From 9db3deeb2de485a9d412f0825f9ab4c8e2bccf44 Mon Sep 17 00:00:00 2001 From: Fabrice Gasnier Date: Wed, 16 Sep 2026 19:18:38 +0200 Subject: iio: adc: stm32-adc: fix check on internal channel availability If an unsupported internal channel like vddgpu is requested, the driver prints a warning but falls through and assigns it a valid int_ch below. This causes a problem later during setup: stm32_adc_int_ch_enable() { ... case STM32_ADC_INT_CH_VDDGPU: stm32_adc_set_bits(adc, adc->cfg->regs->or_vddgpu.reg, adc->cfg->regs->or_vddgpu.mask); ... } Because the register offset is uninitialized (0), this performs a read-modify-write on offset 0, which corresponds to the ISR register. Fix this by returning before a valid int_ch is assigned. Choice is made to keep current driver behavior to warn about the channel name. Fixes: cf0fb80ae167 ("iio: adc: stm32-adc: add stm32mp13 support") Reported-by: Sashiko Closes: https://lore.kernel.org/all/20260911162602.D323F1F000FF@smtp.kernel.org/ Cc: stable@vger.kernel.org Reviewed-by: Andy Shevchenko Signed-off-by: Fabrice Gasnier Signed-off-by: Jonathan Cameron --- drivers/iio/adc/stm32-adc.c | 34 +++++++++++++++++++--------------- 1 file changed, 19 insertions(+), 15 deletions(-) diff --git a/drivers/iio/adc/stm32-adc.c b/drivers/iio/adc/stm32-adc.c index 5c6c06b26..b77f39f30 100644 --- a/drivers/iio/adc/stm32-adc.c +++ b/drivers/iio/adc/stm32-adc.c @@ -2263,33 +2263,37 @@ static int stm32_adc_populate_int_ch(struct iio_dev *indio_dev, const char *ch_n for (i = 0; i < STM32_ADC_INT_CH_NB; i++) { if (!strncmp(stm32_adc_ic[i].name, ch_name, STM32_ADC_CH_SZ)) { + bool na; + /* Check internal channel availability */ switch (i) { case STM32_ADC_INT_CH_VDDCORE: - if (!adc->cfg->regs->or_vddcore.reg) - dev_warn(&indio_dev->dev, - "%s channel not available\n", ch_name); + na = !adc->cfg->regs->or_vddcore.reg; break; case STM32_ADC_INT_CH_VDDCPU: - if (!adc->cfg->regs->or_vddcpu.reg) - dev_warn(&indio_dev->dev, - "%s channel not available\n", ch_name); + na = !adc->cfg->regs->or_vddcpu.reg; break; case STM32_ADC_INT_CH_VDDQ_DDR: - if (!adc->cfg->regs->or_vddq_ddr.reg) - dev_warn(&indio_dev->dev, - "%s channel not available\n", ch_name); + na = !adc->cfg->regs->or_vddq_ddr.reg; break; case STM32_ADC_INT_CH_VREFINT: - if (!adc->cfg->regs->ccr_vref.reg) - dev_warn(&indio_dev->dev, - "%s channel not available\n", ch_name); + na = !adc->cfg->regs->ccr_vref.reg; break; case STM32_ADC_INT_CH_VBAT: - if (!adc->cfg->regs->ccr_vbat.reg) - dev_warn(&indio_dev->dev, - "%s channel not available\n", ch_name); + na = !adc->cfg->regs->ccr_vbat.reg; break; + default: + return -EINVAL; + } + + if (na) { + /* + * Channel label matches an internal STM32 ADC channel. + * Warn about it, as there's normally no restriction on the + * name but that's not among available internal channels. + */ + dev_warn(&indio_dev->dev, "no %s internal channel\n", ch_name); + return 0; } if (stm32_adc_ic[i].idx != STM32_ADC_INT_CH_VREFINT) { -- cgit v1.3.1