i2c: s3c24xx: add support for atomic transfers

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

------------[ cut here ]------------
WARNING: CPU: 0 PID: 1518 at drivers/i2c/i2c-core.h:40 i2c_transfer+0xe8/0xf4
No atomic I2C transfer handler for 'i2c-0'
...
---[ end trace 0000000000000000 ]---

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: Chanho Park <chanho61.park@samsung.com>
Reviewed-by: Andi Shyti <andi.shyti@kernel.org>
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-s3c2410.c b/drivers/i2c/busses/i2c-s3c2410.c
index c0fe96a4f2c4fae48d3bdb85877ea2a926829375..275f7c42165cde7881bad16433c9150f653af91f 100644 (file)
--- 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);
 }
 
@@ -703,7 +704,7 @@ 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);
 
@@ -775,6 +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)
 {
@@ -785,6 +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,
 };