[RFC v1] clk: core: support clocks that need to be enabled during re-parent

From: Weiyi Lu
Date: Sun Jun 09 2019 - 23:49:39 EST


When using property assigned-clock-parents to assign parent clocks,
core clocks might still be disabled during re-parent.
Add flag 'CLK_OPS_CORE_ENABLE' for those clocks must be enabled
during re-parent.

Signed-off-by: Weiyi Lu <weiyi.lu@xxxxxxxxxxxx>
---
drivers/clk/clk.c | 9 +++++++++
include/linux/clk-provider.h | 1 +
2 files changed, 10 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 443711f..b2e6fe3 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -1717,6 +1717,10 @@ static struct clk_core *__clk_set_parent_before(struct clk_core *core,
clk_core_prepare_enable(parent);
}

+ /* enable core if CLK_OPS_CORE_ENABLE is set */
+ if (core->flags & CLK_OPS_CORE_ENABLE)
+ clk_core_prepare_enable(core);
+
/* migrate prepare count if > 0 */
if (core->prepare_count) {
clk_core_prepare_enable(parent);
@@ -1744,6 +1748,10 @@ static void __clk_set_parent_after(struct clk_core *core,
clk_core_disable_unprepare(old_parent);
}

+ /* re-balance ref counting if CLK_OPS_CORE_ENABLE is set */
+ if (core->flags & CLK_OPS_CORE_ENABLE)
+ clk_core_disable_unprepare(core);
+
/* re-balance ref counting if CLK_OPS_PARENT_ENABLE is set */
if (core->flags & CLK_OPS_PARENT_ENABLE) {
clk_core_disable_unprepare(parent);
@@ -2973,6 +2981,7 @@ static int clk_dump_show(struct seq_file *s, void *data)
ENTRY(CLK_IS_CRITICAL),
ENTRY(CLK_OPS_PARENT_ENABLE),
ENTRY(CLK_DUTY_CYCLE_PARENT),
+ ENTRY(CLK_OPS_CORE_ENABLE),
#undef ENTRY
};

diff --git a/include/linux/clk-provider.h b/include/linux/clk-provider.h
index bb6118f..39a1fed 100644
--- a/include/linux/clk-provider.h
+++ b/include/linux/clk-provider.h
@@ -34,6 +34,7 @@
#define CLK_OPS_PARENT_ENABLE BIT(12)
/* duty cycle call may be forwarded to the parent clock */
#define CLK_DUTY_CYCLE_PARENT BIT(13)
+#define CLK_OPS_CORE_ENABLE BIT(14) /* core need enable during re-parent */

struct clk;
struct clk_hw;
--
1.8.1.1.dirty