From: Andi Shyti <andi.shyti@xxxxxxxxxxx>
Commit 'b09d6d991' removes include/linux/clk-private.h and
re-arranges the clock related structures contained in it in
different files. The documentation has not been updated
accordingly, thus it wasn't anymore consistent.
Place the structures referenced by Documentation/clk.txt in the
correct files and update their contents to the latest status.
Signed-off-by: Andi Shyti <andi.shyti@xxxxxxxxxxx>
[geert: Fix path to clk.c, whitespace, more clk_core, ...]
Signed-off-by: Geert Uytterhoeven <geert+renesas@xxxxxxxxx>
---
v2:
- Take over from Andi,
- Correct path to clk.c,
- Drop whitespace changes,
- Replace clk by clk_core where appropriate,
- Update to_clk_gate(),
- Drop final reference to clk-private.h.
---
Documentation/clk.txt | 42 ++++++++++++++++++++++--------------------
1 file changed, 22 insertions(+), 20 deletions(-)
diff --git a/Documentation/clk.txt b/Documentation/clk.txt
index 5c4bc4d01d0c3293..22f026aa2f342024 100644
--- a/Documentation/clk.txt
+++ b/Documentation/clk.txt
@@ -31,24 +31,25 @@ serve as a convenient shorthand for the implementation of the
hardware-specific bits for the hypothetical "foo" hardware.
Tying the two halves of this interface together is struct clk_hw, which
-is defined in struct clk_foo and pointed to within struct clk. This
+is defined in struct clk_foo and pointed to within struct clk_core. This
allows for easy navigation between the two discrete halves of the common
clock interface.
Part 2 - common data structures and api
-Below is the common struct clk definition from
-include/linux/clk-private.h, modified for brevity:
+Below is the common struct clk_core definition from
+drivers/clk/clk.c, modified for brevity:
- struct clk {
+ struct clk_core {
const char *name;
const struct clk_ops *ops;
struct clk_hw *hw;
- char **parent_names;
- struct clk **parents;
- struct clk *parent;
- struct hlist_head children;
- struct hlist_node child_node;
+ struct module *owner;
+ struct clk_core *parent;
+ const char **parent_names;
+ struct clk_core **parents;
+ u8 num_parents;
+ u8 new_parent_index;
...
};
@@ -56,16 +57,19 @@ The members above make up the core of the clk tree topology. The clk
api itself defines several driver-facing functions which operate on
struct clk. That api is documented in include/linux/clk.h.
-Platforms and devices utilizing the common struct clk use the struct
-clk_ops pointer in struct clk to perform the hardware-specific parts of
-the operations defined in clk.h:
+Platforms and devices utilizing the common struct clk_core use the struct
+clk_ops pointer in struct clk_core to perform the hardware-specific parts of
+the operations defined in clk-provider.h:
struct clk_ops {
int (*prepare)(struct clk_hw *hw);
void (*unprepare)(struct clk_hw *hw);
+ int (*is_prepared)(struct clk_hw *hw);
+ void (*unprepare_unused)(struct clk_hw *hw);
int (*enable)(struct clk_hw *hw);
void (*disable)(struct clk_hw *hw);
int (*is_enabled)(struct clk_hw *hw);
+ void (*disable_unused)(struct clk_hw *hw);
unsigned long (*recalc_rate)(struct clk_hw *hw,
unsigned long parent_rate);
long (*round_rate)(struct clk_hw *hw,
@@ -84,6 +88,8 @@ the operations defined in clk.h:
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);
@@ -91,7 +97,7 @@ the operations defined in clk.h:
Part 3 - hardware clk implementations
-The strength of the common struct clk comes from its .ops and .hw pointers
+The strength of the common struct clk_core comes from its .ops and .hw pointers
which abstract the details of struct clk from the hardware-specific bits, and
vice versa. To illustrate consider the simple gateable clk implementation in
drivers/clk/clk-gate.c:
@@ -107,7 +113,7 @@ struct clk_gate contains struct clk_hw hw as well as hardware-specific
knowledge about which register and bit controls this clk's gating.
Nothing about clock topology or accounting, such as enable_count or
notifier_count, is needed here. That is all handled by the common
-framework code and struct clk.
+framework code and struct clk_core.
Let's walk through enabling this clk from driver code:
@@ -139,22 +145,18 @@ static void clk_gate_set_bit(struct clk_gate *gate)
Note that to_clk_gate is defined as:
-#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, clk)
+#define to_clk_gate(_hw) container_of(_hw, struct clk_gate, hw)
This pattern of abstraction is used for every clock hardware
representation.
Part 4 - supporting your own clk hardware
-When implementing support for a new type of clock it only necessary to
+When implementing support for a new type of clock it is only necessary to
include the following header:
#include <linux/clk-provider.h>
-include/linux/clk.h is included within that header and clk-private.h
-must never be included from the code which implements the operations for
-a clock. More on that below in Part 5.
-
To construct a clk hardware structure for your platform you must define
the following:
--
1.9.1
--
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