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path: root/drivers/gpio/gpiolib.c
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Diffstat (limited to 'drivers/gpio/gpiolib.c')
-rw-r--r--drivers/gpio/gpiolib.c115
1 files changed, 100 insertions, 15 deletions
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 572d372899d..faa1cc66e9c 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -67,17 +67,28 @@ static inline void desc_set_label(struct gpio_desc *d, const char *label)
* 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...
+ * message should motivate switching to explicit requests... so should
+ * the weaker cleanup after faults, compared to gpio_request().
*/
-static void gpio_ensure_requested(struct gpio_desc *desc)
+static int gpio_ensure_requested(struct gpio_desc *desc, unsigned offset)
{
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
- pr_warning("GPIO-%d autorequested\n", (int)(desc - gpio_desc));
+ struct gpio_chip *chip = desc->chip;
+ int gpio = chip->base + offset;
+
+ if (!try_module_get(chip->owner)) {
+ pr_err("GPIO-%d: module can't be gotten \n", gpio);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ /* lose */
+ return -EIO;
+ }
+ pr_warning("GPIO-%d autorequested\n", gpio);
desc_set_label(desc, "[auto]");
- if (!try_module_get(desc->chip->owner))
- pr_err("GPIO-%d: module can't be gotten \n",
- (int)(desc - gpio_desc));
+ /* caller must chip->request() w/o spinlock */
+ if (chip->request)
+ return 1;
}
+ return 0;
}
/* caller holds gpio_lock *OR* gpio is marked as requested */
@@ -237,7 +248,7 @@ static ssize_t gpio_value_show(struct device *dev,
if (!test_bit(FLAG_EXPORT, &desc->flags))
status = -EIO;
else
- status = sprintf(buf, "%d\n", gpio_get_value_cansleep(gpio));
+ status = sprintf(buf, "%d\n", !!gpio_get_value_cansleep(gpio));
mutex_unlock(&sysfs_lock);
return status;
@@ -752,6 +763,7 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
int gpio_request(unsigned gpio, const char *label)
{
struct gpio_desc *desc;
+ struct gpio_chip *chip;
int status = -EINVAL;
unsigned long flags;
@@ -760,14 +772,15 @@ int gpio_request(unsigned gpio, const char *label)
if (!gpio_is_valid(gpio))
goto done;
desc = &gpio_desc[gpio];
- if (desc->chip == NULL)
+ chip = desc->chip;
+ if (chip == NULL)
goto done;
- if (!try_module_get(desc->chip->owner))
+ if (!try_module_get(chip->owner))
goto done;
/* NOTE: gpio_request() can be called in early boot,
- * before IRQs are enabled.
+ * before IRQs are enabled, for non-sleeping (SOC) GPIOs.
*/
if (test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0) {
@@ -775,7 +788,20 @@ int gpio_request(unsigned gpio, const char *label)
status = 0;
} else {
status = -EBUSY;
- module_put(desc->chip->owner);
+ module_put(chip->owner);
+ }
+
+ if (chip->request) {
+ /* chip->request may sleep */
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ status = chip->request(chip, gpio - chip->base);
+ spin_lock_irqsave(&gpio_lock, flags);
+
+ if (status < 0) {
+ desc_set_label(desc, NULL);
+ module_put(chip->owner);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
+ }
}
done:
@@ -791,6 +817,9 @@ void gpio_free(unsigned gpio)
{
unsigned long flags;
struct gpio_desc *desc;
+ struct gpio_chip *chip;
+
+ might_sleep();
if (!gpio_is_valid(gpio)) {
WARN_ON(extra_checks);
@@ -802,9 +831,17 @@ void gpio_free(unsigned gpio)
spin_lock_irqsave(&gpio_lock, flags);
desc = &gpio_desc[gpio];
- if (desc->chip && test_and_clear_bit(FLAG_REQUESTED, &desc->flags)) {
+ chip = desc->chip;
+ if (chip && test_bit(FLAG_REQUESTED, &desc->flags)) {
+ if (chip->free) {
+ spin_unlock_irqrestore(&gpio_lock, flags);
+ might_sleep_if(extra_checks && chip->can_sleep);
+ chip->free(chip, gpio - chip->base);
+ spin_lock_irqsave(&gpio_lock, flags);
+ }
desc_set_label(desc, NULL);
module_put(desc->chip->owner);
+ clear_bit(FLAG_REQUESTED, &desc->flags);
} else
WARN_ON(extra_checks);
@@ -869,7 +906,9 @@ int gpio_direction_input(unsigned gpio)
gpio -= chip->base;
if (gpio >= chip->ngpio)
goto fail;
- gpio_ensure_requested(desc);
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
/* now we know the gpio is valid and chip won't vanish */
@@ -877,9 +916,22 @@ int gpio_direction_input(unsigned gpio)
might_sleep_if(extra_checks && chip->can_sleep);
+ if (status) {
+ status = chip->request(chip, gpio);
+ if (status < 0) {
+ pr_debug("GPIO-%d: chip request fail, %d\n",
+ chip->base + gpio, status);
+ /* and it's not available to anyone else ...
