Am Donnerstag, 20. Oktober 2016, 15:47:56 CEST schrieb Tomeu Vizoso: > On 10/20/2016 03:45 PM, Heiko Stübner wrote: > > Am Donnerstag, 20. Oktober 2016, 10:07:25 schrieb Tomeu Vizoso: > >> Add an empty 'i2c-bus' subnode to the edp node just so that the I2C core > >> doesn't attemp to parse the 'ports' subnode as containing i2c devices. > >> > >> This is to avoid spurious failure messages such as: > >> > >> i2c i2c-6: of_i2c: modalias failure on /dp@ff970000/ports > > > > On the one hand, the edp really has an i2c bus - with its only client the > > EDID listening at 0x50 (and maybe 0x30). > > > > On the other hand, adding an empty bus to the (implementation independent) > > devicetree just to make the Linux i2c subsystem happy sounds heavily like > > a > > implementation-specific hack, as the edp i2c bus doesn't leak into the > > outside world otherwise. > > > > I guess this empty i2c bus not being part of the binding document points > > heavily into the implementation-specific corner :-) . > > > > My short search on other patches touching this didn't reveal anything but > > maybe this was already discussed somewhere and found to be ok? > > Here it is: > > http://www.spinics.net/lists/linux-tegra/msg27862.html thanks ... I'm still not sure about the placeholder though, aka needing an undocumented subnode to make a Linux error message silent. In the thread you pointed to I also did not see any dt-maintainer involvement pointing one way or another, but spinics is often not easy to navigate threads, so I may have missed that. > > Another option could be to just make of_i2c_register_device silent if > > of_modalias_node returns -ENODEV? Heiko > >> Signed-off-by: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx> > >> Cc: Randy Li <randy.li@xxxxxxxxxxxxxx> > >> Cc: Jon Hunter <jonathanh@xxxxxxxxxx> > >> --- > >> > >> arch/arm/boot/dts/rk3288.dtsi | 5 +++++ > >> 1 file changed, 5 insertions(+) > >> > >> diff --git a/arch/arm/boot/dts/rk3288.dtsi > >> b/arch/arm/boot/dts/rk3288.dtsi > >> index 2f814ffeb605..94f4b7eecca2 100644 > >> --- a/arch/arm/boot/dts/rk3288.dtsi > >> +++ b/arch/arm/boot/dts/rk3288.dtsi > >> @@ -1075,6 +1075,11 @@ > >> > >> }; > >> > >> }; > >> > >> }; > >> > >> + > >> + i2c-bus { > >> + #address-cells = <1>; > >> + #size-cells = <0>; > >> + }; > >> > >> }; > >> > >> hdmi: hdmi@ff980000 { -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
