Quite a few drivers get an optional clock, e.g. a clock required
to access peripheral's registers that is always enabled on some
devices.
This function behaves the same as of_clk_get_by_name() except that
it will return NULL instead of -EINVAL.
Signed-off-by: Phil Edworthy <phil.edwor...@renesas.com>
---
v3:
- Fix check for clock not present. __of_clk_get() returns -EINVAL
if it's not there. Cover case of when there is no clock name.
- of_clk_get_by_name_optional() should return NULL if !np.
- Add dummy version of of_clk_get_by_name_optional() for the
!OF || !COMMON_CLK case.
---
drivers/clk/clkdev.c | 36 ++++++++++++++++++++++++++++++++----
include/linux/clk.h | 6 ++++++
2 files changed, 38 insertions(+), 4 deletions(-)
diff --git a/drivers/clk/clkdev.c b/drivers/clk/clkdev.c
index 9ab3db8..a710333 100644
--- a/drivers/clk/clkdev.c
+++ b/drivers/clk/clkdev.c
@@ -54,7 +54,8 @@ EXPORT_SYMBOL(of_clk_get);
static struct clk *__of_clk_get_by_name(struct device_node *np,
const char *dev_id,
- const char *name)
+ const char *name,
+ bool optional)
{
struct clk *clk = ERR_PTR(-ENOENT);
@@ -70,6 +71,11 @@ static struct clk *__of_clk_get_by_name(struct device_node
*np,
if (name)
index = of_property_match_string(np, "clock-names",
name);
clk = __of_clk_get(np, index, dev_id, name);
+ if (optional && PTR_ERR(clk) == -EINVAL) {
+ clk = NULL;
+ pr_info("optional clock is not present %pOF:%s\n", np,
+ name ? name : "");
+ }
if (!IS_ERR(clk)) {
break;
} else if (name && index >= 0) {
@@ -106,15 +112,37 @@ struct clk *of_clk_get_by_name(struct device_node *np,
const char *name)
if (!np)
return ERR_PTR(-ENOENT);
- return __of_clk_get_by_name(np, np->full_name, name);
+ return __of_clk_get_by_name(np, np->full_name, name, false);
}
EXPORT_SYMBOL(of_clk_get_by_name);
+/**
+ * of_clk_get_by_name_optional() - Parse and lookup an optional clock
referenced
+ * by a device node
+ * @np: pointer to clock consumer node
+ * @name: name of consumer's clock input, or NULL for the first clock reference
+ *
+ * This function parses the clocks and clock-names properties, and uses them to
+ * look up the struct clk from the registered list of clock providers.
+ * It behaves the same as of_clk_get_by_name(), except when np is NULL or no
+ * clock provider is found, when it then returns NULL.
+ */
+struct clk *of_clk_get_by_name_optional(struct device_node *np,
+ const char *name)
+{
+ if (!np)
+ return NULL;
+
+ return __of_clk_get_by_name(np, np->full_name, name, true);
+}
+EXPORT_SYMBOL(of_clk_get_by_name_optional);
+
#else /* defined(CONFIG_OF) && defined(CONFIG_COMMON_CLK) */
static struct clk *__of_clk_get_by_name(struct device_node *np,
const char *dev_id,
- const char *name)
+ const char *name,
+ bool optional)
{
return ERR_PTR(-ENOENT);
}
@@ -197,7 +225,7 @@ struct clk *clk_get(struct device *dev, const char *con_id)
struct clk *clk;
if (dev && dev->of_node) {
- clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id);
+ clk = __of_clk_get_by_name(dev->of_node, dev_id, con_id, false);
if (!IS_ERR(clk) || PTR_ERR(clk) == -EPROBE_DEFER)
return clk;
}
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 4f750c4..de0e5e0 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -777,6 +777,7 @@ static inline void clk_bulk_disable_unprepare(int num_clks,
#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);
+struct clk *of_clk_get_by_name_optional(struct device_node *np, const char
*name);
struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec);
#else
static inline struct clk *of_clk_get(struct device_node *np, int index)
@@ -788,6 +789,11 @@ static inline struct clk *of_clk_get_by_name(struct
device_node *np,
{
return ERR_PTR(-ENOENT);
}
+static inline struct clk *of_clk_get_by_name_optional(struct device_node *np,
+ const char *name)
+{
+ return NULL;
+}
static inline struct clk *of_clk_get_from_provider(struct of_phandle_args
*clkspec)
{
return ERR_PTR(-ENOENT);
--
2.7.4
