i2c: New driver for the SuperH Mobile I2C bus controller

This is V5 of the SuperH Mobile I2C Controller Driver. A simple Master
only driver for the I2C block included in processors such as sh7343,
sh7722 and sh7723. Tested on a sh7722 MigoR using a rs5c732b rtc.

Signed-off-by: Magnus Damm <damm@igel.co.jp>
Signed-off-by: Paul Mundt <lethal@linux-sh.org>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

3 files changed, 511 insertions, 0 deletions

diff --git a/drivers/i2c/busses/Kconfig b/drivers/i2c/busses/Kconfig
index e70caaf8f10c..48438cc5d0ca 100644
--- a/drivers/i2c/busses/Kconfig
+++ b/drivers/i2c/busses/Kconfig
@@ -695,4 +695,14 @@ config I2C_SH7760
           This driver can also be built as a module.  If so, the module
           will be called i2c-sh7760.
 
+config I2C_SH_MOBILE
+        tristate "SuperH Mobile I2C Controller"
+        depends on SUPERH
+        help
+          If you say yes to this option, support will be included for the
+          built-in I2C interface on the Renesas SH-Mobile processor.
+
+          This driver can also be built as a module.  If so, the module
+          will be called i2c-sh_mobile.
+
 endmenu
diff --git a/drivers/i2c/busses/Makefile b/drivers/i2c/busses/Makefile
index 8e72b2649dc7..e8c882a5ea66 100644
--- a/drivers/i2c/busses/Makefile
+++ b/drivers/i2c/busses/Makefile
@@ -39,6 +39,7 @@ obj-$(CONFIG_I2C_PXA)		+= i2c-pxa.o
 obj-$(CONFIG_I2C_S3C2410)       += i2c-s3c2410.o
 obj-$(CONFIG_I2C_SAVAGE4)       += i2c-savage4.o
 obj-$(CONFIG_I2C_SH7760)        += i2c-sh7760.o
+obj-$(CONFIG_I2C_SH_MOBILE)     += i2c-sh_mobile.o
 obj-$(CONFIG_I2C_SIBYTE)        += i2c-sibyte.o
 obj-$(CONFIG_I2C_SIMTEC)        += i2c-simtec.o
 obj-$(CONFIG_I2C_SIS5595)       += i2c-sis5595.o
diff --git a/drivers/i2c/busses/i2c-sh_mobile.c b/drivers/i2c/busses/i2c-sh_mobile.c
new file mode 100644
index 000000000000..840e634fa31f
--- /dev/null
+++ b/drivers/i2c/busses/i2c-sh_mobile.c
@@ -0,0 +1,500 @@
+/*
+ * SuperH Mobile I2C Controller
+ *
+ * Copyright (C) 2008 Magnus Damm
+ *
+ * Portions of the code based on out-of-tree driver i2c-sh7343.c
+ * Copyright (c) 2006 Carlos Munoz <carlos@kenati.com>
+ *
+ * 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
+ *
+ * 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/module.h>
+#include <linux/init.h>
+#include <linux/delay.h>
+#include <linux/platform_device.h>
+#include <linux/interrupt.h>
+#include <linux/i2c.h>
+#include <linux/err.h>
+#include <linux/clk.h>
+#include <linux/io.h>
+
+enum sh_mobile_i2c_op {
+        OP_START = 0,
+        OP_TX_ONLY,
+        OP_TX_STOP,
+        OP_TX_TO_RX,
+        OP_RX_ONLY,
+        OP_RX_STOP,
+};
+
+struct sh_mobile_i2c_data {
+        struct device *dev;
+        void __iomem *reg;
+        struct i2c_adapter adap;
+
+        struct clk *clk;
+        u_int8_t iccl;
+        u_int8_t icch;
+
+        spinlock_t lock;
+        wait_queue_head_t wait;
+        struct i2c_msg *msg;
+        int pos;
+        int sr;
+};
+
+#define NORMAL_SPEED            100000 /* FAST_SPEED 400000 */
+
+/* Register offsets */
+#define ICDR(pd)                (pd->reg + 0x00)
+#define ICCR(pd)                (pd->reg + 0x04)
+#define ICSR(pd)                (pd->reg + 0x08)
+#define ICIC(pd)                (pd->reg + 0x0c)
+#define ICCL(pd)                (pd->reg + 0x10)
+#define ICCH(pd)                (pd->reg + 0x14)
+
+/* Register bits */
+#define ICCR_ICE                0x80
+#define ICCR_RACK               0x40
+#define ICCR_TRS                0x10
+#define ICCR_BBSY               0x04
+#define ICCR_SCP                0x01
+
+#define ICSR_SCLM               0x80
+#define ICSR_SDAM               0x40
+#define SW_DONE                 0x20
+#define ICSR_BUSY               0x10
+#define ICSR_AL                 0x08
+#define ICSR_TACK               0x04
