On 11/18/21 6:02 PM, Tim Harvey wrote:
On Thu, Nov 18, 2021 at 4:53 AM Marek Vasut <marex@xxxxxxx> wrote:
On 11/18/21 2:25 AM, Tim Harvey wrote:
Greetings,
I'm trying to get a RPI 7" touchscreen display working on an IMX8MM
board and while I've been able to get the MIPI DSI display and
backlight working I still can't seem to figure out the touch
controller.
It's supposed to have an FT5406 controller on it without an interrupt
so I added polling support drivers/input/touchscreen/edt-ft5x06.c
which I was able to verify using another touchscreen with that
controller but when reading data from the FT5406 on the RPI controller
the data does not make sense.
These panels appear to route the I2C from the FT5406 to a STM32F103
MPU that then provides a different I2C slave interface to the 15pin
connector that I'm connected to. On that I2C interface I see an i2c
slave at 0x45 which is managed by the regulator driver Marek wrote
(drivers/regulator/rpi-panel-attiny-regulator.c) and there is also an
i2c slave at 0x38 which I assumed was the FT5406 but I believe the MPU
is perhaps obfuscating that touch data.
Anyone have any ideas on how to make that touch controller useful?
Look around:
https://github.com/dh-electronics/meta-dhsom-stm32-bsp/blob/dunfell-3.1/recipes-kernel/linux/linux-stable/5.10/dh-stm32mp1-dhsom/0038-ARM-dts-stm32-Add-AV96-DTO-for-DH-644-100-DSI-mezzan.patch
Marek,
Thanks. This dt overlay actually disables the touchscreen controller
with a note that the IRQ must be hooked up to work. Did you actually
wire up an IRQ and get it to work? I implemented polling mode for the
controller but the data did not make sense.
The touchscreen IRQ line is accessible on some pin header on the 7"
display control board I think, so you can attach it manually to your
development board that way. I have a new version of that AV96 adapter
board here now, I just didn't get to assembling it yet ... so, feel free
to add that one IRQ patchwire and try it.
This dt overlay also interests me as I am also wanting to get some
overlays in the kernel tree [1]. I'm curious if you have any thoughts
on why there are currently no overlays in the mainline tree.
1 - https://lore.kernel.org/linux-arm-kernel/20211115202426.16114-1-tharvey@xxxxxxxxxxxxx/T/
It would be nice to upstream the DTOs, I think the reason why they're
not upstream is because the DTO support is still incomplete, but I might
be wrong. Thanks for pointing this patch out, I'll keep an eye on it.
