[PATCH v2 3/3] i2c: s3c24xx: add support for atomic transfers

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Add support for atomic transfers using polling mode with interrupts
intentionally disabled to get rid of the warning introduced by commit
63b96983a5dd ("i2c: core: introduce callbacks for atomic transfers")
during system reboot and power-off.

Signed-off-by: Marek Szyprowski <m.szyprowski@xxxxxxxxxxx>
---
 drivers/i2c/busses/i2c-s3c2410.c | 21 +++++++++++++++++++--
 1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index 8da85cb42980..586b82b30bdf 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);
 }
 
@@ -700,7 +701,7 @@ 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) {
+	if (i2c->quirks & (QUIRK_POLL | QUIRK_ATOMIC)) {
 		while ((i2c->msg_num != 0) && is_ack(i2c)) {
 			unsigned long stat = readl(i2c->regs + S3C2410_IICSTAT);
 
@@ -774,6 +775,21 @@ 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)
 {
@@ -784,6 +800,7 @@ 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,
 };
 
-- 
2.34.1




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