Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030288AbbEOB0t (ORCPT ); Thu, 14 May 2015 21:26:49 -0400 Received: from mga01.intel.com ([192.55.52.88]:44166 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030214AbbEOB0q (ORCPT ); Thu, 14 May 2015 21:26:46 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.13,431,1427785200"; d="scan'208";a="729485594" From: Kuppuswamy Sathyanarayanan To: jic23@kernel.org, pmeerw@pmeerw.net Cc: linux-iio@vger.kernel.org, srinivas.pandruvada@linux.intel.com, sathyanarayanan.kuppuswamy@linux.intel.com, linux-kernel@vger.kernel.org Subject: [PATCH v2 1/1] iio: ltr501: Add light channel support Date: Thu, 14 May 2015 18:26:07 -0700 Message-Id: <4c8850e4528f19267255ef6b6940b6a6ae6b470c.1431652926.git.sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 1.9.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3502 Lines: 115 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 --- drivers/iio/light/ltr501.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 57 insertions(+) diff --git a/drivers/iio/light/ltr501.c b/drivers/iio/light/ltr501.c index ca4bf47..449b0fd 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 +574,20 @@ 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, \ + .scan_type = { \ + .sign = 'u', \ + .realbits = 16, \ + .storagebits = 16, \ + .endianness = IIO_CPU, \ + }, \ +} + 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 +615,7 @@ 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 +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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/