Add support for the Pi Vision 10.1" HMI

[kronoidz]

This pull request introduces support for the upcoming SECO Pi Vision product, which consists of an LVDS adapter and a display.

Specifically, it:

• Adds a driver for the Diodes pi4ioe5v6408 GPIO expander
• Enables the following four necessary modules in the bcm2712 defconfig:
  • Atmel MaxTouch driver
  • panel-lvds
  • pi4ioe5v6408 GPIO driver
  • sn65dsi83 bridge driver
• Adds the pivision dtoverlay, which gets automatically loaded by the Raspberry Pi bootloader if the EEPROM on the adapter is correctly programmed

[pelwell]

How does the GPIO driver differ materially from https://github.com/raspberrypi/linux/blob/rpi-6.12.y/drivers/gpio/gpio-fxl6408.c? What happens if you put compatible = "fcs,fxl6408"; in your overlay instead?

[kronoidz]

You're right, they are equivalent and the board works with the fxl6408 driver as well.
I've removed the other driver.

[pelwell]

1. Does the product really only work with Pi 5 hardware?
2. You've only enabled the required drivers for the Pi 5-specific defconfig, which uses 16kB pages. Is there a reason that your product can't be used with the more generic kernel8.img (built from arch/arm64/configs/bcm2711_defconfig) or the new "realtime" kernel8_rt.img?

[6by9]

The guidance for use of panel-lvds is that you should have a panel specific compatible first, and fall back to panel-lvds.
eg https://github.com/raspberrypi/linux/blob/rpi-6.12.y/arch/arm/boot/dts/allwinner/sun8i-a83t-tbs-a711.dts#L74

Having any form of display timings in DT was accepted to mainline very begrudgingly, and this was their compromise to allow fixing up the timings without requiring a DT change (ABI and all that).

[kronoidz]

Added panel-specific compatible: auo,g101ean02-2

[6by9]

1. Does the product really only work with Pi 5 hardware?

Use of GPIO 34 (normally that camera GPIO) for interrupts precludes it working on any board that uses a GPIO expander for the CAM_GPIO lines.
The spec also lists it as exposing PCIe and USB3 ports too, so that does make it CM5 only.

[kronoidz]

2. You've only enabled the required drivers for the Pi 5-specific defconfig, which uses 16kB pages. Is there a reason that your product can't be used with the more generic kernel8.img (built from arch/arm64/configs/bcm2711_defconfig) or the new "realtime" kernel8_rt.img?

No, there's no specific reason. I've updated and tested both bcm2711_defconfig and bcm2711_rt_defconfig to include the necessary drivers.