Commit d23dc4a9 authored by Bartosz Golaszewski's avatar Bartosz Golaszewski
Browse files

gpio: provide and use gpiod_get_label() 



We will soon serialize access to the descriptor label using SRCU. The
write-side of the protection will require calling synchronize_srcu()
which must not be called from atomic context. We have two irq helpers:
gpiochip_lock_as_irq() and gpiochip_unlock_as_irq() that set the label
if the GPIO is not requested but is being used as interrupt. They are
called with a spinlock held from the interrupt subsystem.

They must not do it if we are to use SRCU so instead let's move the
special corner case to a dedicated getter.

First: let's implement and use the getter where it's applicable.

Signed-off-by: default avatarBartosz Golaszewski <bartosz.golaszewski@linaro.org>
Reviewed-by: default avatarLinus Walleij <linus.walleij@linaro.org>
Acked-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
parent 0857c39b

drivers/gpio/gpiolib-cdev.c

+2 −2
Original line number Diff line number Diff line
@@ -2305,8 +2305,8 @@ static void gpio_desc_to_lineinfo(struct gpio_desc *desc, 
		if (desc->name)

			strscpy(info->name, desc->name, sizeof(info->name));



		if (desc->label)

			strscpy(info->consumer, desc->label,

		if (gpiod_get_label(desc))

			strscpy(info->consumer, gpiod_get_label(desc),

				sizeof(info->consumer));



		dflags = READ_ONCE(desc->flags);

drivers/gpio/gpiolib.c

+7 −2
Original line number Diff line number Diff line
@@ -105,6 +105,11 @@ static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gc); 


static bool gpiolib_initialized;



const char *gpiod_get_label(struct gpio_desc *desc)

{

	return desc->label;

}



static inline void desc_set_label(struct gpio_desc *d, const char *label)

{

	d->label = label;
@@ -2391,7 +2396,7 @@ char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset) 
	 *

	 * Until this happens, this allocation needs to be atomic.

	 */

	label = kstrdup(desc->label, GFP_ATOMIC);

	label = kstrdup(gpiod_get_label(desc), GFP_ATOMIC);

	if (!label)

		return ERR_PTR(-ENOMEM);
@@ -4732,7 +4737,7 @@ static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) 
			is_irq = test_bit(FLAG_USED_AS_IRQ, &desc->flags);

			active_low = test_bit(FLAG_ACTIVE_LOW, &desc->flags);

			seq_printf(s, " gpio-%-3d (%-20.20s|%-20.20s) %s %s %s%s\n",

				   gpio, desc->name ?: "", desc->label,

				   gpio, desc->name ?: "", gpiod_get_label(desc),

				   is_out ? "out" : "in ",

				   value >= 0 ? (value ? "hi" : "lo") : "?  ",

				   is_irq ? "IRQ " : "",

drivers/gpio/gpiolib.h

+1 −0
Original line number Diff line number Diff line
@@ -208,6 +208,7 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce); 
int gpiod_hog(struct gpio_desc *desc, const char *name,

		unsigned long lflags, enum gpiod_flags dflags);

int gpiochip_get_ngpios(struct gpio_chip *gc, struct device *dev);

const char *gpiod_get_label(struct gpio_desc *desc);



/*

 * Return the GPIO number of the passed descriptor relative to its chip