[PATCH 04/14] dt-bindings: pinctrl: stm32: add RSVD mux function

[Antonio Borneo]

On Wed, 2024-10-23 at 10:47 +0200, Krzysztof Kozlowski wrote:
> On Tue, Oct 22, 2024 at 05:56:48PM +0200, Antonio Borneo wrote:
> > From: Fabien Dessenne <fabien.dessenne at foss.st.com>
> > 
> > Document the RSVD (Reserved) mux function, used to reserve pins
> > for a coprocessor not running Linux.
> > 
> > Signed-off-by: Fabien Dessenne <fabien.dessenne at foss.st.com>
> > Signed-off-by: Antonio Borneo <antonio.borneo at foss.st.com>
> > ---
> >  .../devicetree/bindings/pinctrl/st,stm32-pinctrl.yaml     | 8 ++++++++
> >  include/dt-bindings/pinctrl/stm32-pinfunc.h               | 1 +
> >  2 files changed, 9 insertions(+)
> > 
> 
> BTW, which *existing* SoCs use it? Aren't you adding it for the new
> platform?
> 

This is already used in ST downstream kernel for STM32MP15x
In this example
https://github.com/STMicroelectronics/linux/blob/v6.1-stm32mp/arch/arm/boot/dts/stm32mp157f-dk2-m4-examples.dts#L112

the GPIOs for LED and for PWM are assigned to the Cortex-M4 and Linux (on Cortex-A7) is not supposed to touch them.

Regards,
Antonio