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Subject[PATCH v2 2/3] clk: add api to get clk consumer from clk_hw
Date
clk_register() is deprecated. Using 'clk' member of struct clk_hw is
discouraged. With this constraint, it is difficult for driver to
register clocks using the clk_hw API and then use the clock with
the consumer API

This adds a simple helper, clk_hw_get_clk(), to get a struct clk from
a struct clk_hw. Like other clk_get() variant, each call to this helper
must be balanced with a call to clk_put(). To make life easier on the
consumers, a memory managed version is provided as well.

Cc: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Jerome Brunet <jbrunet@baylibre.com>
---
drivers/clk/clk.c | 61 ++++++++++++++++++++++++++++++++++++
include/linux/clk-provider.h | 5 +++
2 files changed, 66 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 88e5797bb6b4..d27153f26fa9 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -3667,6 +3667,24 @@ struct clk *clk_hw_create_clk(struct device *dev, struct clk_hw *hw,
return clk;
}

+/**
+ * clk_hw_get_clk: get clk consumer given an clk_hw
+ * @hw: clk_hw associated with the clk being consumed
+ * @con_id: connection ID string on device
+ *
+ * Returns: new clk consumer
+ * This is the function to be used by providers which need
+ * to get a consumer clk and act on the clock element
+ * Calls to this function must be balanced with calls clk_put()
+ */
+struct clk *clk_hw_get_clk(struct clk_hw *hw, const char *con_id)
+{
+ struct device *dev = hw->core->dev;
+
+ return clk_hw_create_clk(dev, hw, dev_name(dev), con_id);
+}
+EXPORT_SYMBOL(clk_hw_get_clk);
+
static int clk_cpy_name(const char **dst_p, const char *src, bool must_exist)
{
const char *dst;
@@ -4187,6 +4205,49 @@ void devm_clk_hw_unregister(struct device *dev, struct clk_hw *hw)
}
EXPORT_SYMBOL_GPL(devm_clk_hw_unregister);

+static void devm_clk_release(struct device *dev, void *res)
+{
+ clk_put(*(struct clk **)res);
+}
+
+/**
+ * devm_clk_hw_get_clk: resource managed clk_hw_get_clk()
+ * @dev: device that is registering this clock
+ * @hw: clk_hw associated with the clk being consumed
+ * @con_id: connection ID string on device
+ *
+ * Managed clk_hw_get_clk(). Clocks got with this function are
+ * automatically clk_put() on driver detach. See clk_put()
+ * for more information.
+ */
+struct clk *devm_clk_hw_get_clk(struct device *dev, struct clk_hw *hw,
+ const char *con_id)
+{
+ struct clk *clk;
+ struct clk **clkp;
+
+ /* This should not happen because it would mean we have drivers
+ * passing around clk_hw pointers instead of having the caller use
+ * proper clk_get() style APIs
+ */
+ WARN_ON_ONCE(dev != hw->core->dev);
+
+ clkp = devres_alloc(devm_clk_release, sizeof(*clkp), GFP_KERNEL);
+ if (!clkp)
+ return ERR_PTR(-ENOMEM);
+
+ clk = clk_hw_get_clk(hw, con_id);
+ if (!IS_ERR(clk)) {
+ *clkp = clk;
+ devres_add(dev, clkp);
+ } else {
+ devres_free(clkp);
+ }
+
+ return clk;
+}
+EXPORT_SYMBOL_GPL(devm_clk_hw_get_clk);
+
/*
* clkdev helpers
*/
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 03a5de5f99f4..86b707520ec0 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -1088,6 +1088,11 @@ static inline struct clk_hw *__clk_get_hw(struct clk *clk)
return (struct clk_hw *)clk;
}
#endif
+
+struct clk *clk_hw_get_clk(struct clk_hw *hw, const char *con_id);
+struct clk *devm_clk_hw_get_clk(struct device *dev, struct clk_hw *hw,
+ const char *con_id);
+
unsigned int clk_hw_get_num_parents(const struct clk_hw *hw);
struct clk_hw *clk_hw_get_parent(const struct clk_hw *hw);
struct clk_hw *clk_hw_get_parent_by_index(const struct clk_hw *hw,
--
2.25.4
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