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Date: Tue, 5 May 2015 16:12:09 +0300
From: Daniel Baluta <daniel.baluta@...il.com>
To: Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com>
Cc: Jonathan Cameron <jic23@...nel.org>,
Peter Meerwald <pmeerw@...erw.net>,
"linux-iio@...r.kernel.org" <linux-iio@...r.kernel.org>,
Srinivas Pandruvada <srinivas.pandruvada@...ux.intel.com>,
Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH v1 1/1] iio: ltr501: Add light channel support
On Sat, May 2, 2015 at 1:39 AM, Kuppuswamy Sathyanarayanan
<sathyanarayanan.kuppuswamy@...ux.intel.com> 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@...ux.intel.com>
Reviewed-by: Daniel Baluta <daniel.baluta@...el.com>
> ---
> 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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