[PATCH 5/5] gpio: move gpio_ensure_requested() into legacy C file

Alexandre Courbot
2014-07-22T07:18:54Z

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>
---
drivers/gpio/gpiolib-legacy.c | 106 ++++++++++++++++++++++++++++++++++
drivers/gpio/gpiolib.c | 129 ++----------------------------------------
include/asm-generic/gpio.h | 15 +----
3 files changed, 113 insertions(+), 137 deletions(-)

diff --git a/drivers/gpio/gpiolib-legacy.c b/drivers/gpio/gpiolib-legacy.c
index c3e3823a40b9..9da5deee716c 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));
@@ -97,3 +155,51 @@ 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);
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 7582207c92e7..412d64e93cfb 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -95,39 +95,6 @@ int desc_to_gpio(const struct gpio_desc *desc)
EXPORT_SYMBOL_GPL(desc_to_gpio);

-/* 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)
-{
- const struct gpio_chip *chip = desc->chip;
- const int gpio = desc_to_gpio(desc);
-
- if (WARN(test_and_set_bit(FLAG_REQUESTED, &desc->flags) == 0,
- "autorequest GPIO-%d\n", gpio)) {
- if (!try_module_get(chip->owner)) {
- gpiod_err(desc, "%s: module can't be gotten\n",
- __func__);
- clear_bit(FLAG_REQUESTED, &desc->flags);
- /* lose */
- return -EIO;
- }
- desc_set_label(desc, "[auto]");
- /* caller must chip->request() w/o spinlock */
- if (chip->request)
- return 1;
- }
- return 0;
-}
-
/**
* gpiod_to_chip - Return the GPIO chip to which a GPIO descriptor belongs
* @desc: descriptor to return the chip of
@@ -964,10 +931,8 @@ void gpiochip_free_own_desc(struct gpio_desc *desc)
*/
int gpiod_direction_input(struct gpio_desc *desc)
{
- unsigned long flags;
struct gpio_chip *chip;
int status = -EINVAL;
- int offset;

if (!desc || !desc->chip) {
pr_warn("%s: invalid GPIO\n", __func__);
@@ -982,52 +947,20 @@ int gpiod_direction_input(struct gpio_desc *desc)
return -EIO;
}

- spin_lock_irqsave(&gpio_lock, flags);
-
- status = gpio_ensure_requested(desc);
- if (status < 0)
- goto fail;
-
- /* now we know the gpio is valid and chip won't vanish */
-
- spin_unlock_irqrestore(&gpio_lock, flags);
-
- might_sleep_if(chip->can_sleep);
-
- offset = gpio_chip_hwgpio(desc);
- if (status) {
- status = chip->request(chip, offset);
- if (status < 0) {
- gpiod_dbg(desc, "%s: chip request fail, %d\n",
- __func__, status);
- /* and it's not available to anyone else ...
- * gpio_request() is the fully clean solution.
- */
- goto lose;
- }
- }
-
- status = chip->direction_input(chip, offset);
+ status = chip->direction_input(chip, gpio_chip_hwgpio(desc));
if (status == 0)
clear_bit(FLAG_IS_OUT, &desc->flags);

trace_gpio_direction(desc_to_gpio(desc), 1, status);
-lose:
- return status;
-fail:
- spin_unlock_irqrestore(&gpio_lock, flags);
- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
+
return status;
}
EXPORT_SYMBOL_GPL(gpiod_direction_input);

static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
{
- unsigned long flags;
struct gpio_chip *chip;
int status = -EINVAL;
- int offset;

/* GPIOs used for IRQs shall not be set as output */
if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
@@ -1053,42 +986,11 @@ static int _gpiod_direction_output_raw(struct gpio_desc *desc, int value)
return -EIO;
}

- spin_lock_irqsave(&gpio_lock, flags);
-
- status = gpio_ensure_requested(desc);
- if (status < 0)
- goto fail;
-
- /* now we know the gpio is valid and chip won't vanish */
-
- spin_unlock_irqrestore(&gpio_lock, flags);
-
- might_sleep_if(chip->can_sleep);
-
- offset = gpio_chip_hwgpio(desc);
- if (status) {
- status = chip->request(chip, offset);
- if (status < 0) {
- gpiod_dbg(desc, "%s: chip request fail, %d\n",
- __func__, status);
- /* and it's not available to anyone else ...
- * gpio_request() is the fully clean solution.
- */
- goto lose;
- }
- }
-
- status = chip->direction_output(chip, offset, value);
+ status = chip->direction_output(chip, gpio_chip_hwgpio(desc), value);
if (status == 0)
set_bit(FLAG_IS_OUT, &desc->flags);
trace_gpio_value(desc_to_gpio(desc), 0, value);
trace_gpio_direction(desc_to_gpio(desc), 0, status);
-lose:
- return status;
-fail:
- spin_unlock_irqrestore(&gpio_lock, flags);
- if (status)
- gpiod_dbg(desc, "%s: gpio status %d\n", __func__, status);
return status;
}

@@ -1147,10 +1049,7 @@ EXPORT_SYMBOL_GPL(gpiod_direction_output);
*/
int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
{
- unsigned long flags;
struct gpio_chip *chip;
- int status = -EINVAL;
- int offset;

if (!desc || !desc->chip) {
pr_warn("%s: invalid GPIO\n", __func__);
@@ -1165,27 +1064,7 @@ int gpiod_set_debounce(struct gpio_desc *desc, unsigned debounce)
return -ENOTSUPP;
}

- spin_lock_irqsave(&gpio_lock, flags);
-
- status = gpio_ensure_requested(desc);
- if (status < 0)
- goto fail;
-
- /* now we know the gpio is valid and chip won't vanish */
-
- spin_unlock_irqrestore(&gpio_lock, flags);
-
- might_sleep_if(chip->can_sleep);
-
- offset = gpio_chip_hwgpio(desc);
- return chip->set_debounce(chip, offset, debounce);
-
-fail:
- spin_unlock_irqrestore(&gpio_lock, flags);
- if (status)
- gpiod_dbg(desc, "%s: status %d\n", __func__, status);
-
- return status;
+ return chip->set_debounce(chip, gpio_chip_hwgpio(desc), debounce);
}
EXPORT_SYMBOL_GPL(gpiod_set_debounce);

diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index c1d4105e1c1d..39a1d06950d9 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -63,19 +63,10 @@ static inline struct gpio_chip *gpio_to_chip(unsigned gpio)
extern int gpio_request(unsigned gpio, const char *label);
extern void gpio_free(unsigned gpio);

-static inline int gpio_direction_input(unsigned gpio)
-{
- return gpiod_direction_input(gpio_to_desc(gpio));
-}
-static inline int gpio_direction_output(unsigned gpio, int value)
-{
- return gpiod_direction_output_raw(gpio_to_desc(gpio), value);
-}
+extern int gpio_direction_input(unsigned gpio);
+extern int gpio_direction_output(unsigned gpio, int value);

-static inline int gpio_set_debounce(unsigned gpio, unsigned debounce)
-{
- return gpiod_set_debounce(gpio_to_desc(gpio), debounce);
-}
+extern int gpio_set_debounce(unsigned gpio, unsigned debounce);

static inline int gpio_get_value_cansleep(unsigned gpio)
{
--
2.0.1