4.14-stable review patch. If anyone has any objections, please let me know.
------------------
[ Upstream commit cec2b18832e26bc866bef2be22eff4e25bbc4034 ]
gpiod_get_value() gives out a warning if access to the underlying gpiochip requires sleeping, which is common for I2C based chips:
WARNING: CPU: 0 PID: 77 at drivers/gpio/gpiolib.c:2500 gpiod_get_value+0xd0/0x100 Modules linked in: CPU: 0 PID: 77 Comm: kworker/0:2 Not tainted 4.14.0-rc3-00589-gf32897915d48-dirty #90 Hardware name: Allwinner sun4i/sun5i Families Workqueue: events deferred_probe_work_func [<c010ec50>] (unwind_backtrace) from [<c010b784>] (show_stack+0x10/0x14) [<c010b784>] (show_stack) from [<c0797224>] (dump_stack+0x88/0x9c) [<c0797224>] (dump_stack) from [<c0125b08>] (__warn+0xe8/0x100) [<c0125b08>] (__warn) from [<c0125bd0>] (warn_slowpath_null+0x20/0x28) [<c0125bd0>] (warn_slowpath_null) from [<c037069c>] (gpiod_get_value+0xd0/0x100) [<c037069c>] (gpiod_get_value) from [<c03778d0>] (pwm_backlight_probe+0x238/0x508) [<c03778d0>] (pwm_backlight_probe) from [<c0411a2c>] (platform_drv_probe+0x50/0xac) [<c0411a2c>] (platform_drv_probe) from [<c0410224>] (driver_probe_device+0x238/0x2e8) [<c0410224>] (driver_probe_device) from [<c040e820>] (bus_for_each_drv+0x44/0x94) [<c040e820>] (bus_for_each_drv) from [<c040ff0c>] (__device_attach+0xb0/0x114) [<c040ff0c>] (__device_attach) from [<c040f4f8>] (bus_probe_device+0x84/0x8c) [<c040f4f8>] (bus_probe_device) from [<c040f944>] (deferred_probe_work_func+0x50/0x14c) [<c040f944>] (deferred_probe_work_func) from [<c013be84>] (process_one_work+0x1ec/0x414) [<c013be84>] (process_one_work) from [<c013ce5c>] (worker_thread+0x2b0/0x5a0) [<c013ce5c>] (worker_thread) from [<c0141908>] (kthread+0x14c/0x154) [<c0141908>] (kthread) from [<c0107ab0>] (ret_from_fork+0x14/0x24)
This was missed in commit 0c9501f823a4 ("backlight: pwm_bl: Handle gpio that can sleep"). The code was then moved to a separate function in commit 7613c922315e ("backlight: pwm_bl: Move the checks for initial power state to a separate function").
The only usage of gpiod_get_value() is during the probe stage, which is safe to sleep in. Switch to gpiod_get_value_cansleep().
Fixes: 0c9501f823a4 ("backlight: pwm_bl: Handle gpio that can sleep") Signed-off-by: Chen-Yu Tsai wens@csie.org Acked-by: Maxime Ripard maxime.ripard@bootlin.com Acked-by: Daniel Thompson daniel.thompson@linaro.org Signed-off-by: Lee Jones lee.jones@linaro.org Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/video/backlight/pwm_bl.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/video/backlight/pwm_bl.c b/drivers/video/backlight/pwm_bl.c index 155153ecb894..2a0ce0c68302 100644 --- a/drivers/video/backlight/pwm_bl.c +++ b/drivers/video/backlight/pwm_bl.c @@ -212,7 +212,7 @@ static int pwm_backlight_initial_power_state(const struct pwm_bl_data *pb) */
/* if the enable GPIO is disabled, do not enable the backlight */ - if (pb->enable_gpio && gpiod_get_value(pb->enable_gpio) == 0) + if (pb->enable_gpio && gpiod_get_value_cansleep(pb->enable_gpio) == 0) return FB_BLANK_POWERDOWN;
/* The regulator is disabled, do not enable the backlight */