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iio: adc: stm32-adc: smart calibration support
Add smart calibration support for STM32MP1. - STM32MP15x: both linear & offset calibration are supported - STM32MP13x: Only offset calibration is supported Linear calibration: Linear calibration is SoC dependent and does not change over time so it can be done only once. Linear calibration may have already been done in u-boot. Skip calibration execution if calibration data are already available. Save calibration factors in private data and restore them from private data on next ADC start. Offset calibration: This calibration may vary over time, depending on temperature or voltage. Run offset single-ended and differential calibration on each ADC start, as it is not time consuming. This calibration do not need to be saved. So, remove calfact_s and calfact_d value and bitfields that are no longer used. Signed-off-by: Olivier Moysan <olivier.moysan@foss.st.com> Reviewed-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com> Link: https://lore.kernel.org/r/20221115103124.70074-2-olivier.moysan@foss.st.com Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Olivier Moysan
Jonathan Cameron
parent
f237cf1914
commit
9d901e356c
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@ -142,6 +142,7 @@
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#define STM32H7_LINCALRDYW3 BIT(24)
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#define STM32H7_LINCALRDYW2 BIT(23)
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#define STM32H7_LINCALRDYW1 BIT(22)
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#define STM32H7_LINCALRDYW_MASK GENMASK(27, 22)
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#define STM32H7_ADCALLIN BIT(16)
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#define STM32H7_BOOST BIT(8)
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#define STM32H7_ADSTP BIT(4)
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@ -119,16 +119,12 @@ struct stm32_adc_trig_info {
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/**
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* struct stm32_adc_calib - optional adc calibration data
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* @calfact_s: Calibration offset for single ended channels
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* @calfact_d: Calibration offset in differential
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* @lincalfact: Linearity calibration factor
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* @calibrated: Indicates calibration status
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* @lincal_saved: Indicates that linear calibration factors are saved
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*/
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struct stm32_adc_calib {
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u32 calfact_s;
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u32 calfact_d;
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u32 lincalfact[STM32H7_LINCALFACT_NUM];
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bool calibrated;
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bool lincal_saved;
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};
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/**
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@ -165,8 +161,6 @@ struct stm32_adc_vrefint {
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* @extsel: trigger selection register & bitfield
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* @res: resolution selection register & bitfield
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* @difsel: differential mode selection register & bitfield
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* @calfact_s: single-ended calibration factors register & bitfield
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* @calfact_d: differential calibration factors register & bitfield
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* @smpr: smpr1 & smpr2 registers offset array
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* @smp_bits: smpr1 & smpr2 index and bitfields
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* @or_vddcore: option register & vddcore bitfield
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@ -186,8 +180,6 @@ struct stm32_adc_regspec {
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const struct stm32_adc_regs extsel;
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const struct stm32_adc_regs res;
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const struct stm32_adc_regs difsel;
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const struct stm32_adc_regs calfact_s;
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const struct stm32_adc_regs calfact_d;
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const u32 smpr[2];
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const struct stm32_adc_regs *smp_bits;
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const struct stm32_adc_regs or_vddcore;
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@ -525,10 +517,6 @@ static const struct stm32_adc_regspec stm32h7_adc_regspec = {
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STM32H7_EXTSEL_SHIFT },
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.res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT },
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.difsel = { STM32H7_ADC_DIFSEL, STM32H7_DIFSEL_MASK},
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.calfact_s = { STM32H7_ADC_CALFACT, STM32H7_CALFACT_S_MASK,
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STM32H7_CALFACT_S_SHIFT },
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.calfact_d = { STM32H7_ADC_CALFACT, STM32H7_CALFACT_D_MASK,
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STM32H7_CALFACT_D_SHIFT },
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.smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
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.smp_bits = stm32h7_smp_bits,
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};
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@ -550,10 +538,6 @@ static const struct stm32_adc_regspec stm32mp13_adc_regspec = {
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STM32H7_EXTSEL_SHIFT },
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.res = { STM32H7_ADC_CFGR, STM32MP13_RES_MASK, STM32MP13_RES_SHIFT },
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.difsel = { STM32MP13_ADC_DIFSEL, STM32MP13_DIFSEL_MASK},
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.calfact_s = { STM32MP13_ADC_CALFACT, STM32MP13_CALFACT_S_MASK,
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STM32MP13_CALFACT_S_SHIFT },
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.calfact_d = { STM32MP13_ADC_CALFACT, STM32MP13_CALFACT_D_MASK,
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STM32MP13_CALFACT_D_SHIFT },
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.smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
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.smp_bits = stm32h7_smp_bits,
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.or_vddcore = { STM32MP13_ADC2_OR, STM32MP13_OP0 },
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@ -575,10 +559,6 @@ static const struct stm32_adc_regspec stm32mp1_adc_regspec = {
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STM32H7_EXTSEL_SHIFT },
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.res = { STM32H7_ADC_CFGR, STM32H7_RES_MASK, STM32H7_RES_SHIFT },
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.difsel = { STM32H7_ADC_DIFSEL, STM32H7_DIFSEL_MASK},
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.calfact_s = { STM32H7_ADC_CALFACT, STM32H7_CALFACT_S_MASK,
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STM32H7_CALFACT_S_SHIFT },
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.calfact_d = { STM32H7_ADC_CALFACT, STM32H7_CALFACT_D_MASK,
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STM32H7_CALFACT_D_SHIFT },
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.smpr = { STM32H7_ADC_SMPR1, STM32H7_ADC_SMPR2 },
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.smp_bits = stm32h7_smp_bits,
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.or_vddcore = { STM32MP1_ADC2_OR, STM32MP1_VDDCOREEN },
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@ -1000,9 +980,6 @@ static int stm32h7_adc_read_selfcalib(struct iio_dev *indio_dev)
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int i, ret;
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u32 lincalrdyw_mask, val;
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if (!adc->cfg->has_linearcal)
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goto skip_linearcal;
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/* Read linearity calibration */
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lincalrdyw_mask = STM32H7_LINCALRDYW6;
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for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
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@ -1024,15 +1001,7 @@ static int stm32h7_adc_read_selfcalib(struct iio_dev *indio_dev)
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lincalrdyw_mask >>= 1;
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}
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skip_linearcal:
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/* Read offset calibration */
