bq20z75: Add i2c retry mechanism

With the support of platform data, now adding support for option i2c
retries on read/write failures. Ths is specified through the optional
platform data.

Signed-off-by: Rhyland Klein <rklein@nvidia.com>
Signed-off-by: Anton Vorontsov <cbouatmailru@gmail.com>

diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c
index a51e98d..e82d10e 100644 (file)
--- a/drivers/power/bq20z75.c
+++ b/drivers/power/bq20z75.c
@@ -156,30 +156,55 @@ struct bq20z75_info {
 
 static int bq20z75_read_word_data(struct i2c_client *client, u8 address)
 {
-       s32 ret;
+       struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
+       s32 ret = 0;
+       int retries = 1;
+
+       if (bq20z75_device->pdata)
+               retries = max(bq20z75_device->pdata->i2c_retry_count + 1, 1);
+
+       while (retries > 0) {
+               ret = i2c_smbus_read_word_data(client, address);
+               if (ret >= 0)
+                       break;
+               retries--;
+       }
 
-       ret = i2c_smbus_read_word_data(client, address);
        if (ret < 0) {
-               dev_err(&client->dev,
+               dev_warn(&client->dev,
                        "%s: i2c read at address 0x%x failed\n",
                        __func__, address);
                return ret;
        }
+
        return le16_to_cpu(ret);
 }
 
 static int bq20z75_write_word_data(struct i2c_client *client, u8 address,
        u16 value)
 {
-       s32 ret;
+       struct bq20z75_info *bq20z75_device = i2c_get_clientdata(client);
+       s32 ret = 0;
+       int retries = 1;
+
+       if (bq20z75_device->pdata)
+               retries = max(bq20z75_device->pdata->i2c_retry_count + 1, 1);
+
+       while (retries > 0) {
+               ret = i2c_smbus_write_word_data(client, address,
+                       le16_to_cpu(value));
+               if (ret >= 0)
+                       break;
+               retries--;
+       }
 
-       ret = i2c_smbus_write_word_data(client, address, le16_to_cpu(value));
        if (ret < 0) {
-               dev_err(&client->dev,
+               dev_warn(&client->dev,
                        "%s: i2c write to address 0x%x failed\n",
                        __func__, address);
                return ret;
        }
+
        return 0;
 }
 

diff --git a/include/linux/power/bq20z75.h b/include/linux/power/bq20z75.h
index 0e1b8a2..b0843b6 100644 (file)
--- a/include/linux/power/bq20z75.h
+++ b/include/linux/power/bq20z75.h
@@ -28,10 +28,12 @@
  * struct bq20z75_platform_data - platform data for bq20z75 devices
  * @battery_detect:            GPIO which is used to detect battery presence
  * @battery_detect_present:    gpio state when battery is present (0 / 1)
+ * @i2c_retry_count:           # of times to retry on i2c IO failure
  */
 struct bq20z75_platform_data {
        int battery_detect;
        int battery_detect_present;
+       int i2c_retry_count;
 };
 
 #endif