Devices relying on GPIO should select GPIO config

[avolmat-st]

Summary

Tree wide, there is a rather large number of driver relying on the GPIO (for example have xx-gpios device-tree properties), yet do not ensure to select GPIO in their Kconfig.

On lot of platform, the CONFIG_GPIO=y is set at platform level, so problem is not always visible, however each drivers should properly ensure to enable GPIOs if they really need it.

I've started to add those at video level, cf PR #113106 but that should be done more widely within the Zephyr tree.

Describe the solution you'd like

Similarly to what is done in PR #113106, each driver should ensure to select GPIO when needed.

Alternatively, we might think of a Zephyr wide dt_any_node_has_gpio_prop or so, allowing to enable the GPIO if any GPIO property is found within the device-tree. However we might wonder why such thing for GPIO specifically would have to be done so 1st approach about having each driver properly select might sound better (even if quite a large amount of work).

Alternatives

No response

Additional Context

No response

[maass-hamburg]

Alternatively, we might think of a Zephyr wide dt_any_node_has_gpio_prop or so, allowing to enable the GPIO if any GPIO property is found within the device-tree. However we might wonder why such thing for GPIO specifically would have to be done so 1st approach about having each driver properly select might sound better (even if quite a large amount of work).

This would enable gpio, even if it is not used. for example if it is used as the interrupt pin of a ethernet api, but we are not enabling CONFIG_NETWORKING (and the Kconfigs for the ethernet drivers), we don't need it.

It would be better to remove CONFIG_GPIO=y from all the boards _defconfig if GPIO code is not used in board specific files or inits (or gpio hogs are used). CONFIG_GPIO=y can be found over 930 times in the boards folder, and I bet the majority should not have it activated there.

[avolmat-st]

Alternatively, we might think of a Zephyr wide dt_any_node_has_gpio_prop or so, allowing to enable the GPIO if any GPIO property is found within the device-tree. However we might wonder why such thing for GPIO specifically would have to be done so 1st approach about having each driver properly select might sound better (even if quite a large amount of work).

This would enable gpio, even if it is not used. for example if it is used as the interrupt pin of a ethernet api, but we are not enabling CONFIG_NETWORKING (and the Kconfigs for the ethernet drivers), we don't need it.

It would be better to remove CONFIG_GPIO=y from all the boards _defconfig if GPIO code is not used in board specific files or inits (or gpio hogs are used). CONFIG_GPIO=y can be found over 930 times in the boards folder, and I bet the majority should not have it activated there.

Right. So this brings-us back to the original proposal of having each driver properly select GPIO if it is necessary, similarly to what I pushed for video drivers then. Then ultimately, as you said CONFIG_GPIO=y can be removed from all the boards _defconfig.