i2c-pca: Fix waitforcompletion() return value

ret is still -1, if during the polling read_byte() returns at once
with I2C_PCA_CON_SI set. So ret > 0 would lead *_waitforcompletion()
to return 0, in spite of the proper behavior.

The routine was rewritten, so that ret has always a proper value,
before returning.

Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>
Reviewed-by: Wolfram Sang <w.sang@pengutronix.de>
Cc: stable@kernel.org
Signed-off-by: Jean Delvare <khali@linux-fr.org>

2 files changed, 15 insertions, 8 deletions

diff --git a/drivers/i2c/busses/i2c-pca-isa.c b/drivers/i2c/busses/i2c-pca-isa.c
index bbd77603a417..29933f87d8fa 100644
--- a/drivers/i2c/busses/i2c-pca-isa.c
+++ b/drivers/i2c/busses/i2c-pca-isa.c
@@ -71,8 +71,8 @@ static int pca_isa_readbyte(void *pd, int reg)
 
 static int pca_isa_waitforcompletion(void *pd)
 {
-        long ret = ~0;
         unsigned long timeout;
+        long ret;
 
         if (irq > -1) {
                 ret = wait_event_timeout(pca_wait,
@@ -81,11 +81,15 @@ static int pca_isa_waitforcompletion(void *pd)
         } else {
                 /* Do polling */
                 timeout = jiffies + pca_isa_ops.timeout;
-                while (((pca_isa_readbyte(pd, I2C_PCA_CON)
-                                & I2C_PCA_CON_SI) == 0)
-                                && (ret = time_before(jiffies, timeout)))
+                do {
+                        ret = time_before(jiffies, timeout);
+                        if (pca_isa_readbyte(pd, I2C_PCA_CON)
+                                        & I2C_PCA_CON_SI)
+                                break;
                         udelay(100);
+                } while (ret);
         }
+
         return ret > 0;
 }
 
diff --git a/drivers/i2c/busses/i2c-pca-platform.c b/drivers/i2c/busses/i2c-pca-platform.c
index ef5c78487eb7..5f6d7f89e225 100644
--- a/drivers/i2c/busses/i2c-pca-platform.c
+++ b/drivers/i2c/busses/i2c-pca-platform.c
@@ -80,8 +80,8 @@ static void i2c_pca_pf_writebyte32(void *pd, int reg, int val)
 static int i2c_pca_pf_waitforcompletion(void *pd)
 {
         struct i2c_pca_pf_data *i2c = pd;
-        long ret = ~0;
         unsigned long timeout;
+        long ret;
 
         if (i2c->irq) {
                 ret = wait_event_timeout(i2c->wait,
@@ -90,10 +90,13 @@ static int i2c_pca_pf_waitforcompletion(void *pd)
         } else {
                 /* Do polling */
                 timeout = jiffies + i2c->adap.timeout;
-                while (((i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
-                                & I2C_PCA_CON_SI) == 0)
-                                && (ret = time_before(jiffies, timeout)))
+                do {
+                        ret = time_before(jiffies, timeout);
+                        if (i2c->algo_data.read_byte(i2c, I2C_PCA_CON)
+                                        & I2C_PCA_CON_SI)
+                                break;
                         udelay(100);
+                } while (ret);
         }
 
         return ret > 0;