Re: [PATCH v2 1/2] iio: light: vcnl4000: Preserve conf bits when toggle power

[Jonathan Cameron <jic23@kernel.org>]

On Fri, 23 Sep 2022 13:40:30 +0200
Mårten Lindahl <marten.lindahl@axis.com> wrote:

> As the vcnl4040 and vcnl4200 chip uses runtime power management for
> turning the ambient light and proximity sensors on/off, it overwrites
> the entire register each time. In ALS_CONF register bit fields ALS_IT,
> ALS_PERS, ALS_INT_EN are overwritten. In PS_CONF1 register bit fields
> PS_DUTY, PS_PERS, PS_IT, PS_HD, and PS_INT are overwritten.
> 
> Add functions for preserving the affected bit fields when changing power
> state.
> 
> Signed-off-by: Mårten Lindahl <marten.lindahl@axis.com>
See inline.
Otherwise looks good to me.

Jonathan

> ---
>  drivers/iio/light/vcnl4000.c | 54 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 51 insertions(+), 3 deletions(-)
> 
> diff --git a/drivers/iio/light/vcnl4000.c b/drivers/iio/light/vcnl4000.c
> index 3db4e26731bb..b2ecf8af1aa5 100644
> --- a/drivers/iio/light/vcnl4000.c
> +++ b/drivers/iio/light/vcnl4000.c
> @@ -74,6 +74,9 @@
>  #define VCNL4000_PROX_EN	BIT(1) /* start proximity measurement */
>  #define VCNL4000_SELF_TIMED_EN	BIT(0) /* start self-timed measurement */
>  
> +#define VCNL4040_ALS_CONF_ALS_SD	BIT(0) /* Enable ambient light sensor */

Comment seems inverted. Bit being set is 'shut down'  I would expand the
name to
VCNL4040_ALS_CONF_ALS_SHUTDOWN 
then drop the comment as the name is self explanatory

> +#define VCNL4040_PS_CONF1_PS_SD	BIT(0) /* Enable proximity sensor */
> +
>  /* Bit masks for interrupt registers. */
>  #define VCNL4010_INT_THR_SEL	BIT(0) /* Select threshold interrupt source */
>  #define VCNL4010_INT_THR_EN	BIT(1) /* Threshold interrupt type */
> @@ -188,16 +191,61 @@ static int vcnl4000_init(struct vcnl4000_data *data)
>  	return data->chip_spec->set_power_state(data, true);
>  };
>  
> +static ssize_t vcnl4000_write_als_enable(struct vcnl4000_data *data, bool en)
> +{
> +	int ret;
> +
> +	mutex_lock(&data->vcnl4000_lock);
> +
> +	ret = i2c_smbus_read_word_data(data->client, VCNL4200_AL_CONF);
> +	if (ret < 0)
> +		goto out;
> +
> +	if (en)
> +		ret &= ~VCNL4040_ALS_CONF_ALS_SD;
> +	else
> +		ret |= VCNL4040_ALS_CONF_ALS_SD;
> +
> +	ret = i2c_smbus_write_word_data(data->client, VCNL4200_AL_CONF, ret);
> +
> +out:
> +	mutex_unlock(&data->vcnl4000_lock);
> +
> +	return ret;
> +}
> +
> +static ssize_t vcnl4000_write_ps_enable(struct vcnl4000_data *data, bool en)
> +{
> +	int ret;
> +
> +	mutex_lock(&data->vcnl4000_lock);
> +
> +	ret = i2c_smbus_read_word_data(data->client, VCNL4200_PS_CONF1);
> +	if (ret < 0)
> +		goto out;
> +
> +	if (en)
> +		ret &= ~VCNL4040_PS_CONF1_PS_SD;
> +	else
> +		ret |= VCNL4040_PS_CONF1_PS_SD;
> +
> +	ret = i2c_smbus_write_word_data(data->client, VCNL4200_PS_CONF1, ret);
> +
> +out:
> +	mutex_unlock(&data->vcnl4000_lock);
> +
> +	return ret;
> +}
> +
>  static int vcnl4200_set_power_state(struct vcnl4000_data *data, bool on)
>  {
> -	u16 val = on ? 0 /* power on */ : 1 /* shut down */;
>  	int ret;
>  
> -	ret = i2c_smbus_write_word_data(data->client, VCNL4200_AL_CONF, val);
> +	ret = vcnl4000_write_als_enable(data, on);
>  	if (ret < 0)
>  		return ret;
>  
> -	ret = i2c_smbus_write_word_data(data->client, VCNL4200_PS_CONF1, val);
> +	ret = vcnl4000_write_ps_enable(data, on);
>  	if (ret < 0)
>  		return ret;
>