diff mbox

[5/6] gpio: reference count the gpio device for each desc

Message ID 1455186383-28004-6-git-send-email-linus.walleij@linaro.org
State Accepted
Commit 33a68e86fd7741f782c71a0daa9111b352e94445
Headers show

Commit Message

Linus Walleij Feb. 11, 2016, 10:26 a.m. UTC
Every time a descriptor is retrieved from the gpiolib, we issue
module_get() to reference count the module supplying the GPIOs.
We also need to call device_get() and device_put() as we also
reference the backing gpio_device when doing this.

Since the sysfs GPIO interface is using gpiod_get() this will
also reference count the sysfs requests until all GPIOs are
unexported.

Signed-off-by: Linus Walleij <linus.walleij@linaro.org>

---
 drivers/gpio/gpiolib.c | 8 ++++++--
 1 file changed, 6 insertions(+), 2 deletions(-)

-- 
2.4.3

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diff mbox

Patch

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index cbc9c764a7fb..157ab40d19b1 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1205,6 +1205,8 @@  int gpiod_request(struct gpio_desc *desc, const char *label)
 		status = __gpiod_request(desc, label);
 		if (status < 0)
 			module_put(gdev->owner);
+		else
+			get_device(&gdev->dev);
 	}
 
 	if (status)
@@ -1248,10 +1250,12 @@  static bool __gpiod_free(struct gpio_desc *desc)
 
 void gpiod_free(struct gpio_desc *desc)
 {
-	if (desc && __gpiod_free(desc))
+	if (desc && desc->gdev && __gpiod_free(desc)) {
 		module_put(desc->gdev->owner);
-	else
+		put_device(&desc->gdev->dev);
+	} else {
 		WARN_ON(extra_checks);
+	}
 }
 
 /**