Re: [PATCH v2] iio: adc: stm32-adc: fix check on internal channel availability

On Wed, Sep 16, 2026 at 04:13:23PM +0200, Fabrice Gasnier wrote:

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 <sashiko-bot@kernel.org>
Link: https://lore.kernel.org/all/20260911162602.D323F1F000FF@smtp.kernel.org/ (local)

Closes: ^^^

Cc: stable@vger.kernel.org
Signed-off-by: Fabrice Gasnier <fabrice.gasnier@foss.st.com>
---
Changes in v2:
- Review comments from Andy: use bool flag closer to the channel
  availabilty checks. Add a default case.
- Link to v1: https://patch.msgid.link/20260915-adc-fix-intchan-v1-v1-1-761a1b35001b@foss.st.com (local)

With the above amendment,
Reviewed-by: Andy Shevchenko <redacted>

-- 
With Best Regards,
Andy Shevchenko