On Thursday, June 16, 2016 at 10:23:50 AM UTC+3, Maxime Ripard wrote: > > 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 >
Ok, I see your point of view. Adding write support is better. I'll re-sync git, look over the latest files and provide a patch that adds write functionality (if not already implemented) - i can reuse most of the code that's converting input to register values Thanks and best regards, Alexandru -- 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.
