Messages in this thread | | | Date | Tue, 5 Jun 2012 11:11:36 -0500 | From | Scott Wood <> | Subject | Re: [PATCH v5 4/5] fsl_pmc: Add API to enable device as wakeup event source |
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On 06/04/2012 11:08 PM, Li Yang-R58472 wrote: > > >> -----Original Message----- >> From: Wood Scott-B07421 >> Sent: Tuesday, June 05, 2012 7:03 AM >> To: Zhao Chenhui-B35336 >> Cc: linuxppc-dev@lists.ozlabs.org; linux-kernel@vger.kernel.org; >> galak@kernel.crashing.org; Li Yang-R58472 >> Subject: Re: [PATCH v5 4/5] fsl_pmc: Add API to enable device as wakeup >> event source >> >> On 06/04/2012 06:36 AM, Zhao Chenhui wrote: >>> On Fri, Jun 01, 2012 at 05:08:52PM -0500, Scott Wood wrote: >>>> On 05/11/2012 06:53 AM, Zhao Chenhui wrote: >>>>> +int mpc85xx_pmc_set_wake(struct platform_device *pdev, bool enable) >>>> >>>> Why does it have to be a platform_device? Would a bare device_node >> work >>>> here? If it's for stuff like device_may_wakeup() that could be in a >>>> platform_device wrapper function. >>> >>> It does not have to be a platform_device. I think it can be a struct >> device. >> >> Why does it even need that? The low level mechanism for influencing >> PMCDR should only need a device node, not a Linux device struct. > > It does no harm to pass the device structure and makes more sense for object oriented interface design.
It does do harm if you don't have a device structure to pass, if for some reason you found the device by directly looking for it rather than going through the device model.
>>>> Who is setting can_wakeup for these devices? >>> >>> The device driver is responsible to set can_wakeup. >> >> How would the device driver know how to set it? Wouldn't this depend on >> the particular SoC and low power mode? > > It is based on the "fsl,magic-packet" and "fsl,wake-on-filer" device tree properties.
fsl,magic-packet was a mistake. It is equivalent to checking the compatible for etsec. It does not convey any information about whether the eTSEC is still active in a given low power mode.
How is fsl,wake-os-filer relevant to this decision? When will it be set but not fsl,magic-packet?
What about devices other than ethernet? What about differences between ordinary sleep and deep sleep?
-Scott
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