linux-kernel - Re: [PATCH v3 4/5] regulator: max14577: Add regulator driver for Maxim 14577

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Date:	Fri, 22 Nov 2013 16:55:48 +0100
From:	Krzysztof Kozlowski <k.kozlowski@...sung.com>
To:	Lee Jones <lee.jones@...aro.org>
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 v3 4/5] regulator: max14577: Add regulator driver for Maxim
 14577

On Fri, 2013-11-22 at 10:15 +0000, Lee Jones wrote:
> > +#ifdef CONFIG_OF
> > +static int max14577_regulator_dt_parse_pdata(struct platform_device *pdev,
> > +					struct max14577_platform_data *pdata)
> > +{
> > +	struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
> > +	struct device_node *np;
> > +	struct max14577_regulator_platform_data *reg_pdata;
> > +	struct of_regulator_match rmatch;
> > +	int i, ret;
> > +
> > +	np = of_get_child_by_name(max14577->dev->of_node, "regulators");
> > +	if (!np)
> > +		return -EINVAL;
> 
> No need to do this. If instead you use a compatible string and set
> it's MFD cell's .of_compatible property, the MFD core will set
> pdev->dev.of_node for you.
> 
> > +	reg_pdata = devm_kzalloc(&pdev->dev, sizeof(*reg_pdata) *
> > +			     ARRAY_SIZE(supported_regulators), GFP_KERNEL);
> > +	if (!reg_pdata)
> > +		return -ENOMEM;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(supported_regulators); i++) {
> > +		rmatch.name = supported_regulators[i].name;
> > +		ret = of_regulator_match(&pdev->dev, np, &rmatch, 1);
> > +		if (ret != 1)
> > +			continue;
> > +		dev_dbg(&pdev->dev, "Found regulator %d/%s\n",
> > +				supported_regulators[i].id,
> > +				supported_regulators[i].name);
> > +		reg_pdata[i].id = supported_regulators[i].id;
> > +		reg_pdata[i].initdata = rmatch.init_data;
> > +		reg_pdata[i].of_node = rmatch.of_node;
> > +	}
> > +
> > +	pdata->regulators = reg_pdata;
> > +
> > +	return 0;
> > +}
> > +#else
> > +static int max14577_regulator_dt_parse_pdata(struct platform_device *pdev,
> > +					struct max14577_platform_data *pdata)
> > +{
> > +	return 0;
> > +}
> > +#endif
> 
> No need for this either. Just check for the device's of_node.
> 
> > +static int max14577_regulator_probe(struct platform_device *pdev)
> > +{
> > +	struct max14577 *max14577 = dev_get_drvdata(pdev->dev.parent);
> > +	struct max14577_platform_data *pdata = dev_get_platdata(max14577->dev);
> > +	int i, size;
> > +	struct regulator_config config = {};
> > +	struct regulator_dev **regulators;
> > +
> > +	if (!pdata) {
> > +		/* Parent must provide pdata */
> > +		dev_err(&pdev->dev, "No MFD driver platform data found.\n");
> > +		return -ENODEV;
> > +	}
> > +
> > +	if (max14577->dev->of_node) {
> > +		int ret = max14577_regulator_dt_parse_pdata(pdev, pdata);
> 
> This will overwrite pdata which is wrong.
> 
> pdata should always take precedence over DT.
> 
> <snip>
> 
> > +	for (i = 0; i < ARRAY_SIZE(supported_regulators); i++) {
> > +		/*
> > +		 * Index of supported_regulators[] is also the id and must
> > +		 * match index of pdata->regulators[].
> > +		 */
> > +		config.init_data = pdata->regulators[i].initdata;
> > +		config.of_node = pdata->regulators[i].of_node;
> 
> I still thing this is superfluous. Why don't you run though the nodes
> here instead of doing it in MFD and passing this stuff through?

I have rewritten the regulator init code (and DT parsing). I think it
reflects your comments. Please look at version 4 of patches.

Best regards,
Krzysztof

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