drivers: clk: Add a managed API to get clocks from the device-tree

Add devm_clk_get(), devm_clk_get_optional() to get clocks from the
device-tree. The clocks is automatically released and the data structure
freed when the device is unbound.
Also add devm_clk_put() to release the clock and free the data structure
manually.

Signed-off-by: Jean-Jacques Hiblot <jjhiblot@ti.com>

drivers/clk/clk-uclass.c

@@ -625,6 +625,54 @@ bool clk_is_match(const struct clk *p, const struct clk *q)
 	return false;
 }
 
+static void devm_clk_release(struct udevice *dev, void *res)
+{
+	clk_free(res);
+}
+
+static int devm_clk_match(struct udevice *dev, void *res, void *data)
+{
+	return res == data;
+}
+
+struct clk *devm_clk_get(struct udevice *dev, const char *id)
+{
+	int rc;
+	struct clk *clk;
+
+	clk = devres_alloc(devm_clk_release, sizeof(struct clk), __GFP_ZERO);
+	if (unlikely(!clk))
+		return ERR_PTR(-ENOMEM);
+
+	rc = clk_get_by_name(dev, id, clk);
+	if (rc)
+		return ERR_PTR(rc);
+
+	devres_add(dev, clk);
+	return clk;
+}
+
+struct clk *devm_clk_get_optional(struct udevice *dev, const char *id)
+{
+	struct clk *clk = devm_clk_get(dev, id);
+
+	if (IS_ERR(clk))
+		return NULL;
+
+	return clk;
+}
+
+void devm_clk_put(struct udevice *dev, struct clk *clk)
+{
+	int rc;
+
+	if (!clk)
+		return;
+
+	rc = devres_release(dev, devm_clk_release, devm_clk_match, clk);
+	WARN_ON(rc);
+}
+
 UCLASS_DRIVER(clk) = {
 	.id		= UCLASS_CLK,
 	.name		= "clk",

drivers/mtd/nand/raw/brcmnand/brcmnand_compat.c

@@ -3,36 +3,6 @@
 #include <common.h>
 #include "brcmnand_compat.h"
 
-struct clk *devm_clk_get(struct udevice *dev, const char *id)
-{
-	struct clk *clk;
-	int ret;
-
-	clk = devm_kzalloc(dev, sizeof(*clk), GFP_KERNEL);
-	if (!clk) {
-		debug("%s: can't allocate clock\n", __func__);
-		return ERR_PTR(-ENOMEM);
-	}
-
-	ret = clk_get_by_name(dev, id, clk);
-	if (ret < 0) {
-		debug("%s: can't get clock (ret = %d)!\n", __func__, ret);
-		return ERR_PTR(ret);
-	}
-
-	return clk;
-}
-
-int clk_prepare_enable(struct clk *clk)
-{
-	return clk_enable(clk);
-}
-
-void clk_disable_unprepare(struct clk *clk)
-{
-	clk_disable(clk);
-}
-
 static char *devm_kvasprintf(struct udevice *dev, gfp_t gfp, const char *fmt,
 			     va_list ap)
 {

drivers/mtd/nand/raw/brcmnand/brcmnand_compat.h

@@ -6,10 +6,6 @@
 #include <clk.h>
 #include <dm.h>
 
-struct clk *devm_clk_get(struct udevice *dev, const char *id);
-int clk_prepare_enable(struct clk *clk);
-void clk_disable_unprepare(struct clk *clk);
-
 char *devm_kasprintf(struct udevice *dev, gfp_t gfp, const char *fmt, ...);
 
 #endif /* __BRCMNAND_COMPAT_H */

include/clk.h

@@ -154,6 +154,37 @@ int clk_get_bulk(struct udevice *dev, struct clk_bulk *bulk);
  */
 int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
 
+/**
+ * devm_clk_get - lookup and obtain a managed reference to a clock producer.
+ * @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.)
+ *
+ * Drivers must assume that the clock source is not enabled.
+ *
+ * devm_clk_get should not be called from within interrupt context.
+ *
+ * The clock will automatically be freed when the device is unbound
+ * from the bus.
+ */
+struct clk *devm_clk_get(struct udevice *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 udevice *dev, const char *id);
+
 /**
  * clk_release_all() - Disable (turn off)/Free an array of previously
  * requested clocks.
@@ -168,6 +199,19 @@ int clk_get_by_name(struct udevice *dev, const char *name, struct clk *clk);
  */
 int clk_release_all(struct clk *clk, int count);
 
+/**
+ * devm_clk_put	- "free" a managed clock source
+ * @dev: device used to acquire the clock
+ * @clk: clock source acquired with devm_clk_get()
+ *
+ * Note: drivers must ensure that all clk_enable calls made on this
+ * clock source are balanced by clk_disable calls prior to calling
+ * this function.
+ *
+ * clk_put should not be called from within interrupt context.
+ */
+void devm_clk_put(struct udevice *dev, struct clk *clk);
+
 #else
 static inline int clk_get_by_index(struct udevice *dev, int index,
 				   struct clk *clk)
@@ -379,3 +423,6 @@ int clk_get_by_id(ulong id, struct clk **clkp);
  */
 bool clk_dev_binded(struct clk *clk);
 #endif
+
+#define clk_prepare_enable(clk) clk_enable(clk)
+#define clk_disable_unprepare(clk) clk_disable(clk)