DRIVERS:I2C: I2C driver polling mode support

This patch adds polling mode support for i2c s3c-2410 driver.
The I2C_SATAPHY controller lacks an interrupt line but the s3c-2410 driver
is interrupt driven. Hence this support is required for functioning
of the I2C_SATAPHY controller.

Signed-off-by: Vasanth Ananthan <vasanth.a@samsung.com>

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 9d902725bac94f28c91aa26ec57615988cd96e77..eae6ee9c8bd52716c13f37fd131b9bb903ff2e74 100644 (file)
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -48,6 +48,7 @@
 #define QUIRK_S3C2440          (1 << 0)
 #define QUIRK_HDMIPHY          (1 << 1)
 #define QUIRK_NO_GPIO          (1 << 2)
+#define QUIRK_SATAPHY          (1 << 3)
 
 /* i2c controller state */
 enum s3c24xx_i2c_state {
@@ -102,10 +103,14 @@ static struct platform_device_id s3c24xx_driver_ids[] = {
 };
 MODULE_DEVICE_TABLE(platform, s3c24xx_driver_ids);
 
+static int i2c_s3c_irq_nextbyte(struct s3c24xx_i2c *i2c, unsigned long iicstat);
+
 #ifdef CONFIG_OF
 static const struct of_device_id s3c24xx_i2c_match[] = {
        { .compatible = "samsung,s3c2410-i2c", .data = (void *)0 },
        { .compatible = "samsung,s3c2440-i2c", .data = (void *)QUIRK_S3C2440 },
+       { .compatible = "samsung,exynos5-sata-phy-i2c",
+         .data = (void *)(QUIRK_S3C2440 | QUIRK_SATAPHY | QUIRK_NO_GPIO) },
        { .compatible = "samsung,s3c2440-hdmiphy-i2c",
          .data = (void *)(QUIRK_S3C2440 | QUIRK_HDMIPHY | QUIRK_NO_GPIO) },
        {},
@@ -146,7 +151,8 @@ static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
        if (ret)
                i2c->msg_idx = ret;
 
-       wake_up(&i2c->wait);
+       if (!(i2c->quirks & QUIRK_SATAPHY))
+               wake_up(&i2c->wait);
 }
 
 static inline void s3c24xx_i2c_disable_ack(struct s3c24xx_i2c *i2c)
@@ -184,6 +190,23 @@ static inline void s3c24xx_i2c_enable_irq(struct s3c24xx_i2c *i2c)
 }
 
 
+static bool is_ack(struct s3c24xx_i2c *i2c)
+{
+       u32 time_out = i2c->tx_setup;
+
+       while (--time_out) {
+               if (readl(i2c->regs + S3C2410_IICCON)
+                       & S3C2410_IICCON_IRQPEND) {
+                       if (!(readl(i2c->regs + S3C2410_IICSTAT)
+                               & S3C2410_IICSTAT_LASTBIT))
+                               return true;
+               }
+               udelay(time_out);
+       }
+
+       return false;
+}
+
 /* s3c24xx_i2c_message_start
  *
  * put the start of a message onto the bus
@@ -227,6 +250,15 @@ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 
        stat |= S3C2410_IICSTAT_START;
        writel(stat, i2c->regs + S3C2410_IICSTAT);
+
+       if (i2c->quirks & QUIRK_SATAPHY) {
+               while ((i2c->msg_num != 0) && is_ack(i2c)) {
+                       i2c_s3c_irq_nextbyte(i2c, stat);
+                       stat = readl(i2c->regs + S3C2410_IICSTAT);
+                       if (stat & S3C2410_IICSTAT_ARBITR)
+                               dev_err(i2c->dev, "deal with arbitration loss\n");
+               }
+       }
 }
 
 static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
@@ -552,19 +584,23 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
        s3c24xx_i2c_message_start(i2c, msgs);
        spin_unlock_irq(&i2c->lock);
 
-       timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
+       if (!(i2c->quirks & QUIRK_SATAPHY)) {
 
-       ret = i2c->msg_idx;
+               timeout = wait_event_timeout(i2c->wait,
+                               i2c->msg_num == 0, HZ * 5);
+               
+               ret = i2c->msg_idx;
 
-       /* having these next two as dev_err() makes life very
-        * noisy when doing an i2cdetect */
+               /* having these next two as dev_err() makes life very
+               * noisy when doing an i2cdetect */
 
-       if (timeout == 0)
-               dev_dbg(i2c->dev, "timeout\n");
-       else if (ret != num)
-               dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
+               if (timeout == 0)
+                       dev_dbg(i2c->dev, "timeout\n");
+               else if (ret != num)
+                       dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
 
-       /* ensure the stop has been through the bus */
+               /* ensure the stop has been through the bus */
+       }
 
        dev_dbg(i2c->dev, "waiting for bus idle\n");
 
@@ -710,6 +746,9 @@ static int s3c24xx_i2c_clockrate(struct s3c24xx_i2c *i2c, unsigned int *got)
        if (div1 == 512)
                iiccon |= S3C2410_IICCON_TXDIV_512;
 
+       if (i2c->quirks & QUIRK_SATAPHY)
+               iiccon |= S3C2410_IICCON_SCALE(2);
+
        writel(iiccon, i2c->regs + S3C2410_IICCON);
 
        if (i2c->quirks & QUIRK_S3C2440) {
@@ -1024,18 +1063,20 @@ static int s3c24xx_i2c_probe(struct platform_device *pdev)
         * ensure no current IRQs pending
         */
 
-       i2c->irq = ret = platform_get_irq(pdev, 0);
-       if (ret <= 0) {
-               dev_err(&pdev->dev, "cannot find IRQ\n");
-               goto err_iomap;
-       }
+       if (!(i2c->quirks & QUIRK_SATAPHY)) {
+               i2c->irq = ret = platform_get_irq(pdev, 0);
+               if (ret <= 0) {
+                       dev_err(&pdev->dev, "cannot find IRQ\n");
+                       goto err_iomap;
+               }
 
-       ret = request_irq(i2c->irq, s3c24xx_i2c_irq, 0,
+               ret = request_irq(i2c->irq, s3c24xx_i2c_irq, 0,
                          dev_name(&pdev->dev), i2c);
 
-       if (ret != 0) {
-               dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
-               goto err_iomap;
+               if (ret != 0) {
+                       dev_err(&pdev->dev, "cannot claim IRQ %d\n", i2c->irq);
+                       goto err_iomap;
+               }
        }
 
        ret = s3c24xx_i2c_register_cpufreq(i2c);