Hi Javier & Mark,

I am educated. Thank you all.

-----Original Message-----
From: Javier Martinez Canillas [mailto:javier at dowhile0.org]
Sent: 2016?1?29? 19:50
To: Mark Brown <broonie@kernel.org>
Cc: Yang, Wenyou <redacted>; Liam Girdwood
[off-list ref]; Rob Herring [off-list ref]; Pawel Moll
[off-list ref]; Ian Campbell [off-list ref]; Kumar
Gala [off-list ref]; Krzysztof Kozlowski
[off-list ref]; Lee Jones [off-list ref]; Peter
Korsgaard [off-list ref]; Ferre, Nicolas [off-list ref];
linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org;
devicetree at vger.kernel.org
Subject: Re: [PATCH v4 1/2] regulator: act8945a: add regulator driver for
ACT8945A

Hello Mark,

On Fri, Jan 29, 2016 at 8:35 AM, Mark Brown [off-list ref] wrote:

quoted

On Fri, Jan 29, 2016 at 01:20:08AM +0000, Yang, Wenyou wrote:

quoted

quoted

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+static const struct of_device_id act8945a_pmic_of_match[] = {  {
+.compatible = "active-semi,act8945a-regulator" },  { }, };
+MODULE_DEVICE_TABLE(of, act8945a_pmic_of_match);

quoted

quoted

This seems mostly OK but why do we have a compatible string here -
shouldn't the MFD be able to instantiate the regulator function without

needing this?

quoted

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Because I got feedback from Javier for the act8945a-charger patches
of this MFD series, He said missing the OF match table will cause the module

autoloading broken.

quoted

quoted

http://lists.infradead.org/pipermail/linux-arm-kernel/2016-January/39
8113.html

quoted

What do you think about it?

If then device is not being loaded from the DT (and it shouldn't be,
the device looks like it should be instantiated directly by the MFD as
it can't exist separately to that MFD) an OF table will do nothing.

Then he should remove the .of_compatible from the MFD cell definition.

I tried it,

But if removed this .of_compatible, and reserved the OF table. 
the &pdev->dev->of_node is NULL, the driver fails to get the configuration value from DT, 

It seems the OF table still doesn't work. Where is wrong?

Could you help give some suggestion?

Otherwise the MFD core will assign an of_node to this device in mfd_add_device(),
making the platform core to believe the device was instantiated by OF. So an OF
modalias uevent will be reported to load the module and the OF table should be
used for matching the device with the driver.

IOW, the MFD and regulator driver have to agree on this. Either everything should
have OF or platform information, both work but mixing these as it was on a
previous version doesn't.

Best regards,
Javier

Best Regards,
Wenyou Yang