Re: [PATCH v3 2/5] ARM: dts: aspeed: ast2600evb: Add comment for gpio regulator of sdhci

From: Steven Lee <steven_lee@aspeedtech.com>
To: Andrew Jeffery <andrew@aj.id.au>
Cc: Ulf Hansson <ulf.hansson@linaro.org>,
	Rob Herring <robh+dt@kernel.org>, Joel Stanley <joel@jms.id.au>,
	Adrian Hunter <adrian.hunter@intel.com>,
	Philipp Zabel <p.zabel@pengutronix.de>,
	Ryan Chen <ryanchen.aspeed@gmail.com>,
	"moderated list:ASPEED SD/MMC DRIVER"
	<linux-aspeed@lists.ozlabs.org>,
	"moderated list:ASPEED SD/MMC DRIVER" <openbmc@lists.ozlabs.org>,
	linux-mmc <linux-mmc@vger.kernel.org>,
	"open list:OPEN FIRMWARE AND FLATTENED DEVICE TREE BINDINGS"
	<devicetree@vger.kernel.org>,
	"moderated list:ARM/ASPEED MACHINE SUPPORT"
	<linux-arm-kernel@lists.infradead.org>,
	open list <linux-kernel@vger.kernel.org>,
	Ryan Chen <ryan_chen@aspeedtech.com>,
	Chin-Ting Kuo <chin-ting_kuo@aspeedtech.com>,
	Hongwei Zhang <Hongweiz@ami.com>
Subject: Re: [PATCH v3 2/5] ARM: dts: aspeed: ast2600evb: Add comment for gpio regulator of sdhci
Date: Fri, 7 May 2021 11:30:21 +0800	[thread overview]
Message-ID: <20210507033021.GB23749@aspeedtech.com> (raw)
In-Reply-To: <8611c4a7-8c65-4d7d-90d5-37c80faa3142@www.fastmail.com>

The 05/07/2021 09:40, Andrew Jeffery wrote:
> 
> 
> On Thu, 6 May 2021, at 19:33, Steven Lee wrote:
> > Add the description for describing the AST2600-A2 EVB reference design of
> > GPIO regulators.
> > 
> > Signed-off-by: Steven Lee <steven_lee@aspeedtech.com>
> > ---
> >  arch/arm/boot/dts/aspeed-ast2600-evb.dts | 15 +++++++++++++++
> >  1 file changed, 15 insertions(+)
> > 
> > diff --git a/arch/arm/boot/dts/aspeed-ast2600-evb.dts 
> > b/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > index 2772796e215e..1ae0facc3d5f 100644
> > --- a/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > +++ b/arch/arm/boot/dts/aspeed-ast2600-evb.dts
> > @@ -104,6 +104,21 @@
> >  	status = "okay";
> >  };
> >  
> > +/*
> > + * The signal voltage of sdhci0 and sdhci1 on AST2600-A2 EVB is able to be
> > + * toggled by GPIO pins.
> > + * In the reference design, GPIOV0 of AST2600-A2 EVB is connected to the
> > + * power load switch that providing 3.3v to sdhci0 vdd, GPIOV1 is connected to
> > + * a 1.8v and a 3.3v power load switch that providing signal voltage to
> > + * sdhci0 bus.
> > + * If GPIOV0 is active high, sdhci0 is enabled, otherwise, sdhci0 is disabled.
> > + * If GPIOV1 is active high, 3.3v power load switch is enabled, sdhci0 signal
> > + * voltage is 3.3v, otherwise, 1.8v power load switch will be enabled,
> > + * sdhci0 signal voltage becomes 1.8v.
> > + * AST2600-A2 EVB also support toggling signal voltage for sdhci1.
> > + * The design is the same as sdhci0, it uses GPIOV2 as power-gpio and GPIOV3
> > + * as power-switch-gpio.
> > + */
> 
> Okay, I think the comment is in the right place, but I feel this patch 
> should also add the regulator nodes and hook them up to the SDHCIs.
> 
> Given Rob isn't super keen on a second example in the binding document 
> I think you can just cut the example out and paste it in here.
> 

Hi Andrew,

Since AST2600-A0 and AST2600-A1 don't have regulators, do you mean cut
the example from dt-binding and paste it to aspeed-ast2600-evb.dts but
comment out the example?

> Andrew

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