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

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Message-ID: <20160804225929.33a94511@aktux>
Date:	Thu, 4 Aug 2016 22:59:29 +0200
From:	Andreas Kemnade <andreas@...nade.info>
To:	"H. Nikolaus Schaller" <hns@...delico.com>
Cc:	Tony Lindgren <tony@...mide.com>, Bin Liu <b-liu@...com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	Linux USB Mailing List <linux-usb@...r.kernel.org>,
	linux-omap <linux-omap@...r.kernel.org>,
	LKML <linux-kernel@...r.kernel.org>,
	Discussions about the Letux Kernel 
	<letux-kernel@...nphoenux.org>
Subject: Re: [Letux-kernel] [PATCH v2] musb: omap2430: do not assume
 balanced enable()/disable()

On Thu, 4 Aug 2016 16:49:30 +0200
"H. Nikolaus Schaller" <hns@...delico.com> wrote:

> > Rationale:
> > 
> > The charger driver calls pm_runtime_get_sync(bci->transceiver->dev);
> > which should indirectly call twl4030_usb_set_mode to set the
> > POWER_CTRL_OTG_ENAB bit. This enables the prescaler hardware
> > for ADC8 (VBUS) channel. But this does not happen for reasons
> > outside the charger driver.
> > 
how should that work?
I only have seen the call trace from the musb/omap2430.c glue though
the phy subsystem (via phy_ops) to  twl4030_phy_power_on (which sets
the important bit).
And the phy subsystem has its own power refcounting system which
is brought into disorder by unbalanced calls from the musb system...

Regards,
Andreas