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-rw-r--r--drivers/i2c/busses/i2c-s3c2410.c53
1 files changed, 48 insertions, 5 deletions
diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index b723b0b..61c9365 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -201,18 +201,29 @@ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
static inline void s3c24xx_i2c_stop(struct s3c24xx_i2c *i2c, int ret)
{
- unsigned long iicstat = readl(i2c->regs + S3C2410_IICSTAT);
+ unsigned long iicstat;
+ unsigned long iiccon;
dev_dbg(i2c->dev, "STOP\n");
/* stop the transfer */
+
+ /* Disable irq */
+ s3c24xx_i2c_disable_irq(i2c);
+
+ /* STOP signal generation : MTx(0xD0) */
+ iicstat = readl(i2c->regs + S3C2410_IICSTAT);
iicstat &= ~S3C2410_IICSTAT_START;
writel(iicstat, i2c->regs + S3C2410_IICSTAT);
- i2c->state = STATE_STOP;
+ /* Clear pending bit */
+ iiccon = readl(i2c->regs + S3C2410_IICCON);
+ iiccon &= ~S3C2410_IICCON_IRQPEND;
+ writel(iiccon, i2c->regs + S3C2410_IICCON);
s3c24xx_i2c_master_complete(i2c, ret);
- s3c24xx_i2c_disable_irq(i2c);
+
+ i2c->state = STATE_STOP;
}
/* helper functions to determine the current state in the set of
@@ -484,7 +495,8 @@ static int s3c24xx_i2c_set_master(struct s3c24xx_i2c *i2c)
static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
struct i2c_msg *msgs, int num)
{
- unsigned long timeout;
+ unsigned long iicstat, timeout;
+ int spins = 20;
int ret;
if (i2c->suspended)
@@ -523,7 +535,38 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
/* ensure the stop has been through the bus */
- udelay(10);
+ dev_dbg(i2c->dev, "waiting for bus idle\n");
+
+ /* first, try busy waiting briefly */
+ do {
+ cpu_relax();
+ iicstat = readl(i2c->regs + S3C2410_IICSTAT);
+ } while ((iicstat & S3C2410_IICSTAT_START) && --spins);
+
+ /* if that timed out sleep */
+ if (!spins) {
+ msleep(1);
+ iicstat = readl(i2c->regs + S3C2410_IICSTAT);
+ }
+
+ /* if still not finished, clean it up */
+ spin_lock_irq(&i2c->lock);
+
+ if (iicstat & S3C2410_IICSTAT_BUSBUSY) {
+ dev_dbg(i2c->dev, "timeout waiting for bus idle\n");
+
+ if (i2c->state != STATE_STOP) {
+ dev_dbg(i2c->dev,
+ "timeout : i2c interrupt hasn't occurred\n");
+ s3c24xx_i2c_stop(i2c, 0);
+ }
+
+ /* Disable Serial Out : To forcely terminate the connection */
+ iicstat = readl(i2c->regs + S3C2410_IICSTAT);
+ iicstat &= ~S3C2410_IICSTAT_TXRXEN;
+ writel(iicstat, i2c->regs + S3C2410_IICSTAT);
+ }
+ spin_unlock_irq(&i2c->lock);
out:
return ret;