clk: Add a function to retrieve phase

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@free-electrons.com>
Reviewed-by: Heiko Stuebner <heiko@sntech.de>
Acked-by: Hans de Goede <hdegoede@redhat.com>

1 files changed, 5 insertions, 0 deletions

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index 69b20d4c1e1a..abec961092a7 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -130,6 +130,10 @@ 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.
@@ -182,6 +186,7 @@ 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);