01		/* reset tx fifo	*/
+
+#define FSR_TEND	0x04		/* last byte sent	*/
+#define FSR_RDF		0x02		/* rx fifo trigger	*/
+#define FSR_TDFE	0x01		/* tx fifo empty	*/
+
+#define FIER_TEIE	0x04		/* tx fifo empty irq en	*/
+#define FIER_RXIE	0x02		/* rx fifo trig irq en	*/
+#define FIER_TXIE	0x01		/* tx fifo trig irq en	*/
+
+#define FIFO_SIZE	16
+
+struct cami2c {
+	void __iomem *iobase;
+	struct i2c_adapter adap;
+
+	/* message processing */
+	struct i2c_msg	*msg;
+#define IDF_SEND	1
+#define IDF_RECV	2
+#define IDF_STOP	4
+	int		flags;
+
+#define IDS_DONE	1
+#define IDS_ARBLOST	2
+#define IDS_NACK	4
+	int		status;
+	struct completion xfer_done;
+
+	int irq;
+	struct resource *ioarea;
+};
+
+static inline void OUT32(struct cami2c *cam, int reg, unsigned long val)
+{
+	ctrl_outl(val, (unsigned long)cam->iobase + reg);
+}
+
+static inline unsigned long IN32(struct cami2c *cam, int reg)
+{
+	return ctrl_inl((unsigned long)cam->iobase + reg);
+}
+
+static irqreturn_t sh7760_i2c_irq(int irq, void *ptr)
+{
+	struct cami2c *id = ptr;
+	struct i2c_msg *msg = id->msg;
+	char *data = msg->buf;
+	unsigned long msr, fsr, fier, len;
+
+	msr = IN32(id, I2CMSR);
+	fsr = IN32(id, I2CFSR);
+
+	/* arbitration lost */
+	if (msr & MSR_MAL) {
+		OUT32(id, I2CMCR, 0);
+		OUT32(id, I2CSCR, 0);
+		OUT32(id, I2CSAR, 0);
+		id->status |= IDS_DONE | IDS_ARBLOST;
+		goto out;
+	}
+
+	if (msr & MSR_MNR) {
+		/* NACK handling is very screwed up.  After receiving a
+		 * NAK IRQ one has to wait a bit  before writing to any
+		 * registers, or the ctl will lock up. After that delay
+		 * do a normal i2c stop. Then wait at least 1 ms before
+		 * attempting another transfer or ctl will stop working
+		 */
+		udelay(100);	/* wait or risk ctl hang */
+		OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
+		OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
+		OUT32(id, I2CFIER, 0);
+		OUT32(id, I2CMIER, MIE_MSTE);
+		OUT32(id, I2CSCR, 0);
+		OUT32(id, I2CSAR, 0);
+		id->status |= IDS_NACK;
+		msr &= ~MSR_MAT;
+		fsr = 0;
+		/* In some cases the MST bit is also set. */
+	}
+
+	/* i2c-stop was sent */
+	if (msr & MSR_MST) {
+		id->status |= IDS_DONE;
+		goto out;
+	}
+
+	/* i2c slave addr was sent; set to "normal" operation */
+	if (msr & MSR_MAT)
+		OUT32(id, I2CMCR, MCR_MIE);
+
+	fier = IN32(id, I2CFIER);
+
+	if (fsr & FSR_RDF) {
+		len = IN32(id, I2CRFDR);
+		if (msg->len <= len) {
+			if (id->flags & IDF_STOP) {
+				OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
+				OUT32(id, I2CFIER, 0);
+				/* manual says: wait >= 0.5 SCL times */
+				udelay(5);
+				/* next int should be MST */
+			} else {
+				id->status |= IDS_DONE;
+				/* keep the RDF bit: ctrl holds SCL low
+				 * until the setup for the next i2c_msg
+				 * clears this bit.
+				 */
+				fsr &= ~FSR_RDF;
+			}
+		}
+		while (msg->len && len) {
+			*data++ = IN32(id, I2CRXTX);
+			msg->len--;
+			len--;
+		}
+
+		if (msg->len) {
+			len = (msg->len >= FIFO_SIZE) ? FIFO_SIZE - 1
+						      : msg->len - 1;
+
+			OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xf) << 4));
+		}
+
+	} else if (id->flags & IDF_SEND) {
+		if ((fsr & FSR_TEND) && (msg->len < 1)) {
+			if (id->flags & IDF_STOP) {
+				OUT32(id, I2CMCR, MCR_MIE | MCR_FSB);
+			} else {
+				id->status |= IDS_DONE;
+				/* keep the TEND bit: ctl holds SCL low
+				 * until the setup for the next i2c_msg
+				 * clears this bit.
