Re: [PATCH] arm64: dts: qcom: msm8916/39-samsung-a2015: Add flash LED

[Henrik Grimler <henrik@grimler.se>]

Hi Konrad,

On Sat, Aug 26, 2023 at 02:09:38PM +0200, Konrad Dybcio wrote:
> On 22.08.2023 17:01, Raymond Hackley wrote:
> > Hi Konrad,
> > 
> >> What about the other subdevices registered with the RT5033 MFD?
> > 
> > Currently the MFD is not able to control the flash LED, due to missing
> > driver for it.
> > Alternatively we control it with GPIO pins. With driver leds-sgm3140, the
> > binding is not under the RT5033 MFD.
> Hm.. I have mixed feelings..
> 
> Does the led controlled onboard this chip have some super complex
> functionality that is going to be exposed through a specific driver
> and that is not exposed through the sgm3140 driver?

The rt5033-led&sgm3140 situation was discussed in msm8916-mainline
matrix room before, here is a summary for list.

Using the full rt5033-led driver (old patchset here [1]) has some
benefits, like:
* led can have different intensity levels
* led can (supposedly) be used in strobe mode

Using sgm3140 driver mostly works fine, but there could potentially be
situations where led stops working and a reboot to stock android
kernel is required to get it working again.  So far that has only been
reproduced by first booting a kernel with full rt5033-led driver
(based on [1]), and then booting a kernel using sgm3140 driver
instead.

[1] https://lore.kernel.org/linux-leds/1448446948-13729-1-git-send-email-ingi2.kim@samsung.com/

Best regards,
Henrik Grimler