Commit 71a2f115 authored by Kuninori Morimoto's avatar Kuninori Morimoto Committed by Stephen Boyd
Browse files

clk: add devm_get_clk_from_child() API 



Some driver is using this type of DT bindings for clock (more detail,
see ${LINUX}/Documentation/devicetree/bindings/sound/simple-card.txt).

	sound_soc {
		...
		cpu {
			clocks = <&xxx>;
			...
		};
		codec {
			clocks = <&xxx>;
			...
		};
	};

Current driver in this case uses of_clk_get() for each node, but there
is no devm_of_clk_get() today.
OTOH, the problem of having devm_of_clk_get() is that it encourages the
use of of_clk_get() when clk_get() is more desirable.

Thus, this patch adds new devm_get_clk_from_chile() which explicitly
reads as get a clock from a child node of this device.
By this function, we can also use this type of DT bindings

	sound_soc {
		clocks = <&xxx>, <&xxx>;
		clock-names = "cpu", "codec";
		clock-ranges;
		...
		cpu {
			...
		};
		codec {
			...
		};
	};

Signed-off-by: default avatarKuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[sboyd@codeurora.org: Rename subject to clk + add API]
Signed-off-by: default avatarStephen Boyd <sboyd@codeaurora.org>
parent 16cd7764

drivers/clk/clk-devres.c

+21 −0
Original line number Diff line number Diff line
@@ -53,3 +53,24 @@ void devm_clk_put(struct device *dev, struct clk *clk) 
	WARN_ON(ret);

}

EXPORT_SYMBOL(devm_clk_put);



struct clk *devm_get_clk_from_child(struct device *dev,

				    struct device_node *np, const char *con_id)

{

	struct clk **ptr, *clk;



	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);

	if (!ptr)

		return ERR_PTR(-ENOMEM);



	clk = of_clk_get_by_name(np, con_id);

	if (!IS_ERR(clk)) {

		*ptr = clk;

		devres_add(dev, ptr);

	} else {

		devres_free(ptr);

	}



	return clk;

}

EXPORT_SYMBOL(devm_get_clk_from_child);

include/linux/clk.h

+25 −4
Original line number Diff line number Diff line
@@ -17,8 +17,9 @@ 
#include <linux/notifier.h>



struct device;



struct clk;

struct device_node;

struct of_phandle_args;



/**

 * DOC: clk notifier callback types
@@ -248,6 +249,23 @@ struct clk *clk_get(struct device *dev, const char *id); 
 */

struct clk *devm_clk_get(struct device *dev, const char *id);



/**

 * devm_get_clk_from_child - lookup and obtain a managed reference to a

 *			     clock producer from child node.

 * @dev: device for clock "consumer"

 * @np: pointer to clock consumer node

 * @con_id: clock consumer ID

 *

 * This function parses the clocks, and uses them to look up the

 * struct clk from the registered list of clock providers by using

 * @np and @con_id

 *

 * The clock will automatically be freed when the device is unbound

 * from the bus.

 */

struct clk *devm_get_clk_from_child(struct device *dev,

				    struct device_node *np, const char *con_id);



/**

 * clk_enable - inform the system when the clock source should be running.

 * @clk: clock source
@@ -432,6 +450,12 @@ static inline struct clk *devm_clk_get(struct device *dev, const char *id) 
	return NULL;

}



static inline struct clk *devm_get_clk_from_child(struct device *dev,

				struct device_node *np, const char *con_id)

{

	return NULL;

}



static inline void clk_put(struct clk *clk) {}



static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
@@ -501,9 +525,6 @@ static inline void clk_disable_unprepare(struct clk *clk) 
	clk_unprepare(clk);

}



struct device_node;

struct of_phandle_args;



#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)

struct clk *of_clk_get(struct device_node *np, int index);

struct clk *of_clk_get_by_name(struct device_node *np, const char *name);

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