On Wed, May 27, 2020 at 04:07:58PM +0200, Linus Walleij wrote:
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 Cc: Russell King linux@armlinux.org.uk Cc: stable@vger.kernel.org Fixes: 256efaea1fdc ("gpiolib: fix up emulated open drain outputs")
As I've pointed out in the reporting thread, I don't think it can be justified as a regression - it's a bug in its own right that has been discovered by unifying the gpiolib semantics, since the cec-gpio code will fail on hardware that can provide real open-drain outputs irrespective of that commit.
So, you're really fixing a deeper problem that was never discovered until gpiolib's semantics were fixed to be more uniform.
Signed-off-by: Linus Walleij linus.walleij@linaro.org
drivers/gpio/gpiolib.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c index b4b5792fe2ff..edd74ff31cea 100644 --- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -4220,7 +4220,9 @@ int gpiochip_lock_as_irq(struct gpio_chip *gc, 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)) {-- 2.25.4