Commit 9411e3aa authored by Andy Shevchenko's avatar Andy Shevchenko Committed by Linus Walleij
Browse files

gpiolib: Initialize the hardware with a callback 



After changing the drivers to use GPIO core to add an IRQ chip
it appears that some of them requires a hardware initialization
before adding the IRQ chip.

Add an optional callback ->init_hw() to allow that drivers
to initialize hardware if needed.

This change is a part of the fix NULL pointer dereference
brought to the several drivers recently.

Cc: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: default avatarAndy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: default avatarLinus Walleij <linus.walleij@linaro.org>
parent 6658f87f

drivers/gpio/gpiolib.c

+21 −1
Original line number Diff line number Diff line
@@ -86,6 +86,7 @@ static int gpiochip_add_irqchip(struct gpio_chip *gpiochip, 
				struct lock_class_key *lock_key,

				struct lock_class_key *request_key);

static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip);

static int gpiochip_irqchip_init_hw(struct gpio_chip *gpiochip);

static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip);

static void gpiochip_irqchip_free_valid_mask(struct gpio_chip *gpiochip);
@@ -1406,6 +1407,10 @@ int gpiochip_add_data_with_key(struct gpio_chip *chip, void *data, 


	machine_gpiochip_add(chip);



	ret = gpiochip_irqchip_init_hw(chip);

	if (ret)

		goto err_remove_acpi_chip;



	ret = gpiochip_irqchip_init_valid_mask(chip);

	if (ret)

		goto err_remove_acpi_chip;
@@ -1622,6 +1627,16 @@ static struct gpio_chip *find_chip_by_name(const char *name) 
 * The following is irqchip helper code for gpiochips.

 */



static int gpiochip_irqchip_init_hw(struct gpio_chip *gc)

{

	struct gpio_irq_chip *girq = &gc->irq;



	if (!girq->init_hw)

		return 0;



	return girq->init_hw(gc);

}



static int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gc)

{

	struct gpio_irq_chip *girq = &gc->irq;
@@ -2446,8 +2461,13 @@ static inline int gpiochip_add_irqchip(struct gpio_chip *gpiochip, 
{

	return 0;

}



static void gpiochip_irqchip_remove(struct gpio_chip *gpiochip) {}



static inline int gpiochip_irqchip_init_hw(struct gpio_chip *gpiochip)

{

	return 0;

}



static inline int gpiochip_irqchip_init_valid_mask(struct gpio_chip *gpiochip)

{

	return 0;

include/linux/gpio/driver.h

+8 −0
Original line number Diff line number Diff line
@@ -201,6 +201,14 @@ struct gpio_irq_chip { 
	 */

	bool threaded;



	/**

	 * @init_hw: optional routine to initialize hardware before

	 * an IRQ chip will be added. This is quite useful when

	 * a particular driver wants to clear IRQ related registers

	 * in order to avoid undesired events.

	 */

	int (*init_hw)(struct gpio_chip *chip);



	/**

	 * @init_valid_mask: optional routine to initialize @valid_mask, to be

	 * used if not all GPIO lines are valid interrupts. Sometimes some

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