From e9bdf7e655b9ee81ee912fae1d59df48ce7311b6 Mon Sep 17 00:00:00 2001
From: Linus Walleij <linus.walleij@linaro.org>
Date: Wed, 27 May 2020 16:07:58 +0200
Subject: [PATCH] gpio: fix locking open drain IRQ lines
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>
---
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 b4b5792fe2ffc..c14f0784274ae 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)) {
chip_err(gc,
"%s: tried to flag a GPIO set as output for IRQ\n",
__func__);
@@ -4283,7 +4285,12 @@ void gpiochip_enable_irq(struct gpio_chip *gc, 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);
}
}
--
GitLab