Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754417AbbEOIC6 (ORCPT ); Fri, 15 May 2015 04:02:58 -0400 Received: from ns.pmeerw.net ([84.19.176.92]:50988 "EHLO pmeerw.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753229AbbEOICy (ORCPT ); Fri, 15 May 2015 04:02:54 -0400 Date: Fri, 15 May 2015 10:02:52 +0200 (CEST) From: Peter Meerwald To: Kuppuswamy Sathyanarayanan cc: jic23@kernel.org, linux-iio@vger.kernel.org, srinivas.pandruvada@linux.intel.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH v2 1/1] iio: ltr501: Add light channel support In-Reply-To: <4c8850e4528f19267255ef6b6940b6a6ae6b470c.1431652926.git.sathyanarayanan.kuppuswamy@linux.intel.com> Message-ID: References: <4c8850e4528f19267255ef6b6940b6a6ae6b470c.1431652926.git.sathyanarayanan.kuppuswamy@linux.intel.com> User-Agent: Alpine 2.02 (DEB 1266 2009-07-14) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3906 Lines: 127 > 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. minor comment below > 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, \ I think there is no need for .scan_type if scan_index == -1 bad examples include: adc/ad7298.c and pressure/st_pressure_core.c > + .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; > -- Peter Meerwald +43-664-2444418 (mobile) -- 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/