+#define ICSR_WAIT               0x02
+#define ICSR_DTE                0x01
+
+#define ICIC_ALE                0x08
+#define ICIC_TACKE              0x04
+#define ICIC_WAITE              0x02
+#define ICIC_DTEE               0x01
+
+static void activate_ch(struct sh_mobile_i2c_data *pd)
+{
+        /* Make sure the clock is enabled */
+        clk_enable(pd->clk);
+
+        /* Enable channel and configure rx ack */
+        iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
+
+        /* Mask all interrupts */
+        iowrite8(0, ICIC(pd));
+
+        /* Set the clock */
+        iowrite8(pd->iccl, ICCL(pd));
+        iowrite8(pd->icch, ICCH(pd));
+}
+
+static void deactivate_ch(struct sh_mobile_i2c_data *pd)
+{
+        /* Clear/disable interrupts */
+        iowrite8(0, ICSR(pd));
+        iowrite8(0, ICIC(pd));
+
+        /* Disable channel */
+        iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
+
+        /* Disable clock */
+        clk_disable(pd->clk);
+}
+
+static unsigned char i2c_op(struct sh_mobile_i2c_data *pd,
+                            enum sh_mobile_i2c_op op, unsigned char data)
+{
+        unsigned char ret = 0;
+        unsigned long flags;
+
+        dev_dbg(pd->dev, "op %d, data in 0x%02x\n", op, data);
+
+        spin_lock_irqsave(&pd->lock, flags);
+
+        switch (op) {
+        case OP_START:
+                iowrite8(0x94, ICCR(pd));
+                break;
+        case OP_TX_ONLY:
+                iowrite8(data, ICDR(pd));
+                break;
+        case OP_TX_STOP:
+                iowrite8(data, ICDR(pd));
+                iowrite8(0x90, ICCR(pd));
+                iowrite8(ICIC_ALE | ICIC_TACKE, ICIC(pd));
+                break;
+        case OP_TX_TO_RX:
+                iowrite8(data, ICDR(pd));
+                iowrite8(0x81, ICCR(pd));
+                break;
+        case OP_RX_ONLY:
+                ret = ioread8(ICDR(pd));
+                break;
+        case OP_RX_STOP:
+                ret = ioread8(ICDR(pd));
+                iowrite8(0xc0, ICCR(pd));
+                break;
+        }
+
+        spin_unlock_irqrestore(&pd->lock, flags);
+
+        dev_dbg(pd->dev, "op %d, data out 0x%02x\n", op, ret);
+        return ret;
+}
+
+static irqreturn_t sh_mobile_i2c_isr(int irq, void *dev_id)
+{
+        struct platform_device *dev = dev_id;
+        struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
+        struct i2c_msg *msg = pd->msg;
+        unsigned char data, sr;
+        int wakeup = 0;
+
+        sr = ioread8(ICSR(pd));
+        pd->sr |= sr;
+
+        dev_dbg(pd->dev, "i2c_isr 0x%02x 0x%02x %s %d %d!\n", sr, pd->sr,
+               (msg->flags & I2C_M_RD) ? "read" : "write",
+               pd->pos, msg->len);
+
+        if (sr & (ICSR_AL | ICSR_TACK)) {
+                iowrite8(0, ICIC(pd)); /* disable interrupts */
+                wakeup = 1;
+                goto do_wakeup;
+        }
+
+        if (pd->pos == msg->len) {
+                i2c_op(pd, OP_RX_ONLY, 0);
+                wakeup = 1;
+                goto do_wakeup;
+        }
+
+        if (pd->pos == -1) {
+                data = (msg->addr & 0x7f) << 1;
+                data |= (msg->flags & I2C_M_RD) ? 1 : 0;
+        } else
+                data = msg->buf[pd->pos];
+
+        if ((pd->pos == -1) || !(msg->flags & I2C_M_RD)) {
+                if (msg->flags & I2C_M_RD)
+                        i2c_op(pd, OP_TX_TO_RX, data);
+                else if (pd->pos == (msg->len - 1)) {
+                        i2c_op(pd, OP_TX_STOP, data);
+                        wakeup = 1;
+                } else
+                        i2c_op(pd, OP_TX_ONLY, data);
+        } else {
+                if (pd->pos == (msg->len - 1))
+                        data = i2c_op(pd, OP_RX_STOP, 0);
