Re: [PATCH v1 1/1] iio: ltr501: Add light channel support

[Daniel Baluta]

On Sat, May 2, 2015 at 1:39 AM, Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx> wrote:
> Added support to calculate lux value from visible
> and IR spectrum adc count values. Also added IIO_LIGHT
> channel to enable user read the lux value directly
> from device using illuminance input ABI.
>
> Signed-off-by: Kuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@xxxxxxxxxxxxxxx>

Reviewed-by: Daniel Baluta <daniel.baluta@xxxxxxxxx>

> ---
>  drivers/iio/light/ltr501.c | 71 +++++++++++++++++++++++++++++++++++++++++-----
>  1 file changed, 64 insertions(+), 7 deletions(-)
>
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index ca4bf47..242cf20 100644
> --- a/drivers/iio/light/ltr501.c
> +++ b/drivers/iio/light/ltr501.c
> @@ -66,6 +66,9 @@
>
>  #define LTR501_REGMAP_NAME "ltr501_regmap"
>
> +#define LTR501_LUX_CONV(vis_coeff, vis_data, ir_coeff, ir_data) \
> +                       ((vis_coeff * vis_data) - (ir_coeff * ir_data))
> +
>  static const int int_time_mapping[] = {100000, 50000, 200000, 400000};
>
>  static const struct reg_field reg_field_it =
> @@ -298,6 +301,29 @@ static int ltr501_ps_read_samp_period(struct ltr501_data *data, int *val)
>         return IIO_VAL_INT;
>  }
>
> +/* IR and visible spectrum coeff's are given in data sheet */
> +static unsigned long ltr501_calculate_lux(u16 vis_data, u16 ir_data)
> +{
> +       unsigned long ratio, lux;
> +
> +       if (vis_data == 0)
> +               return 0;
> +
> +       /* multiply numerator by 100 to avoid handling ratio < 1 */
> +       ratio = DIV_ROUND_UP(ir_data * 100, ir_data + vis_data);
> +
> +       if (ratio < 45)
> +               lux = LTR501_LUX_CONV(1774, vis_data, -1105, ir_data);
> +       else if (ratio >= 45 && ratio < 64)
> +               lux = LTR501_LUX_CONV(3772, vis_data, 1336, ir_data);
> +       else if (ratio >= 64 && ratio < 85)
> +               lux = LTR501_LUX_CONV(1690, vis_data, 169, ir_data);
> +       else
> +               lux = 0;
> +
> +       return lux / 1000;
> +}
> +
>  static int ltr501_drdy(struct ltr501_data *data, u8 drdy_mask)
>  {
>         int tries = 100;
> @@ -548,11 +574,24 @@ static const struct iio_event_spec ltr501_pxs_event_spec[] = {
>         .num_event_specs = _evsize,\
>  }
>
> +#define LTR501_LIGHT_CHANNEL(_idx) { \
> +       .type = IIO_LIGHT, \
> +       .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> +       .scan_index = 0, \
> +       .scan_type = { \
> +               .sign = 'u', \
> +               .realbits = 16, \
> +               .storagebits = 16, \
> +               .endianness = IIO_CPU, \
> +       }, \
> +}
> +
>  static const struct iio_chan_spec ltr501_channels[] = {
> -       LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
> +       LTR501_LIGHT_CHANNEL(0),
> +       LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
>                                  ltr501_als_event_spec,
>                                  ARRAY_SIZE(ltr501_als_event_spec)),
> -       LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
> +       LTR501_INTENSITY_CHANNEL(2, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
>                                  BIT(IIO_CHAN_INFO_SCALE) |
>                                  BIT(IIO_CHAN_INFO_INT_TIME) |
>                                  BIT(IIO_CHAN_INFO_SAMP_FREQ),
> @@ -562,7 +601,7 @@ static const struct iio_chan_spec ltr501_channels[] = {
>                 .address = LTR501_PS_DATA,
>                 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
>                         BIT(IIO_CHAN_INFO_SCALE),
> -               .scan_index = 2,
> +               .scan_index = 3,
>                 .scan_type = {
>                         .sign = 'u',
>                         .realbits = 11,
> @@ -572,19 +611,20 @@ static const struct iio_chan_spec ltr501_channels[] = {
>                 .event_spec = ltr501_pxs_event_spec,
>                 .num_event_specs = ARRAY_SIZE(ltr501_pxs_event_spec),
>         },
> -       IIO_CHAN_SOFT_TIMESTAMP(3),
> +       IIO_CHAN_SOFT_TIMESTAMP(4),
>  };
>
>  static const struct iio_chan_spec ltr301_channels[] = {
> -       LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
> +       LTR501_LIGHT_CHANNEL(0),
> +       LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
>                                  ltr501_als_event_spec,
>                                  ARRAY_SIZE(ltr501_als_event_spec)),
> -       LTR501_INTENSITY_CHANNEL(1, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
> +       LTR501_INTENSITY_CHANNEL(2, LTR501_ALS_DATA1, IIO_MOD_LIGHT_IR,
>                                  BIT(IIO_CHAN_INFO_SCALE) |
>                                  BIT(IIO_CHAN_INFO_INT_TIME) |
>                                  BIT(IIO_CHAN_INFO_SAMP_FREQ),
>                                  NULL, 0),
> -       IIO_CHAN_SOFT_TIMESTAMP(2),
> +       IIO_CHAN_SOFT_TIMESTAMP(3),
>  };
>
>  static int ltr501_read_raw(struct iio_dev *indio_dev,
> @@ -596,6 +636,23 @@ static int ltr501_read_raw(struct iio_dev *indio_dev,
>         int ret, i;
>
>         switch (mask) {
> +       case IIO_CHAN_INFO_PROCESSED:
> +               if (iio_buffer_enabled(indio_dev))
> +                       return -EBUSY;
> +
> +               switch (chan->type) {
> +               case IIO_LIGHT:
> +                       mutex_lock(&data->lock_als);
> +                       ret = ltr501_read_als(data, buf);
> +                       mutex_unlock(&data->lock_als);
> +                       if (ret < 0)
> +                               return ret;
> +                       *val = ltr501_calculate_lux(le16_to_cpu(buf[1]),
> +                                                   le16_to_cpu(buf[0]));
> +                       return IIO_VAL_INT;
> +               default:
> +                       return -EINVAL;
> +               }
>         case IIO_CHAN_INFO_RAW:
>                 if (iio_buffer_enabled(indio_dev))
>                         return -EBUSY;
> --
> 1.9.1
>
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