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SubjectRe: [PATCH 1/2] hwmon: adt7411: set sane values for CFG1 and CFG3
On Fri, Jul 22, 2016 at 06:10:54PM +0200, Michael Walle wrote:
> According to the datasheet we have to set some bits as 0 and others as 1.
> Make sure we do this for CFG1 and CFG3.
>
> Signed-off-by: Michael Walle <michael@walle.cc>
> ---
> drivers/hwmon/adt7411.c | 53 +++++++++++++++++++++++++++++++++++++++++++++----
> 1 file changed, 49 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/hwmon/adt7411.c b/drivers/hwmon/adt7411.c
> index a7f8869..410405b 100644
> --- a/drivers/hwmon/adt7411.c
> +++ b/drivers/hwmon/adt7411.c
> @@ -30,6 +30,7 @@
>
> #define ADT7411_REG_CFG1 0x18
> #define ADT7411_CFG1_START_MONITOR (1 << 0)
> +#define ADT7411_CFG1_RESERVED_BIT1 (1 << 1)
> #define ADT7411_CFG1_RESERVED_BIT3 (1 << 3)
>
> #define ADT7411_REG_CFG2 0x19
> @@ -37,6 +38,9 @@
>
> #define ADT7411_REG_CFG3 0x1a
> #define ADT7411_CFG3_ADC_CLK_225 (1 << 0)
> +#define ADT7411_CFG3_RESERVED_BIT1 (1 << 1)
> +#define ADT7411_CFG3_RESERVED_BIT2 (1 << 2)
> +#define ADT7411_CFG3_RESERVED_BIT3 (1 << 3)
> #define ADT7411_CFG3_REF_VDD (1 << 4)
>
> #define ADT7411_REG_DEVICE_ID 0x4d
> @@ -280,6 +284,50 @@ static int adt7411_detect(struct i2c_client *client,
> return 0;
> }
>
> +static int adt7411_init_device(struct adt7411_data *data)
> +{
> + int ret;
> + u8 val;
> +
> + mutex_lock(&data->device_lock);
> +
This is only called from the probe function. Locking is therefore not
necessary.

Thanks,
Guenter

> + ret = i2c_smbus_read_byte_data(data->client, ADT7411_REG_CFG3);
> + if (ret < 0)
> + goto exit_unlock;
> +
> + /*
> + * We must only write zero to bit 1 and bit 2 and only one to bit 3
> + * according to the datasheet.
> + */
> + val = ret;
> + val &= ~(ADT7411_CFG3_RESERVED_BIT1 | ADT7411_CFG3_RESERVED_BIT2);
> + val |= ADT7411_CFG3_RESERVED_BIT3;
> +
> + ret = i2c_smbus_write_byte_data(data->client, ADT7411_REG_CFG3, val);
> + if (ret < 0)
> + goto exit_unlock;
> +
> + ret = i2c_smbus_read_byte_data(data->client, ADT7411_REG_CFG1);
> + if (ret < 0)
> + goto exit_unlock;
> +
> + /*
> + * We must only write zero to bit 1 and only one to bit 3 according to
> + * the datasheet.
> + */
> + val = ret;
> + val &= ~ADT7411_CFG1_RESERVED_BIT1;
> + val |= ADT7411_CFG1_RESERVED_BIT3;
> +
> + /* enable monitoring */
> + val |= ADT7411_CFG1_START_MONITOR;
> +
> + ret = i2c_smbus_write_byte_data(data->client, ADT7411_REG_CFG1, val);
> + exit_unlock:
> + mutex_unlock(&data->device_lock);
> + return ret;
> +}
> +
> static int adt7411_probe(struct i2c_client *client,
> const struct i2c_device_id *id)
> {
> @@ -297,10 +345,7 @@ static int adt7411_probe(struct i2c_client *client,
> mutex_init(&data->device_lock);
> mutex_init(&data->update_lock);
>
> - /* According to the datasheet, we must only write 1 to bit 3 */
> - ret = adt7411_modify_bit(client, ADT7411_REG_CFG1,
> - ADT7411_CFG1_RESERVED_BIT3
> - | ADT7411_CFG1_START_MONITOR, 1);
> + ret = adt7411_init_device(data);
> if (ret < 0)
> return ret;
>
> --
> 2.1.4
>
> --
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