gpio: move gpio_ensure_requested() into legacy C file

gpio_ensure_requested() only makes sense when using the integer-based
GPIO API, so make sure it is called from there instead of the gpiod
API which we know cannot be called with a non-requested GPIO anyway.

The uses of gpio_ensure_requested() in the gpiod API were kind of
out-of-place anyway, so putting them in gpio-legacy.c helps clearing the
code.

Actually, considering the time this ensure_requested mechanism has been
around, maybe we should just turn this patch into "remove
gpio_ensure_requested()" if we know for sure that no user depend on it
anymore?

Signed-off-by: Alexandre Courbot <acourbot@nvidia.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

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);