From ff28fcef1bedcfbdf49500fee1573dc2f3eedb22 Mon Sep 17 00:00:00 2001 From: Rhyland Klein Date: Mon, 28 Feb 2011 16:55:29 -0800 Subject: [PATCH] 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 Signed-off-by: Anton Vorontsov --- drivers/power/bq20z75.c | 37 +++++++++++++++++++++++++++++++------ include/linux/power/bq20z75.h | 2 ++ 2 files changed, 33 insertions(+), 6 deletions(-) diff --git a/drivers/power/bq20z75.c b/drivers/power/bq20z75.c index a51e98d..e82d10e 100644 --- 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 --- 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 -- 2.7.4