+				 */
+				fsr &= ~FSR_TEND;
+			}
+		}
+		if (fsr & FSR_TDFE) {
+			while (msg->len && (IN32(id, I2CTFDR) < FIFO_SIZE)) {
+				OUT32(id, I2CRXTX, *data++);
+				msg->len--;
+			}
+
+			if (msg->len < 1) {
+				fier &= ~FIER_TXIE;
+				OUT32(id, I2CFIER, fier);
+			} else {
+				len = (msg->len >= FIFO_SIZE) ? 2 : 0;
+				OUT32(id, I2CFCR,
+					  FCR_RFRST | ((len & 3) << 2));
+			}
+		}
+	}
+out:
+	if (id->status & IDS_DONE) {
+		OUT32(id, I2CMIER, 0);
+		OUT32(id, I2CFIER, 0);
+		id->msg = NULL;
+		complete(&id->xfer_done);
+	}
+	/* clear status flags and ctrl resumes work */
+	OUT32(id, I2CMSR, ~msr);
+	OUT32(id, I2CFSR, ~fsr);
+	OUT32(id, I2CSSR, 0);
+
+	return IRQ_HANDLED;
+}
+
+
+/* prepare and start a master receive operation */
+static void sh7760_i2c_mrecv(struct cami2c *id)
+{
+	int len;
+
+	id->flags |= IDF_RECV;
+
+	/* set the slave addr reg; otherwise rcv wont work! */
+	OUT32(id, I2CSAR, 0xfe);
+	OUT32(id, I2CMAR, (id->msg->addr << 1) | 1);
+
+	/* adjust rx fifo trigger */
+	if (id->msg->len >= FIFO_SIZE)
+		len = FIFO_SIZE - 1;	/* trigger at fifo full */
+	else
+		len = id->msg->len - 1;	/* trigger before all received */
+
+	OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
+	OUT32(id, I2CFCR, FCR_TFRST | ((len & 0xF) << 4));
+
+	OUT32(id, I2CMSR, 0);
+	OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
+	OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
+	OUT32(id, I2CFIER, FIER_RXIE);
+}
+
+/* prepare and start a master send operation */
+static void sh7760_i2c_msend(struct cami2c *id)
+{
+	int len;
+
+	id->flags |= IDF_SEND;
+
+	/* set the slave addr reg; otherwise xmit wont work! */
+	OUT32(id, I2CSAR, 0xfe);
+	OUT32(id, I2CMAR, (id->msg->addr << 1) | 0);
+
+	/* adjust tx fifo trigger */
+	if (id->msg->len >= FIFO_SIZE)
+		len = 2;	/* trig: 2 bytes left in TX fifo */
+	else
+		len = 0;	/* trig: 8 bytes left in TX fifo */
+
+	OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
+	OUT32(id, I2CFCR, FCR_RFRST | ((len & 3) << 2));
+
+	while (id->msg->len && IN32(id, I2CTFDR) < FIFO_SIZE) {
+		OUT32(id, I2CRXTX, *(id->msg->buf));
+		(id->msg->len)--;
+		(id->msg->buf)++;
+	}
+
+	OUT32(id, I2CMSR, 0);
+	OUT32(id, I2CMCR, MCR_MIE | MCR_ESG);
+	OUT32(id, I2CFSR, 0);
+	OUT32(id, I2CMIER, MIE_MNRE | MIE_MALE | MIE_MSTE | MIE_MATE);
+	OUT32(id, I2CFIER, FIER_TEIE | (id->msg->len ? FIER_TXIE : 0));
+}
+
+static inline int sh7760_i2c_busy_check(struct cami2c *id)
+{
+	return (IN32(id, I2CMCR) & MCR_FSDA);
+}
+
+static int sh7760_i2c_master_xfer(struct i2c_adapter *adap,
+				  struct i2c_msg *msgs,
+				  int num)
+{
+	struct cami2c *id = adap->algo_data;
+	int i, retr;
+
+	if (sh7760_i2c_busy_check(id)) {
+		dev_err(&adap->dev, "sh7760-i2c%d: bus busy!\n", adap->nr);
+		return -EBUSY;
+	}
+
+	i = 0;
+	while (i < num) {
+		retr = adap->retries;
+retry:
+		id->flags = ((i == (num-1)) ? IDF_STOP : 0);
