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 71492d2..828cd77 100644 (file)
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -57,6 +57,8 @@
 #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;
@@ -2591,8 +2593,8 @@ int gpiod_direction_output(struct gpio_desc *desc, int value)
                value = !!value;
 
        /* GPIOs used for enabled IRQs shall not be set as output */
-       if (test_bit(FLAG_USED_AS_IRQ, &desc->flags) &&
-           test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) {
+       if (dont_test_bit(FLAG_USED_AS_IRQ, &desc->flags) &&
+           dont_test_bit(FLAG_IRQ_IS_ENABLED, &desc->flags)) {
                gpiod_err(desc,
                          "%s: tried to set a GPIO tied to an IRQ as output\n",
                          __func__);
@@ -3470,8 +3472,8 @@ int gpiochip_lock_as_irq(struct gpio_chip *gc, unsigned int offset)
        }
 
        /* 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)) {
+       if (dont_test_bit(FLAG_IS_OUT, &desc->flags) &&
+           !dont_test_bit(FLAG_OPEN_DRAIN, &desc->flags)) {
                chip_err(gc,
                         "%s: tried to flag a GPIO set as output for IRQ\n",
                         __func__);