+                else
+                        data = i2c_op(pd, OP_RX_ONLY, 0);
+
+                msg->buf[pd->pos] = data;
+        }
+        pd->pos++;
+
+ do_wakeup:
+        if (wakeup) {
+                pd->sr |= SW_DONE;
+                wake_up(&pd->wait);
+        }
+
+        return IRQ_HANDLED;
+}
+
+static int start_ch(struct sh_mobile_i2c_data *pd, struct i2c_msg *usr_msg)
+{
+        /* Initialize channel registers */
+        iowrite8(ioread8(ICCR(pd)) & ~ICCR_ICE, ICCR(pd));
+
+        /* Enable channel and configure rx ack */
+        iowrite8(ioread8(ICCR(pd)) | ICCR_ICE, ICCR(pd));
+
+        /* Set the clock */
+        iowrite8(pd->iccl, ICCL(pd));
+        iowrite8(pd->icch, ICCH(pd));
+
+        pd->msg = usr_msg;
+        pd->pos = -1;
+        pd->sr = 0;
+
+        /* Enable all interrupts except wait */
+        iowrite8(ioread8(ICIC(pd)) | ICIC_ALE | ICIC_TACKE | ICIC_DTEE,
+                 ICIC(pd));
+        return 0;
+}
+
+static int sh_mobile_i2c_xfer(struct i2c_adapter *adapter,
+                              struct i2c_msg *msgs,
+                              int num)
+{
+        struct sh_mobile_i2c_data *pd = i2c_get_adapdata(adapter);
+        struct i2c_msg  *msg;
+        int err = 0;
+        u_int8_t val;
+        int i, k, retry_count;
+
+        activate_ch(pd);
+
+        /* Process all messages */
+        for (i = 0; i < num; i++) {
+                msg = &msgs[i];
+
+                err = start_ch(pd, msg);
+                if (err)
+                        break;
+
+                i2c_op(pd, OP_START, 0);
+
+                /* The interrupt handler takes care of the rest... */
+                k = wait_event_timeout(pd->wait,
+                                       pd->sr & (ICSR_TACK | SW_DONE),
+                                       5 * HZ);
+                if (!k)
+                        dev_err(pd->dev, "Transfer request timed out\n");
+
+                retry_count = 10;
+again:
+                val = ioread8(ICSR(pd));
+
+                dev_dbg(pd->dev, "val 0x%02x pd->sr 0x%02x\n", val, pd->sr);
+
+                if ((val | pd->sr) & (ICSR_TACK | ICSR_AL)) {
+                        err = -EIO;
+                        break;
+                }
+
+                /* the interrupt handler may wake us up before the
+                 * transfer is finished, so poll the hardware
+                 * until we're done.
+                 */
+
+                if (!(!(val & ICSR_BUSY) && (val & ICSR_SCLM) &&
+                      (val & ICSR_SDAM))) {
+                        msleep(1);
+                        if (retry_count--)
+                                goto again;
+
+                        err = -EIO;
+                        dev_err(pd->dev, "Polling timed out\n");
+                        break;
+                }
+        }
+
+        deactivate_ch(pd);
+
+        if (!err)
+                err = num;
+        return err;
+}
+
+static u32 sh_mobile_i2c_func(struct i2c_adapter *adapter)
+{
+        return I2C_FUNC_I2C | I2C_FUNC_SMBUS_EMUL;
+}
+
+static struct i2c_algorithm sh_mobile_i2c_algorithm = {
+        .functionality  = sh_mobile_i2c_func,
+        .master_xfer    = sh_mobile_i2c_xfer,
+};
+
+static void sh_mobile_i2c_setup_channel(struct platform_device *dev)
+{
+        struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
+        unsigned long peripheral_clk = clk_get_rate(pd->clk);
+        u_int32_t num;
+        u_int32_t denom;
+        u_int32_t tmp;
+
+        spin_lock_init(&pd->lock);
+        init_waitqueue_head(&pd->wait);
+
+        /* Calculate the value for iccl. From the data sheet:
+         * iccl = (p clock / transfer rate) * (L / (L + H))
+         * where L and H are the SCL low/high ratio (5/4 in this case).
+         * We also round off the result.
