This is a note to let you know that I've just added the patch titled
gpio: mmio: do not calculate bgpio_bits via "ngpios"
to the 6.9-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
gpio-mmio-do-not-calculate-bgpio_bits-via-ngpios.patch
and it can be found in the queue-6.9 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 1a9dc7a58560622daf10af515734c8042c8857c4
Author: Shiji Yang <yangshiji66@xxxxxxxxxxx>
Date: Tue Jun 25 09:19:49 2024 +0800
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@xxxxxxxxxxxx>
Signed-off-by: Shiji Yang <yangshiji66@xxxxxxxxxxx>
Suggested-By: Mark Mentovai <mark@xxxxxxxxxxxx>
Reviewed-by: Jonas Gorski <jonas.gorski@xxxxxxxxx>
Tested-by: Lóránd Horváth <lorand.horvath82@xxxxxxxxx>
Reviewed-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Link: https://lore.kernel.org/r/TYCP286MB089577B47D70F0AB25ABA6F5BCD52@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Signed-off-by: Bartosz Golaszewski <bartosz.golaszewski@xxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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)
