Re: [PATCH] input/touchscreen: add S3C24XX SoC touchscreen input driver

[Juergen Beisert <jbe@pengutronix.de>]

On Montag, 19. Oktober 2009, Maurus Cuelenaere wrote:
> Op 19-10-09 12:55, linux-arm-kernel-request@lists.infradead.org schreef:
> > This touchscreen driver is for touchscreen controller on Samsung
> > S3C2410/S3C2440 SoC chip. S3C2410/S3C2440 has the on chip touchscreen
> > controller based on it's analog to digital converter(8-channel analog
> > inputs, touchscreen uses 4 of them). This driver uses the exsiting S3C
> > ADC driver to make the touchscreen controller of S3C2410/S3C2440 work
> > well together with other ADC devices connected to the S3C24XX SoC chip.
> >
> > The patch is created against kernel 2.6.32-rc4 and tested with S3C2440
> > SoC and Samsung LTE430WQ-F0C touchscreen.
> >
> >
> > Signed-off-by: Shine Liu<liuxian@redflag-linux.com>
> > Signed-off-by: Shine Liu<shinel@foxmail.com>
>
> Do you know that there's another patch (at Openmoko) created by Nelson
> Castillo that does the same, but also has support for kernel-space
> touchscreen filters? (I think [1] is his latest version)
> I don't know how your patch performs, but according to [2] the filters
> should help a lot avoiding jitter etc.
>
> I'm not sure whether Nelson has submitted his patches for mainline
> review yet and what the status is on the kernel filters, but IMHO doing
> some filtering in kernel space (see the "Why are we doing filtering in
> kernel space?" part of [2]) which results in a "cleaner" output is
> preferred over reporting possible "jittery" data.

Filtering can be done perfectly in userland (like all the other ts do). IMHO I 
can't see any need to do it in kernel space.

jbe

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