diff options
Diffstat (limited to 'drivers/gpio/gpiolib-legacy.c')
-rw-r--r-- | drivers/gpio/gpiolib-legacy.c | 106 |
1 files changed, 106 insertions, 0 deletions
diff --git a/drivers/gpio/gpiolib-legacy.c b/drivers/gpio/gpiolib-legacy.c index 078ae6c2df79..0f9429b2522a 100644 --- a/drivers/gpio/gpiolib-legacy.c +++ b/drivers/gpio/gpiolib-legacy.c @@ -5,6 +5,64 @@ #include "gpiolib.h" +/* Warn when drivers omit gpio_request() calls -- legal but ill-advised + * when setting direction, and otherwise illegal. Until board setup code + * and drivers use explicit requests everywhere (which won't happen when + * those calls have no teeth) we can't avoid autorequesting. This nag + * message should motivate switching to explicit requests... so should + * the weaker cleanup after faults, compared to gpio_request(). + * + * NOTE: the autorequest mechanism is going away; at this point it's + * only "legal" in the sense that (old) code using it won't break yet, + * but instead only triggers a WARN() stack dump. + */ +static int gpio_ensure_requested(struct gpio_desc *desc) +{ + struct gpio_chip *chip = desc->chip; + unsigned long flags; + bool request = false; + int err = 0; + + spin_lock_irqsave(&gpio_lock, flags); + + if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0, + "autorequest GPIO-%d\n", desc_to_gpio(desc))) { + if (!try_module_get(chip->owner)) { + gpiod_err(desc, "%s: module can't be gotten\n", + __func__); + clear_bit(FLAG_REQUESTED, &desc->flags); + /* lose */ + err = -EIO; + goto end; + } + desc->label = "[auto]"; + /* caller must chip->request() w/o spinlock */ + if (chip->request) + request = true; + } + +end: + spin_unlock_irqrestore(&gpio_lock, flags); + + if (request) { + might_sleep_if(chip->can_sleep); + err = chip->request(chip, gpio_chip_hwgpio(desc)); + + if (err < 0) { + gpiod_dbg(desc, "%s: chip request fail, %d\n", + __func__, err); + spin_lock_irqsave(&gpio_lock, flags); + + desc->label = NULL; + clear_bit(FLAG_REQUESTED, &desc->flags); + + spin_unlock_irqrestore(&gpio_lock, flags); + } + } + + return err; +} + void gpio_free(unsigned gpio) { gpiod_free(gpio_to_desc(gpio)); @@ -100,3 +158,51 @@ void gpio_free_array(const struct gpio *array, size_t num) gpio_free((array++)->gpio); } EXPORT_SYMBOL_GPL(gpio_free_array); + +int gpio_direction_input(unsigned gpio) +{ + struct gpio_desc *desc = gpio_to_desc(gpio); + int err; + + if (!desc) + return -EINVAL; + + err = gpio_ensure_requested(desc); + if (err < 0) + return err; + + return gpiod_direction_input(desc); +} +EXPORT_SYMBOL_GPL(gpio_direction_input); + +int gpio_direction_output(unsigned gpio, int value) +{ + struct gpio_desc *desc = gpio_to_desc(gpio); + int err; + + if (!desc) + return -EINVAL; + + err = gpio_ensure_requested(desc); + if (err < 0) + return err; + + return gpiod_direction_output_raw(desc, value); +} +EXPORT_SYMBOL_GPL(gpio_direction_output); + +int gpio_set_debounce(unsigned gpio, unsigned debounce) +{ + struct gpio_desc *desc = gpio_to_desc(gpio); + int err; + + if (!desc) + return -EINVAL; + + err = gpio_ensure_requested(desc); + if (err < 0) + return err; + + return gpiod_set_debounce(desc, debounce); +} +EXPORT_SYMBOL_GPL(gpio_set_debounce); |