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pinctrl: apple: Implement GPIO func check callback

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This function will check if the indicated function enumerator
i.e. the value set into bits 5 and 6 of the pin configuration
register, is zero and thus corresponds to the GPIO mode of the
pin.

This may be necessary to know since the pin controller is
flagged as "strict": once you set a pin *explicitly* to GPIO
mode using function 0, the core is unaware that this is
actually the GPIO mode, and clients may be denied to
retrieve the pin as a GPIO.

Currently none of the in-kernel device trees sets any pin to
GPIO mode, but this may happen any day.

Reviewed-by: Sven Peter <sven@kernel.org>
Reviewed-by: Bartosz Golaszewski <bartosz.golaszewski@oss.qualcomm.com>
Signed-off-by: Linus Walleij <linusw@kernel.org>
This commit is contained in:
Linus Walleij 2026-01-12 11:20:32 +01:00
parent 7b9a9cafc4
commit 881238a852
1 changed files with 8 additions and 0 deletions
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8
drivers/pinctrl/pinctrl-apple-gpio.c
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@ -170,6 +170,13 @@ static const struct pinctrl_ops apple_gpio_pinctrl_ops = {
/* Pin multiplexer functions */
static bool apple_gpio_pinmux_func_is_gpio(struct pinctrl_dev *pctldev,
unsigned int selector)
{
/* Function selector 0 is always the GPIO mode */
return (selector == 0);
}
static int apple_gpio_pinmux_set(struct pinctrl_dev *pctldev, unsigned int func,
unsigned int group)
{
@ -186,6 +193,7 @@ static const struct pinmux_ops apple_gpio_pinmux_ops = {
.get_functions_count = pinmux_generic_get_function_count,
.get_function_name = pinmux_generic_get_function_name,
.get_function_groups = pinmux_generic_get_function_groups,
.function_is_gpio = apple_gpio_pinmux_func_is_gpio,
.set_mux = apple_gpio_pinmux_set,
.strict = true,
};