1 files changed, 40 insertions, 21 deletions

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index c56886af724e..275f7c42165c 100644
--- a/drivers/i2c/busses/i2c-s3c2410.c
+++ b/drivers/i2c/busses/i2c-s3c2410.c
@@ -76,6 +76,7 @@
 #define QUIRK_HDMIPHY		(1 << 1)
 #define QUIRK_NO_GPIO		(1 << 2)
 #define QUIRK_POLL		(1 << 3)
+#define QUIRK_ATOMIC		(1 << 4)
 
 /* Max time to wait for bus to become idle after a xfer (in us) */
 #define S3C2410_IDLE_TIMEOUT	5000
@@ -174,7 +175,7 @@ static inline void s3c24xx_i2c_master_complete(struct s3c24xx_i2c *i2c, int ret)
 	if (ret)
 		i2c->msg_idx = ret;
 
-	if (!(i2c->quirks & QUIRK_POLL))
+	if (!(i2c->quirks & (QUIRK_POLL | QUIRK_ATOMIC)))
 		wake_up(&i2c->wait);
 }
 
@@ -216,8 +217,17 @@ static bool is_ack(struct s3c24xx_i2c *i2c)
 	int tries;
 
 	for (tries = 50; tries; --tries) {
-		if (readl(i2c->regs + S3C2410_IICCON)
-			& S3C2410_IICCON_IRQPEND) {
+		unsigned long tmp = readl(i2c->regs + S3C2410_IICCON);
+
+		if (!(tmp & S3C2410_IICCON_ACKEN)) {
+			/*
+			 * Wait a bit for the bus to stabilize,
+			 * delay estimated experimentally.
+			 */
+			usleep_range(100, 200);
+			return true;
+		}
+		if (tmp & S3C2410_IICCON_IRQPEND) {
 			if (!(readl(i2c->regs + S3C2410_IICSTAT)
 				& S3C2410_IICSTAT_LASTBIT))
 				return true;
@@ -270,16 +280,6 @@ static void s3c24xx_i2c_message_start(struct s3c24xx_i2c *i2c,
 
 	stat |= S3C2410_IICSTAT_START;
 	writel(stat, i2c->regs + S3C2410_IICSTAT);
-
-	if (i2c->quirks & QUIRK_POLL) {
-		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)
@@ -685,7 +685,7 @@ static void s3c24xx_i2c_wait_idle(struct s3c24xx_i2c *i2c)
 static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 			      struct i2c_msg *msgs, int num)
 {
-	unsigned long timeout;
+	unsigned long timeout = 0;
 	int ret;
 
 	ret = s3c24xx_i2c_set_master(i2c);
@@ -704,17 +704,20 @@ static int s3c24xx_i2c_doxfer(struct s3c24xx_i2c *i2c,
 	s3c24xx_i2c_enable_irq(i2c);
 	s3c24xx_i2c_message_start(i2c, msgs);
 
-	if (i2c->quirks & QUIRK_POLL) {
-		ret = i2c->msg_idx;
+	if (i2c->quirks & (QUIRK_POLL | QUIRK_ATOMIC)) {
+		while ((i2c->msg_num != 0) && is_ack(i2c)) {
+			unsigned long stat = readl(i2c->regs + S3C2410_IICSTAT);
 
-		if (ret != num)
-			dev_dbg(i2c->dev, "incomplete xfer (%d)\n", ret);
+			i2c_s3c_irq_nextbyte(i2c, stat);
 
-		goto out;
+			stat = readl(i2c->regs + S3C2410_IICSTAT);
+			if (stat & S3C2410_IICSTAT_ARBITR)
+				dev_err(i2c->dev, "deal with arbitration loss\n");
+		}
+	} else {
+		timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
 	}
 
-	timeout = wait_event_timeout(i2c->wait, i2c->msg_num == 0, HZ * 5);
-
 	ret = i2c->msg_idx;
 
 	/*
@@ -773,6 +776,21 @@ static int s3c24xx_i2c_xfer(struct i2c_adapter *adap,
 	return -EREMOTEIO;
 }
 
+static int s3c24xx_i2c_xfer_atomic(struct i2c_adapter *adap,
+				   struct i2c_msg *msgs, int num)
+{
+	struct s3c24xx_i2c *i2c = (struct s3c24xx_i2c *)adap->algo_data;
+	int ret;
+
+	disable_irq(i2c->irq);
+	i2c->quirks |= QUIRK_ATOMIC;
+	ret = s3c24xx_i2c_xfer(adap, msgs, num);
+	i2c->quirks &= ~QUIRK_ATOMIC;
+	enable_irq(i2c->irq);
+
+	return ret;
+}
+
 /* declare our i2c functionality */
 static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 {
@@ -783,6 +801,7 @@ static u32 s3c24xx_i2c_func(struct i2c_adapter *adap)
 /* i2c bus registration info */
 static const struct i2c_algorithm s3c24xx_i2c_algorithm = {
 	.master_xfer		= s3c24xx_i2c_xfer,
+	.master_xfer_atomic     = s3c24xx_i2c_xfer_atomic,
 	.functionality		= s3c24xx_i2c_func,
 };