Merge tag 'rtc-4.6-2' of git://git.kernel.org/pub/scm/linux/kernel/git/abelloni/linux

[deliverable/linux.git] / drivers / rtc / rtc-rv8803.c

diff --git a/drivers/rtc/rtc-rv8803.c b/drivers/rtc/rtc-rv8803.c
index 8d9f35ceb8081805c7b932e537cd52fdef41b1da..f623038e586ecf270989a8c0bb0246d2ff279925 100644 (file)
--- a/drivers/rtc/rtc-rv8803.c
+++ b/drivers/rtc/rtc-rv8803.c
@@ -61,11 +61,14 @@ static irqreturn_t rv8803_handle_irq(int irq, void *dev_id)
        struct i2c_client *client = dev_id;
        struct rv8803_data *rv8803 = i2c_get_clientdata(client);
        unsigned long events = 0;
-       int flags;
+       int flags, try = 0;
 
        mutex_lock(&rv8803->flags_lock);
 
-       flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+       do {
+               flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+               try++;
+       } while ((flags == -ENXIO) && (try < 3));
        if (flags <= 0) {
                mutex_unlock(&rv8803->flags_lock);
                return IRQ_NONE;
@@ -424,7 +427,7 @@ static int rv8803_probe(struct i2c_client *client,
 {
        struct i2c_adapter *adapter = to_i2c_adapter(client->dev.parent);
        struct rv8803_data *rv8803;
-       int err, flags;
+       int err, flags, try = 0;
 
        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA |
                                     I2C_FUNC_SMBUS_I2C_BLOCK)) {
@@ -441,7 +444,16 @@ static int rv8803_probe(struct i2c_client *client,
        rv8803->client = client;
        i2c_set_clientdata(client, rv8803);
 
-       flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+       /*
+        * There is a 60µs window where the RTC may not reply on the i2c bus in
+        * that case, the transfer is not ACKed. In that case, ensure there are
+        * multiple attempts.
+        */
+       do {
+               flags = i2c_smbus_read_byte_data(client, RV8803_FLAG);
+               try++;
+       } while ((flags == -ENXIO) && (try < 3));
+
        if (flags < 0)
                return flags;
 
@@ -476,8 +488,12 @@ static int rv8803_probe(struct i2c_client *client,
                return PTR_ERR(rv8803->rtc);
        }
 
-       err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
-                                       RV8803_EXT_WADA);
+       try = 0;
+       do {
+               err = i2c_smbus_write_byte_data(rv8803->client, RV8803_EXT,
+                                               RV8803_EXT_WADA);
+               try++;
+       } while ((err == -ENXIO) && (try < 3));
        if (err)
                return err;