linux-kernel - Re: [PATCH v3 06/12] power: pwrseq: simple: Add support for regulator and generic property

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Date:	Thu, 09 Jun 2016 07:11:32 +0200
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Chen-Yu Tsai <wens@...e.org>, Rob Herring <robh@...nel.org>
Cc:	Mark Rutland <mark.rutland@....com>,
	devicetree <devicetree@...r.kernel.org>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	linux-samsung-soc@...r.kernel.org, Pawel Moll <pawel.moll@....com>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Dmitry Eremin-Solenikov <dbaryshkov@...il.com>,
	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-usb <linux-usb@...r.kernel.org>,
	"linux-mmc@...r.kernel.org" <linux-mmc@...r.kernel.org>,
	Sebastian Reichel <sre@...nel.org>,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Kukjin Kim <kgene@...nel.org>,
	Alan Stern <stern@...land.harvard.edu>,
	linux-arm-kernel <linux-arm-kernel@...ts.infradead.org>,
	Kumar Gala <galak@...eaurora.org>,
	David Woodhouse <dwmw2@...radead.org>, hzpeterchen@...il.com,
	linux-pm@...r.kernel.or
Subject: Re: [PATCH v3 06/12] power: pwrseq: simple: Add support for regulator
 and generic property

On 06/09/2016 04:34 AM, Chen-Yu Tsai wrote:
> Hi
> 
> On Thu, Jun 9, 2016 at 3:03 AM, Rob Herring <robh@...nel.org> wrote:
>> On Tue, Jun 07, 2016 at 11:29:02AM +0200, Krzysztof Kozlowski wrote:
>>> On 06/03/2016 04:02 AM, Rob Herring wrote:
>>>>>  Optional properties:
>>>>>  - reset-gpios : contains a list of GPIO specifiers. The reset GPIOs are asserted
>>>>> @@ -16,6 +22,7 @@ Optional properties:
>>>>>    See ../clocks/clock-bindings.txt for details.
>>>>>  - clock-names : Must include the following entry:
>>>>>    "ext_clock" (External clock provided to the card).
>>>>> +- ext-supply : External regulator supply
>>>>
>>>> What happens when there are 2 supplies?
>>>>
>>>> I'd prefer the name not be genericish and use the real supply names.
>>>> Then the power seq code should just turn on all supplies it finds. If
>>>> the order or timing to turn on matters, then sorry, no generic sequence.
>>>
>>> I think the generic part for regulators might be a problem. Regulator
>>> API requires a name for the supply... it cannot get "something" or
>>> "everything".
>>
>> That's the downside of variable property names...
>>
>>> The driver could attach itself to any kind of node (where power-sequence
>>> property exists) so the supply name depends on the bindings of device
>>> (not bindings of power sequence driver).
>>>
>>> The power sequence driver could however iterate over child properties
>>> and get the names of all supplies. It is a little bit ugly...
>>
>> Yes. Like this, right?
>>
>> for_each_property_of_node(np, pp) {
>>         if (!strstr(pp->name, "-supply"))
>>                 continue;
>>         // found supply
>> }
>>
>> The uglyness can always be improved with a function to do this parsing.
> 
> There's already a version of this in simplefb. Maybe it's time to move
> this to a common function?

Thanks, I'll make a generic one and let's see how Mark will respond to it.

Best regards,
Krzysztof