[Letux-kernel] towards the the root of charging problems

Andreas Kemnade andreas at kemnade.info
Fri Jul 29 19:07:02 CEST 2016

On Fri, 29 Jul 2016 18:19:54 +0200
Andreas Kemnade <andreas at kemnade.info> wrote:

> Hi,
> I am digging towards the root of charging problems and share some of
> my insights.
> phy_power_on is called with phy->power_count = -1
> so it does not call the corresponding power on function in phy-twl4030
> to set OTG_EN.
> I do not know yet where and why that counter gets wrong.

digging deeper:
is not balanced in musb_core.c
There is the following interesting piece of code
	/* be sure interrupts are disabled before connecting ISR */

in musb_init_controller() to switch from an unknown state to off state
which seems to be a good idea.
So there phy->power_count get -1. When the gadget driver gets loaded,
phy->power_count becomes 0 (not 1) so the phy is not powered.

I am developing a patch.


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