Re: [PATCH v5 1/2] drm/bridge: Add sii902x driver

From: Boris Brezillon <boris.brezillon@free-electrons.com>
To: Meng Yi <meng.yi@nxp.com>
Cc: Mark Rutland <mark.rutland@arm.com>,
	devicetree <devicetree@vger.kernel.org>,
	Xiubo Li <lixiubo@cmss.chinamobile.com>,
	Pawel Moll <pawel.moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Nicolas Ferre <nicolas.ferre@atmel.com>,
	Huan Wang <alison.wang@nxp.com>,
	Emil Velikov <emil.l.velikov@gmail.com>,
	ML dri-devel <dri-devel@lists.freedesktop.org>,
	Rob Herring <robh+dt@kernel.org>,
	Alexandre Belloni <alexandre.belloni@free-electrons.com>,
	Kumar Gala <galak@codeaurora.org>,
	Maxime Ripard <maxime.ripard@free-electrons.com>,
	Jean-Christophe Plagniol-Villard <plagnioj@jcrosoft.com>,
	Jianwei Wang <jianwei.wang.chn@gmail.com>
Subject: Re: [PATCH v5 1/2] drm/bridge: Add sii902x driver
Date: Tue, 7 Jun 2016 07:31:59 +0200	[thread overview]
Message-ID: <20160607073159.20541da1@bbrezillon> (raw)
In-Reply-To: <HE1PR04MB10516B0A27EEBFDA8019C1A1EC5D0@HE1PR04MB1051.eurprd04.prod.outlook.com>

Hi Meng,

On Tue, 7 Jun 2016 02:40:56 +0000
Meng Yi <meng.yi@nxp.com> wrote:

> Hi Boris,
> 
> Sorry for reply late, I was on PTO. And another PTO on  June 9~11, 2016.UTC+8
> 
> >  
> > > > +       gpiod_set_value(sii902x->reset_gpio, 1);
> > > > +
> > > > +       msleep(100);  
> > > Ouch that is some juicy number. Can we get a comment with
> > > reasoning/origin of it ?  
> > 
> > As already explained to Maxime, I just don't know why this is needed, simply
> > because I don't have access to the datasheet and I just based my
> > implementation on another driver.
> > I can add a comment stating that this was extracted from another
> > implementation, but with no explanation on why this is needed.
> > 
> > Meng, do you have any information about startup-time, or something like that?
> >   
> 
> I had checked the datasheet of sii9022a, which said the Min of TRESET is 100 μs, and Max is not specified.

Oh, thanks a lot. treset-min is exactly what I needed.

Regards,

Boris

-- 
Boris Brezillon, Free Electrons
Embedded Linux and Kernel engineering
http://free-electrons.com
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