linux-kernel - Re: [PATCH v6 03/12] regulator: Move OF-specific regulator lookup code to of

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Message-ID: <ZthcBpx8WFIvsrJj@smile.fi.intel.com>
Date: Wed, 4 Sep 2024 16:09:26 +0300
From: Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To: Chen-Yu Tsai <wenst@...omium.org>
Cc: Rob Herring <robh@...nel.org>, Saravana Kannan <saravanak@...gle.com>,
	Matthias Brugger <matthias.bgg@...il.com>,
	AngeloGioacchino Del Regno <angelogioacchino.delregno@...labora.com>,
	Wolfram Sang <wsa@...nel.org>, Benson Leung <bleung@...omium.org>,
	Tzung-Bi Shih <tzungbi@...nel.org>, Mark Brown <broonie@...nel.org>,
	Liam Girdwood <lgirdwood@...il.com>,
	chrome-platform@...ts.linux.dev, devicetree@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-mediatek@...ts.infradead.org, linux-kernel@...r.kernel.org,
	Douglas Anderson <dianders@...omium.org>,
	Johan Hovold <johan@...nel.org>, Jiri Kosina <jikos@...nel.org>,
	linux-i2c@...r.kernel.org
Subject: Re: [PATCH v6 03/12] regulator: Move OF-specific regulator lookup
 code to of_regulator.c

On Wed, Sep 04, 2024 at 05:00:05PM +0800, Chen-Yu Tsai wrote:
> There's still a bit of OF-specific code in the regulator device lookup
> function.
> 
> Move those bits of code over to of_regulator.c, and create a new
> function of_regulator_dev_lookup() to encapsulate the code moved out of
> regulator_dev_lookup().
> 
> Also mark of_find_regulator_by_node() as static, since there are no
> other users in other compile units.
> 
> There are no functional changes. A line alignment was also fixed.

...

> +/**
> + * of_get_child_regulator - get a child regulator device node
> + * based on supply name
> + * @parent: Parent device node
> + * @prop_name: Combination regulator supply name and "-supply"
> + *
> + * Traverse all child nodes.
> + * Extract the child regulator device node corresponding to the supply name.
> + *
> + * Return: Pointer to the &struct device_node corresponding to the regulator
> + *	   if found, or %NULL if not found.
> + */
> +static struct device_node *of_get_child_regulator(struct device_node *parent,
> +						  const char *prop_name)
> +{
> +	struct device_node *regnode = NULL;
> +	struct device_node *child = NULL;
> +
> +	for_each_child_of_node(parent, child) {

> +		regnode = of_parse_phandle(child, prop_name, 0);
> +		if (!regnode) {
> +			regnode = of_get_child_regulator(child, prop_name);
> +			if (regnode)
> +				goto err_node_put;
> +		} else {
> +			goto err_node_put;
> +		}

I know this is just a move of the existing code, but consider negating the
conditional and have something like

		regnode = of_parse_phandle(child, prop_name, 0);
		if (regnode)
			goto err_node_put;

		regnode = of_get_child_regulator(child, prop_name);
		if (regnode)
			goto err_node_put;

> +	}
> +	return NULL;
> +
> +err_node_put:
> +	of_node_put(child);
> +	return regnode;
> +}

...

I assume the use of _scoped() macros is in mind for the future changes?

...

> +/**
> + * of_get_regulator - get a regulator device node based on supply name
> + * @dev: Device pointer for the consumer (of regulator) device
> + * @supply: regulator supply name
> + *
> + * Extract the regulator device node corresponding to the supply name.
> + *
> + * Return: Pointer to the &struct device_node corresponding to the regulator
> + *	   if found, or %NULL if not found.
> + */
> +static struct device_node *of_get_regulator(struct device *dev, const char *supply)
> +{
> +	struct device_node *regnode = NULL;
> +	char prop_name[64]; /* 64 is max size of property name */
> +
> +	dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);
> +
> +	snprintf(prop_name, 64, "%s-supply", supply);
> +	regnode = of_parse_phandle(dev->of_node, prop_name, 0);

> +	if (!regnode) {

Similarly here

	snprintf(prop_name, 64, "%s-supply", supply);
	regnode = of_parse_phandle(dev->of_node, prop_name, 0);
	if (regnode)
		return regnode;


> +		regnode = of_get_child_regulator(dev->of_node, prop_name);
> +		if (regnode)
> +			return regnode;
> +
> +		dev_dbg(dev, "Looking up %s property in node %pOF failed\n",
> +			prop_name, dev->of_node);
> +		return NULL;
> +	}
> +	return regnode;

	regnode = of_get_child_regulator(dev->of_node, prop_name);
	if (regnode)
		return regnode;

	dev_dbg(dev, "Looking up %s property in node %pOF failed\n", prop_name, dev->of_node);
	return NULL;

> +}

-- 
With Best Regards,
Andy Shevchenko