Re: [PATCH 2/2] iio: light: ltrf216a: Add LTR-308 support

[Jonathan Cameron <jic23@kernel.org>]

On Fri,  5 Jul 2024 11:11:45 +0200
Marek Vasut <marex@denx.de> wrote:

> Add LiteOn LTR-308 support into LTR-F216A kernel driver.
> 
> The two devices seem to have almost identical register map, except that
> the LTR-308 does not have three CLEAR_DATA registers, which are unused
> by this driver. Furthermore, LTR-308 and LTR-F216A use different lux
> calculation constants, 0.6 and 0.45 respectively. Both differences are
> handled using chip info data.
> 
> https://optoelectronics.liteon.com/upload/download/DS86-2016-0027/LTR-308ALS_Final_%20DS_V1%201.pdf
> https://optoelectronics.liteon.com/upload/download/DS86-2019-0016/LTR-F216A_Final_DS_V1.4.PDF
> 
> Signed-off-by: Marek Vasut <marex@denx.de>
One additional question inline...

> ---
>  drivers/iio/light/ltrf216a.c | 49 ++++++++++++++++++++++++++++--------
>  1 file changed, 39 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iio/light/ltrf216a.c b/drivers/iio/light/ltrf216a.c
> index 68dc48420a886..375312db4ef58 100644
> --- a/drivers/iio/light/ltrf216a.c
> +++ b/drivers/iio/light/ltrf216a.c
> @@ -68,6 +68,13 @@ static const int ltrf216a_int_time_reg[][2] = {
>  	{  25, 0x40 },
> @@ -382,15 +394,19 @@ static bool ltrf216a_writable_reg(struct device *dev, unsigned int reg)
>  
>  static bool ltrf216a_volatile_reg(struct device *dev, unsigned int reg)
>  {
> +	struct iio_dev *indio_dev = i2c_get_clientdata(to_i2c_client(dev));
> +	struct ltrf216a_data *data = iio_priv(indio_dev);
> +
>  	switch (reg) {
>  	case LTRF216A_MAIN_STATUS:
> -	case LTRF216A_ALS_CLEAR_DATA_0:
> -	case LTRF216A_ALS_CLEAR_DATA_1:
> -	case LTRF216A_ALS_CLEAR_DATA_2:
>  	case LTRF216A_ALS_DATA_0:
>  	case LTRF216A_ALS_DATA_1:
>  	case LTRF216A_ALS_DATA_2:
>  		return true;
> +	case LTRF216A_ALS_CLEAR_DATA_0:
> +	case LTRF216A_ALS_CLEAR_DATA_1:
> +	case LTRF216A_ALS_CLEAR_DATA_2:

Is there any point in this covering registers we have already stated above are
not readable?  I guess we could argue that having this change is acting
as a form of documentation.  Maybe just adding a comment that they
don't exist would be clearer?


> +		return data->info->has_clear_data;
>  	default:
>  		return false;
>  	}
;