Re: [PATCH v2 2/2] Input: ads7846: convert to one message
From: Oleksij Rempel
Date: Wed Jan 20 2021 - 02:42:33 EST
On Tue, Nov 17, 2020 at 04:31:38PM -0800, Dmitry Torokhov wrote:
> On Tue, Nov 10, 2020 at 09:50:41AM +0100, Oleksij Rempel wrote:
> > Convert multiple full duplex transfers in to a single transfer to reduce
> > CPU load.
> > Current driver version support following filtering modes:
> > - ads7846_no_filter() - not filtered
> > - ads7846_debounce_filter() - driver specific debounce filter
> > - pdata->filter - platform specific debounce filter (do any platform
> > provides such filter?)
> > Without filter this HW is not really usable, since the physic of
> > resistive touchscreen can provide some bounce effects. With driver internal
> > filter, we have constant amount of retries + debounce retries if some anomaly
> > was detected.
> > High amount of tiny SPI transfers is the primer reason of high CPU load
> > and interrupt frequency.
> > This patch create one SPI transfer with all fields and not optional retires. If
> > bounce anomaly was detected, we will make more transfer if needed.
> > Without this patch, we will get about 10% CPU load on iMX6S on pen-down event.
> > For example by holding stylus on the screen.
> > With this patch, depending in the amount of retries, the CPU load will
> > be 1% with "ti,debounce-rep = <3>".
> > One buffer transfer allows us to use PIO FIFO or DMA engine, depending
> > on the platform.
> > Signed-off-by: Oleksij Rempel <o.rempel@xxxxxxxxxxxxxx>
> Applied, thank you.
I can't find this patch in your git repository. Should I rebase it
against latest git and resend it?
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