[PATCH] gpiolib: notify user-space about line state changes triggered by kernel

Bartosz Golaszewski
2023-08-18T19:10:56Z

From: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>

We currently only emit CHANGED_CONFIG events when the user-space changes
GPIO config. We won't be notified if changes come from in-kernel. Let's
call the notifier chain whenever kernel users change direction or any of
the active-low, debounce or consumer name settings. We don't notify the
user-space about the persistence as the uAPI has no notion of it.

Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
---
drivers/gpio/gpiolib.c | 21 +++++++++++++++++++--
1 file changed, 19 insertions(+), 2 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 76e0c38026c3..77e0d0afa2b5 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2421,6 +2421,9 @@ int gpiod_direction_input(struct gpio_desc *desc)
}
if (ret == 0) {
clear_bit(FLAG_IS_OUT, &desc->flags);
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG,
+ desc);
ret = gpio_set_bias(desc);
}

@@ -2466,8 +2469,12 @@ static int gpiod_direction_output_raw_commit(struct gpio_desc *desc, int value)
gc->set(gc, gpio_chip_hwgpio(desc), val);
}

- if (!ret)
+ if (!ret) {
set_bit(FLAG_IS_OUT, &desc->flags);
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG,
+ desc);
+ }
trace_gpio_value(desc_to_gpio(desc), 0, val);
trace_gpio_direction(desc_to_gpio(desc), 0, ret);
return ret;
@@ -2654,9 +2661,15 @@ EXPORT_SYMBOL_GPL(gpiod_set_config);
int gpiod_set_debounce(struct gpio_desc *desc, unsigned int debounce)
{
unsigned long config;
+ int ret;

config = pinconf_to_config_packed(PIN_CONFIG_INPUT_DEBOUNCE, debounce);
- return gpiod_set_config(desc, config);
+ ret = gpiod_set_config(desc, config);
+ if (!ret)
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG,
+ desc);
+ return ret;
}
EXPORT_SYMBOL_GPL(gpiod_set_debounce);

@@ -2705,6 +2718,8 @@ void gpiod_toggle_active_low(struct gpio_desc *desc)
{
VALIDATE_DESC_VOID(desc);
change_bit(FLAG_ACTIVE_LOW, &desc->flags);
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG, desc);
}
EXPORT_SYMBOL_GPL(gpiod_toggle_active_low);

@@ -3312,6 +3327,8 @@ int gpiod_set_consumer_name(struct gpio_desc *desc, const char *name)

kfree_const(desc->label);
desc_set_label(desc, name);
+ blocking_notifier_call_chain(&desc->gdev->notifier,
+ GPIO_V2_LINE_CHANGED_CONFIG, desc);

return 0;
}
--
2.39.2