Add a new flag to struct gpio_chip indicating that the chip doesn't model a real device. When setting up the line event queue, check if a device is a mockup chip and don't actually request the interrupt.
This way we can monitor mockup GPIOs. Signed-off-by: Bartosz Golaszewski <[email protected]> --- drivers/gpio/gpiolib.c | 27 +++++++++++++++++---------- include/linux/gpio/driver.h | 4 ++++ 2 files changed, 21 insertions(+), 10 deletions(-) diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index 6722579..19b4b8b 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -735,6 +735,7 @@ static irqreturn_t lineevent_irq_thread(int irq, void *p) static int lineevent_create(struct gpio_device *gdev, void __user *ip) { + struct gpio_chip *chip = gdev->chip; struct gpioevent_request eventreq; struct lineevent_state *le; struct gpio_desc *desc; @@ -807,7 +808,8 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip) goto out_free_desc; le->irq = gpiod_to_irq(desc); - if (le->irq <= 0) { + /* Mockup gpiochips don't have to support this. */ + if (le->irq <= 0 && !chip->mockup) { ret = -ENODEV; goto out_free_desc; } @@ -823,15 +825,20 @@ static int lineevent_create(struct gpio_device *gdev, void __user *ip) init_waitqueue_head(&le->wait); mutex_init(&le->read_lock); - /* Request a thread to read the events */ - ret = request_threaded_irq(le->irq, - NULL, - lineevent_irq_thread, - irqflags, - le->label, - le); - if (ret) - goto out_free_desc; + if (!chip->mockup) { + /* + * Request a thread to read the events unless we're dealing + * with a mockup gpiochip. + */ + ret = request_threaded_irq(le->irq, + NULL, + lineevent_irq_thread, + irqflags, + le->label, + le); + if (ret) + goto out_free_desc; + } fd = get_unused_fd_flags(O_RDONLY | O_CLOEXEC); if (fd < 0) { diff --git a/include/linux/gpio/driver.h b/include/linux/gpio/driver.h index e973fab..912eae1 100644 --- a/include/linux/gpio/driver.h +++ b/include/linux/gpio/driver.h @@ -82,6 +82,9 @@ enum single_ended_mode { * implies that if the chip supports IRQs, these IRQs need to be threaded * as the chip access may sleep when e.g. reading out the IRQ status * registers. + * @mockup: if set, the flag signifies that this gpiochip does not model a + * real device; this can affect the way the chip is handled internally + * by gpiolib. * @read_reg: reader function for generic GPIO * @write_reg: writer function for generic GPIO * @pin2mask: some generic GPIO controllers work with the big-endian bits @@ -166,6 +169,7 @@ struct gpio_chip { u16 ngpio; const char *const *names; bool can_sleep; + bool mockup; #if IS_ENABLED(CONFIG_GPIO_GENERIC) unsigned long (*read_reg)(void __iomem *reg); -- 2.9.3
