Re: [PATCH v2 3/6] pinctrl: sh-pfc: r8a7790: Add separate functions for SDHI 1.8V operation

From: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
To: Ben Hutchings <ben.hutchings@codethink.co.uk>
Cc: Ian Molton <ian@mnementh.co.uk>,
	linux-mmc@vger.kernel.org, linux-sh@vger.kernel.org,
	linux-gpio@vger.kernel.org, linux-kernel@lists.codethink.co.uk,
	Sergei Shtylyov <sergei.shtylyov@cogentembedded.com>,
	Simon Horman <horms@verge.net.au>,
	Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
	Linus Walleij <linus.walleij@linaro.org>
Subject: Re: [PATCH v2 3/6] pinctrl: sh-pfc: r8a7790: Add separate functions for SDHI 1.8V operation
Date: Fri, 12 Jun 2015 19:07:19 +0000	[thread overview]
Message-ID: <34148355.aYdSK9R7Ck@avalon> (raw)
In-Reply-To: <1434115435.25446.1.camel@codethink.co.uk>

Hi Ben,

On Friday 12 June 2015 14:23:55 Ben Hutchings wrote:
> On Fri, 2015-06-12 at 10:18 +0300, Laurent Pinchart wrote:
> > Hi Ben,
> > 
> > (CC'ing Linus Walleij)
> > 
> > Thank you for the patch.
> > 
> > On Wednesday 10 June 2015 00:23:31 Ben Hutchings wrote:
> > > All the SHDIs can operate with either 3.3V or 1.8V signals, depending
> > > on negotiation with the card.
> > > 
> > > Add separate functions for the 1.8V mode, and implement the set_mux
> > > operation on all SDHI functions to configure the voltage for each
> > > group of pins.
> > 
> > I don't think duplicating all functions for 1.8V and 3.3V is the right way
> > to go. Can't we use the pinconf API instead, and in particular the
> > PIN_CONFIG_POWER_SOURCE configuration ?
> 
> [...]
> 
> So far as I could see, you can't use the pinconf API with pinmux groups.

Can't you ? Both Documentation/devicetree/bindings/pinctrl/pinctrl-
bindings.txt and Documentation/devicetree/bindings/pinctrl/renesas,pfc-
pinctrl.txt document the usage of pinconf with groups (see for instance 
example 3 in the latter).

-- 
Regards,

Laurent Pinchart