[PATCH v4] clkdev: add devm_of_clk_get()

[PATCH v4] clkdev: add devm_of_clk_get()

[Kuninori Morimoto]

From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>

Current Linux has of_clk_get(), but doesn't have devm_of_clk_get().
This patch adds it. It is implemeted in clk-devres.c to share
devm_clk_release().

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
---
v3 -> v4

 - git log explain why it is implemeted in clk-devres
 - it is related to CONFIG_HAVE_CLK

 drivers/clk/clk-devres.c | 21 +++++++++++++++++++++
 include/linux/clk.h      | 27 +++++++++++++++++++++++----
 2 files changed, 44 insertions(+), 4 deletions(-)

diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index 8f57154..2449b25 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -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_of_clk_get(struct device *dev,
+			    struct device_node *np, int index)
+{
+	struct clk **ptr, *clk;
+
+	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
+	if (!ptr)
+		return ERR_PTR(-ENOMEM);
+
+	clk = of_clk_get(np, index);
+	if (!IS_ERR(clk)) {
+		*ptr = clk;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return clk;
+}
+EXPORT_SYMBOL(devm_of_clk_get);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 123c027..7f50c5f 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -17,8 +17,9 @@
 #include <linux/notifier.h>
 
 struct device;
-
 struct clk;
+struct device_node;
+struct of_phandle_args;
 
 /**
  * DOC: clk notifier callback types
@@ -249,6 +250,21 @@ static inline void clk_unprepare(struct clk *clk)
 struct clk *devm_clk_get(struct device *dev, const char *id);
 
 /**
+ * devm_clk_get - lookup and obtain a managed reference to a clock producer.
+ * @dev: device for clock "consumer"
+ * @np: pointer to clock consumer node
+ * @index: clock index
+ *
+ * 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 @index.
+ *
+ * The clock will automatically be freed when the device is unbound
+ * from the bus.
+ */
+struct clk *devm_of_clk_get(struct device *dev, struct device_node *np, int index);
+
+/**
  * clk_enable - inform the system when the clock source should be running.
  * @clk: clock source
  *
@@ -432,6 +448,12 @@ static inline struct clk *devm_clk_get(struct device *dev, const char *id)
 	return NULL;
 }
 
+static inline struct clk *devm_of_clk_get(struct device *dev,
+					  struct device_node *np, int index)
+{
+	return NULL;
+}
+
 static inline void clk_put(struct clk *clk) {}
 
 static inline void devm_clk_put(struct device *dev, struct clk *clk) {}
@@ -501,9 +523,6 @@ 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);
-- 
1.9.1

Re: [PATCH v4] clkdev: add devm_of_clk_get()

[Stephen Boyd]

On 11/29, Kuninori Morimoto wrote:
> 
> From: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> 
> Current Linux has of_clk_get(), but doesn't have devm_of_clk_get().
> This patch adds it. It is implemeted in clk-devres.c to share
> devm_clk_release().

Please add an explanation of why we want this sort of API. The
example you gave for audio sound card is useful. We're not going
to remember 5 months from now why we did something, so we should
put that here instead of digging through mailing list archives.

> 
> Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
> 
> diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
> index 8f57154..2449b25 100644
> --- a/drivers/clk/clk-devres.c
> +++ b/drivers/clk/clk-devres.c
> @@ -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_of_clk_get(struct device *dev,
> +			    struct device_node *np, int index)

Please call this devm_get_clk_from_child() instead. Also, replace
the index argument with a string called con_id. Then call
of_clk_get_by_name() instead of of_clk_get().

> +{
> +	struct clk **ptr, *clk;
> +
> +	ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
> +	if (!ptr)
> +		return ERR_PTR(-ENOMEM);
> +
> +	clk = of_clk_get(np, index);
> +	if (!IS_ERR(clk)) {
> +		*ptr = clk;
> +		devres_add(dev, ptr);
> +	} else {
> +		devres_free(ptr);
> +	}
> +
> +	return clk;
> +}
> +EXPORT_SYMBOL(devm_of_clk_get);
> diff --git a/include/linux/clk.h b/include/linux/clk.h
> index 123c027..7f50c5f 100644
> --- a/include/linux/clk.h
> +++ b/include/linux/clk.h
> @@ -17,8 +17,9 @@
>  #include <linux/notifier.h>
>  
>  struct device;
> -
>  struct clk;
> +struct device_node;
> +struct of_phandle_args;
>  
>  /**
>   * DOC: clk notifier callback types
> @@ -249,6 +250,21 @@ static inline void clk_unprepare(struct clk *clk)
>  struct clk *devm_clk_get(struct device *dev, const char *id);
>  
>  /**
> + * devm_clk_get - lookup and obtain a managed reference to a clock producer.

That doesn't even match the name of the function.

> + * @dev: device for clock "consumer"
> + * @np: pointer to clock consumer node
> + * @index: clock index
> + *
> + * 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 @index.
> + *
> + * The clock will automatically be freed when the device is unbound
> + * from the bus.
> + */
> +struct clk *devm_of_clk_get(struct device *dev, struct device_node *np, int index);

-- 
Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum,
a Linux Foundation Collaborative Project

Re: [PATCH v4] clkdev: add devm_of_clk_get()

[Kuninori Morimoto]

Hi Stephen

> > Current Linux has of_clk_get(), but doesn't have devm_of_clk_get().
> > This patch adds it. It is implemeted in clk-devres.c to share
> > devm_clk_release().
> 
> Please add an explanation of why we want this sort of API. The
> example you gave for audio sound card is useful. We're not going
> to remember 5 months from now why we did something, so we should
> put that here instead of digging through mailing list archives.

OK, will do

> > +struct clk *devm_of_clk_get(struct device *dev,
> > +			    struct device_node *np, int index)
> 
> Please call this devm_get_clk_from_child() instead. Also, replace
> the index argument with a string called con_id. Then call
> of_clk_get_by_name() instead of of_clk_get().

I guess we want to have _of_ on function name ?

  devm_get_clk_from_child() ?
  devm_of_get_clk_from_child ?

Best regards
---
Kuninori Morimoto