+         */
+        num = peripheral_clk * 5;
+        denom = NORMAL_SPEED * 9;
+        tmp = num * 10 / denom;
+        if (tmp % 10 >= 5)
+                pd->iccl = (u_int8_t)((num/denom) + 1);
+        else
+                pd->iccl = (u_int8_t)(num/denom);
+
+        /* Calculate the value for icch. From the data sheet:
+           icch = (p clock / transfer rate) * (H / (L + H)) */
+        num = peripheral_clk * 4;
+        tmp = num * 10 / denom;
+        if (tmp % 10 >= 5)
+                pd->icch = (u_int8_t)((num/denom) + 1);
+        else
+                pd->icch = (u_int8_t)(num/denom);
+}
+
+static int sh_mobile_i2c_hook_irqs(struct platform_device *dev, int hook)
+{
+        struct resource *res;
+        int ret = -ENXIO;
+        int q, m;
+        int k = 0;
+        int n = 0;
+
+        while ((res = platform_get_resource(dev, IORESOURCE_IRQ, k))) {
+                for (n = res->start; hook && n <= res->end; n++) {
+                        if (request_irq(n, sh_mobile_i2c_isr, IRQF_DISABLED,
+                                        dev->dev.bus_id, dev))
+                                goto rollback;
+                }
+                k++;
+        }
+
+        if (hook)
+                return k > 0 ? 0 : -ENOENT;
+
+        k--;
+        ret = 0;
+
+ rollback:
+        for (q = k; k >= 0; k--) {
+                for (m = n; m >= res->start; m--)
+                        free_irq(m, dev);
+
+                res = platform_get_resource(dev, IORESOURCE_IRQ, k - 1);
+                m = res->end;
+        }
+
+        return ret;
+}
+
+static int sh_mobile_i2c_probe(struct platform_device *dev)
+{
+        struct sh_mobile_i2c_data *pd;
+        struct i2c_adapter *adap;
+        struct resource *res;
+        int size;
+        int ret;
+
+        pd = kzalloc(sizeof(struct sh_mobile_i2c_data), GFP_KERNEL);
+        if (pd == NULL) {
+                dev_err(&dev->dev, "cannot allocate private data\n");
+                return -ENOMEM;
+        }
+
+        pd->clk = clk_get(&dev->dev, "peripheral_clk");
+        if (IS_ERR(pd->clk)) {
+                dev_err(&dev->dev, "cannot get peripheral clock\n");
+                ret = PTR_ERR(pd->clk);
+                goto err;
+        }
+
+        ret = sh_mobile_i2c_hook_irqs(dev, 1);
+        if (ret) {
+                dev_err(&dev->dev, "cannot request IRQ\n");
+                goto err_clk;
+        }
+
+        pd->dev = &dev->dev;
+        platform_set_drvdata(dev, pd);
+
+        res = platform_get_resource(dev, IORESOURCE_MEM, 0);
+        if (res == NULL) {
+                dev_err(&dev->dev, "cannot find IO resource\n");
+                ret = -ENOENT;
+                goto err_irq;
+        }
+
+        size = (res->end - res->start) + 1;
+
+        pd->reg = ioremap(res->start, size);
+        if (pd->reg == NULL) {
+                dev_err(&dev->dev, "cannot map IO\n");
+                ret = -ENXIO;
+                goto err_irq;
+        }
+
+        /* setup the private data */
+        adap = &pd->adap;
+        i2c_set_adapdata(adap, pd);
+
+        adap->owner = THIS_MODULE;
+        adap->algo = &sh_mobile_i2c_algorithm;
+        adap->dev.parent = &dev->dev;
+        adap->retries = 5;
+        adap->nr = dev->id;
+
+        strlcpy(adap->name, dev->name, sizeof(adap->name));
+
+        sh_mobile_i2c_setup_channel(dev);
+
+        ret = i2c_add_numbered_adapter(adap);
+        if (ret < 0) {
+                dev_err(&dev->dev, "cannot add numbered adapter\n");
+                goto err_all;
+        }
+
+        return 0;
+
+ err_all:
+        iounmap(pd->reg);
+ err_irq:
+        sh_mobile_i2c_hook_irqs(dev, 0);
+ err_clk:
+        clk_put(pd->clk);
+ err:
+        kfree(pd);
+        return ret;
+}
+
+static int sh_mobile_i2c_remove(struct platform_device *dev)
+{
+        struct sh_mobile_i2c_data *pd = platform_get_drvdata(dev);
+
+        i2c_del_adapter(&pd->adap);
+        iounmap(pd->reg);
+        sh_mobile_i2c_hook_irqs(dev, 0);
+        clk_put(pd->clk);
+        kfree(pd);
+        return 0;
+}
+
+static struct platform_driver sh_mobile_i2c_driver = {
+        .driver         = {
+                .name           = "i2c-sh_mobile",
+                .owner          = THIS_MODULE,
+        },
+        .probe          = sh_mobile_i2c_probe,
+        .remove         = sh_mobile_i2c_remove,
+};
+
+static int __init sh_mobile_i2c_adap_init(void)
+{
+        return platform_driver_register(&sh_mobile_i2c_driver);
+}
+
+static void __exit sh_mobile_i2c_adap_exit(void)
+{
+        platform_driver_unregister(&sh_mobile_i2c_driver);
+}
+
+module_init(sh_mobile_i2c_adap_init);
+module_exit(sh_mobile_i2c_adap_exit);
+
+MODULE_DESCRIPTION("SuperH Mobile I2C Bus Controller driver");
+MODULE_AUTHOR("Magnus Damm");
+MODULE_LICENSE("GPL v2");