Controlling Omega2Pro Multi LED At boot time
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Device: Omega2 Pro
OS: 22 Beta et al
Expected behaviour: Multi-Colour LED should remain off until it is utilised.Observed Behaviour:
During boot the Multi-Colour LED flashes random colours then settled on some random colour.
This issue is not specific to the Beta, I have the same issue on stock 18 but I post it here as a placeholder for the issue.
I think the core issue is that the DTS defines the pin as UART2, with functions of uart2 and gpio, however we know that uart2 can also function as a pwm pin (pwm23). Since the yaml schema for the device tree does not know anything about pwm23 as a function, I can only default the pin to gpio or uart2 in the dts.
Of course I can use devmem to change the function of the pin, just as omega2-ctrl gpiomux does, however I want to force the multi-colour led to "shut up!!" during boot and this approach will only have effect once devmem is available. I can also use omega2-ctrl and then ledchain (by @luz) to shut down the LED but this is too late for my purpose.
So before I spend any more time digging into the kernel drivers to try to control the LED, I thought I'd ask if anyone else has any ideas. I suspect the core issue is that the pin defaults to uart2 so it's flapping around during boot, but if I can default it to pwm23 in the device tree then maybe I could quiet it down much earlier. I can default it to gpio using a dts but that had no effect other than to default it to gpio.
I'm completing my omega2pro dts and will try to submit it to the Openwrt kernel because the omega2(+) led definitions are up the spout for the Omega2 Pro, but I'd like to sort this out first.
Any ideas welcome.
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This is fixed in u-boot 1.1.3 release date 18th November 2020.
There is another version 1.1.3 with release data Feb 2019, which still has this bug.