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

[Marten Lindahl <martenli@axis.com>]

On Sat, Sep 24, 2022 at 06:37:24PM +0200, Jonathan Cameron wrote:
> 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 */
>

Hi Jonathan!

> 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

Ok, I'll do so. Thanks!

Kind regards
Mårten

> 
> > +#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;
> >  
>