On Wednesday, May 21, 2014 at 04:01:55 AM, Peter Schumann wrote: > This patch makes it possible to boot from battery on olinuxino Boards > from Olimex. > > We should not set DOUBLE_FETS in HW_POWER_MINPWR
Please explain how you arrived to this conclusion. > , it makes my system > reset with in seconds while running on battery power. > > Also mxs_power_enable_4p2() should not be called if running from > battery. It switches VDDD and VDDA to LinReg mode and than turns off > the VDDIO DCDC supply. At this point the system resets. This has been tested on i.MX28 , can you please check what the differences are between these two chips and why it works only on one of them ? > If we run on battery this is no good idea because the LinRegs are > chained behind VDDIO and battery voltage seems not enough to power > the system from LinRegs. > Also is the power system already running on DCDC after BootROM hands > over to u-boot, so no sense in switching back to LinRegs. The BootROM never hands over to U-Boot, so this really makes no sense. Can you please explain ? The BootROM handles over to U-Boot SPL, which configures the power block. Also, I find it a very bad idea to depend on the BootROM to actually start the DCDC converter. I don't think we can universally say the DCDC converter is running when entering U-Boot SPL. I also don't think we can even depend on the power block configuration when exiting the BootROM -- for example in JTAG Boot Mode, the BootROM halts early in the boot process and will likely not configure anything with regards to the power block. [...] THanks! Best regards, Marek Vasut _______________________________________________ U-Boot mailing list U-Boot@lists.denx.de http://lists.denx.de/mailman/listinfo/u-boot
