Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver

From	Kishon Vijay Abraham I <kishon@ti.com>
Newsgroups	linux.kernel
Subject	Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver
Date	2017-08-20 13:10 +0200
Message-ID	<ugwhc-6cM-15@gated-at.bofh.it> (permalink)
References	(2 earlier) <ueFoB-7kE-13@gated-at.bofh.it> <ufm0y-tP-9@gated-at.bofh.it> <ufmWC-17m-7@gated-at.bofh.it> <ufo2m-25Q-25@gated-at.bofh.it> <ufovo-2hc-33@gated-at.bofh.it>
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Adrian,

On Thursday 17 August 2017 01:53 PM, Adrian Hunter wrote:
> On 17/08/17 10:59, Kishon Vijay Abraham I wrote:
>> Hi Adrian,
>>
>> On Thursday 17 August 2017 12:13 PM, Adrian Hunter wrote:
>>> On 17/08/17 08:57, Kishon Vijay Abraham I wrote:
>>>> Hi Adrian,
>>>>
>>>> On Tuesday 15 August 2017 01:52 PM, Adrian Hunter wrote:
>>>>> On 07/08/17 19:01, Kishon Vijay Abraham I wrote:
> 
> <SNIP>
> 
>>>>>> +	pm_runtime_enable(dev);
>>>>>> +	ret = pm_runtime_get_sync(dev);
>>>>>
>>>>> What are you trying to do with runtime pm?  There don't seem to be any pm
>>>>> callbacks, so does this do anything?
>>>>
>>>> yeah, pm_runtime_get_sync enables the functional clock and also configures the
>>>> SYSCONFIG regiters present in the controller. It gets the details for
>>>> configuring those from arch/arm/mach-omap2/omap_hwmod_*
>>>
>>> You mean it will do those things when you add the callbacks?  I would prefer
>>> you leave out runtime pm until you can add the callbacks as well.
>>
>> No. Generally in callbacks, 'optional' functional clocks are enabled. But main
>> functional clock and interface clocks are enabled in pm_runtime_get_sync.
>> Without pm_runtime_get_sync, we won't be able to access controller registers.
> 
> So that is done by the pm domain?  Please add comments to the code to explain.

right, it's done by omap_device_pm_domain.
Invoking pm_runtime_get_sync of a platform device in OMAP platforms will
eventually come to omap_hwmod_enable where main functional clock, interface
clock and sysconfig are programmed.

Thanks
Kishon

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Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver Adrian Hunter <adrian.hunter@intel.com> - 2017-08-15 10:30 +0200
  Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver Kishon Vijay Abraham I <kishon@ti.com> - 2017-08-17 08:00 +0200
    Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver Adrian Hunter <adrian.hunter@intel.com> - 2017-08-17 09:00 +0200
      Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver Kishon Vijay Abraham I <kishon@ti.com> - 2017-08-17 10:10 +0200
        Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver Adrian Hunter <adrian.hunter@intel.com> - 2017-08-17 10:40 +0200
          Re: [RFC PATCH 6/7] mmc: sdhci-omap: Add OMAP SDHCI driver Kishon Vijay Abraham I <kishon@ti.com> - 2017-08-20 13:10 +0200

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