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Subject[PATCH] clk: Add functions to get optional clocks
Date
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. 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@renesas.com>
---
drivers/clk/clk-devres.c | 11 +++++++++++
drivers/clk/clkdev.c | 11 +++++++++++
include/linux/clk.h | 27 +++++++++++++++++++++++++++
3 files changed, 49 insertions(+)

diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index d854e26..63295d9 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 *c = devm_clk_get(dev, id);
+
+ if (PTR_ERR(c) == -ENOENT)
+ return NULL;
+
+ return c;
+}
+EXPORT_SYMBOL(devm_clk_get_optional);
+
struct clk_bulk_devres {
struct clk_bulk_data *clks;
int num_clks;
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 7513411..7f2cd1e 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -209,6 +209,17 @@ struct clk *clk_get(struct device *dev, const char *con_id)
}
EXPORT_SYMBOL(clk_get);

+struct clk *clk_get_optional(struct device *dev, const char *id)
+{
+ struct clk *c = clk_get(dev, id);
+
+ if (PTR_ERR(c) == -ENOENT)
+ return NULL;
+
+ return c;
+}
+EXPORT_SYMBOL(clk_get_optional);
+
void clk_put(struct clk *clk)
{
__clk_put(clk);
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 0dbd088..907202b 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -258,6 +258,14 @@ static inline void clk_bulk_unprepare(int num_clks, struct clk_bulk_data *clks)
struct clk *clk_get(struct device *dev, const char *id);

/**
+ * clk_get_optional - lookup and obtain a reference to optional clock producer.
+ *
+ * Behaves the same as clk_get except where there is no clock producer. In this
+ * case, instead of returning -ENOENT, the function returns NULL.
+ */
+struct clk *clk_get_optional(struct device *dev, const char *id);
+
+/**
* clk_bulk_get - lookup and obtain a number of references to clock producer.
* @dev: device for clock "consumer"
* @num_clks: the number of clk_bulk_data
@@ -316,6 +324,14 @@ 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.
+ * 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.
* @dev: device for clock "consumer"
@@ -603,6 +619,11 @@ static inline struct clk *clk_get(struct device *dev, const char *id)
return NULL;
}

+static inline struct clk *clk_get_optional(struct device *dev, const char *id)
+{
+ return NULL;
+}
+
static inline int __must_check clk_bulk_get(struct device *dev, int num_clks,
struct clk_bulk_data *clks)
{
@@ -614,6 +635,12 @@ 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)
{
--
2.7.4
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