The current phase API doesn't look into the actual hardware to get the phase
value, but will rather get it from a variable only set by the set_phase
function.
This will cause issue when the client driver will never call the set_phase
function, where we can end up having a reported phase that will not match what
the hardware has been programmed to by the bootloader or what phase is
programmed out of reset.
Add a new get_phase function for the drivers to implement so that we can get
this value.
Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
---
drivers/clk/clk.c | 17 ++++++++++++++---
include/linux/clk-provider.h | 5 +++++
2 files changed, 19 insertions(+), 3 deletions(-)
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 3eae203cda47..a6471df0a3f5 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1825,8 +1825,8 @@ out:
* 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.
+ * Returns the phase shift of a clock node in degrees. Any negative
+ * values are errors.
*/
int clk_get_phase(struct clk *clk)
{
@@ -1836,7 +1836,18 @@ int clk_get_phase(struct clk *clk)
goto out;
clk_prepare_lock();
- ret = clk->phase;
+
+ if (clk->phase) {
+ ret = clk->phase;
+ goto out_unlock;
+ }
+
+ if (!clk->ops->get_phase)
+ goto out_unlock;
+
+ ret = clk->ops->get_phase(clk->hw);
+
+out_unlock:
clk_prepare_unlock();
out:
diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 3a35a0647118..fa53f90456a9 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -129,6 +129,10 @@ struct dentry;
* set then clock accuracy will be initialized to parent accuracy
* or 0 (perfect clock) if clock has no parent.
*
+ * @get_phase: Queries the hardware to get the current phase of a clock.
+ * Returned values are 0-359 degrees on success, negative
+ * error codes on failure.
+ *
* @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.
@@ -181,6 +185,7 @@ struct clk_ops {
unsigned long parent_rate, u8 index);
unsigned long (*recalc_accuracy)(struct clk_hw *hw,
unsigned long parent_accuracy);
+ int (*get_phase)(struct clk_hw *hw);
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);
--
2.0.1
--
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