[PATCH] ARM: dts: imx6qdl-sabresd: add always on pcie regulator

[Lucas Stach]

Hi Shawn,

Am Dienstag, den 22.07.2014, 10:57 +0800 schrieb Shawn Guo:
> On Fri, Jul 18, 2014 at 08:14:30PM +0200, Lucas Stach wrote:
> > Everything in the PCI specification assumes devices to be
> > enumerable on startup. This is only possible if they have
> > power available.
> > 
> > A future improvement may allow this regulator to be switched
> > off for D3hot and D3cold power states, but there is a lot
> > of work to do the pcie host controller side for this to work.
> > To keep things simple always enable the regulator for now.
> > 
> > Signed-off-by: Lucas Stach <l.stach at pengutronix.de>
> 
> Just curious if this fixes any known PCIe issue?

Yes this allows PCIe devices to work on my SabreSD board. I don't know
if it's required for all revisions, the schematics certainly show a
mounting option where the load switch isn't populated but bridged by 0R
resistor.

> 
> > ---
> >  arch/arm/boot/dts/imx6qdl-sabresd.dtsi | 12 ++++++++++++
> >  1 file changed, 12 insertions(+)
> > 
> > diff --git a/arch/arm/boot/dts/imx6qdl-sabresd.dtsi b/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > index ec43dde78525..bbbd501098e6 100644
> > --- a/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > +++ b/arch/arm/boot/dts/imx6qdl-sabresd.dtsi
> > @@ -54,6 +54,17 @@
> >  			gpio = <&gpio4 10 0>;
> >  			enable-active-high;
> >  		};
> > +
> > +		reg_pcie: regulator at 3 {
> > +			compatible = "regulator-fixed";
> > +			reg = <3>;
> > +			regulator-name = "pcie-supply";
> 
> I would start asking to name the regulator in the same way that board
> document like schematics names it.  In this case, it should be
> "MPCIE_3V3".
> 
> > +			regulator-min-microvolt = <3300000>;
> > +			regulator-max-microvolt = <3300000>;
> > +			gpio = <&gpio3 19 0>;
> > +			regulator-always-on;
> > +			enable-active-high;
> > +		};
> >  	};
> >  
> >  	gpio-keys {
> > @@ -323,6 +334,7 @@
> >  				MX6QDL_PAD_ENET_TXD1__GPIO1_IO29 0x80000000
> >  				MX6QDL_PAD_EIM_D22__GPIO3_IO22  0x80000000
> >  				MX6QDL_PAD_ENET_CRS_DV__GPIO1_IO25 0x80000000
> > +				MX6QDL_PAD_EIM_D19__GPIO3_IO19  0x80000000
> 
> No more GPIO setup in hog group, and no more 0x80000000 on pad config.
> Please have a dedicate pinctrl entry for it with a proper config value,
> and refer to the entry in that reg_pcie node.
> 
Ok, will fix.

-- 
Pengutronix e.K.             | Lucas Stach                 |
Industrial Linux Solutions   | http://www.pengutronix.de/  |