We already import the API from Linux, so let's import the documentation
for reference as well and add a note about clk_unprepare/clk_prepare.
Signed-off-by: Ahmad Fatoum <a.fatoum@xxxxxxxxxxxxxx>
---
include/linux/clk.h | 65 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 65 insertions(+)
diff --git a/include/linux/clk.h b/include/linux/clk.h
index edcc43d9f1df..7657ab6fc245 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -240,6 +240,71 @@ static inline void clk_put(struct clk *clk)
#define CLK_GATE_SET_TO_DISABLE (1 << 0)
#define CLK_GATE_HIWORD_MASK (1 << 1)
+/**
+ * struct clk_ops - Callback operations for hardware clocks; these are to
+ * be provided by the clock implementation, and will be called by drivers
+ * through the clk_* api.
+ *
+ * @init: Perform platform-specific initialization magic.
+ * This is not used by any of the basic clock types.
+ * This callback exist for HW which needs to perform some
+ * initialisation magic for CCF to get an accurate view of the
+ * clock. It may also be used dynamic resource allocation is
+ * required. It shall not used to deal with clock parameters,
+ * such as rate or parents.
+ * Returns 0 on success, -EERROR otherwise.
+ *
+ * @enable: Prepare and enable the clock atomically. This must not return
+ * until the clock is generating a valid clock signal, usable by
+ * consumer devices.
+ *
+ * @disable: Unprepare and disable the clock atomically.
+ *
+ * @is_enabled: Queries the hardware to determine if the clock is enabled.
+ * Optional, if this op is not set then the enable count will be
+ * used.
+ *
+ * @recalc_rate Recalculate the rate of this clock, by querying hardware. The
+ * parent rate is an input parameter. If the driver cannot figure
+ * out a rate for this clock, it must return 0. Returns the
+ * calculated rate. Optional, but recommended - if this op is not
+ * set then clock rate will be initialized to 0.
+ *
+ * @round_rate: Given a target rate as input, returns the closest rate actually
+ * supported by the clock. The parent rate is an input/output
+ * parameter.
+ *
+ * @set_parent: Change the input source of this clock; for clocks with multiple
+ * possible parents specify a new parent by passing in the index
+ * as a u8 corresponding to the parent in either the .parent_names
+ * or .parents arrays. This function in affect translates an
+ * array index into the value programmed into the hardware.
+ * Returns 0 on success, -EERROR otherwise.
+ *
+ * @get_parent: Queries the hardware to determine the parent of a clock. The
+ * return value is a u8 which specifies the index corresponding to
+ * the parent clock. This index can be applied to either the
+ * .parent_names or .parents arrays. In short, this function
+ * translates the parent value read from hardware into an array
+ * index.
+ *
+ * @set_rate: Change the rate of this clock. The requested rate is specified
+ * by the second argument, which should typically be the return
+ * of .round_rate call. The third argument gives the parent rate
+ * which is likely helpful for most .set_rate implementation.
+ * Returns 0 on success, -EERROR otherwise.
+ *
+ * @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.
+ *
+ * @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.
+ *
+ * Unlike Linux, there is no differentiation between clk_prepare/clk_enable
+ * and clk_unprepare/clk_disable in barebox as all work is atomic.
+ */
struct clk_ops {
int (*init)(struct clk_hw *hw);
int (*enable)(struct clk_hw *hw);
--
2.39.2
