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Date: Thu, 07 May 2015 17:21:40 -0700
From: sathyanarayanan kuppuswamy
<sathyanarayanan.kuppuswamy@...ux.intel.com>
To: Jonathan Cameron <jic23@...nel.org>, pmeerw@...erw.net
CC: linux-iio@...r.kernel.org, srinivas.pandruvada@...ux.intel.com,
linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 1/1] iio: ltr501: Add light channel support
Hi Jonathan,
On 05/07/2015 03:44 PM, Jonathan Cameron wrote:
> On 01/05/15 23:39, 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@...ux.intel.com>
> something odd going on here.
> you have changed the scan_index values, but not modified the trigger
> handler to deal with the change. Note these only have relevant in
> buffered mode. If you want this to only be exposed via sysfs, that
> is fine (and perhaps reasonable) then set the scan_index to -1 (iirc)
> and leave the other channels alone.
Thanks for the review. Yes, I agree that scan_index change is not
required for this feature. I intended to just add the raw read support
for this channel.
>
> Jonathan
>> ---
>> 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;
>>
> --
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>
--
Sathyanarayanan Kuppuswamy
Android kernel developer
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