PM / clock_ops: Add pm_clk_add_clk()

The existing pm_clk_add() allows to pass a clock by con_id. However,
when referring to a specific clock from DT, no con_id is available.

Add pm_clk_add_clk(), which allows to specify the struct clk * directly.
The will will increment refcount on clock pointer, so the caller has
to use clk_put() on clock pointer when done.

Reviewed-by: Santosh Shilimkar <santosh.shilimkar@ti.com>
Reviewed-by: Kevin Hilman <khilman@linaro.org>
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Signed-off-by: Grygorii Strashko <grygorii.strashko@ti.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

drivers/base/power/clock_ops.c

@@ -12,6 +12,7 @@
 #include <linux/pm.h>
 #include <linux/pm_clock.h>
 #include <linux/clk.h>
+#include <linux/clkdev.h>
 #include <linux/slab.h>
 #include <linux/err.h>
 
@@ -53,7 +54,8 @@ static inline int __pm_clk_enable(struct device *dev, struct clk *clk)
  */
 static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
 {
-	ce->clk = clk_get(dev, ce->con_id);
+	if (!ce->clk)
+		ce->clk = clk_get(dev, ce->con_id);
 	if (IS_ERR(ce->clk)) {
 		ce->status = PCE_STATUS_ERROR;
 	} else {
@@ -63,15 +65,8 @@ static void pm_clk_acquire(struct device *dev, struct pm_clock_entry *ce)
 	}
 }
 
-/**
+static int __pm_clk_add(struct device *dev, const char *con_id,
- * pm_clk_add - Start using a device clock for power management.
+			struct clk *clk)
- * @dev: Device whose clock is going to be used for power management.
- * @con_id: Connection ID of the clock.
- *
- * Add the clock represented by @con_id to the list of clocks used for
- * the power management of @dev.
- */
-int pm_clk_add(struct device *dev, const char *con_id)
 {
 	struct pm_subsys_data *psd = dev_to_psd(dev);
 	struct pm_clock_entry *ce;
@@ -93,6 +88,12 @@ int pm_clk_add(struct device *dev, const char *con_id)
 			kfree(ce);
 			return -ENOMEM;
 		}
+	} else {
+		if (IS_ERR(ce->clk) || !__clk_get(clk)) {
+			kfree(ce);
+			return -ENOENT;
+		}
+		ce->clk = clk;
 	}
 
 	pm_clk_acquire(dev, ce);
@@ -103,6 +104,32 @@ int pm_clk_add(struct device *dev, const char *con_id)
 	return 0;
 }
 
+/**
+ * pm_clk_add - Start using a device clock for power management.
+ * @dev: Device whose clock is going to be used for power management.
+ * @con_id: Connection ID of the clock.
+ *
+ * Add the clock represented by @con_id to the list of clocks used for
+ * the power management of @dev.
+ */
+int pm_clk_add(struct device *dev, const char *con_id)
+{
+	return __pm_clk_add(dev, con_id, NULL);
+}
+
+/**
+ * pm_clk_add_clk - Start using a device clock for power management.
+ * @dev: Device whose clock is going to be used for power management.
+ * @clk: Clock pointer
+ *
+ * Add the clock to the list of clocks used for the power management of @dev.
+ * It will increment refcount on clock pointer, use clk_put() on it when done.
+ */
+int pm_clk_add_clk(struct device *dev, struct clk *clk)
+{
+	return __pm_clk_add(dev, NULL, clk);
+}
+
 /**
  * __pm_clk_remove - Destroy PM clock entry.
  * @ce: PM clock entry to destroy.

include/linux/pm_clock.h

@@ -18,6 +18,8 @@ struct pm_clk_notifier_block {
 	char *con_ids[];
 };
 
+struct clk;
+
 #ifdef CONFIG_PM_CLK
 static inline bool pm_clk_no_clocks(struct device *dev)
 {
@@ -29,6 +31,7 @@ extern void pm_clk_init(struct device *dev);
 extern int pm_clk_create(struct device *dev);
 extern void pm_clk_destroy(struct device *dev);
 extern int pm_clk_add(struct device *dev, const char *con_id);
+extern int pm_clk_add_clk(struct device *dev, struct clk *clk);
 extern void pm_clk_remove(struct device *dev, const char *con_id);
 extern int pm_clk_suspend(struct device *dev);
 extern int pm_clk_resume(struct device *dev);
@@ -51,6 +54,11 @@ static inline int pm_clk_add(struct device *dev, const char *con_id)
 {
 	return -EINVAL;
 }
+
+static inline int pm_clk_add_clk(struct device *dev, struct clk *clk)
+{
+	return -EINVAL;
+}
 static inline void pm_clk_remove(struct device *dev, const char *con_id)
 {
 }