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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: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
alistair/sunxi64-5.4-dsi
Andy Shevchenko 2019-10-09 17:34:44 +03:00 committed by Linus Walleij
parent 6658f87f21
commit 9411e3aaa6
2 changed files with 29 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
drivers/gpio/gpiolib.c
View File

@ -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;

8
include/linux/gpio/driver.h
View File

@ -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