From: Linus Walleij linus.walleij@linaro.org
[ Upstream commit e9bdf7e655b9ee81ee912fae1d59df48ce7311b6 ]
We provided the right semantics on open drain lines being by definition output but incidentally the irq set up function would only allow IRQs on lines that were "not output".
Fix the semantics to allow output open drain lines to be used for IRQs.
Reported-by: Hans Verkuil hverkuil@xs4all.nl Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Hans Verkuil hverkuil@xs4all.nl Tested-by: Hans Verkuil hverkuil@xs4all.nl Cc: Russell King linux@armlinux.org.uk Cc: stable@vger.kernel.org # v5.3+ Link: https://lore.kernel.org/r/20200527140758.162280-1-linus.walleij@linaro.org Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpio/gpiolib.c | 11 +++++++++-- 1 file changed, 9 insertions(+), 2 deletions(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index a8cf55eb54d8..abdf448b11a3 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -3894,7 +3894,9 @@ int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset) } }
- if (test_bit(FLAG_IS_OUT, &desc->flags)) { + /* To be valid for IRQ the line needs to be input or open drain */ + if (test_bit(FLAG_IS_OUT, &desc->flags) && + !test_bit(FLAG_OPEN_DRAIN, &desc->flags)) { chip_err(chip, "%s: tried to flag a GPIO set as output for IRQ\n", __func__); @@ -3957,7 +3959,12 @@ void gpiochip_enable_irq(struct gpio_chip *chip, unsigned int offset)
if (!IS_ERR(desc) && !WARN_ON(!test_bit(FLAG_USED_AS_IRQ, &desc->flags))) { - WARN_ON(test_bit(FLAG_IS_OUT, &desc->flags)); + /* + * We must not be output when using IRQ UNLESS we are + * open drain. + */ + WARN_ON(test_bit(FLAG_IS_OUT, &desc->flags) && + !test_bit(FLAG_OPEN_DRAIN, &desc->flags)); set_bit(FLAG_IRQ_IS_ENABLED, &desc->flags); } }