+		id->status = 0;
+		id->msg = msgs;
+		init_completion(&id->xfer_done);
+
+		if (msgs->flags & I2C_M_RD)
+			sh7760_i2c_mrecv(id);
+		else
+			sh7760_i2c_msend(id);
+
+		wait_for_completion(&id->xfer_done);
+
+		if (id->status == 0) {
+			num = -EIO;
+			break;
+		}
+
+		if (id->status & IDS_NACK) {
+			/* wait a bit or i2c module stops working */
+			mdelay(1);
+			num = -EREMOTEIO;
+			break;
+		}
+
+		if (id->status & IDS_ARBLOST) {
+			if (retr--) {
+				mdelay(2);
+				goto retry;
+			}
+			num = -EREMOTEIO;
+			break;
+		}
+
+		msgs++;
+		i++;
+	}
+
+	id->msg = NULL;
+	id->flags = 0;
+	id->status = 0;
+
+	OUT32(id, I2CMCR, 0);
+	OUT32(id, I2CMSR, 0);
+	OUT32(id, I2CMIER, 0);
+	OUT32(id, I2CFIER, 0);
+
+	/* reset slave module registers too: master mode enables slave
+	 * module for receive ops (ack, data). Without this reset,
+	 * eternal bus activity might be reported after NACK / ARBLOST.
+	 */
+	OUT32(id, I2CSCR, 0);
+	OUT32(id, I2CSAR, 0);
+	OUT32(id, I2CSSR, 0);
+
+	return num;
+}
+
+static u32 sh7760_i2c_func(struct i2c_adapter *adap)
+{
+	return I2C_FUNC_I2C | (I2C_FUNC_SMBUS_EMUL & ~I2C_FUNC_SMBUS_QUICK);
+}
+
+static const struct i2c_algorithm sh7760_i2c_algo = {
+	.master_xfer	= sh7760_i2c_master_xfer,
+	.functionality	= sh7760_i2c_func,
+};
+
+/* calculate CCR register setting for a desired scl clock.  SCL clock is
+ * derived from I2C module clock  (iclk)  which in turn is derived from
+ * peripheral module clock (mclk, usually around 33MHz):
+ * iclk = mclk/(CDF + 1).  iclk must be < 20MHz.
+ * scl = iclk/(SCGD*8 + 20).
+ */
+static int __devinit calc_CCR(unsigned long scl_hz)
+{
+	struct clk *mclk;
+	unsigned long mck, m1, dff, odff, iclk;
+	signed char cdf, cdfm;
+	int scgd, scgdm, scgds;
+
+	mclk = clk_get(NULL, "module_clk");
+	if (IS_ERR(mclk)) {
+		return PTR_ERR(mclk);
+	} else {
+		mck = mclk->rate;
+		clk_put(mclk);
+	}
+
+	odff = scl_hz;
+	scgdm = cdfm = m1 = 0;
+	for (cdf = 3; cdf >= 0; cdf--) {
+		iclk = mck / (1 + cdf);
+		if (iclk >= 20000000)
+			continue;
+		scgds = ((iclk / scl_hz) - 20) >> 3;
+		for (scgd = scgds; (scgd < 63) && scgd <= scgds + 1; scgd++) {
+			m1 = iclk / (20 + (scgd << 3));
+			dff = abs(scl_hz - m1);
+			if (dff < odff) {
+				odff = dff;
+				cdfm = cdf;
+				scgdm = scgd;
+			}
+		}
+	}
+	/* fail if more than 25% off of requested SCL */
+	if (odff > (scl_hz >> 2))
+		return -EINVAL;
+
+	/* create a CCR register value */
+	return ((scgdm << 2) | cdfm);
+}
+
+static int __devinit sh7760_i2c_probe(struct platform_device *pdev)
+{
+	struct sh7760_i2c_platdata *pd;
+	struct resource *res;
+	struct cami2c *id;
+	int ret;
+
+	pd = pdev->dev.platform_data;
+	if (!pd) {
+		dev_err(&pdev->dev, "no platform_data!\n");
+		ret = -ENODEV;
+		goto out0;
+	}
+
+	id = kzalloc(sizeof(struct cami2c), GFP_KERNEL);
+	if (!id) {
+		dev_err(&pdev->dev, "no mem for private data\n");
