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Diffstat (limited to 'drivers/i2c/busses/i2c-sh7760.c')
-rw-r--r--drivers/i2c/busses/i2c-sh7760.c564
1 files changed, 564 insertions, 0 deletions
diff --git a/drivers/i2c/busses/i2c-sh7760.c b/drivers/i2c/busses/i2c-sh7760.c
new file mode 100644
index 000000000..051b904cb
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sh7760.c
@@ -0,0 +1,564 @@
+/*
+ * 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/interrupt.h>
+#include <linux/ioport.h>
+#include <linux/platform_device.h>
+#include <linux/slab.h>
+#include <linux/io.h>
+#include <linux/module.h>
+
+#include <asm/clock.h>
+#include <asm/i2c-sh7760.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)
+{
+ __raw_writel(val, (unsigned long)cam->iobase + reg);
+}
+
+static inline unsigned long IN32(struct cami2c *cam, int reg)
+{
+ return __raw_readl((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 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, "peripheral_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 sh7760_i2c_probe(struct platform_device *pdev)
+{
+ struct sh7760_i2c_platdata *pd;
+ struct resource *res;
+ struct cami2c *id;
+ int ret;
+
+ pd = dev_get_platdata(&pdev->dev);
+ if (!pd) {
+ dev_err(&pdev->dev, "no platform_data!\n");
+ ret = -ENODEV;
+ goto out0;
+ }
+
+ id = kzalloc(sizeof(*id), GFP_KERNEL);
+ if (!id) {
+ 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;
+ }
+
+ ret = platform_get_irq(pdev, 0);
+ if (ret < 0)
+ goto out3;
+ id->irq = ret;
+
+ id->adap.nr = pdev->id;
+ id->adap.algo = &sh7760_i2c_algo;
+ id->adap.class = I2C_CLASS_HWMON | I2C_CLASS_SPD;
+ 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, 0,
+ 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)
+ 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 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);
+
+ return 0;
+}
+
+static struct platform_driver sh7760_i2c_drv = {
+ .driver = {
+ .name = SH7760_I2C_DEVNAME,
+ },
+ .probe = sh7760_i2c_probe,
+ .remove = sh7760_i2c_remove,
+};
+
+module_platform_driver(sh7760_i2c_drv);
+
+MODULE_LICENSE("GPL");
+MODULE_DESCRIPTION("SH7760 I2C bus driver");
+MODULE_AUTHOR("Manuel Lauss <mano@roarinelk.homelinux.net>");
generated by cgit v1.2.3 (git 2.39.1) at 2024-11-01 08:58:03 +0000