i2c: sprd: use a specific timeout to avoid system hang up issue

If the i2c device SCL bus being pulled up due to some exception before
message transfer done, the system cannot receive the completing interrupt
signal any more, it would not exit waiting loop until MAX_SCHEDULE_TIMEOUT
jiffies eclipse, that would make the system seemed hang up. To avoid that
happen, this patch adds a specific timeout for message transfer.

Fixes: 8b9ec0719834 ("i2c: Add Spreadtrum I2C controller driver")
Signed-off-by: Linhua Xu <linhua.xu@unisoc.com>
Signed-off-by: Chunyan Zhang <chunyan.zhang@unisoc.com>
[wsa: changed errno to ETIMEDOUT]
Signed-off-by: Wolfram Sang <wsa@kernel.org>

diff --git a/drivers/i2c/busses/i2c-sprd.c b/drivers/i2c/busses/i2c-sprd.c
index 19cda6742423d98ab3d53a897d1897ac6e93eae4..2917fecf6c80d08b118cd0c1ec70da3e0483ecd1 100644 (file)
--- a/drivers/i2c/busses/i2c-sprd.c
+++ b/drivers/i2c/busses/i2c-sprd.c
@@ -72,6 +72,8 @@
 
 /* timeout (ms) for pm runtime autosuspend */
 #define SPRD_I2C_PM_TIMEOUT    1000
+/* timeout (ms) for transfer message */
+#define I2C_XFER_TIMEOUT       1000
 
 /* SPRD i2c data structure */
 struct sprd_i2c {
@@ -244,6 +246,7 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
                               struct i2c_msg *msg, bool is_last_msg)
 {
        struct sprd_i2c *i2c_dev = i2c_adap->algo_data;
+       unsigned long time_left;
 
        i2c_dev->msg = msg;
        i2c_dev->buf = msg->buf;
@@ -273,7 +276,10 @@ static int sprd_i2c_handle_msg(struct i2c_adapter *i2c_adap,
 
        sprd_i2c_opt_start(i2c_dev);
 
-       wait_for_completion(&i2c_dev->complete);
+       time_left = wait_for_completion_timeout(&i2c_dev->complete,
+                               msecs_to_jiffies(I2C_XFER_TIMEOUT));
+       if (!time_left)
+               return -ETIMEDOUT;
 
        return i2c_dev->err;
 }