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[PATCH v2] clk: add devm_of_clk_get() and devm_of_clk_get_by_name() functions

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  [PATCH v2] clk: add devm_of_clk_get() and devm_of_clk_get_by_name() functions Paul Osmialowski <newchief@king.net.pl> - 2015-09-30 09:50 +0200
    Re: [PATCH v2] clk: add devm_of_clk_get() and  devm_of_clk_get_by_name() functions kbuild test robot <lkp@intel.com> - 2015-09-30 11:20 +0200

#1235857 — [PATCH v2] clk: add devm_of_clk_get() and devm_of_clk_get_by_name() functions

From: Paul Osmialowski <pawelo@king.net.pl>

These two functions are added to ease management of clocks obtained
from OF device nodes.

They are particulary useful while iterating over DT subnodes using e.g.
for_each_child_of_node(dev->of_node, child) in order do get resources
(i.e. clocks) for subdevices defined by these DT subnodes.

For example:

some_device {
    compatible = "something"
    #address-cells = <1>;
    #size-cells = <1>;
    ranges;

    subdevice1: some_subdevice@some_address1 {
        reg = <0xsome_address1 0xsome_size>
        clocks = <&some_clock1>
    }

    subdevice2: some_subdevice@some_address2 {
        reg = <0xsome_address2 0xsome_size>
        clocks = <&some_clock2>
    }
}

Normally, I'd have to use of_clk_get() on each subdevice node and then
worry about proper resource release myself.

IMHO using devres infrastructure for this is far better. This patch adds
missing functions needed to do it a better way.

Signed-off-by: Paul Osmialowski <pawelo@king.net.pl>
---
 Documentation/driver-model/devres.txt |  2 ++
 drivers/clk/clk-devres.c              | 46 +++++++++++++++++++++++++++++++++++
 include/linux/clk.h                   | 46 +++++++++++++++++++++++++++++++++++
 3 files changed, 94 insertions(+)

diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 831a536..f3ad67a 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -235,6 +235,8 @@ certainly invest a bit more effort into libata core layer).
 
 CLOCK
   devm_clk_get()
+  devm_of_clk_get()
+  devm_of_clk_get_by_name()
   devm_clk_put()
 
 DMA
diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index 8f57154..197075a 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -34,6 +34,52 @@ struct clk *devm_clk_get(struct device *dev, const char *id)
 }
 EXPORT_SYMBOL(devm_clk_get);
 
+#ifdef CONFIG_OF
+
+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);
+
+struct clk *devm_of_clk_get_by_name(struct device *dev, struct device_node *np,
+				    const char *name)
+{
+	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, name);
+	if (!IS_ERR(clk)) {
+		*ptr = clk;
+		devres_add(dev, ptr);
+	} else {
+		devres_free(ptr);
+	}
+
+	return clk;
+}
+EXPORT_SYMBOL(devm_of_clk_get_by_name);
+
+#endif /* CONFIG_OF */
+
 static int devm_clk_match(struct device *dev, void *res, void *data)
 {
 	struct clk **c = res;
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 0df4a51..8f31f9a 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -504,4 +504,50 @@ static inline struct clk *of_clk_get_by_name(struct device_node *np,
 }
 #endif
 
+#if defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK)
+/**
+ * devm_of_clk_get - obtain a managed reference to a clock producer
+ *                   from device tree node (by index).
+ * @dev: device for clock "consumer"
+ * @np: device tree node
+ * @index: clock consumer index (within the node)
+ *
+ * devm_of_clk_get should not be called from within interrupt context.
+ *
+ * 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);
+
+/**
+ * devm_of_clk_get_by_name - obtain a managed reference to a clock producer
+ *                           from device tree node (by name).
+ * @dev: device for clock "consumer"
+ * @np: device tree node
+ * @name: clock consumer name (within the node)
+ *
+ * devm_of_clk_get_by_name should not be called from within interrupt context.
+ *
+ * The clock will automatically be freed when the device is unbound
+ * from the bus.
+ */
+struct clk *devm_of_clk_get_by_name(struct device *dev, struct device_node *np,
+				    const char *name);
+
+#else
+static inline struct clk *devm_of_clk_get(struct device *dev,
+					  struct device_node *np,
+					  int index)
+{
+	return ERR_PTR(-ENOENT);
+}
+static inline struct clk *devm_of_clk_get_by_name(struct device *dev,
+						  struct device_node *np,
+						  const char *name)
+{
+	return ERR_PTR(-ENOENT);
+}
+#endif
+
 #endif
-- 
2.4.9

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#1235929 — Re: [PATCH v2] clk: add devm_of_clk_get() and devm_of_clk_get_by_name() functions

[Multipart message — attachments visible in raw view] — view raw

Hi Paul,

[auto build test results on v4.3-rc3 -- if it's inappropriate base, please ignore]

config: arm-sa1100 (attached as .config)
reproduce:
  wget https://git.kernel.org/cgit/linux/kernel/git/wfg/lkp-tests.git/plain/sbin/make.cross -O ~/bin/make.cross
  chmod +x ~/bin/make.cross
  git checkout 4b38631724b90dc5a717a4467cbf9377e3bf9af2
  # save the attached .config to linux build tree
  make.cross ARCH=arm 

All error/warnings (new ones prefixed by >>):

>> drivers/clk/clk-devres.c:39:13: error: redefinition of 'devm_of_clk_get'
    struct clk *devm_of_clk_get(struct device *dev, struct device_node *np,
                ^
   In file included from drivers/clk/clk-devres.c:7:0:
   include/linux/clk.h:539:27: note: previous definition of 'devm_of_clk_get' was here
    static inline struct clk *devm_of_clk_get(struct device *dev,
                              ^
>> drivers/clk/clk-devres.c:60:13: error: redefinition of 'devm_of_clk_get_by_name'
    struct clk *devm_of_clk_get_by_name(struct device *dev, struct device_node *np,
                ^
   In file included from drivers/clk/clk-devres.c:7:0:
   include/linux/clk.h:545:27: note: previous definition of 'devm_of_clk_get_by_name' was here
    static inline struct clk *devm_of_clk_get_by_name(struct device *dev,
                              ^

vim +/devm_of_clk_get +39 drivers/clk/clk-devres.c

    33		return clk;
    34	}
    35	EXPORT_SYMBOL(devm_clk_get);
    36	
    37	#ifdef CONFIG_OF
    38	
  > 39	struct clk *devm_of_clk_get(struct device *dev, struct device_node *np,
    40				    int index)
    41	{
    42		struct clk **ptr, *clk;
    43	
    44		ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
    45		if (!ptr)
    46			return ERR_PTR(-ENOMEM);
    47	
    48		clk = of_clk_get(np, index);
    49		if (!IS_ERR(clk)) {
    50			*ptr = clk;
    51			devres_add(dev, ptr);
    52		} else {
    53			devres_free(ptr);
    54		}
    55	
    56		return clk;
    57	}
    58	EXPORT_SYMBOL(devm_of_clk_get);
    59	
  > 60	struct clk *devm_of_clk_get_by_name(struct device *dev, struct device_node *np,
    61					    const char *name)
    62	{
    63		struct clk **ptr, *clk;

---
0-DAY kernel test infrastructure                Open Source Technology Center
https://lists.01.org/pipermail/kbuild-all                   Intel Corporation

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