linux-kernel - Re: [Letux-kernel] [PATCH v2] musb: omap2430: do not assume balanced enable()/disable()

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Message-ID: <20160805135501.GJ28140@atomide.com>
Date:	Fri, 5 Aug 2016 06:55:01 -0700
From:	Tony Lindgren <tony@...mide.com>
To:	Andreas Kemnade <andreas@...nade.info>
Cc:	Discussions about the Letux Kernel <letux-kernel@...nphoenux.org>,
	Linux USB Mailing List <linux-usb@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-omap <linux-omap@...r.kernel.org>, Bin Liu <b-liu@...com>
Subject: Re: [Letux-kernel] [PATCH v2] musb: omap2430: do not assume balanced
 enable()/disable()

* Andreas Kemnade <andreas@...nade.info> [160804 09:44]:
> Nothing happens here, so the previous state of the phy remains.
> It would be disabled by the generic phy layer in drivers/phy/phy-core.c
>
> > gadget driver is loaded.
> > musb_start() is called
> >     omap2430_musb_enable() is called
> > 	calls phy_power_on(),
> > 	phy->power_count goes to 0,
> > 	phy is not powered on because power_count != 1
> > -> no gadget working, no charging.
> > 
> ... if not configured by u-boot before. USB gadget might work when
> initialized earlier in the boot process (u-boot/x-loader/mlo ...)
> and phy-twl4030 cannot do anything about it besides if we change
> drivers/phy/phy-core.c

Ssounds like an issue in the phy-twl4030-usb.c. Let's try to figure
out what all we need set there for the various components there.

PM runtime for phy-twl4030-usb.c should be for the whole PHY
device including all it's components. Then the charger and
MUSB should separately increment the PM runtime count and then
enable the component specific things. And then we have the
errata to deal with when VBUS is enabled.

If there are MUSB specific PM runtime issues then let's fix
those separately.

Regards,

Tony