From 7cb2303dd02487cc18bc9ff0fc1338e8c78ae846 Mon Sep 17 00:00:00 2001 From: Olivier Moysan Date: Wed, 12 Oct 2022 16:22:01 +0200 Subject: [PATCH] iio: adc: stm32: manage min sampling time on all internal channels Force minimum sampling time for all internal channels according to datasheet requirement. This value can be increased through DT st,min-sample-time-ns property. Signed-off-by: Olivier Moysan Reviewed-by: Andy Shevchenko Reviewed-by: Fabrice Gasnier Link: https://lore.kernel.org/r/20221012142205.13041-5-olivier.moysan@foss.st.com Signed-off-by: Jonathan Cameron --- drivers/iio/adc/stm32-adc.c | 26 +++++++++++++++++++------- 1 file changed, 19 insertions(+), 7 deletions(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index d36c024..8d03d21 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -215,7 +215,7 @@ struct stm32_adc; * @unprepare: optional unprepare routine (disable, power-down) * @irq_clear: routine to clear irqs * @smp_cycles: programmable sampling time (ADC clock cycles) - * @ts_vrefint_ns: vrefint minimum sampling time in ns + * @ts_int_ch: pointer to array of internal channels minimum sampling time in ns */ struct stm32_adc_cfg { const struct stm32_adc_regspec *regs; @@ -232,7 +232,7 @@ struct stm32_adc_cfg { void (*unprepare)(struct iio_dev *); void (*irq_clear)(struct iio_dev *indio_dev, u32 msk); const unsigned int *smp_cycles; - const unsigned int ts_vrefint_ns; + const unsigned int *ts_int_ch; }; /** @@ -1910,14 +1910,15 @@ static void stm32_adc_smpr_init(struct stm32_adc *adc, int channel, u32 smp_ns) { const struct stm32_adc_regs *smpr = &adc->cfg->regs->smp_bits[channel]; u32 period_ns, shift = smpr->shift, mask = smpr->mask; - unsigned int smp, r = smpr->reg; + unsigned int i, smp, r = smpr->reg; /* - * For vrefint channel, ensure that the sampling time cannot + * For internal channels, ensure that the sampling time cannot * be lower than the one specified in the datasheet */ - if (channel == adc->int_ch[STM32_ADC_INT_CH_VREFINT]) - smp_ns = max(smp_ns, adc->cfg->ts_vrefint_ns); + for (i = 0; i < STM32_ADC_INT_CH_NB; i++) + if (channel == adc->int_ch[i] && adc->int_ch[i] != STM32_ADC_INT_CH_NONE) + smp_ns = max(smp_ns, adc->cfg->ts_int_ch[i]); /* Determine sampling time (ADC clock cycles) */ period_ns = NSEC_PER_SEC / adc->common->rate; @@ -2568,6 +2569,9 @@ static const struct stm32_adc_cfg stm32f4_adc_cfg = { .irq_clear = stm32f4_adc_irq_clear, }; +const unsigned int stm32_adc_min_ts_h7[] = { 0, 0, 0, 4300, 9000 }; +static_assert(ARRAY_SIZE(stm32_adc_min_ts_h7) == STM32_ADC_INT_CH_NB); + static const struct stm32_adc_cfg stm32h7_adc_cfg = { .regs = &stm32h7_adc_regspec, .adc_info = &stm32h7_adc_info, @@ -2581,8 +2585,12 @@ static const struct stm32_adc_cfg stm32h7_adc_cfg = { .unprepare = stm32h7_adc_unprepare, .smp_cycles = stm32h7_adc_smp_cycles, .irq_clear = stm32h7_adc_irq_clear, + .ts_int_ch = stm32_adc_min_ts_h7, }; +const unsigned int stm32_adc_min_ts_mp1[] = { 100, 100, 100, 4300, 9800 }; +static_assert(ARRAY_SIZE(stm32_adc_min_ts_mp1) == STM32_ADC_INT_CH_NB); + static const struct stm32_adc_cfg stm32mp1_adc_cfg = { .regs = &stm32mp1_adc_regspec, .adc_info = &stm32h7_adc_info, @@ -2597,9 +2605,12 @@ static const struct stm32_adc_cfg stm32mp1_adc_cfg = { .unprepare = stm32h7_adc_unprepare, .smp_cycles = stm32h7_adc_smp_cycles, .irq_clear = stm32h7_adc_irq_clear, - .ts_vrefint_ns = 4300, + .ts_int_ch = stm32_adc_min_ts_mp1, }; +const unsigned int stm32_adc_min_ts_mp13[] = { 100, 0, 0, 4300, 9800 }; +static_assert(ARRAY_SIZE(stm32_adc_min_ts_mp13) == STM32_ADC_INT_CH_NB); + static const struct stm32_adc_cfg stm32mp13_adc_cfg = { .regs = &stm32mp13_adc_regspec, .adc_info = &stm32mp13_adc_info, @@ -2610,6 +2621,7 @@ static const struct stm32_adc_cfg stm32mp13_adc_cfg = { .unprepare = stm32h7_adc_unprepare, .smp_cycles = stm32mp13_adc_smp_cycles, .irq_clear = stm32h7_adc_irq_clear, + .ts_int_ch = stm32_adc_min_ts_mp13, }; static const struct of_device_id stm32_adc_of_match[] = { -- 2.7.4