From: Bartosz Golaszewski bgolaszewski@baylibre.com
commit 2c60e6b5c9241b24b8b523fefd3e44fb85622cda upstream.
If the driver doesn't support open-drain/source config options, we emulate this behavior when setting the direction by calling gpiod_direction_input() if the default value is 0 (open-source) or 1 (open-drain), thus not actively driving the line in those cases.
This however clears the FLAG_IS_OUT bit for the GPIO line descriptor and makes the LINEINFO ioctl() incorrectly report this line's mode as 'input' to user-space.
This commit modifies the ioctl() to always set the GPIOLINE_FLAG_IS_OUT bit in the lineinfo structure's flags field. Since it's impossible to use the input mode and open-drain/source options at the same time, we can be sure the reported information will be correct.
Fixes: 521a2ad6f862 ("gpio: add userspace ABI for GPIO line information") Cc: stable stable@vger.kernel.org Signed-off-by: Bartosz Golaszewski bgolaszewski@baylibre.com Link: https://lore.kernel.org/r/20190806114151.17652-1-brgl@bgdev.pl Signed-off-by: Linus Walleij linus.walleij@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org
--- drivers/gpio/gpiolib.c | 6 ++++-- 1 file changed, 4 insertions(+), 2 deletions(-)
--- a/drivers/gpio/gpiolib.c +++ b/drivers/gpio/gpiolib.c @@ -953,9 +953,11 @@ static long gpio_ioctl(struct file *filp if (test_bit(FLAG_ACTIVE_LOW, &desc->flags)) lineinfo.flags |= GPIOLINE_FLAG_ACTIVE_LOW; if (test_bit(FLAG_OPEN_DRAIN, &desc->flags)) - lineinfo.flags |= GPIOLINE_FLAG_OPEN_DRAIN; + lineinfo.flags |= (GPIOLINE_FLAG_OPEN_DRAIN | + GPIOLINE_FLAG_IS_OUT); if (test_bit(FLAG_OPEN_SOURCE, &desc->flags)) - lineinfo.flags |= GPIOLINE_FLAG_OPEN_SOURCE; + lineinfo.flags |= (GPIOLINE_FLAG_OPEN_SOURCE | + GPIOLINE_FLAG_IS_OUT);
if (copy_to_user(ip, &lineinfo, sizeof(lineinfo))) return -EFAULT;