clk: introduce clk_set_phase function & callback
A common operation for a clock signal generator is to shift the phase of
that signal. This patch introduces a new function to the clk.h API to
dynamically adjust the phase of a clock signal. Additionally this patch
introduces support for the new function in the common clock framework
via the .set_phase call back in struct clk_ops.
Signed-off-by: Mike Turquette <mturquette@linaro.org>
Signed-off-by: Maxime Ripard <maxime.ripard@free-electrons.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>
diff --git a/include/linux/clk-private.h b/include/linux/clk-private.h
index efbf70b..845be30 100644
--- a/include/linux/clk-private.h
+++ b/include/linux/clk-private.h
@@ -46,6 +46,7 @@
unsigned int enable_count;
unsigned int prepare_count;
unsigned long accuracy;
+ int phase;
struct hlist_head children;
struct hlist_node child_node;
unsigned int notifier_count;
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 411dd7e..201a619 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -129,6 +129,10 @@
* set then clock accuracy will be initialized to parent accuracy
* or 0 (perfect clock) if clock has no parent.
*
+ * @set_phase: Shift the phase this clock signal in degrees specified
+ * by the second argument. Valid values for degrees are
+ * 0-359. Return 0 on success, otherwise -EERROR.
+ *
* @init: Perform platform-specific initialization magic.
* This is not not used by any of the basic clock types.
* Please consider other ways of solving initialization problems
@@ -177,6 +181,7 @@
unsigned long parent_rate, u8 index);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
+ int (*set_phase)(struct clk_hw *hw, int degrees);
void (*init)(struct clk_hw *hw);
int (*debug_init)(struct clk_hw *hw, struct dentry *dentry);
};
diff --git a/include/linux/clk.h b/include/linux/clk.h
index fb5e097..38bdedd 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -106,6 +106,25 @@
*/
long clk_get_accuracy(struct clk *clk);
+/**
+ * clk_set_phase - adjust the phase shift of a clock signal
+ * @clk: clock signal source
+ * @degrees: number of degrees the signal is shifted
+ *
+ * Shifts the phase of a clock signal by the specified degrees. Returns 0 on
+ * success, -EERROR otherwise.
+ */
+int clk_set_phase(struct clk *clk, int degrees);
+
+/**
+ * clk_get_phase - return the phase shift of a clock signal
+ * @clk: clock signal source
+ *
+ * Returns the phase shift of a clock node in degrees, otherwise returns
+ * -EERROR.
+ */
+int clk_get_phase(struct clk *clk);
+
#else
static inline long clk_get_accuracy(struct clk *clk)
@@ -113,6 +132,16 @@
return -ENOTSUPP;
}
+static inline long clk_set_phase(struct clk *clk, int phase)
+{
+ return -ENOTSUPP;
+}
+
+static inline long clk_get_phase(struct clk *clk)
+{
+ return -ENOTSUPP;
+}
+
#endif
/**