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Commit 71a2f115 authored Dec 05, 2016 by Kuninori Morimoto Committed by Stephen Boyd Dec 08, 2016

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: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
[sboyd@codeurora.org: Rename subject to clk + add API]
Signed-off-by: Stephen 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);