diff options
Diffstat (limited to 'drivers/gpio/gpiolib.c')
| -rw-r--r-- | drivers/gpio/gpiolib.c | 145 |
1 files changed, 77 insertions, 68 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 95d2a7b2ea3e..44c8f5743a24 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -45,19 +45,6 @@ * GPIOs can sometimes cost only an instruction or two per bit. */ - -/* When debugging, extend minimal trust to callers and platform code. - * Also emit diagnostic messages that may help initial bringup, when - * board setup or driver bugs are most common. - * - * Otherwise, minimize overhead in what may be bitbanging codepaths. - */ -#ifdef DEBUG -#define extra_checks 1 -#else -#define extra_checks 0 -#endif - /* Device and char device-related information */ static DEFINE_IDA(gpio_ida); static dev_t gpio_devt; @@ -255,6 +242,20 @@ int gpio_device_get_base(struct gpio_device *gdev) EXPORT_SYMBOL_GPL(gpio_device_get_base); /** + * gpio_device_get_label() - Get the label of this GPIO device + * @gdev: GPIO device + * + * Returns: + * Pointer to the string containing the GPIO device label. The string's + * lifetime is tied to that of the underlying GPIO device. + */ +const char *gpio_device_get_label(struct gpio_device *gdev) +{ + return gdev->label; +} +EXPORT_SYMBOL(gpio_device_get_label); + +/** * gpio_device_get_chip() - Get the gpio_chip implementation of this GPIO device * @gdev: GPIO device * @@ -276,7 +277,7 @@ struct gpio_chip *gpio_device_get_chip(struct gpio_device *gdev) EXPORT_SYMBOL_GPL(gpio_device_get_chip); /* dynamic allocation of GPIOs, e.g. on a hotplugged device */ -static int gpiochip_find_base(int ngpio) +static int gpiochip_find_base_unlocked(int ngpio) { struct gpio_device *gdev; int base = GPIO_DYNAMIC_BASE; @@ -349,7 +350,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_direction); * Return -EBUSY if the new chip overlaps with some other chip's integer * space. */ -static int gpiodev_add_to_list(struct gpio_device *gdev) +static int gpiodev_add_to_list_unlocked(struct gpio_device *gdev) { struct gpio_device *prev, *next; @@ -655,11 +656,6 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_valid); static void gpiodev_release(struct device *dev) { struct gpio_device *gdev = to_gpio_device(dev); - unsigned long flags; - - spin_lock_irqsave(&gpio_lock, flags); - list_del(&gdev->list); - spin_unlock_irqrestore(&gpio_lock, flags); ida_free(&gpio_ida, gdev->id); kfree_const(gdev->label); @@ -893,7 +889,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, */ base = gc->base; if (base < 0) { - base = gpiochip_find_base(gc->ngpio); + base = gpiochip_find_base_unlocked(gc->ngpio); if (base < 0) { spin_unlock_irqrestore(&gpio_lock, flags); ret = base; @@ -913,7 +909,7 @@ int gpiochip_add_data_with_key(struct gpio_chip *gc, void *data, } gdev->base = base; - ret = gpiodev_add_to_list(gdev); + ret = gpiodev_add_to_list_unlocked(gdev); if (ret) { spin_unlock_irqrestore(&gpio_lock, flags); chip_err(gc, "GPIO integer space overlap, cannot add chip\n"); @@ -1048,8 +1044,8 @@ EXPORT_SYMBOL_GPL(gpiochip_add_data_with_key); void gpiochip_remove(struct gpio_chip *gc) { struct gpio_device *gdev = gc->gpiodev; - unsigned long flags; - unsigned int i; + unsigned long flags; + unsigned int i; down_write(&gdev->sem); @@ -1071,7 +1067,7 @@ void gpiochip_remove(struct gpio_chip *gc) spin_lock_irqsave(&gpio_lock, flags); for (i = 0; i < gdev->ngpio; i++) { - if (gpiochip_is_requested(gc, i)) + if (test_bit(FLAG_REQUESTED, &gdev->descs[i].flags)) break; } spin_unlock_irqrestore(&gpio_lock, flags); @@ -1080,6 +1076,9 @@ void gpiochip_remove(struct gpio_chip *gc) dev_crit(&gdev->dev, "REMOVING GPIOCHIP WITH GPIOS STILL REQUESTED\n"); + scoped_guard(spinlock_irqsave, &gpio_lock) + list_del(&gdev->list); + /* * The gpiochip side puts its use of the device to rest here: * if there are no userspace clients, the chardev and device will @@ -2185,10 +2184,10 @@ EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges); */ static int gpiod_request_commit(struct gpio_desc *desc, const char *label) { - struct gpio_chip *gc = desc->gdev->chip; - int ret; - unsigned long flags; - unsigned offset; + struct gpio_chip *gc = desc->gdev->chip; + unsigned long flags; + unsigned int offset; + int ret; if (label) { label = kstrdup_const(label, GFP_KERNEL); @@ -2300,9 +2299,9 @@ int gpiod_request(struct gpio_desc *desc, const char *label) static bool gpiod_free_commit(struct gpio_desc *desc) { - bool ret = false; - unsigned long flags; - struct gpio_chip *gc; + struct gpio_chip *gc; + unsigned long flags; + bool ret = false; might_sleep(); @@ -2331,9 +2330,6 @@ static bool gpiod_free_commit(struct gpio_desc *desc) #ifdef CONFIG_OF_DYNAMIC desc->hog = NULL; #endif -#ifdef CONFIG_GPIO_CDEV - WRITE_ONCE(desc->debounce_period_us, 0); -#endif ret = true; } @@ -2353,38 +2349,53 @@ void gpiod_free(struct gpio_desc *desc) return; if (!gpiod_free_commit(desc)) - WARN_ON(extra_checks); + WARN_ON(1); module_put(desc->gdev->owner); gpio_device_put(desc->gdev); } /** - * gpiochip_is_requested - return string iff signal was requested - * @gc: controller managing the signal - * @offset: of signal within controller's 0..(ngpio - 1) range + * gpiochip_dup_line_label - Get a copy of the consumer label. + * @gc: GPIO chip controlling this line. + * @offset: Hardware offset of the line. * - * Returns NULL if the GPIO is not currently requested, else a string. - * The string returned is the label passed to gpio_request(); if none has been - * passed it is a meaningless, non-NULL constant. + * Returns: + * Pointer to a copy of the consumer label if the line is requested or NULL + * if it's not. If a valid pointer was returned, it must be freed using + * kfree(). In case of a memory allocation error, the function returns %ENOMEM. * - * This function is for use by GPIO controller drivers. The label can - * help with diagnostics, and knowing that the signal is used as a GPIO - * can help avoid accidentally multiplexing it to another controller. + * Must not be called from atomic context. */ -const char *gpiochip_is_requested(struct gpio_chip *gc, unsigned int offset) +char *gpiochip_dup_line_label(struct gpio_chip *gc, unsigned int offset) { struct gpio_desc *desc; + char *label; desc = gpiochip_get_desc(gc, offset); if (IS_ERR(desc)) return NULL; - if (test_bit(FLAG_REQUESTED, &desc->flags) == 0) + guard(spinlock_irqsave)(&gpio_lock); + + if (!test_bit(FLAG_REQUESTED, &desc->flags)) return NULL; - return desc->label; + + /* + * FIXME: Once we mark gpiod_direction_input/output() and + * gpiod_get_direction() with might_sleep(), we'll be able to protect + * the GPIO descriptors with mutex (while value setting operations will + * become lockless). + * + * Until this happens, this allocation needs to be atomic. + */ + label = kstrdup(desc->label, GFP_ATOMIC); + if (!label) + return ERR_PTR(-ENOMEM); + + return label; } -EXPORT_SYMBOL_GPL(gpiochip_is_requested); +EXPORT_SYMBOL_GPL(gpiochip_dup_line_label); /** * gpiochip_request_own_desc - Allow GPIO chip to request its