On 16/05/15 02:23, Kuppuswamy Sathyanarayanan 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>
Applied to the togreg branch of iio.git - initially pushed out as testing for
the autobuilders to play with it.
Jonathan
> ---
> drivers/iio/light/ltr501.c | 51 ++++++++++++++++++++++++++++++++++++++++++++++
> 1 file changed, 51 insertions(+)
>
> v2: Changed scan index of light channel to -1
> v3: Removed scan type info from light channel
>
> diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c
> index ca4bf47..d7245c6 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;
> @@ -548,7 +574,14 @@ static const struct iio_event_spec ltr501_pxs_event_spec[] = {
> .num_event_specs = _evsize,\
> }
>
> +#define LTR501_LIGHT_CHANNEL() { \
> + .type = IIO_LIGHT, \
> + .info_mask_separate = BIT(IIO_CHAN_INFO_PROCESSED), \
> + .scan_index = -1, \
> +}
> +
> static const struct iio_chan_spec ltr501_channels[] = {
> + LTR501_LIGHT_CHANNEL(),
> LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
> ltr501_als_event_spec,
> ARRAY_SIZE(ltr501_als_event_spec)),
> @@ -576,6 +609,7 @@ static const struct iio_chan_spec ltr501_channels[] = {
> };
>
> static const struct iio_chan_spec ltr301_channels[] = {
> + LTR501_LIGHT_CHANNEL(),
> LTR501_INTENSITY_CHANNEL(0, LTR501_ALS_DATA0, IIO_MOD_LIGHT_BOTH, 0,
> ltr501_als_event_spec,
> ARRAY_SIZE(ltr501_als_event_spec)),
> @@ -596,6 +630,23 @@ 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;
>
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