Re: [PATCH v4 07/14] ARM: dts: koelsch: use demuxer for I2C4

[Simon Horman <horms@verge.net.au>]

On Tue, Nov 15, 2016 at 04:45:01PM +0100, Geert Uytterhoeven wrote:
> Hi Wolfram,
> 
> On Sun, Nov 6, 2016 at 9:20 PM, Wolfram Sang
> <wsa+renesas@sang-engineering.com> wrote:
> > From: Simon Horman <horms+renesas@verge.net.au>
> >
> > Make it possible to fallback to GPIO for I2C4 on the EXIO-E connector.
> >
> > This is based on reference work for the I2C0 core of the lager/r8a7790
> > by Wolfram Sang.
> >
> > Signed-off-by: Simon Horman <horms+renesas@verge.net.au>
> > [wsa: rebased and fixed aliases]
> > Signed-off-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
> > ---
> >  arch/arm/boot/dts/r8a7791-koelsch.dts | 35 +++++++++++++++++++++++++++++++++++
> >  1 file changed, 35 insertions(+)
> >
> > diff --git a/arch/arm/boot/dts/r8a7791-koelsch.dts b/arch/arm/boot/dts/r8a7791-koelsch.dts
> > index 8d653920957a4b..442d1512a8fa9c 100644
> > --- a/arch/arm/boot/dts/r8a7791-koelsch.dts
> > +++ b/arch/arm/boot/dts/r8a7791-koelsch.dts
> 
> > @@ -476,6 +501,11 @@
> >                 function = "i2c2";
> >         };
> >
> > +       i2c4_pins: i2c4 {
> > +               groups = "i2c4";
> > +               function = "i2c4";
> > +       };
> > +
> >         du_pins: du {
> >                 groups = "du_rgb888", "du_sync", "du_disp", "du_clk_out_0";
> >                 function = "du";
> > @@ -732,6 +762,11 @@
> >         clock-frequency = <100000>;
> >  };
> >
> > +&i2c4 {
> > +       pinctrl-0 = <&i2c4_pins>;
> > +       pinctrl-names = "i2c-exio4";
> > +};
> 
> i2c4 shares pins with vin0. Hence enabling the former breaks the latter:
> 
>     sh-pfc e6060000.pfc: pin GP_4_13 already requested by
> e6520000.i2c; cannot claim for e6ef0000.video
>     sh-pfc e6060000.pfc: pin-141 (e6ef0000.video) status -22
>     sh-pfc e6060000.pfc: could not request pin 141 (GP_4_13) from
> group vin0_data24  on device sh-pfc
>     rcar-vin e6ef0000.video: Error applying setting, reverse things back
>     rcar-vin: probe of e6ef0000.video failed with error -22
> 
> There may be similar issues on other boards. Haven't checked yet.

Thanks, I will drop this patch for now.

I checked the boot logs of other boards with similar patches and didn't see
anything there.