From ba71704af4a0aae0d9e5812dbdd7bca95e181b14 Mon Sep 17 00:00:00 2001 From: Rama Krishna Phani A Date: Fri, 9 Dec 2016 20:31:49 +0530 Subject: iio: adc: spmi-vadc: Update function for generic voltage conversion Several channels are supported in ADC of PMIC which can be used to measure voltage, temperature, current etc., Hardware provides readings for all channels in adc code. That adc code needs to be converted to voltage. Logic for conversion of adc code to voltage is common for all ADC channels(voltage, temperature, current .,etc). Implement separate function for generic conversion logic. Signed-off-by: Rama Krishna Phani A Signed-off-by: Jonathan Cameron --- drivers/iio/adc/qcom-spmi-vadc.c | 52 +++++++++++++++++++++------------------- 1 file changed, 28 insertions(+), 24 deletions(-) (limited to 'drivers/iio') diff --git a/drivers/iio/adc/qcom-spmi-vadc.c b/drivers/iio/adc/qcom-spmi-vadc.c index c2babe50a0d8..93c0639e21a3 100644 --- a/drivers/iio/adc/qcom-spmi-vadc.c +++ b/drivers/iio/adc/qcom-spmi-vadc.c @@ -1,5 +1,5 @@ /* - * Copyright (c) 2012-2014, The Linux Foundation. All rights reserved. + * Copyright (c) 2012-2016, The Linux Foundation. All rights reserved. * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License version 2 and @@ -468,27 +468,38 @@ err: return ret; } -static s32 vadc_calibrate(struct vadc_priv *vadc, - const struct vadc_channel_prop *prop, u16 adc_code) +static void vadc_scale_calib(struct vadc_priv *vadc, u16 adc_code, + const struct vadc_channel_prop *prop, + s64 *scale_voltage) { - const struct vadc_prescale_ratio *prescale; - s64 voltage; + *scale_voltage = (adc_code - + vadc->graph[prop->calibration].gnd); + *scale_voltage *= vadc->graph[prop->calibration].dx; + *scale_voltage = div64_s64(*scale_voltage, + vadc->graph[prop->calibration].dy); + if (prop->calibration == VADC_CALIB_ABSOLUTE) + *scale_voltage += + vadc->graph[prop->calibration].dx; - voltage = adc_code - vadc->graph[prop->calibration].gnd; - voltage *= vadc->graph[prop->calibration].dx; - voltage = div64_s64(voltage, vadc->graph[prop->calibration].dy); + if (*scale_voltage < 0) + *scale_voltage = 0; +} - if (prop->calibration == VADC_CALIB_ABSOLUTE) - voltage += vadc->graph[prop->calibration].dx; +static int vadc_scale_volt(struct vadc_priv *vadc, + const struct vadc_channel_prop *prop, u16 adc_code, + int *result_uv) +{ + const struct vadc_prescale_ratio *prescale; + s64 voltage = 0, result = 0; - if (voltage < 0) - voltage = 0; + vadc_scale_calib(vadc, adc_code, prop, &voltage); prescale = &vadc_prescale_ratios[prop->prescale]; - voltage = voltage * prescale->den; + result = div64_s64(voltage, prescale->num); + *result_uv = result; - return div64_s64(voltage, prescale->num); + return 0; } static int vadc_decimation_from_dt(u32 value) @@ -552,11 +563,8 @@ static int vadc_read_raw(struct iio_dev *indio_dev, if (ret) break; - *val = vadc_calibrate(vadc, prop, adc_code); + vadc_scale_volt(vadc, prop, adc_code, val); - /* 2mV/K, return milli Celsius */ - *val /= 2; - *val -= KELVINMIL_CELSIUSMIL; return IIO_VAL_INT; case IIO_CHAN_INFO_RAW: prop = &vadc->chan_props[chan->address]; @@ -564,12 +572,8 @@ static int vadc_read_raw(struct iio_dev *indio_dev, if (ret) break; - *val = vadc_calibrate(vadc, prop, adc_code); + *val = (int)adc_code; return IIO_VAL_INT; - case IIO_CHAN_INFO_SCALE: - *val = 0; - *val2 = 1000; - return IIO_VAL_INT_PLUS_MICRO; default: ret = -EINVAL; break; @@ -617,7 +621,7 @@ struct vadc_channels { #define VADC_CHAN_VOLT(_dname, _pre) \ VADC_CHAN(_dname, IIO_VOLTAGE, \ - BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_SCALE), \ + BIT(IIO_CHAN_INFO_RAW) | BIT(IIO_CHAN_INFO_PROCESSED),\ _pre) \ /* -- cgit v1.2.3