From: Andrei Lalaev andrei.lalaev@emlid.com
commit e75f88efac05bf4e107e4171d8db6d8c3937252d upstream.
Gpiolib interprets the elements of "gpio-reserved-ranges" as "start,size" because it clears "size" bits starting from the "start" bit in the according bitmap. So it has to use "greater" instead of "greater or equal" when performs bounds check to make sure that GPIOs are in the available range. Previous implementation skipped ranges that include the last GPIO in the range.
I wrote the mail to the maintainers (https://lore.kernel.org/linux-gpio/20220412115554.159435-1-andrei.lalaev@eml...) of the questioned DTSes (because I couldn't understand how the maintainers interpreted this property), but I haven't received a response. Since the questioned DTSes use "gpio-reserved-ranges = <0 4>" (i.e., the beginning of the range), this patch doesn't affect these DTSes at all. TBH this patch doesn't break any existing DTSes because none of them reserve gpios at the end of range.
Fixes: 726cb3ba4969 ("gpiolib: Support 'gpio-reserved-ranges' property") Signed-off-by: Andrei Lalaev andrei.lalaev@emlid.com Reviewed-by: Andy Shevchenko andy.shevchenko@gmail.com Reviewed-by: Linus Walleij linus.walleij@linaro.org Cc: stable@vger.kernel.org Signed-off-by: Bartosz Golaszewski brgl@bgdev.pl Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/gpio/gpiolib-of.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
--- a/drivers/gpio/gpiolib-of.c +++ b/drivers/gpio/gpiolib-of.c @@ -783,7 +783,7 @@ static void of_gpiochip_init_valid_mask( i, &start); of_property_read_u32_index(np, "gpio-reserved-ranges", i + 1, &count); - if (start >= chip->ngpio || start + count >= chip->ngpio) + if (start >= chip->ngpio || start + count > chip->ngpio) continue;
bitmap_clear(chip->valid_mask, start, count);