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gpio: Automatically add lockdep keys

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In order to avoid lockdep boilerplate in individual drivers, turn the
gpiochip_add_data() function into a macro that creates a unique class
key for each driver.

Note that this has the slight disadvantage of adding a key for each
driver registered with the system. However, these keys are 8 bytes in
size, which is negligible and a small price to pay for generic
infrastructure.

Suggested-by: Grygorii Strashko <grygorii.strashko@ti.com>
Signed-off-by: Thierry Reding <treding@nvidia.com>
Acked-by: Grygorii Strashko <grygorii.strashko@ti.com>
[renane __gpiochip_add_data() to gpiochip_add_data_with_key]
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
This commit is contained in:
Thierry Reding
2017-11-07 19:15:59 +01:00
committed by Linus Walleij
parent 8302cf5852
commit 959bc7b22b
2 changed files with 47 additions and 30 deletions
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36
include/linux/gpio/driver.h
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@@ -321,7 +321,41 @@ extern const char *gpiochip_is_requested(struct gpio_chip *chip,
unsigned offset);
/* add/remove chips */
extern int gpiochip_add_data(struct gpio_chip *chip, void *data);
extern int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data,
struct lock_class_key *lock_key);
/**
* gpiochip_add_data() - register a gpio_chip
* @chip: the chip to register, with chip->base initialized
* @data: driver-private data associated with this chip
*
* Context: potentially before irqs will work
*
* When gpiochip_add_data() is called very early during boot, so that GPIOs
* can be freely used, the chip->parent device must be registered before
* the gpio framework's arch_initcall(). Otherwise sysfs initialization
* for GPIOs will fail rudely.
*
* gpiochip_add_data() must only be called after gpiolib initialization,
* ie after core_initcall().
*
* If chip->base is negative, this requests dynamic assignment of
* a range of valid GPIOs.
*
* Returns:
* A negative errno if the chip can't be registered, such as because the
* chip->base is invalid or already associated with a different chip.
* Otherwise it returns zero as a success code.
*/
#ifdef CONFIG_LOCKDEP
#define gpiochip_add_data(chip, data) ({ \
static struct lock_class_key key; \
gpiochip_add_data_with_key(chip, data, &key); \
})
#else
#define gpiochip_add_data(chip, data) gpiochip_add_data_with_key(chip, data, NULL)
#endif
static inline int gpiochip_add(struct gpio_chip *chip)
{
return gpiochip_add_data(chip, NULL);