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Commit c06cee8d authored by Kuppuswamy Sathyanarayanan's avatar Kuppuswamy Sathyanarayanan Committed by Jonathan Cameron
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iio: ltr501: Add light channel support 



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: default avatarKuppuswamy Sathyanarayanan <sathyanarayanan.kuppuswamy@linux.intel.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent c24e7daf

drivers/iio/light/ltr501.c

+51 −0
Original line number Diff line number Diff line
@@ -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;