target/linux/brcm2708/patches-4.14/950-0280-gpiolib-Don-t-prevent-IRQ-usage-of-output-GPIOs.patch

   1 From aeb94070e992a60cf33f0300c8317b39e3ae16db Mon Sep 17 00:00:00 2001
   2 From: Phil Elwell <phil@raspberrypi.org>
   3 Date: Tue, 24 Apr 2018 14:42:27 +0100
   4 Subject: [PATCH 280/454] gpiolib: Don't prevent IRQ usage of output GPIOs
   5
   6 Upstream Linux deems using output GPIOs to generate IRQs as a bogus
   7 use case, even though the BCM2835 GPIO controller is capable of doing
   8 so. A number of users would like to make use of this facility, so
   9 disable the checks.
  10
  11 See: https://github.com/raspberrypi/linux/issues/2527
  12
  13 Signed-off-by: Phil Elwell <phil@raspberrypi.org>
  14 ---
  15  drivers/gpio/gpiolib.c | 6 ++++--
  16  1 file changed, 4 insertions(+), 2 deletions(-)
  17
  18 --- a/drivers/gpio/gpiolib.c
  19 +++ b/drivers/gpio/gpiolib.c
  20 @@ -53,6 +53,8 @@
  21  #define        extra_checks    0
  22  #endif
  23
  24 +#define dont_test_bit(b,d) (0)
  25 +
  26  /* Device and char device-related information */
  27  static DEFINE_IDA(gpio_ida);
  28  static dev_t gpio_devt;
  29 @@ -2306,7 +2308,7 @@ static int _gpiod_direction_output_raw(s
  30         int ret;
  31
  32         /* GPIOs used for IRQs shall not be set as output */
  33 -       if (test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
  34 +       if (dont_test_bit(FLAG_USED_AS_IRQ, &desc->flags)) {
  35                 gpiod_err(desc,
  36                           "%s: tried to set a GPIO tied to an IRQ as output\n",
  37                           __func__);
  38 @@ -2832,7 +2834,7 @@ int gpiochip_lock_as_irq(struct gpio_chi
  39                         set_bit(FLAG_IS_OUT, &desc->flags);
  40         }
  41
  42 -       if (test_bit(FLAG_IS_OUT, &desc->flags)) {
  43 +       if (dont_test_bit(FLAG_IS_OUT, &desc->flags)) {
  44                 chip_err(chip,
  45                           "%s: tried to flag a GPIO set as output for IRQ\n",
  46                           __func__);