On Tue, Jun 14, 2016 at 01:28:08PM -0700, Ene Alexandru wrote: > > There's already everything needed in the power_supply framework to > > change that, why would you want to do this in the device tree? > > I know that this can be implemented by providing proper write interfaces > via the power supply class but I am not aware of any application that will > properly configure the power supply to board specific values once the > system is up.
Any application can do it, including a shell script. It's just a simple write in a file in sysfs. > The reason behind this patch and some other that i have in mind is that one > of my boards and psu got damaged after switching from the 3.4 allwinner > kernel to the mainline one: the axp chip was properly configured in the > .fex file but it's left to the default values that might not be safe in the > linux-sunxi drivers ( and were not in my set-up ) That's bad, but it's not the proper solution. Even with that fix, you have no guarantee that the driver will be loaded (because it might not have been compiled in) or that the board would not be damaged before it loads (because it was a module). > This patch is intended to provide a way to configure some of the AXP20x > registers to a proper state as fast as possible after boot. > Some of the boards might have hardware limitation regarding the maximum > power the board can draw from the USB VCC line ( connector / layout / > protection circuits in line, etc). > If it gets approved then board vendors / users can add proper limits for > each hardware implementation. Except that if users are expected to modify this, DT is definitely not the right place to put this. If you want to put sane defaults that would always be there, please do this in the bootloader... > Adding write support via the /sys/class/... interface is the next step i > have planned, but i decided to go with this one first. ... And with write support, users will be able to change it if they want. Maxime -- Maxime Ripard, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
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