Re: [PATCH v1 09/11] leds: st1202: Do not set brightness from atomic context

[sashiko-bot@kernel.org]

> st1202_brightness_set() takes the chip mutex and performs I2C transfers,
> both of which can sleep, but it is installed as the brightness_set
> callback. led_set_brightness_nopm() calls that op directly on the
> assumption that it never sleeps, including from softirq context, so the
> driver can sleep in atomic context.
> 
> The driver also installs brightness_set_blocking, but the core only
> falls back to it when brightness_set is absent, so st1202_led_set() was
> never reached. It merely turned the channel on or off and ignored the
> requested brightness, so dropping brightness_set on its own would have
> lost brightness control entirely.
> 
> Move the register programming into st1202_led_set() so the blocking
> callback honours the brightness value, and drop brightness_set. The core
> now defers the update to a work queue, where sleeping is allowed. Errors
> from the register writes are propagated rather than discarded.
> 
> Programming every PWM slot to full scale is kept: it is what makes the
> brightness visible while the global sequencer is running, without having
> to stop the sequencer and disturb the other channels.
> 
> Fixes: 259230378c65 ("leds: Add LED1202 I2C driver")
> Signed-off-by: Manuel Fombuena <fombuena@outlook.com>

Sashiko has reviewed this patch and found no issues. It looks great!

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