Re: [PATCH 2/2] iio: potentiometer: tpl0102: add IIO_AVAIL_RANGE support

[Jonathan Cameron <jic23@kernel.org>]

On Wed, 24 Oct 2018 11:38:58 +0100
Matt Ranostay <matt.ranostay@konsulko.com> wrote:

> Report back the step range of the respective potentiometers that are
> possible back to userspace.
> 
> Signed-off-by: Matt Ranostay <matt.ranostay@konsulko.com>
Hi Matt,

Hmm. I had to actually look at the code to remember how we register
the available stuff.  The early plan was to just do it for all provided
info_mask elements but in the end we decided that was too much to
require and went with individual masks.

So to actually have these appear to userspace I think you need an
entry in 
info_mask_separate_available which is missing here.

Jonathan

> ---
>  drivers/iio/potentiometer/tpl0102.c | 33 +++++++++++++++++++++++------
>  1 file changed, 26 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/iio/potentiometer/tpl0102.c b/drivers/iio/potentiometer/tpl0102.c
> index 8e8adabe672b..d5aedf358fc2 100644
> --- a/drivers/iio/potentiometer/tpl0102.c
> +++ b/drivers/iio/potentiometer/tpl0102.c
> @@ -15,7 +15,7 @@
>  
>  struct tpl0102_cfg {
>  	int wipers;
> -	int max_pos;
> +	int avail[3];
>  	int kohms;
>  };
>  
> @@ -28,11 +28,11 @@ enum tpl0102_type {
>  
>  static const struct tpl0102_cfg tpl0102_cfg[] = {
>  	/* on-semiconductor parts */
> -	[CAT5140_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, },
> -	[CAT5140_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, },
> +	[CAT5140_503] = { .wipers = 1, .avail = { 0, 1, 255 }, .kohms = 50, },
> +	[CAT5140_104] = { .wipers = 1, .avail = { 0, 1, 255 }, .kohms = 100, },
>  	/* ti parts */
> -	[TPL0102_104] = { .wipers = 2, .max_pos = 256, .kohms = 100 },
> -	[TPL0401_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, },
> +	[TPL0102_104] = { .wipers = 2, .avail = { 0, 1, 255 }, .kohms = 100 },
> +	[TPL0401_103] = { .wipers = 1, .avail = { 0, 1, 127 }, .kohms = 10, },
>  };
>  
>  struct tpl0102_data {
> @@ -73,13 +73,31 @@ static int tpl0102_read_raw(struct iio_dev *indio_dev,
>  	}
>  	case IIO_CHAN_INFO_SCALE:
>  		*val = 1000 * data->cfg->kohms;
> -		*val2 = data->cfg->max_pos;
> +		*val2 = data->cfg->avail[2] + 1;
>  		return IIO_VAL_FRACTIONAL;
>  	}
>  
>  	return -EINVAL;
>  }
>  
> +static int tpl0102_read_avail(struct iio_dev *indio_dev,
> +			      struct iio_chan_spec const *chan,
> +			      const int **vals, int *type, int *length,
> +			      long mask)
> +{
> +	struct tpl0102_data *data = iio_priv(indio_dev);
> +
> +	switch (mask) {
> +	case IIO_CHAN_INFO_RAW:
> +		*length = ARRAY_SIZE(data->cfg->avail);
> +		*vals = data->cfg->avail;
> +		*type = IIO_VAL_INT;
> +		return IIO_AVAIL_RANGE;
> +	}
> +
> +	return -EINVAL;
> +}
> +
>  static int tpl0102_write_raw(struct iio_dev *indio_dev,
>  			     struct iio_chan_spec const *chan,
>  			     int val, int val2, long mask)
> @@ -89,7 +107,7 @@ static int tpl0102_write_raw(struct iio_dev *indio_dev,
>  	if (mask != IIO_CHAN_INFO_RAW)
>  		return -EINVAL;
>  
> -	if (val >= data->cfg->max_pos || val < 0)
> +	if (val > data->cfg->avail[2] || val < 0)
>  		return -EINVAL;
>  
>  	return regmap_write(data->regmap, chan->channel, val);
> @@ -97,6 +115,7 @@ static int tpl0102_write_raw(struct iio_dev *indio_dev,
>  
>  static const struct iio_info tpl0102_info = {
>  	.read_raw = tpl0102_read_raw,
> +	.read_avail = tpl0102_read_avail,
>  	.write_raw = tpl0102_write_raw,
>  };
>