On Fri, Nov 11, 2016 at 1:17 PM, Laxman Dewangan [off-list ref] wrote:

quoted

Yeah but since pinctrl and pinmux has its own debugfs files why is this
necessary? I understand it is convenient but only for debugging
right? They the inconvenience of using pinctrls debugfs files should
be bearable.

Yes, it is debugging and capturing all the info at single place. Currently,
gpio debugFs shows the gpio related stuff and the pinctrl on pinconfig but
there is not any dump which shows the complete pin mapping.
The effort is to compile all the data in single place with proper message to
avoid any manual work for decoding multiple outputs.

I don't know if this is a good idea. I don't want to clutter the
gpiolib ABI for no good reason.

For certain this should only be available for drivers using pin
control as a back-end for their GPIOs.

For that purpose we have (in <linux/pinctrl/consumer.h>:

/* External interface to pin control */
extern int pinctrl_request_gpio(unsigned gpio);
extern void pinctrl_free_gpio(unsigned gpio);
extern int pinctrl_gpio_direction_input(unsigned gpio);
extern int pinctrl_gpio_direction_output(unsigned gpio);

It would be more natural to add a function pinctrl_is_gpio(unsigned gpio)
to call back to the pin controller, then that can be called from
the generic or driver-specific debug print callback.

Yours,
Linus Walleij