Re: [PATCH v2 8/8] ARM: bcm2835: Disable i2c2 in the Device Tree

[Noralf TrÃnnes]

Den 27.09.2016 19:25, skrev Stefan Wahren:
> > Noralf TrÃnnes <noralf@xxxxxxxxxxx> hat am 27. September 2016 um 13:57
> > geschrieben:
> >
> >
> > i2c2 is connected to the HDMI connector and is controlled by the
> > firmware. Disable it to stay out of harms way.
> Until this point the commit message is okay, the rest is more confusing.
>
> Btw this should avoid a warning about missing clock frequency.
>
> >  From the downstream commit:
> > i2c-bcm2708/BCM270X_DT: Add support for I2C2
> >
> > The third I2C bus (I2C2) is normally reserved for HDMI use. Careless
> > use of this bus can break an attached display - use with caution.
> >
> > It is recommended to disable accesses by VideoCore by setting
> > hdmi_ignore_edid=1 or hdmi_edid_file=1 in config.txt.
> >
> > Signed-off-by: Noralf TrÃnnes <noralf@xxxxxxxxxxx>
> > ---
> >   arch/arm/boot/dts/bcm2835-rpi.dtsi | 4 ----
> >   1 file changed, 4 deletions(-)
> >
> > diff --git a/arch/arm/boot/dts/bcm2835-rpi.dtsi
> > b/arch/arm/boot/dts/bcm2835-rpi.dtsi
> > index e9b47b2..8bffbee 100644
> > --- a/arch/arm/boot/dts/bcm2835-rpi.dtsi
> > +++ b/arch/arm/boot/dts/bcm2835-rpi.dtsi
> > @@ -59,10 +59,6 @@
> >   	clock-frequency = <100000>;
> >   };
> >   
> > -&i2c2 {
> > -	status = "okay";
> > -};
> > -
> I'm not sure if this the right fix. According to bcm283x.dtsi the 3 i2c busses
> have the same compatible string "brcm,bcm2835-i2c", but the changelog suggests
> that this bus is "special".

I just rounded up all the differences from downstream that I knew about
into this patchset. But looking closer I see that the vc4 driver uses
i2c2. So I'll drop this patch.


Noralf.


> Shouldn't we use a different compatible string? Our intention isn't to disable
> i2c2 but avoid any claims of the usual i2c driver.
>
> >   &sdhci {
> >   	status = "okay";
> >   	bus-width = <4>;
> > --
> > 2.8.2
> >
> >
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