[PATCH 8/9] regulator: helper to extract regulator node based on supply name

[grant.likely@secretlab.ca (Grant Likely)]

On Tue, Sep 27, 2011 at 03:42:51PM +0530, Rajendra Nayak wrote:
> Device nodes in DT can associate themselves with one or more
> regulators by providing a list of phandles (to regulator nodes)
> and corresponding supply names.
> 
> For Example:
> 	devicenode: node at 0x0 {
> 		...
> 		...
> 		vmmc-supply = <&regulator1>;
> 		vpll-supply = <&regulator1>;
> 	};
> 
> The driver would then do a regulator_get(dev, "vmmc"); to get
> regulator1 and do a regulator_get(dev, "vpll"); to get
> regulator2.
> 
> of_get_regulator() extracts the regulator node for a given
> device, based on the supply name.
> 
> Signed-off-by: Rajendra Nayak <rnayak@ti.com>
> ---
>  drivers/regulator/of_regulator.c       |   39 ++++++++++++++++++++++++++++++++
>  include/linux/regulator/of_regulator.h |    7 +++++
>  2 files changed, 46 insertions(+), 0 deletions(-)
> 
> diff --git a/drivers/regulator/of_regulator.c b/drivers/regulator/of_regulator.c
> index 7fa63ff..49dd105 100644
> --- a/drivers/regulator/of_regulator.c
> +++ b/drivers/regulator/of_regulator.c
> @@ -14,6 +14,45 @@
>  #include <linux/of.h>
>  #include <linux/regulator/machine.h>
>  
> +
> +/**
> + * 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.
> + * retruns the device node corresponding to the regulator if found, else
> + * returns NULL.
> + */
> +struct device_node *of_get_regulator(struct device *dev, const char *supply)
> +{
> +	struct device_node *regnode = NULL;
> +	u32 reghandle;
> +	char prop_name[32]; /* 32 is max size of property name */
> +	const void *prop;
> +	int sz;
> +
> +	if (!dev)
> +		return NULL;
> +
> +	dev_dbg(dev, "Looking up %s-supply from device tree\n", supply);
> +
> +	snprintf(prop_name, 32, "%s-supply", supply);
> +
> +	prop = of_get_property(dev->of_node, prop_name, &sz);
> +	if (!prop || sz < 4)
> +		return NULL;
> +
> +	reghandle = be32_to_cpup(prop);
> +	regnode = of_find_node_by_phandle(reghandle);

of_parse_phandle()

> +	if (!regnode) {
> +		pr_warn("%s: %s property in node %s references invalid phandle",
> +			__func__, prop_name, dev->of_node->full_name);
> +		return NULL;
> +	}
> +	return regnode;
> +}
> +
>  static void of_get_regulation_constraints(struct device_node *np,
>  					struct regulator_init_data **init_data)
>  {
> diff --git a/include/linux/regulator/of_regulator.h b/include/linux/regulator/of_regulator.h
> index 3f63be9..edaba1a 100644
> --- a/include/linux/regulator/of_regulator.h
> +++ b/include/linux/regulator/of_regulator.h
> @@ -9,12 +9,19 @@
>  #if defined(CONFIG_OF_REGULATOR)
>  extern struct regulator_init_data
>  	*of_get_regulator_init_data(struct device *dev);
> +extern struct device_node *of_get_regulator(struct device *dev,
> +	const char *supply);
>  #else
>  static inline struct regulator_init_data
>  	*of_get_regulator_init_data(struct device_node *np)
>  {
>  	return NULL;
>  }
> +static inline struct device_node *of_get_regulator(struct device *dev,
> +	const char *id)
> +{
> +	return NULL;
> +}
>  #endif /* CONFIG_OF_REGULATOR */
>  
>  #endif /* __LINUX_OF_REG_H */
> -- 
> 1.7.1
>