Re: [RFC PATCH] Input: tm2-touchkey - add hardware dependency

[Jean Delvare <jdelvare@suse.de>]

Hi Andi,

On Tue, 25 Apr 2017 20:00:56 +0900, Andi Shyti wrote:
> > > On Mon, Apr 24, 2017 at 09:42:31AM +0200, Jean Delvare wrote:
> > So it really boils down to this question: is that chip a generic part
> > from Cypress, and if so, what is the real part number? Or was is
> > designed privately by Cypress specifically for Samsung for this one
> > board (and possibly others to come)?
> 
> I knew that the naming was bringing confusion and we had a
> previous discussion about it with Chanwoo [1].
>
> This is indeed a generic device from Cypress. The driver has been
> ported from Android's Kernel [2]; it says that the device
> part is cy8cmbr3xxx, but the datasheet [3] doesn't have any
> connection with what the TM2 board has (i.e. the registers don't
> match). That's why we suspected that (as you said) this might be
> a touch key sensor specifically designed for the TM2 board.

Thanks for the pointers, it helps.

> Cypress was not that helpful.

I've been there before with other manufacturers. Chipsets designed
specifically for one hardware vendor are the hardest to support for this
reason.

> The alternative was to not provide support, but it didn't look
> right.

I agree, you did the right thing by getting the driver upstream. But it
doesn't mean this driver must be enabled in all distribution kernels.

-- 
Jean Delvare
SUSE L3 Support