own descriptor @@ -2564,8 +2575,8 @@ int gpio_set_debounce_timeout(struct gpio_desc *desc, unsigned int debounce) */ int gpiod_direction_input(struct gpio_desc *desc) { - struct gpio_chip *gc; - int ret = 0; + struct gpio_chip *gc; + int ret = 0; VALIDATE_DESC(desc); gc = desc->gdev->chip; @@ -2914,7 +2925,7 @@ static int gpio_chip_get_value(struct gpio_chip *gc, const struct gpio_desc *des static int gpiod_get_raw_value_commit(const struct gpio_desc *desc) { - struct gpio_chip *gc; + struct gpio_chip *gc; int value; gc = desc->gdev->chip; @@ -3209,7 +3220,7 @@ static void gpio_set_open_source_value_commit(struct gpio_desc *desc, bool value static void gpiod_set_raw_value_commit(struct gpio_desc *desc, bool value) { - struct gpio_chip *gc; + struct gpio_chip *gc; gc = desc->gdev->chip; trace_gpio_value(desc_to_gpio(desc), 0, value); @@ -3716,7 +3727,7 @@ EXPORT_SYMBOL_GPL(gpiochip_line_is_persistent); */ int gpiod_get_raw_value_cansleep(const struct gpio_desc *desc) { - might_sleep_if(extra_checks); + might_sleep(); VALIDATE_DESC(desc); return gpiod_get_raw_value_commit(desc); } @@ -3735,7 +3746,7 @@ int gpiod_get_value_cansleep(const struct gpio_desc *desc) { int value; - might_sleep_if(extra_checks); + might_sleep(); VALIDATE_DESC(desc); value = gpiod_get_raw_value_commit(desc); if (value < 0) @@ -3766,7 +3777,7 @@ int gpiod_get_raw_array_value_cansleep(unsigned int array_size, struct gpio_array *array_info, unsigned long *value_bitmap) { - might_sleep_if(extra_checks); + might_sleep(); if (!desc_array) return -EINVAL; return gpiod_get_array_value_complex(true, true, array_size, @@ -3792,7 +3803,7 @@ int gpiod_get_array_value_cansleep(unsigned int array_size, struct gpio_array *array_info, unsigned long *value_bitmap) { - might_sleep_if(extra_checks); + might_sleep(); if (!desc_array) return -EINVAL; return gpiod_get_array_value_complex(false, true, array_size, @@ -3813,7 +3824,7 @@ EXPORT_SYMBOL_GPL(gpiod_get_array_value_cansleep); */ void gpiod_set_raw_value_cansleep(struct gpio_desc *desc, int value) { - might_sleep_if(extra_checks); + might_sleep(); VALIDATE_DESC_VOID(desc); gpiod_set_raw_value_commit(desc, value); } @@ -3831,7 +3842,7 @@ EXPORT_SYMBOL_GPL(gpiod_set_raw_value_cansleep); */ void gpiod_set_value_cansleep(struct gpio_desc *desc, int value) { - might_sleep_if(extra_checks); + might_sleep(); VALIDATE_DESC_VOID(desc); gpiod_set_value_nocheck(desc, value); } @@ -3854,7 +3865,7 @@ int gpiod_set_raw_array_value_cansleep(unsigned int array_size, struct gpio_array *array_info, unsigned long *value_bitmap) { - might_sleep_if(extra_checks); + might_sleep(); if (!desc_array) return -EINVAL; return gpiod_set_array_value_complex(true, true, array_size, desc_array, @@ -3896,7 +3907,7 @@ int gpiod_set_array_value_cansleep(unsigned int array_size, struct gpio_array *array_info, unsigned long *value_bitmap) { - might_sleep_if(extra_checks); + might_sleep(); if (!desc_array) return -EINVAL; return gpiod_set_array_value_complex(false, true, array_size, @@ -4696,13 +4707,11 @@ core_initcall(gpiolib_dev_init); static void gpiolib_dbg_show(struct seq_file *s, struct gpio_device *gdev) { - struct gpio_chip *gc = gdev->chip; - struct gpio_desc *desc; - unsigned gpio = gdev->base; - int value; - bool is_out; - bool is_irq; - bool active_low; + struct gpio_chip *gc = gdev->chip; + bool active_low, is_irq, is_out; + unsigned int gpio = gdev->base; + struct gpio_desc *desc; + int value; for_each_gpio_desc(gc, desc) { if (test_bit(FLAG_REQUESTED, &desc->flags)) { |