Hi, On Mon, Nov 18, 2019 at 03:37:12PM +0100, H. Nikolaus Schaller wrote: > > Am 18.11.2019 um 15:33 schrieb Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx>: > > On Mon, Nov 18, 2019 at 03:05:07PM +0200, Tomi Valkeinen wrote: > >> On 17/11/2019 04:39, Sebastian Reichel wrote: > >>> The standard binding for DSI requires, that the channel number > >>> of the panel is encoded in DT. This adds the channel number in > >>> all OMAP3-5 boards, in preparation for using common infrastructure. > >>> > >>> Signed-off-by: Sebastian Reichel <sebastian.reichel@xxxxxxxxxxxxx> > >>> --- > >>> .../devicetree/bindings/display/panel/panel-dsi-cm.txt | 4 +++- > >>> arch/arm/boot/dts/omap3-n950.dts | 3 ++- > >>> arch/arm/boot/dts/omap3.dtsi | 3 +++ > >>> arch/arm/boot/dts/omap4-droid4-xt894.dts | 3 ++- > >>> arch/arm/boot/dts/omap4-sdp.dts | 6 ++++-- > >>> arch/arm/boot/dts/omap4.dtsi | 6 ++++++ > >>> arch/arm/boot/dts/omap5.dtsi | 6 ++++++ > >>> 7 files changed, 26 insertions(+), 5 deletions(-) > >> > >> Is this required only in the .txt, or also by the driver? This does break > >> backward compatibility with the dtbs, and there's always someone who won't > >> like it. > > > > I add a compatible string for the Droid 4 panel in addition to the > > generic one, which is not really required and just a precaution in > > case we need some quirks in the future. > > > > But I had to add the DSI channel to DT, which is required to follow > > the standard DSI bindings. We cannot use the generic infrastructure > > without this change. Technically it should have been there all the > > time, it is only working because it is currently hardcoded to 0 in > > the panel driver. > > Is it possible to change it to default to channel <0> if reg is not > specified? Currently nodes without reg property are skipped by of_mipi_dsi_device_add() and of_mipi_dsi_device_add() fails if reg node is missing. Technically it should be possible to default to channel 0 there. That affects all platforms, though. Considering the small amount of boards affected, I think its better to just fix the DT. Also the fixed DT does not make problems with older kernels and can be backported. > > TLDR: Yes, it is required by the driver and it does break backward > > compatibility for N950 (panel does not yet work on mainline, since > > the OMAP3 quirks are missing in the omapdrm DSI code), omap4-sdp ( > > untested, I do not know if its working) and Droid 4 (known to be > > working with current mainline code, most likely people update their > > DT anyways). -- Sebastian
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