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

From: Chen-Yu Tsai <wens@csie.org>
To: Rob Herring <robh@kernel.org>
Cc: Krzysztof Kozlowski <k.kozlowski@samsung.com>,
	Mark Rutland <mark.rutland@arm.com>,
	devicetree <devicetree@vger.kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	linux-samsung-soc@vger.kernel.org,
	Pawel Moll <pawel.moll@arm.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	linux-usb <linux-usb@vger.kernel.org>,
	"linux-mmc@vger.kernel.org" <linux-mmc@vger.kernel.org>,
	Sebastian Reichel <sre@kernel.org>,
	linux-kernel <linux-kernel@vger.kernel.org>,
	Javier Martinez Canillas <javier@osg.samsung.com>,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@samsung.com>,
	Kukjin Kim <kgene@kernel.org>,
	Alan Stern <stern@rowland.harvard.edu>,
	linux-arm-kernel <linux-arm-kernel@lists.infradead.org>,
	Kumar Gala <galak@codeaurora.org>,
	David Woodhouse <dwmw2@infradead.org>,
	hzpeterchen@gmail.com, linux-pm@vger.kernel.or
Subject: Re: [PATCH v3 06/12] power: pwrseq: simple: Add support for regulator and generic property
Date: Thu, 9 Jun 2016 10:34:06 +0800	[thread overview]
Message-ID: <CAGb2v66OO0QJ75=hLnRukhXWdX7HgSy0LDakdZ_jxFRCHTUuJw@mail.gmail.com> (raw)
In-Reply-To: <20160608190333.GA5126@rob-hp-laptop>

Hi

On Thu, Jun 9, 2016 at 3:03 AM, Rob Herring <robh@kernel.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?

ChenYu