diff options
| author | Shiji Yang <yangshiji66@outlook.com> | 2024-06-25 09:19:49 +0800 |
|---|---|---|
| committer | Bartosz Golaszewski <bartosz.golaszewski@linaro.org> | 2024-07-03 15:27:59 +0200 |
| commit | f07798d7bb9c46d17d80103fb772fd2c75d47919 (patch) | |
| tree | 308fe5f604b00d6d7e1986ae433d329d26807adb | |
| parent | 3645ffaf2b334abaf5f53e5ca0f47465d91e69d2 (diff) | |
gpio: mmio: do not calculate bgpio_bits via "ngpios"
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@TYCP286MB0895.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
| -rw-r--r-- | drivers/gpio/gpio-mmio.c | 2 |
1 files changed, 0 insertions, 2 deletions
diff --git a/drivers/gpio/gpio-mmio.c b/drivers/gpio/gpio-mmio.c index 71e1af7c2184..d89e78f0ead3 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) |