[PATCH v2 06/14] iio: adc: stm32-adc: add vreg enable option to manage diversity

[Fabrice Gasnier]

Add a boolean (has_vregen) in adc configuration structure to prevent
setting the reserved bit (CR_ADVREGEN bit 28) on STM32MP2 SoCs.
This bit is present on earlier stm32h7, stm32mp13 and stm32mp15.
No functional change intended.

Co-developed-by: Cheick Traore <cheick.traore-ext at st.com>
Signed-off-by: Cheick Traore <cheick.traore-ext at st.com>
Signed-off-by: Fabrice Gasnier <fabrice.gasnier at foss.st.com>
---
Changes in v2:
- new precursor patch, e.g. split as suggested by Andy and Jonathan, to
  prepare the infrastructure for stm32mp23/25 support.
---
 drivers/iio/adc/stm32-adc.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c
index ac60c31de7a5..eecdc4cce1b4 100644
--- a/drivers/iio/adc/stm32-adc.c
+++ b/drivers/iio/adc/stm32-adc.c
@@ -193,6 +193,7 @@ struct stm32_adc;
  * @has_linearcal:	linear calibration support flag
  * @has_presel:		channel preselection support flag
  * @has_oversampling:	oversampling support flag
+ * @has_vregen:		voltage regulator enable/disable flag
  * @prepare:		optional prepare routine (power-up, enable)
  * @start_conv:		routine to start conversions
  * @stop_conv:		routine to stop conversions
@@ -213,6 +214,7 @@ struct stm32_adc_cfg {
 	bool has_linearcal;
 	bool has_presel;
 	bool has_oversampling;
+	bool has_vregen;
 	int (*prepare)(struct iio_dev *);
 	void (*start_conv)(struct iio_dev *, bool dma);
 	void (*stop_conv)(struct iio_dev *);
@@ -961,7 +963,8 @@ static int stm32h7_adc_exit_pwr_down(struct iio_dev *indio_dev)
 
 	/* Exit deep power down, then enable ADC voltage regulator */
 	stm32_adc_clr_bits(adc, STM32H7_ADC_CR, STM32H7_DEEPPWD);
-	stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN);
+	if (adc->cfg->has_vregen)
+		stm32_adc_set_bits(adc, STM32H7_ADC_CR, STM32H7_ADVREGEN);
 
 	if (adc->cfg->has_boostmode &&
 	    adc->common->rate > STM32H7_BOOST_CLKRATE)
@@ -2719,6 +2722,7 @@ static const struct stm32_adc_cfg stm32h7_adc_cfg = {
 	.has_linearcal = true,
 	.has_presel = true,
 	.has_oversampling = true,
+	.has_vregen = true,
 	.start_conv = stm32h7_adc_start_conv,
 	.stop_conv = stm32h7_adc_stop_conv,
 	.prepare = stm32h7_adc_prepare,
@@ -2745,6 +2749,7 @@ static const struct stm32_adc_cfg stm32mp1_adc_cfg = {
 	.has_linearcal = true,
 	.has_presel = true,
 	.has_oversampling = true,
+	.has_vregen = true,
 	.start_conv = stm32h7_adc_start_conv,
 	.stop_conv = stm32h7_adc_stop_conv,
 	.prepare = stm32h7_adc_prepare,
@@ -2769,6 +2774,7 @@ static const struct stm32_adc_cfg stm32mp13_adc_cfg = {
 	.adc_info = &stm32mp13_adc_info,
 	.trigs = stm32h7_adc_trigs,
 	.has_oversampling = true,
+	.has_vregen = true,
 	.start_conv = stm32mp13_adc_start_conv,
 	.stop_conv = stm32h7_adc_stop_conv,
 	.prepare = stm32h7_adc_prepare,

-- 
2.43.0