The RTL8231 LED driver is using the .brightness_set op, which according
to the documentation should not sleep. Since the RTL8231 is controlled
via an MDIO bus, this is not the case.
When using a non-offloaded LED driver such as netdev, this may currently
trigger kernel warnings:
WARNING: CPU: 0 PID: 14 at kernel/time/timer.c:1754 call_timer_fn.isra.0+0x84/0x8c
timer: led_timer_function+0x0/0x1d8 preempt leak: 00000100 -> 00000000
Switch to the .brightness_set_blocking op to indicate the operation
might sleep.
Fixes: 6ef6014887 ("realtek: Add pinctrl support for RTL8231")
Signed-off-by: Sander Vanheule <sander@svanheule.net>
0d769903dd