patches/openwrt/kernel: Update Turris Omnia 5.15 patches (LEDs + MCU)

Update Turris Omnia LED driver patches from upstream, and add pending patches to support Turris Omnia MCU.

This MCU driver adds the following abilities if the user has upgraded MCU firmware (see below as to how to do that):

• the poweroff command now completely powers the device off (the power consumption goes to minimum). To power the router on, the user needs to press the front button,
• the device can be configured to automatically power on from powered off state at a specific time by using the omnia-mcutool --wakeup option, for example

  omnia-mcutool --wakeup '+10 hours'

  or

  omnia-mcutool --wakeup '2023-10-19 08:00'

With upgraded MCU firmware the updated LED driver now supports:

• enabling/disabling LED gamma correction with

  echo 1 >/sys/bus/i2c/devices/1-002b/gamma_correction

  or

  echo 0 >/sys/bus/i2c/devices/1-002b/gamma_correction

  The gamma correction table is calibrated for new Omnia boards (2020+), it may give weird colors for older boards. In the future we might add the ability to configure gamma correction table dynamically,
• the LED panel global brightness file /sys/bus/i2c/devices/1-002b/brightness can now be polled for changes using the epoll() system call. It will emit a MODIFY event when the user changes the brightness by pressing the front button. This will be used in rainbow-ng's button-sync daemon. Currently the button-sync.sh script periodically reads the file every 2 seconds to determine if the user has changed the brightness.

The following features are supported by the MCU driver even without upgrading the MCU firmware:

• the factory reset level can be read by

  cat /sys/bus/i2c/devices/1-002a/reset_selector

• the front button can be configured to act as an input device (via the kmod-input-gpio-keys driver). This is done by executing

  echo cpu >/sys/bus/i2c/devices/1-002a/front_button_mode

  To configure the default option (pressing front button dimms the front LEDs panel), execute

  echo mcu >/sys/bus/i2c/devices/1-002a/front_button_mode

• some of the MCU GPIOs are now available via /sys/class/gpio. For example we can now enable/disable power for USB ports via sysfs:

  cd /sys/class/gpio
  echo 456 >export
  cd '/sys/class/gpio/gpio456.Front USB3 port power'

  Now to disable USB port power

  echo 0 >value

  and to enable it back

  echo 1 >value

The user can upgrade the MCU firmware by executing

opkg update
opkg install omnia-mcutool
omnia-mcutool --upgrade
reboot