clk: Introduce optional is_prepared callback

To reflect whether a clk_hw is prepared the clk_hw may implement
the optional is_prepared callback. If not implemented we fall back
to use the software prepare counter.

Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Mike Turquette <mturquette@linaro.org>

2 files changed, 27 insertions, 0 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index ed87b2405806..7571b5054f3c 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -451,6 +451,27 @@ unsigned long __clk_get_flags(struct clk *clk)
         return !clk ? 0 : clk->flags;
 }
 
+bool __clk_is_prepared(struct clk *clk)
+{
+        int ret;
+
+        if (!clk)
+                return false;
+
+        /*
+         * .is_prepared is optional for clocks that can prepare
+         * fall back to software usage counter if it is missing
+         */
+        if (!clk->ops->is_prepared) {
+                ret = clk->prepare_count ? 1 : 0;
+                goto out;
+        }
+
+        ret = clk->ops->is_prepared(clk->hw);
+out:
+        return !!ret;
+}
+
 bool __clk_is_enabled(struct clk *clk)
 {
         int ret;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 7f197d7addb0..ee946862e058 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -45,6 +45,10 @@ struct clk_hw;
  *              undo any work done in the @prepare callback. Called with
  *              prepare_lock held.
  *
+ * @is_prepared: Queries the hardware to determine if the clock is prepared.
+ *              This function is allowed to sleep. Optional, if this op is not
+ *              set then the prepare count will be used.
+ *
  * @enable:     Enable the clock atomically. This must not return until the
  *              clock is generating a valid clock signal, usable by consumer
  *              devices. Called with enable_lock held. This function must not
@@ -108,6 +112,7 @@ struct clk_hw;
 struct clk_ops {
         int             (*prepare)(struct clk_hw *hw);
         void            (*unprepare)(struct clk_hw *hw);
+        int             (*is_prepared)(struct clk_hw *hw);
         int             (*enable)(struct clk_hw *hw);
         void            (*disable)(struct clk_hw *hw);
         int             (*is_enabled)(struct clk_hw *hw);
@@ -351,6 +356,7 @@ unsigned int __clk_get_enable_count(struct clk *clk);
 unsigned int __clk_get_prepare_count(struct clk *clk);
 unsigned long __clk_get_rate(struct clk *clk);
 unsigned long __clk_get_flags(struct clk *clk);
+bool __clk_is_prepared(struct clk *clk);
 bool __clk_is_enabled(struct clk *clk);
 struct clk *__clk_lookup(const char *name);