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val = stm32_adc_readl(adc, adc->cfg->regs->calfact_s.reg);
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adc->cal.calfact_s = (val & adc->cfg->regs->calfact_s.mask);
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adc->cal.calfact_s >>= adc->cfg->regs->calfact_s.shift;
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adc->cal.calfact_d = (val & adc->cfg->regs->calfact_d.mask);
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adc->cal.calfact_d >>= adc->cfg->regs->calfact_d.shift;
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adc->cal.calibrated = true;
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adc->cal.lincal_saved = true;
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return 0;
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}
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@ -1048,13 +1017,6 @@ static int stm32h7_adc_restore_selfcalib(struct iio_dev *indio_dev)
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int i, ret;
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u32 lincalrdyw_mask, val;
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val = (adc->cal.calfact_s << adc->cfg->regs->calfact_s.shift) |
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(adc->cal.calfact_d << adc->cfg->regs->calfact_d.shift);
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stm32_adc_writel(adc, adc->cfg->regs->calfact_s.reg, val);
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if (!adc->cfg->has_linearcal)
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return 0;
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lincalrdyw_mask = STM32H7_LINCALRDYW6;
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for (i = STM32H7_LINCALFACT_NUM - 1; i >= 0; i--) {
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/*
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@ -1116,19 +1078,20 @@ static int stm32h7_adc_restore_selfcalib(struct iio_dev *indio_dev)
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/**
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* stm32h7_adc_selfcalib() - Procedure to calibrate ADC
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* @indio_dev: IIO device instance
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* @do_lincal: linear calibration request flag
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* Note: Must be called once ADC is out of power down.
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*
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* Run offset calibration unconditionally.
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* Run linear calibration if requested & supported.
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*/
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static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev)
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static int stm32h7_adc_selfcalib(struct iio_dev *indio_dev, int do_lincal)
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{
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struct stm32_adc *adc = iio_priv(indio_dev);
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int ret;
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u32 msk = STM32H7_ADCALDIF;
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u32 val;
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if (adc->cal.calibrated)
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return true;
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if (adc->cfg->has_linearcal)
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if (adc->cfg->has_linearcal && do_lincal)
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msk |= STM32H7_ADCALLIN;
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/* ADC must be disabled for calibration */
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stm32h7_adc_disable(indio_dev);
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@ -1172,6 +1135,33 @@ out:
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return ret;
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}
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/**
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* stm32h7_adc_check_selfcalib() - Check linear calibration status
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* @indio_dev: IIO device instance
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*
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* Used to check if linear calibration has been done.
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* Return true if linear calibration factors are already saved in private data
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* or if a linear calibration has been done at boot stage.
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*/
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static int stm32h7_adc_check_selfcalib(struct iio_dev *indio_dev)
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{
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struct stm32_adc *adc = iio_priv(indio_dev);
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u32 val;
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if (adc->cal.lincal_saved)
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return true;
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/*
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* Check if linear calibration factors are available in ADC registers,
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* by checking that all LINCALRDYWx bits are set.
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*/
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val = stm32_adc_readl(adc, STM32H7_ADC_CR) & STM32H7_LINCALRDYW_MASK;
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if (val == STM32H7_LINCALRDYW_MASK)
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return true;
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return false;
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}
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/**
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* stm32h7_adc_prepare() - Leave power down mode to enable ADC.
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* @indio_dev: IIO device instance
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@ -1186,16 +1176,20 @@ out:
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static int stm32h7_adc_prepare(struct iio_dev *indio_dev)
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{
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struct stm32_adc *adc = iio_priv(indio_dev);
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int calib, ret;
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int lincal_done = false;
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int ret;
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ret = stm32h7_adc_exit_pwr_down(indio_dev);
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if (ret)
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return ret;
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ret = stm32h7_adc_selfcalib(indio_dev);
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if (adc->cfg->has_linearcal)
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lincal_done = stm32h7_adc_check_selfcalib(indio_dev);
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/* Always run offset calibration. Run linear calibration only once */
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ret = stm32h7_adc_selfcalib(indio_dev, !lincal_done);
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if (ret < 0)
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goto pwr_dwn;
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calib = ret;
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stm32_adc_int_ch_enable(indio_dev);
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@ -1205,13 +1199,15 @@ static int stm32h7_adc_prepare(struct iio_dev *indio_dev)
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if (ret)
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goto ch_disable;
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/* Either restore or read calibration result for future reference */
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if (calib)
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ret = stm32h7_adc_restore_selfcalib(indio_dev);
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else
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ret = stm32h7_adc_read_selfcalib(indio_dev);
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if (ret)
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goto disable;
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if (adc->cfg->has_linearcal) {
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if (!adc->cal.lincal_saved)
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ret = stm32h7_adc_read_selfcalib(indio_dev);
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else
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ret = stm32h7_adc_restore_selfcalib(indio_dev);
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if (ret)
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goto disable;
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}
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if (adc->cfg->has_presel)
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stm32_adc_writel(adc, STM32H7_ADC_PCSEL, adc->pcsel);
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