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Subject[PATCH 1/2] clk: provide new devm helpers for prepared and enabled clocks
Date
When a driver keeps a clock prepared (or enabled) during the whole
lifetime of the driver, these helpers allow to simplify the drivers.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
---
drivers/clk/clk-devres.c | 85 ++++++++++++++++++++++++++++++++-------
include/linux/clk.h | 87 +++++++++++++++++++++++++++++++++++++++-
2 files changed, 157 insertions(+), 15 deletions(-)

diff --git a/drivers/clk/clk-devres.c b/drivers/clk/clk-devres.c
index be160764911b..a56289c04921 100644
--- a/drivers/clk/clk-devres.c
+++ b/drivers/clk/clk-devres.c
@@ -4,42 +4,99 @@
#include <linux/export.h>
#include <linux/gfp.h>

+struct devm_clk_state {
+ struct clk *clk;
+ void (*exit)(struct clk *clk);
+};
+
static void devm_clk_release(struct device *dev, void *res)
{
- clk_put(*(struct clk **)res);
+ struct devm_clk_state *state = *(struct devm_clk_state **)res;
+
+ if (state->exit)
+ state->exit(state->clk);
+ clk_put(state->clk);
}

-struct clk *devm_clk_get(struct device *dev, const char *id)
+static struct clk *__devm_clk_get(struct device *dev, const char *id,
+ struct clk *(*get)(struct device *dev, const char *id),
+ int (*init)(struct clk *clk),
+ void (*exit)(struct clk *clk))
{
- struct clk **ptr, *clk;
+ struct devm_clk_state **ptr, *state;
+ struct clk *clk;
+ int ret;

ptr = devres_alloc(devm_clk_release, sizeof(*ptr), GFP_KERNEL);
if (!ptr)
return ERR_PTR(-ENOMEM);

- clk = clk_get(dev, id);
- if (!IS_ERR(clk)) {
- *ptr = clk;
- devres_add(dev, ptr);
- } else {
- devres_free(ptr);
+ clk = get(dev, id);
+ if (IS_ERR(clk))
+ goto err_clk_get;
+
+ state->clk = clk;
+
+ ret = init ? init(clk) : 0;
+ if (ret) {
+ clk = ERR_PTR(ret);
+ goto err_init;
}

+ state->exit = exit;
+ *ptr = state;
+ devres_add(dev, ptr);
+
+ return clk;
+
+err_init:
+
+ clk_put(state->clk);
+err_clk_get:
+
return clk;
}
+
+struct clk *devm_clk_get(struct device *dev, const char *id)
+{
+ return __devm_clk_get(dev, id, clk_get, NULL, NULL);
+}
EXPORT_SYMBOL(devm_clk_get);

-struct clk *devm_clk_get_optional(struct device *dev, const char *id)
+struct clk *devm_clk_get_prepared(struct device *dev, const char *id)
{
- struct clk *clk = devm_clk_get(dev, id);
+ return __devm_clk_get(dev, id, clk_get,
+ clk_prepare, clk_disable);
+}
+EXPORT_SYMBOL(devm_clk_get_prepared);

- if (clk == ERR_PTR(-ENOENT))
- return NULL;
+struct clk *devm_clk_get_enabled(struct device *dev, const char *id)
+{
+ return __devm_clk_get(dev, id, clk_get,
+ clk_prepare_enable, clk_disable_unprepare);
+}
+EXPORT_SYMBOL(devm_clk_get_enabled);

- return clk;
+struct clk *devm_clk_get_optional(struct device *dev, const char *id)
+{
+ return __devm_clk_get(dev, id, clk_get_optional, NULL, NULL);
}
EXPORT_SYMBOL(devm_clk_get_optional);

