linux-kernel - Re: [PATCH v2 1/5] mfd: max14577: Add max14577 MFD driver core

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Date:	Thu, 21 Nov 2013 12:20:11 +0000
From:	Lee Jones <lee.jones@...aro.org>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
Cc:	MyungJoo Ham <myungjoo.ham@...sung.com>,
	Chanwoo Choi <cw00.choi@...sung.com>,
	Samuel Ortiz <sameo@...ux.intel.com>,
	Anton Vorontsov <anton@...msg.org>,
	David Woodhouse <dwmw2@...radead.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	Mark Brown <broonie@...nel.org>,
	Grant Likely <grant.likely@...aro.org>,
	Rob Herring <rob.herring@...xeda.com>,
	linux-kernel@...r.kernel.org, devicetree@...r.kernel.org,
	Pawel Moll <pawel.moll@....com>,
	Stephen Warren <swarren@...dotorg.org>,
	Ian Campbell <ijc+devicetree@...lion.org.uk>,
	Rob Landley <rob@...dley.net>, linux-doc@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>,
	Marek Szyprowski <m.szyprowski@...sung.com>,
	Kyungmin Park <kyungmin.park@...sung.com>
Subject: Re: [PATCH v2 1/5] mfd: max14577: Add max14577 MFD driver core

> Thanks for pointing these out however after using regmap_irq_chip whole
> file won't be needed anymore.

That's fine.

> > > +static int max14577_i2c_probe(struct i2c_client *i2c,
> > > +			      const struct i2c_device_id *id)
> > > +{
> > > +	struct max14577 *max14577;
> > > +	struct max14577_platform_data *pdata = dev_get_platdata(&i2c->dev);
> > > +	u8 reg_data;
> > > +	int ret = 0;
> > > +
> > > +	if (i2c->dev.of_node) {
> > 
> > Can you pull this out. It looks neater as the top as:
> >   struct device_node *np = i2c->dev.of_node;
> 
> I am not sure if I understand you correctly. You would like to change
> this to:
> -------------------------
> static int max14577_i2c_probe(struct i2c_client *i2c,
>                               const struct i2c_device_id *id)
> {
>         struct max14577 *max14577;
>         struct max14577_platform_data *pdata =
> dev_get_platdata(&i2c->dev);
>         struct device_node *np = i2c->dev.of_node;
>         u8 reg_data;
>         int ret = 0;
> 
>         if (np) {
>                 pdata = devm_kzalloc(&i2c->dev,
>                                 sizeof(struct max14577_platform_data),
>                                 GFP_KERNEL);
> -------------------------
> The variable 'np' would be used only once.

I know, but it's more in keeping with the rest of the subsystem.

> > > +
> > > +	ret = mfd_add_devices(max14577->dev, -1, max14577_devs,
> > > +			ARRAY_SIZE(max14577_devs), NULL, 0, NULL);
> > 
> > You should be passing the irqdomain as the final parameter here.
> 
> I replaced the IRQ handling with regmap_irq_chip so this would look like
> this:
> -------------------------
>         ret = mfd_add_devices(max14577->dev, -1, max14577_devs,
>                         ARRAY_SIZE(max14577_devs), NULL, 0,
>                         regmap_irq_get_domain(max14577->irq_data));
> -------------------------
> Am I correct?

if regmap_irq_get_domain() returns an irqdomain, then yes.

> > > +	return i2c_add_driver(&max14577_i2c_driver);
> > > +}
> > > +subsys_initcall(max14577_i2c_init);
> > > +
> > > +static void __exit max14577_i2c_exit(void)
> > > +{
> > > +	i2c_del_driver(&max14577_i2c_driver);
> > > +}
> > > +module_exit(max14577_i2c_exit);
> > 
> > >>>>>>>>>>>>>>>>>>>>>>
> > 
> > Remove all this and replace with:
> >   module_i2c_driver(max14577_i2c_driver);
> 
> The subsys_initcall is needed. Marek Szyprowski replied to this here:
> http://thread.gmane.org/gmane.linux.drivers.devicetree/51903/focus=1594651

Okay, but this will need to be changed when USB Gadget starts to
support -EPROBE_DEFER

> > > +struct max14577_regulator_platform_data {
> > > +	int id;
> > > +	struct regulator_init_data *initdata;
> > > +	struct device_node *of_node;
> > 
> > Do you ever set this? What's the point of it is it's set in the device?
> 
> Do you mean the whole struct max14577_regulator_platform_data or only
> some member of it (of_node?)?

Initially only the of_node. Usually MFD children are able to call back
into their parent to fetch these details. Also mfd_add_device() goes
out of its way to fill in the child's own of_node.

-- 
Lee Jones
Linaro STMicroelectronics Landing Team Lead
Linaro.org │ Open source software for ARM SoCs
Follow Linaro: Facebook | Twitter | Blog
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