6.9-stable review patch. If anyone has any objections, please let me know.
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From: Shiji Yang yangshiji66@outlook.com
[ Upstream commit f07798d7bb9c46d17d80103fb772fd2c75d47919 ]
bgpio_bits must be aligned with the data bus width. For example, on a 32 bit big endian system and we only have 16 GPIOs. If we only assume bgpio_bits=16 we can never control the GPIO because the base address is the lowest address.
low address high address ------------------------------------------------- | byte3 | byte2 | byte1 | byte0 | ------------------------------------------------- | NaN | NaN | gpio8-15 | gpio0-7 | -------------------------------------------------
Fixes: 55b2395e4e92 ("gpio: mmio: handle "ngpios" properly in bgpio_init()") Fixes: https://github.com/openwrt/openwrt/issues/15739 Reported-by: Mark Mentovai mark@mentovai.com Signed-off-by: Shiji Yang yangshiji66@outlook.com Suggested-By: Mark Mentovai mark@mentovai.com Reviewed-by: Jonas Gorski jonas.gorski@gmail.com Tested-by: Lóránd Horváth lorand.horvath82@gmail.com Reviewed-by: Linus Walleij linus.walleij@linaro.org Link: https://lore.kernel.org/r/TYCP286MB089577B47D70F0AB25ABA6F5BCD52@TYCP286MB08... Signed-off-by: Bartosz Golaszewski bartosz.golaszewski@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/gpio/gpio-mmio.c | 2 -- 1 file changed, 2 deletions(-)
diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c index 71e1af7c21847..d89e78f0ead31 100644 --- a/drivers/gpio/gpio-mmio.c +++ b/drivers/gpio/gpio-mmio.c @@ -619,8 +619,6 @@ int bgpio_init(struct gpio_chip *gc, struct device *dev, ret = gpiochip_get_ngpios(gc, dev); if (ret) gc->ngpio = gc->bgpio_bits; - else - gc->bgpio_bits = roundup_pow_of_two(round_up(gc->ngpio, 8));
ret = bgpio_setup_io(gc, dat, set, clr, flags); if (ret)