From 594fa265e084073443390c5b93d5410fd28e9bcd Mon Sep 17 00:00:00 2001 From: Grant Likely Date: Tue, 8 Jun 2010 07:48:16 -0600 Subject: of/gpio: stop using device_node data pointer to find gpio_chip Currently the kernel uses the struct device_node.data pointer to resolve a struct gpio_chip pointer from a device tree node. However, the .data member doesn't provide any type checking and there aren't any rules enforced on what it should be used for. There's no guarantee that the data stored in it actually points to an gpio_chip pointer. Instead of relying on the .data pointer, this patch modifies the code to add a lookup function which scans through the registered gpio_chips and returns the gpio_chip that has a pointer to the specified device_node. Signed-off-by: Grant Likely CC: Andrew Morton CC: Anton Vorontsov CC: Grant Likely CC: David Brownell CC: Bill Gatliff CC: Dmitry Eremin-Solenikov CC: Benjamin Herrenschmidt CC: Jean Delvare CC: linux-kernel@vger.kernel.org CC: devicetree-discuss@lists.ozlabs.org --- drivers/gpio/gpiolib.c | 32 ++++++++++++++++++++++++++++++++ 1 file changed, 32 insertions(+) (limited to 'drivers/gpio') diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 713ca0e..73fd328 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -1153,6 +1153,38 @@ int gpiochip_remove(struct gpio_chip *chip) } EXPORT_SYMBOL_GPL(gpiochip_remove); +/** + * gpiochip_find() - iterator for locating a specific gpio_chip + * @data: data to pass to match function + * @callback: Callback function to check gpio_chip + * + * Similar to bus_find_device. It returns a reference to a gpio_chip as + * determined by a user supplied @match callback. The callback should return + * 0 if the device doesn't match and non-zero if it does. If the callback is + * non-zero, this function will return to the caller and not iterate over any + * more gpio_chips. + */ +struct gpio_chip *gpiochip_find(void *data, + int (*match)(struct gpio_chip *chip, void *data)) +{ + struct gpio_chip *chip = NULL; + unsigned long flags; + int i; + + spin_lock_irqsave(&gpio_lock, flags); + for (i = 0; i < ARCH_NR_GPIOS; i++) { + if (!gpio_desc[i].chip) + continue; + + if (match(gpio_desc[i].chip, data)) { + chip = gpio_desc[i].chip; + break; + } + } + spin_unlock_irqrestore(&gpio_lock, flags); + + return chip; +} /* These "optional" allocation calls help prevent drivers from stomping * on each other, and help provide better diagnostics in debugfs. -- cgit v1.1