Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 23.128.96.18 as permitted sender) client-ip=23.128.96.18;
Date:   Wed, 20 Jan 2021 23:24:18 -0800
From:   Dmitry Torokhov <dmitry.torokhov@gmail.com>
To:     Oleksij Rempel <o.rempel@pengutronix.de>
Cc:     Alexandru Ardelean <alexandru.ardelean@analog.com>,
        Mark Brown <broonie@kernel.org>, kernel@pengutronix.de,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        linux-spi@vger.kernel.org, David Jander <david@protonic.nl>
Subject: Re: [PATCH v2 2/2] Input: ads7846: convert to one message
Message-ID: <YAksInM07b3ACwMa@google.com>
References: <20201110085041.16303-1-o.rempel@pengutronix.de>
 <20201110085041.16303-3-o.rempel@pengutronix.de>
 <20201118003138.GD2009714@dtor-ws>
 <20210120074032.2swvp7iqli6xttul@pengutronix.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <20210120074032.2swvp7iqli6xttul@pengutronix.de>
Precedence: bulk

On Wed, Jan 20, 2021 at 08:40:32AM +0100, Oleksij Rempel wrote:
> 
> Hi Dmitry,
> 
> 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@pengutronix.de>
> > 
> > Applied, thank you.
> 
> I can't find this patch in your git repository. Should I rebase it
> against latest git and resend it?

Ugh, sorry, now applied for realz.

Thanks.

-- 
Dmitry