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Subject[RFC PATCH 2/2] gpio: provide a consumer when requesting a gpio
Date
It can be useful for the pinmuxing layer to know which device is
requesting a GPIO. Add a consumer variant for gpiod_request to
reach this goal.

GPIO chips managed by pin controllers should provide the new
request_consumer operation. They can rely on
gpiochip_generic_request_consumer instead of
gpiochip_generic_request.

Signed-off-by: Ludovic Desroches <ludovic.desroches@microchip.com>
---
drivers/gpio/gpiolib.c | 40 +++++++++++++++++++++++++++++++++-------
include/linux/gpio/driver.h | 5 +++++
2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 39a0144d5be5..e6645101ec74 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1970,6 +1970,20 @@ int gpiochip_generic_request(struct gpio_chip *chip, unsigned offset)
EXPORT_SYMBOL_GPL(gpiochip_generic_request);

/**
+ * gpiochip_generic_request_consumer() - request the gpio function for a pin
+ * @chip: the gpiochip owning the GPIO
+ * @offset: the offset of the GPIO to request for GPIO function
+ * @consumer: name of the device requesting the GPIO
+ */
+int gpiochip_generic_request_consumer(struct gpio_chip *chip, unsigned offset,
+ const char *consumer)
+{
+ return pinctrl_gpio_request_consumer(chip->gpiodev->base + offset,
+ consumer);
+}
+EXPORT_SYMBOL_GPL(gpiochip_generic_request_consumer);
+
+/**
* gpiochip_generic_free() - free the gpio function from a pin
* @chip: the gpiochip to request the gpio function for
* @offset: the offset of the GPIO to free from GPIO function
@@ -2119,7 +2133,8 @@ EXPORT_SYMBOL_GPL(gpiochip_remove_pin_ranges);
* on each other, and help provide better diagnostics in debugfs.
* They're called even less than the "set direction" calls.
*/
-static int gpiod_request_commit(struct gpio_desc *desc, const char *label)
+static int gpiod_request_commit(struct gpio_desc *desc, const char *label,
+ const char *consumer)
{
struct gpio_chip *chip = desc->gdev->chip;
int status;
@@ -2139,10 +2154,14 @@ static int gpiod_request_commit(struct gpio_desc *desc, const char *label)
goto done;
}

- if (chip->request) {
+ if (chip->request || chip->request_consumer) {
/* chip->request may sleep */
spin_unlock_irqrestore(&gpio_lock, flags);
- status = chip->request(chip, gpio_chip_hwgpio(desc));
+ if (chip->request_consumer)
+ status = chip->request_consumer(chip,
+ gpio_chip_hwgpio(desc), consumer);
+ else
+ status = chip->request(chip, gpio_chip_hwgpio(desc));
spin_lock_irqsave(&gpio_lock, flags);

if (status < 0) {
@@ -2200,7 +2219,8 @@ static int validate_desc(const struct gpio_desc *desc, const char *func)
return; \
} while (0)

-int gpiod_request(struct gpio_desc *desc, const char *label)
+int gpiod_request_consumer(struct gpio_desc *desc, const char *label,
+ const char *consumer)
{
int status = -EPROBE_DEFER;
struct gpio_device *gdev;
@@ -2209,7 +2229,7 @@ int gpiod_request(struct gpio_desc *desc, const char *label)
gdev = desc->gdev;

if (try_module_get(gdev->owner)) {
- status = gpiod_request_commit(desc, label);
+ status = gpiod_request_commit(desc, label, consumer);
if (status < 0)
module_put(gdev->owner);
else
@@ -2222,6 +2242,11 @@ int gpiod_request(struct gpio_desc *desc, const char *label)
return status;
}

+int gpiod_request(struct gpio_desc *desc, const char *label)
+{
+ return gpiod_request_consumer(desc, label, NULL);
+}
+
static bool gpiod_free_commit(struct gpio_desc *desc)
{
bool ret = false;
@@ -2320,7 +2345,7 @@ struct gpio_desc *gpiochip_request_own_desc(struct gpio_chip *chip, u16 hwnum,
return desc;
}

- err = gpiod_request_commit(desc, label);
+ err = gpiod_request_commit(desc, label, NULL);
if (err < 0)
return ERR_PTR(err);

@@ -3672,7 +3697,8 @@ struct gpio_desc *__must_check gpiod_get_index(struct device *dev,
}

/* If a connection label was passed use that, else use the device name as label */
- status = gpiod_request(desc, con_id ? con_id : dev_name(dev));
+ status = gpiod_request_consumer(desc, con_id ? con_id : dev_name(dev),
+ dev_name(dev));
if (status < 0)
return ERR_PTR(status);

diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h
index 1ba9a331ec51..6bc5c57f0cbd 100644
--- a/include/linux/gpio/driver.h
+++ b/include/linux/gpio/driver.h
@@ -228,6 +228,9 @@ struct gpio_chip {

int (*request)(struct gpio_chip *chip,
unsigned offset);
+ int (*request_consumer)(struct gpio_chip *chip,
+ unsigned offset,
+ const char *consumer);
void (*free)(struct gpio_chip *chip,
unsigned offset);
int (*get_direction)(struct gpio_chip *chip,
@@ -500,6 +503,8 @@ static inline int gpiochip_irqchip_add_nested(struct gpio_chip *gpiochip,
#endif /* CONFIG_GPIOLIB_IRQCHIP */

int gpiochip_generic_request(struct gpio_chip *chip, unsigned offset);
+int gpiochip_generic_request_consumer(struct gpio_chip *chip, unsigned offset,
+ const char *consumer);
void gpiochip_generic_free(struct gpio_chip *chip, unsigned offset);
int gpiochip_generic_config(struct gpio_chip *chip, unsigned offset,
unsigned long config);
--
2.12.2
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