Hi Eric, On Tuesday 16 May 2017 09:47:49 Eric Anholt wrote: > Rob Herring <robh+dt@xxxxxxxxxx> writes: > > On Mon, May 15, 2017 at 7:03 PM, Eric Anholt <eric@xxxxxxxxxx> wrote: > >> Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx> writes: > >>> Hi Eric, > >>> > >>> Thank you for the patch. > >>> > >>> On Thursday 11 May 2017 16:56:23 Eric Anholt wrote: > >>>> The Raspberry Pi 7" Touchscreen is a DPI touchscreen panel with > >>>> DSI->DPI bridge and touchscreen controller integrated, that connects > >>>> to the Raspberry Pi through its 15-pin "DSI" connector (some lines are > >>>> DSI, some lines are I2C). > >>>> > >>>> This device is represented in the DT as three nodes (DSI device, I2C > >>>> device, panel). Input will be left to a separate binding later, as it > >>>> will be a basic I2C client device. > >>>> > >>>> Signed-off-by: Eric Anholt <eric@xxxxxxxxxx> > >>>> --- > >>>> > >>>> .../raspberrypi,7inch-touchscreen-bridge.txt | 68 ++++++++++++++ > >>>> .../panel/raspberrypi,7inch-touchscreen-panel.txt | 7 +++ > >>>> 2 files changed, 75 insertions(+) > >>>> create mode 100644 > >>>> > >>>> Documentation/devicetree/bindings/display/bridge/raspberrypi,7inch-touc > >>>> hscreen-bridge.txt create mode 100644 > >>>> Documentation/devicetree/bindings/display/panel/raspberrypi,7inch-touch > >>>> screen-panel.txt > >>>> > >>>> diff --git > >>>> a/Documentation/devicetree/bindings/display/bridge/raspberrypi,7inch-to > >>>> uchscreen-bridge.txt > >>>> b/Documentation/devicetree/bindings/display/bridge/raspberrypi,7inch-to > >>>> uchscreen-bridge.txt new file mode 100644 > >>>> index 000000000000..a5669beaf68f > >>>> --- /dev/null > >>>> +++ > >>>> b/Documentation/devicetree/bindings/display/bridge/raspberrypi,7inch-to > >>>> uchscreen-bridge.txt > >>>> @@ -0,0 +1,68 @@ > >>>> +Official 7" (800x480) Raspberry Pi touchscreen panel's bridge. > >>>> + > >>>> +This DSI panel contains: > >>>> + > >>>> +- TC358762 DSI->DPI bridge > >>>> +- Atmel microcontroller on I2C for power sequencing the DSI bridge and > >>>> + controlling backlight > >>>> +- Touchscreen controller on I2C for touch input > >>>> + > >>>> +and this covers the TC358762 bridge and Atmel microcontroller, while > >>>> +../panel/raspberrypi,7inch-touchscreen-panel.txt covers the panel. > >>> > >>> The TC358762 is a standalone bridge that doesn't depend on the ATTiny > >>> microcontroller used by the RPI. As it's usable standalone, I believe > >>> this binding should be split in two. > >> > >> Do you have a plan for how I would implement a driver on top of that > >> binding change, though? Note that we don't program the Toshiba > >> directly, we only send commands to the Atmel. > > > > I agree. If it is a black box and the interface to the host is defined > > by the Atmel uC firmware, then that's what the DT should describe. > > Perhaps a diagram here or pointer to one would help and remove > > mentioning what kind of bridge chip it is. > > It's a *very* black box. I have some non-public schematics that don't > even say what panel is involved, and no documentation of the uc > interface. The driver code is just replicating the firmware's > programming sequence. > > I would certainly love to be building a generic TC358762 driver, which > would be a lot more satisfying. I just don't think it's doable for this > panel. Given that, what do I need to do to the DT? Should I just drop > mention of the Toshiba and talk about this being a bridge with a custom > microcontroller firmware? I think that would be best, yes. Could you share a simple block-diagram of the hardware ? It would help turning my random advices into semi-random advices :-) -- Regards, Laurent Pinchart -- 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
