[U-Boot] [PATCH 0/8] Stop AXP from crashing when enabeling LDO3

[Maxime Ripard]

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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