Re: [PATCH v5 07/11] leds: flash: add support for Samsung S2M series PMIC flash LED device

[Lee Jones <lee@kernel.org>]

On Thu, 07 May 2026, Jacek Anaszewski wrote:

> Hi Lee,
> 
> On 5/7/26 6:46 PM, Lee Jones wrote:
> > On Fri, 24 Apr 2026, Kaustabh Chakraborty wrote:
> > 
> > > Add support for flash LEDs in certain Samsung S2M series PMICs.
> > > The device has two channels for LEDs, typically for the back and front
> > > cameras in mobile devices. Both channels can be independently
> > > controlled, and can be operated in torch or flash modes.
> > > 
> > > The driver includes initial support for the S2MU005 PMIC flash LEDs.
> > > 
> > > Signed-off-by: Kaustabh Chakraborty <kauschluss@disroot.org>
> > > ---
> > >   drivers/leds/flash/Kconfig          |  12 ++
> > >   drivers/leds/flash/Makefile         |   1 +
> > >   drivers/leds/flash/leds-s2m-flash.c | 358 ++++++++++++++++++++++++++++++++++++
> > >   3 files changed, 371 insertions(+)
> > > 
> > > diff --git a/drivers/leds/flash/Kconfig b/drivers/leds/flash/Kconfig
> > > index 5e08102a67841..be62e05277429 100644
> > > --- a/drivers/leds/flash/Kconfig
> > > +++ b/drivers/leds/flash/Kconfig
> > > @@ -114,6 +114,18 @@ config LEDS_RT8515
> > >   	  To compile this driver as a module, choose M here: the module
> > >   	  will be called leds-rt8515.
> > > +config LEDS_S2M_FLASH
> > > +	tristate "Samsung S2M series PMICs flash/torch LED support"
> > > +	depends on LEDS_CLASS
> > > +	depends on MFD_SEC_CORE
> > > +	depends on V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS
> > 
> > The `|| !V4L2_FLASH_LED_CLASS` part of this dependency makes it
> > unconditionally true. Was this intended? Perhaps this dependency can be
> > removed entirely.
> This is for a reason to allow building the driver if
> V4L2_FLASH_LED_CLASS is turned off, or build it as a module
> if V4L2_FLASH_LED_CLASS=m. You will get nice explanation from
> Google AI if you type just
> "V4L2_FLASH_LED_CLASS || !V4L2_FLASH_LED_CLASS".
> 
> See e.g. [0], which fixes undefined symbol error by adding this.
> 
> [0] https://git.paulk.fr/projects/linux.git/commit/drivers?h=sunxi/cedrus/jpeg-nv16&id=dbeb02a0bc41b9e9b9c05e460890351efecf1352

I see.  Thanks for the explanation.

-- 
Lee Jones