inac wrote: ↑
Wed Sep 19, 2018 3:06 pm
I’m trying to set the pin mux at the right values and I want to do that as early as possible.
What I see is that I can use the dt-blob.dts or the overlay method.
The preferred method is the dt-blob.dts way. But the firmware/kernel source doesn’t have the dt-blob.dts file anymore. So I have the following questions.
??? https://github.com/raspberrypi/firmware ... t-blob.dts
inac wrote:1) Is the dt-blob.dts replaced by bcm2710-rpi-cm3.dts or is the dt-blob.dts completely obsolete?
dt-blob.dts configures the firmware and sets the initial GPIO state. bcm27xx*.dts configure the Linux kernel.
inac wrote:2) Wat is the purpose of the bcm2710-rpi-cm3.dts file?
It configures the Linux kernel.
inac wrote:3) Is there a big time gap between the default setting (bootloader) of the mux and the execution of the config.txt settings?
A few hundred ms if booting from SD card. Longer if booting from USB or network.
It sounds like you're trying to do something wrong if you have any form of hard time contraints on GPIOs adopting particular values.
inac wrote:4) Will the dt-blob.dts still work?
Why not use the gpio command in config.txt - https://www.raspberrypi.org/forums/view ... 7&t=208748
That gets around the fact that dt-blob.dts can't act as an overlay and so is a pain from a maintenance perspective.
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