+struct clk *devm_clk_get_optional_prepared(struct device *dev, const char *id)
+{
+ return __devm_clk_get(dev, id, clk_get_optional,
+ clk_prepare, clk_unprepare);
+}
+EXPORT_SYMBOL(devm_clk_get_optional_prepared);
+
+struct clk *devm_clk_get_optional_enabled(struct device *dev, const char *id)
+{
+ return __devm_clk_get(dev, id, clk_get_optional,
+ clk_prepare_enable, clk_disable_unprepare);
+}
+EXPORT_SYMBOL(devm_clk_get_optional_enabled);
+
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 7fd6a1febcf4..14050d9b5b38 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -409,7 +409,7 @@ int __must_check devm_clk_bulk_get_all(struct device *dev,
* the clock producer. (IOW, @id may be identical strings, but
* clk_get may return different clock producers depending on @dev.)
*
- * Drivers must assume that the clock source is not enabled.
+ * Drivers must assume that the clock source is neither prepared nor enabled.
*
* devm_clk_get should not be called from within interrupt context.
*
@@ -418,6 +418,47 @@ int __must_check devm_clk_bulk_get_all(struct device *dev,
*/
struct clk *devm_clk_get(struct device *dev, const char *id);

+/**
+ * devm_clk_get_prepared - devm_clk_get() + clk_prepare()
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Returns a struct clk corresponding to the clock producer, or
+ * valid IS_ERR() condition containing errno. The implementation
+ * uses @dev and @id to determine the clock consumer, and thereby
+ * the clock producer. (IOW, @id may be identical strings, but
+ * clk_get may return different clock producers depending on @dev.)
+ *
+ * The returned clk (if valid) is prepared. Drivers must however assume that the
+ * clock is not enabled.
+ *
+ * devm_clk_get_prepared should not be called from within interrupt context.
+ *
+ * The clock will automatically be unprepared and freed when the
+ * device is unbound from the bus.
+ */
+struct clk *devm_clk_get_prepared(struct device *dev, const char *id);
+
+/**
+ * devm_clk_get_enabled - devm_clk_get() + clk_prepare_enable()
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Returns a struct clk corresponding to the clock producer, or
+ * valid IS_ERR() condition containing errno. The implementation
+ * uses @dev and @id to determine the clock consumer, and thereby
+ * the clock producer. (IOW, @id may be identical strings, but
+ * clk_get may return different clock producers depending on @dev.)
+ *
+ * The returned clk (if valid) is prepared and enabled.
+ *
+ * devm_clk_get_prepared should not be called from within interrupt context.
+ *
+ * The clock will automatically be disabled, unprepared and freed when the
+ * device is unbound from the bus.
+ */
+struct clk *devm_clk_get_enabled(struct device *dev, const char *id);
+
/**
* devm_clk_get_optional - lookup and obtain a managed reference to an optional
* clock producer.
@@ -429,6 +470,26 @@ struct clk *devm_clk_get(struct device *dev, const char *id);
*/
struct clk *devm_clk_get_optional(struct device *dev, const char *id);

+/**
+ * devm_clk_get_optional_prepared - devm_clk_get_optional() + clk_prepare()
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Behaves the same as devm_clk_get_prepared() except where there is no clock producer.
+ * In this case, instead of returning -ENOENT, the function returns NULL.
+ */
+struct clk *devm_clk_get_optional_prepared(struct device *dev, const char *id);
+
+/**
+ * devm_clk_get_optional_enabled - devm_clk_get_optional() + clk_prepare_enable()
+ * @dev: device for clock "consumer"
+ * @id: clock consumer ID
+ *
+ * Behaves the same as devm_clk_get_enabled() except where there is no clock producer.
+ * In this case, instead of returning -ENOENT, the function returns NULL.
+ */
+struct clk *devm_clk_get_optional_enabled(struct device *dev, const char *id);
+
/**
* devm_get_clk_from_child - lookup and obtain a managed reference to a
* clock producer from child node.
@@ -773,12 +834,36 @@ static inline struct clk *devm_clk_get(struct device *dev, const char *id)
return NULL;
}

+static inline struct clk *devm_clk_get_prepared(struct device *dev,
+ const char *id)
+{
+ return NULL;
+}
+
+static inline struct clk *devm_clk_get_enabled(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 struct clk *devm_clk_get_optional_prepared(struct device *dev,
+ const char *id)
+{
+ return NULL;
+}
+
+static inline struct clk *devm_clk_get_optional_enabled(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)
{
--
2.28.0
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