+ * gpio_request() is the fully clean solution.
+ */
+ goto lose;
+ }
+ }
+
status = chip->direction_input(chip, gpio);
if (status == 0)
clear_bit(FLAG_IS_OUT, &desc->flags);
+lose:
return status;
fail:
spin_unlock_irqrestore(&gpio_lock, flags);
@@ -907,7 +959,9 @@ int gpio_direction_output(unsigned gpio, int value)
gpio -= chip->base;
if (gpio >= chip->ngpio)
goto fail;
- gpio_ensure_requested(desc);
+ status = gpio_ensure_requested(desc, gpio);
+ if (status < 0)
+ goto fail;
/* now we know the gpio is valid and chip won't vanish */
@@ -915,9 +969,22 @@ int gpio_direction_output(unsigned gpio, int value)
might_sleep_if(extra_checks && chip->can_sleep);
+ if (status) {
+ status = chip->request(chip, gpio);
+ if (status < 0) {
+ pr_debug("GPIO-%d: chip request fail, %d\n",
+ chip->base + gpio, status);
+ /* and it's not available to anyone else ...
+ * gpio_request() is the fully clean solution.
+ */
+ goto lose;
+ }
+ }
+
status = chip->direction_output(chip, gpio, value);
if (status == 0)
set_bit(FLAG_IS_OUT, &desc->flags);
+lose:
return status;
fail:
spin_unlock_irqrestore(&gpio_lock, flags);
@@ -1008,6 +1075,24 @@ int __gpio_cansleep(unsigned gpio)
}
EXPORT_SYMBOL_GPL(__gpio_cansleep);
+/**
+ * __gpio_to_irq() - return the IRQ corresponding to a GPIO
+ * @gpio: gpio whose IRQ will be returned (already requested)
+ * Context: any
+ *
+ * This is used directly or indirectly to implement gpio_to_irq().
+ * It returns the number of the IRQ signaled by this (input) GPIO,
+ * or a negative errno.
+ */
+int __gpio_to_irq(unsigned gpio)
+{
+ struct gpio_chip *chip;
+
+ chip = gpio_to_chip(gpio);
+ return chip->to_irq ? chip->to_irq(chip, gpio - chip->base) : -ENXIO;
+}
+EXPORT_SYMBOL_GPL(__gpio_to_irq);
+
/* There's no value in making it easy to inline GPIO calls that may sleep.
@@ -1020,7 +1105,7 @@ int gpio_get_value_cansleep(unsigned gpio)
might_sleep_if(extra_checks);
chip = gpio_to_chip(gpio);
- return chip->get(chip, gpio - chip->base);
+ return chip->get ? chip->get(chip, gpio - chip->base) : 0;
}
EXPORT_SYMBOL_GPL(gpio_get_value_cansleep);
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-11-18 13:05:24 +0000