From: Phil Elwell <phil@raspberrypi.org>
Date: Tue, 24 Apr 2018 13:42:27 +0000 (+0100)
Subject: gpiolib: Don't prevent IRQ usage of output GPIOs
X-Git-Tag: accepted/tizen/unified/20190614.051536~552
X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=6fa2790354d827f2fe4bf4eab315a802b2a1611a;p=platform%2Fkernel%2Flinux-rpi3.git

gpiolib: Don't prevent IRQ usage of output GPIOs

Upstream Linux deems using output GPIOs to generate IRQs as a bogus
use case, even though the BCM2835 GPIO controller is capable of doing
so. A number of users would like to make use of this facility, so
disable the checks.

See: https://github.com/raspberrypi/linux/issues/2527

Signed-off-by: Phil Elwell <phil@raspberrypi.org>
---

diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index fd713326..f54b2b7 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -53,6 +53,8 @@
 #define	extra_checks	0
 #endif
 
+#define dont_test_bit(b,d) (0)
+
 /* Device and char device-related information */
 static DEFINE_IDA(gpio_ida);
 static dev_t gpio_devt;
@@ -2624,7 +2626,7 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
 		value = !!value;
 
 	/* GPIOs used for IRQs shall not be set as output */
-	if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
+	if (dont_test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
 		gpiod_err(desc,
 			  "%s: tried to set a GPIO tied to an IRQ as output\n",
 			  __func__);
@@ -3311,7 +3313,7 @@ int gpiochip_lock_as_irq(struct gpio_chip *chip, unsigned int offset)
 		}
 	}
 
-	if (test_bit(FLAG_IS_OUT, &desc->flags)) {
+	if (dont_test_bit(FLAG_IS_OUT, &desc->flags)) {
 		chip_err(chip,
 			 "%s: tried to flag a GPIO set as output for IRQ\n",
 			 __func__);