gpiolib: don't crash on enabling GPIO HOG pins

On Qualcomm platforms if the board uses GPIO hogs msm_pinmux_request()
calls gpiochip_line_is_valid(). After commit 8015443e ("gpio: Hide
valid_mask from direct assignments") gpiochip_line_is_valid() uses
gc->gpiodev, which is NULL when GPIO hog pins are being processed.
Thus after this commit using GPIO hogs causes the following crash. In
order to fix this, verify that gc->gpiodev is not NULL.

Note: it is not possible to reorder calls (e.g. by calling
msm_gpio_init() before pinctrl registration or by splitting
pinctrl_register() into _and_init() and pinctrl_enable() and calling the
latter function after msm_gpio_init()) because GPIO chip registration
would fail with EPROBE_DEFER if pinctrl is not enabled at the time of
registration.

pc : gpiochip_line_is_valid+0x4/0x28
lr : msm_pinmux_request+0x24/0x40
sp : ffff8000808eb870
x29: ffff8000808eb870 x28: 0000000000000000 x27: 0000000000000000
x26: 0000000000000000 x25: ffff726240f9d040 x24: 0000000000000000
x23: ffff7262438c0510 x22: 0000000000000080 x21: ffff726243ea7000
x20: ffffab13f2c4e698 x19: 0000000000000080 x18: 00000000ffffffff
x17: ffff726242ba6000 x16: 0000000000000100 x15: 0000000000000028
x14: 0000000000000000 x13: 0000000000002948 x12: 0000000000000003
x11: 0000000000000078 x10: 0000000000002948 x9 : ffffab13f50eb5e8
x8 : 0000000003ecb21b x7 : 000000000000002d x6 : 0000000000000b68
x5 : 0000007fffffffff x4 : ffffab13f52f84a8 x3 : ffff8000808eb804
x2 : ffffab13f1de8190 x1 : 0000000000000080 x0 : 0000000000000000
Call trace:
 gpiochip_line_is_valid+0x4/0x28 (P)
 pin_request+0x208/0x2c0
 pinmux_enable_setting+0xa0/0x2e0
 pinctrl_commit_state+0x150/0x26c
 pinctrl_enable+0x6c/0x2a4
 pinctrl_register+0x3c/0xb0
 devm_pinctrl_register+0x58/0xa0
 msm_pinctrl_probe+0x2a8/0x584
 sdm845_pinctrl_probe+0x20/0x88
 platform_probe+0x68/0xc0
 really_probe+0xbc/0x298
 __driver_probe_device+0x78/0x12c
 driver_probe_device+0x3c/0x160
 __device_attach_driver+0xb8/0x138
 bus_for_each_drv+0x84/0xe0
 __device_attach+0x9c/0x188
 device_initial_probe+0x14/0x20
 bus_probe_device+0xac/0xb0
 deferred_probe_work_func+0x8c/0xc8
 process_one_work+0x208/0x5e8
 worker_thread+0x1b4/0x35c
 kthread+0x144/0x220
 ret_from_fork+0x10/0x20
Code: b5fffba0 17fffff2 9432ec27 f9400400 (f9428800)

Fixes: 8015443e ("gpio: Hide valid_mask from direct assignments")
Reported-by: Doug Anderson <dianders@chromium.org>
Closes: https://lore.kernel.org/r/CAD=FV=Vg8_ZOLgLoC4WhFPzhVsxXFC19NrF38W6cW_W_3nFjbw@mail.gmail.com


Tested-by: Douglas Anderson <dianders@chromium.org>
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@oss.qualcomm.com>
Reviewed-by: Matti Vaittinen <mazziesaccount@gmail.com>
Acked-by: Bartosz Golaszewski <bartosz.golaszewski@linaro.org>
Link: https://lore.kernel.org/20250513-pinctrl-msm-fix-v2-1-249999af0fc1@oss.qualcomm.com


Signed-off-by: Linus Walleij <linus.walleij@linaro.org>