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From: Bjorn Andersson <bjorn.andersson@sonymobile.com>
To: Mark Brown <broonie@kernel.org>
Cc: Chanwoo Choi <cw00.choi@samsung.com>,
	Ian Campbell <ijc+devicetree@hellion.org.uk>,
	Krzysztof Kozlowski <k.kozlowski@samsung.com>,
	Kumar Gala <galak@codeaurora.org>,
	Lee Jones <lee.jones@linaro.org>,
	Liam Girdwood <lgirdwood@gmail.com>,
	Mark Rutland <mark.rutland@arm.com>,
	Pawel Moll <pawel.moll@arm.com>, Rob Herring <robh+dt@kernel.org>,
	Stephen Boyd <sboyd@codeaurora.org>,
	Andy Gross <agross@codeaurora.org>,
	Srinivas Kandagatla <srinivas.kandagatla@linaro.org>,
	"devicetree@vger.kernel.org" <devicetree@vger.kernel.org>,
	"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-arm-msm@vger.kernel.org" <linux-arm-msm@vger.kernel.org>
Subject: Re: [PATCH 2/4] regulator: core: Expose init_data to of_parse_cb
Date: Tue, 3 Mar 2015 08:15:41 -0800	[thread overview]
Message-ID: <20150303161541.GE26334@sonymobile.com> (raw)
In-Reply-To: <20150303125033.GO21293@sirena.org.uk>

On Tue 03 Mar 04:50 PST 2015, Mark Brown wrote:

> On Mon, Mar 02, 2015 at 08:25:38PM -0800, Bjorn Andersson wrote:
> 
> > Expose the newly created init_data to the driver's parse callback so
> > that it can futher enhance it with e.g. constraints of the regulator.
> 
> Why would the driver need to do that?  I guess I'll see later on in the
> series but the changelog should make that clear.  Drivers aren't
> supposed to ever need to look at their init data, modifying the init
> data from what the machine provied is usually a red flag.
> 

I think what you're getting at is that the init_data should come from a
board file or device tree. With the reworkings done in patch 4 this
makes more sense than it did before (e.g. I no longer call
of_get_regulator_init_data()).

However, by calling register_regulator() with dev->of_node being
non-NULL and desc->of_match being something that will match a DT entry
all init_data is now coming from device tree, through:

regulator_register()
  regulator_of_get_init_data()
    of_get_regulator_init_data()
      of_get_regulation_constraints()

As this matches a regulator, there is no way for the driver (or anyone
else to affect the init_data).

The problem at hand is that there is nothing in this code path telling
the core that we can do DRMS - something we can figure out in the driver
by basically looking at the ops for the registering regulator.

> > This is needed because calling regulator_register() with a of_node and
> > of_match will overwrite the passed config->init_data. An alternative way
> > would be to merge the parsed init_data with the driver provided one.
> 
> Put any explanation as to why the feature is needed in the changelog.

Point taken.

Let me know if you think I'm on a sane path with the above reasoning and
I can resend the patch with a better description of the problem at hand.

Regards,
Bjorn

  reply	other threads:[~2015-03-03 16:16 UTC|newest]

Thread overview: 31+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-03-03  4:25 [PATCH 0/4] Refactor Qualcomm RPM regulator to single platform_device Bjorn Andersson
2015-03-03  4:25 ` [PATCH 1/4] mfd: devicetree: bindings: Add Qualcomm RPM regulator subnodes Bjorn Andersson
2015-03-03 12:47   ` Mark Brown
2015-03-03 16:02     ` Bjorn Andersson
2015-03-05  0:33       ` Mark Brown
2015-03-03 18:53   ` Stephen Boyd
2015-03-03 21:54     ` Bjorn Andersson
2015-03-03 22:02       ` Stephen Boyd
2015-03-03 22:17         ` Bjorn Andersson
2015-03-03 23:25           ` Stephen Boyd
2015-03-03  4:25 ` [PATCH 2/4] regulator: core: Expose init_data to of_parse_cb Bjorn Andersson
2015-03-03 12:50   ` Mark Brown
2015-03-03 16:15     ` Bjorn Andersson [this message]
2015-03-05  0:42       ` Mark Brown
2015-03-03  4:25 ` [PATCH 3/4] regulator: qcom: Refactor of-parsing code Bjorn Andersson
2015-03-03 14:13   ` Mark Brown
2015-03-03 16:26     ` Bjorn Andersson
2015-03-03 18:56   ` Stephen Boyd
2015-03-03 22:07     ` Bjorn Andersson
2015-03-03  4:25 ` [PATCH 4/4] regulator: qcom: Rework to single platform device Bjorn Andersson
2015-03-03 22:09   ` Stephen Boyd
2015-03-03 22:32     ` Bjorn Andersson
2015-03-03 23:52       ` Mark Brown
2015-03-04  0:01         ` Stephen Boyd
2015-03-04  0:09           ` Mark Brown
2015-03-04 19:35   ` Stephen Boyd
2015-03-04 23:51     ` Bjorn Andersson
2015-03-05  0:56       ` Mark Brown
2015-03-05  0:30     ` Mark Brown
2015-03-05  1:46       ` Stephen Boyd
2015-03-05 10:38         ` Mark Brown

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