linux-kernel - Re: [PATCH 1/2] arm: omap: usb: enable I/O wakeups of ehci and ohci hwmods of omap4

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Date:	Fri, 09 Sep 2011 11:27:37 -0700
From:	Kevin Hilman <khilman@...com>
To:	Keshava Munegowda <keshava_mgowda@...com>
Cc:	<linux-usb@...r.kernel.org>, <linux-omap@...r.kernel.org>,
	<linux-kernel@...r.kernel.org>, <balbi@...com>, <gadiyar@...com>,
	<sameo@...ux.intel.com>, <parthab@...ia.ti.com>,
	<tony@...mide.com>, <b-cousson@...com>, <paul@...an.com>,
	<johnstul@...ibm.com>, <vishwanath.bs@...com>,
	Kishon Vijay Abraham <kishon@...com>
Subject: Re: [PATCH 1/2] arm: omap: usb: enable I/O wakeups of ehci and ohci hwmods of omap4

Keshava Munegowda <keshava_mgowda@...com> writes:

> From: Kishon Vijay Abraham <kishon@...com>
>
> For ehci and ohci hwmods, the omap4 I/O wakeup capablity is enabled.
> for ehci in phy mode,
> 	- the DAT0 and DIR I/O pad is set as wakeup capable
> for ohci in serial mode
> 	- usbb*_mm_rxdp is set as I/O wakeup for 6 pin serial mode
> 	- usbb*_mm_rxrcv is set as I/O wakeup for 4 pin serial mode
> 	- usbb*_mm_txen is set as I/O wakeup for 3 pin serial mode
> 	- usbb*_mm_txdat is set as I/O wakeup for 2 pin serial mode
>
> Signed-off-by: Kishon Vijay Abraham <kishon@...com>
> Signed-off-by: Keshava Munegowda <keshava_mgowda@...com>

What if the end user doesn't want this device to be a wakeup source?

Currently, the IO pad wakeup for these pins is enabled unconditionally.
While having it enabled as a wakeup source by default is fine, it should
not generate wakeups if the user has disable them by doing:

    $ echo disabled > /sys/devices/.../power/wakeup

IOW, whether wakeups are enabled or not should depend on the driver
checking device_may_wakeup()

Kevin
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