+		ret = -ENOMEM;
+		goto out0;
+	}
+
+	res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
+	if (!res) {
+		dev_err(&pdev->dev, "no mmio resources\n");
+		ret = -ENODEV;
+		goto out1;
+	}
+
+	id->ioarea = request_mem_region(res->start, REGSIZE, pdev->name);
+	if (!id->ioarea) {
+		dev_err(&pdev->dev, "mmio already reserved\n");
+		ret = -EBUSY;
+		goto out1;
+	}
+
+	id->iobase = ioremap(res->start, REGSIZE);
+	if (!id->iobase) {
+		dev_err(&pdev->dev, "cannot ioremap\n");
+		ret = -ENODEV;
+		goto out2;
+	}
+
+	id->irq = platform_get_irq(pdev, 0);
+
+	id->adap.nr = pdev->id;
+	id->adap.algo = &sh7760_i2c_algo;
+	id->adap.class = I2C_CLASS_ALL;
+	id->adap.retries = 3;
+	id->adap.algo_data = id;
+	id->adap.dev.parent = &pdev->dev;
+	snprintf(id->adap.name, sizeof(id->adap.name),
+		"SH7760 I2C at %08lx", (unsigned long)res->start);
+
+	OUT32(id, I2CMCR, 0);
+	OUT32(id, I2CMSR, 0);
+	OUT32(id, I2CMIER, 0);
+	OUT32(id, I2CMAR, 0);
+	OUT32(id, I2CSIER, 0);
+	OUT32(id, I2CSAR, 0);
+	OUT32(id, I2CSCR, 0);
+	OUT32(id, I2CSSR, 0);
+	OUT32(id, I2CFIER, 0);
+	OUT32(id, I2CFCR, FCR_RFRST | FCR_TFRST);
+	OUT32(id, I2CFSR, 0);
+
+	ret = calc_CCR(pd->speed_khz * 1000);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "invalid SCL clock: %dkHz\n",
+			pd->speed_khz);
+		goto out3;
+	}
+	OUT32(id, I2CCCR, ret);
+
+	if (request_irq(id->irq, sh7760_i2c_irq, IRQF_DISABLED,
+			SH7760_I2C_DEVNAME, id)) {
+		dev_err(&pdev->dev, "cannot get irq %d\n", id->irq);
+		ret = -EBUSY;
+		goto out3;
+	}
+
+	ret = i2c_add_numbered_adapter(&id->adap);
+	if (ret < 0) {
+		dev_err(&pdev->dev, "reg adap failed: %d\n", ret);
+		goto out4;
+	}
+
+	platform_set_drvdata(pdev, id);
+
+	dev_info(&pdev->dev, "%d kHz mmio %08x irq %d\n",
+		 pd->speed_khz, res->start, id->irq);
+
+	return 0;
+
+out4:
+	free_irq(id->irq, id);
+out3:
+	iounmap(id->iobase);
+out2:
+	release_resource(id->ioarea);
+	kfree(id->ioarea);
+out1:
+	kfree(id);
+out0:
+	return ret;
+}
+
+static int __devexit sh7760_i2c_remove(struct platform_device *pdev)
+{
+	struct cami2c *id = platform_get_drvdata(pdev);
+
+	i2c_del_adapter(&id->adap);
+	free_irq(id->irq, id);
+	iounmap(id->iobase);
+	release_resource(id->ioarea);
+	kfree(id->ioarea);
+	kfree(id);
+	platform_set_drvdata(pdev, NULL);
+
+	return 0;
+}
+
+static struct platform_driver sh7760_i2c_drv = {
+	.driver	= {
+		.name	= SH7760_I2C_DEVNAME,
+		.owner	= THIS_MODULE,
+	},
+	.probe		= sh7760_i2c_probe,
+	.remove		= __devexit_p(sh7760_i2c_remove),
+};
+
+static int __init sh7760_i2c_init(void)
+{
+	return platform_driver_register(&sh7760_i2c_drv);
+}
+
+static void __exit sh7760_i2c_exit(void)
+{
+	platform_driver_unregister(&sh7760_i2c_drv);
+}
+
+module_init(sh7760_i2c_init);
+module_exit(sh7760_i2c_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SH7760 I2C bus driver");
+MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");