This is a note to let you know that I've just added the patch titled
clk: Add (devm_)clk_get_optional() functions
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
clk-add-devm_-clk_get_optional-functions.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 95fb980022b8dca629ee43003bb5204f7af43f85
Author: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
Date: Mon Dec 3 11:13:09 2018 +0000
clk: Add (devm_)clk_get_optional() functions
[ Upstream commit 60b8f0ddf1a927ef02141a6610fd52575134f821 ]
This adds clk_get_optional() and devm_clk_get_optional() functions to get
optional clocks.
They behave the same as (devm_)clk_get() except where there is no clock
producer. In this case, instead of returning -ENOENT, the function
returns NULL. This makes error checking simpler and allows
clk_prepare_enable, etc to be called on the returned reference
without additional checks.
Signed-off-by: Phil Edworthy <phil.edworthy@xxxxxxxxxxx>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@xxxxxxxxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxx>
[sboyd@xxxxxxxxxx: Document in devres.txt]
Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
Stable-dep-of: a6191a3d1811 ("gpio: aspeed: Use devm_clk api to manage clock source")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/Documentation/driver-model/devres.txt b/Documentation/driver-model/devres.txt
index 43681ca0837f8..5a2d8c7ce2474 100644
--- a/Documentation/driver-model/devres.txt
+++ b/Documentation/driver-model/devres.txt
@@ -235,6 +235,7 @@ certainly invest a bit more effort into libata core layer).
CLOCK
devm_clk_get()
+ devm_clk_get_optional()
devm_clk_put()
devm_clk_hw_register()
devm_of_clk_add_hw_provider()
diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index d854e26a8ddbc..a062389ccd3d5 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -34,6 +34,17 @@ struct clk *devm_clk_get(struct device *dev, const char *id)
}
EXPORT_SYMBOL(devm_clk_get);
+struct clk *devm_clk_get_optional(struct device *dev, const char *id)
+{
+ struct clk *clk = devm_clk_get(dev, id);
+
+ if (clk == ERR_PTR(-ENOENT))
+ return NULL;
+
+ return clk;
+}
+EXPORT_SYMBOL(devm_clk_get_optional);
+
struct clk_bulk_devres {
struct clk_bulk_data *clks;
int num_clks;
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 0a2382d3f68c8..55b08adaaa3c1 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -388,6 +388,17 @@ int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
*/
struct clk *devm_clk_get(struct device *dev, const char *id);
+/**
+ * devm_clk_get_optional - lookup and obtain a managed reference to an optional
+ * clock producer.
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Behaves the same as devm_clk_get() except where there is no clock producer.
+ * In this case, instead of returning -ENOENT, the function returns NULL.
+ */
+struct clk *devm_clk_get_optional(struct device *dev, const char *id);
+
/**
* devm_get_clk_from_child - lookup and obtain a managed reference to a
* clock producer from child node.
@@ -655,6 +666,12 @@ static inline struct clk *devm_clk_get(struct device *dev, const char *id)
return NULL;
}
+static inline struct clk *devm_clk_get_optional(struct device *dev,
+ const char *id)
+{
+ return NULL;
+}
+
static inline int __must_check devm_clk_bulk_get(struct device *dev, int num_clks,
struct clk_bulk_data *clks)
{
@@ -774,6 +791,25 @@ static inline void clk_bulk_disable_unprepare(int num_clks,
clk_bulk_unprepare(num_clks, clks);
}
+/**
+ * clk_get_optional - lookup and obtain a reference to an optional clock
+ * producer.
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Behaves the same as clk_get() except where there is no clock producer. In
+ * this case, instead of returning -ENOENT, the function returns NULL.
+ */
+static inline struct clk *clk_get_optional(struct device *dev, const char *id)
+{
+ struct clk *clk = clk_get(dev, id);
+
+ if (clk == ERR_PTR(-ENOENT))
+ return NULL;
+
+ return clk;
+}
+
#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);
