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path: root/drivers/gpio/gpiolib-legacy.c
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Diffstat (limited to 'drivers/gpio/gpiolib-legacy.c')
-rw-r--r--drivers/gpio/gpiolib-legacy.c106
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);

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