diff options
| author | Shiji Yang <yangshiji66@outlook.com> | 2024-06-25 04:19:49 +0300 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2024-07-11 13:49:13 +0300 |
| commit | dee87316b5f5f167a201491a774bbd6e10c8dd94 (patch) | |
| tree | ac19370ce04149762ffb3d1fdafcd86d8fa1ff25 | |
| parent | e3af5b14e7632bf12058533d69055393e2d126c9 (diff) | |
| download | linux-dee87316b5f5f167a201491a774bbd6e10c8dd94.tar.xz | |
gpio: mmio: do not calculate bgpio_bits via "ngpios"
[ 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@TYCP286MB0895.JPNP286.PROD.OUTLOOK.COM
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Signed-off-by: Sasha Levin <sashal@kernel.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 74fdf0d87b2c..c9f9f4e36c89 100644 --- a/drivers/gpio/gpio-mmio.c +++ b/drivers/gpio/gpio-mmio.c @@ -622,8 +622,6 @@ 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) |