Hi Oliver, On Wed, Mar 01, 2017 at 01:52:16PM +0100, Olliver Schinagl wrote: > Hi list, > > When powering up an AXP209, the default value for LDO3 output is enabled. This > works fine. However if for whatever reason, LDO3 is disabled, for example by > OS > during reboot and u-boot enables LDO3 again, the PMIC shutsdown (without > setting an interrupt) causing the board to hang. This behavior has been seen > from Linux as well, u-boot disables LDO3 as a default value, the kernel > enables > it per its DTS, the kernel hangs as the PMIC gets shut down. > > The root cause is that some boards have to high capacitance on the LDO3 output > port causing inrush currents exceeding the maximum of the AXP209. > > The fix is to turn on the LDO3 at the lowest possible voltage and then set the > final voltage. > > If the capacitance is really big (due to a connected device for example) the > AXP209 also features VRC, or Voltage Rate Control, which allows the voltage > ramp up to be even slower. > > This patch series implements the above with a few tiny, cleanups I ran into > underway. > > The initial discussion with some scope screenshots can be found in the > linux-sunxi mailing list [0].
If you don't CC the proper maintainers, no one is going to pick the patches. Maxime -- Maxime Ripard, Free Electrons Embedded Linux and Kernel engineering http://free-electrons.com
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