Patch "clk: core: Honor CLK_OPS_PARENT_ENABLE for clk gate ops" has been added to the 5.19-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    clk: core: Honor CLK_OPS_PARENT_ENABLE for clk gate ops

to the 5.19-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     clk-core-honor-clk_ops_parent_enable-for-clk-gate-op.patch
and it can be found in the queue-5.19 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit b64e986cc7eac523608441c96647fd5690560016
Author: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
Date:   Mon Aug 22 16:14:23 2022 +0800

    clk: core: Honor CLK_OPS_PARENT_ENABLE for clk gate ops
    
    [ Upstream commit 35b0fac808b95eea1212f8860baf6ad25b88b087 ]
    
    In the previous commits that added CLK_OPS_PARENT_ENABLE, support for
    this flag was only added to rate change operations (rate setting and
    reparent) and disabling unused subtree. It was not added to the
    clock gate related operations. Any hardware driver that needs it for
    these operations will either see bogus results, or worse, hang.
    
    This has been seen on MT8192 and MT8195, where the imp_ii2_* clk
    drivers set this, but dumping debugfs clk_summary would cause it
    to hang.
    
    Fixes: fc8726a2c021 ("clk: core: support clocks which requires parents enable (part 2)")
    Fixes: a4b3518d146f ("clk: core: support clocks which requires parents enable (part 1)")
    Signed-off-by: Chen-Yu Tsai <wenst@xxxxxxxxxxxx>
    Reviewed-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
    Tested-by: Nícolas F. R. A. Prado <nfraprado@xxxxxxxxxxxxx>
    Link: https://lore.kernel.org/r/20220822081424.1310926-2-wenst@xxxxxxxxxxxx
    Signed-off-by: Stephen Boyd <sboyd@xxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index f00d4c1158d72..03427e3be727f 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -196,6 +196,9 @@ static bool clk_core_rate_is_protected(struct clk_core *core)
 	return core->protect_count;
 }
 
+static int clk_core_prepare_enable(struct clk_core *core);
+static void clk_core_disable_unprepare(struct clk_core *core);
+
 static bool clk_core_is_prepared(struct clk_core *core)
 {
 	bool ret = false;
@@ -208,7 +211,11 @@ static bool clk_core_is_prepared(struct clk_core *core)
 		return core->prepare_count;
 
 	if (!clk_pm_runtime_get(core)) {
+		if (core->flags & CLK_OPS_PARENT_ENABLE)
+			clk_core_prepare_enable(core->parent);
 		ret = core->ops->is_prepared(core->hw);
+		if (core->flags & CLK_OPS_PARENT_ENABLE)
+			clk_core_disable_unprepare(core->parent);
 		clk_pm_runtime_put(core);
 	}
 
@@ -244,7 +251,13 @@ static bool clk_core_is_enabled(struct clk_core *core)
 		}
 	}
 
+	if (core->flags & CLK_OPS_PARENT_ENABLE)
+		clk_core_prepare_enable(core->parent);
+
 	ret = core->ops->is_enabled(core->hw);
+
+	if (core->flags & CLK_OPS_PARENT_ENABLE)
+		clk_core_disable_unprepare(core->parent);
 done:
 	if (core->rpm_enabled)
 		pm_runtime_put(core->dev);
@@ -812,6 +825,9 @@ int clk_rate_exclusive_get(struct clk *clk)
 }
 EXPORT_SYMBOL_GPL(clk_rate_exclusive_get);
 
+static int clk_core_enable_lock(struct clk_core *core);
+static void clk_core_disable_lock(struct clk_core *core);
+
 static void clk_core_unprepare(struct clk_core *core)
 {
 	lockdep_assert_held(&prepare_lock);
@@ -835,6 +851,9 @@ static void clk_core_unprepare(struct clk_core *core)
 
 	WARN(core->enable_count > 0, "Unpreparing enabled %s\n", core->name);
 
+	if (core->flags & CLK_OPS_PARENT_ENABLE)
+		clk_core_enable_lock(core->parent);
+
 	trace_clk_unprepare(core);
 
 	if (core->ops->unprepare)
@@ -843,6 +862,9 @@ static void clk_core_unprepare(struct clk_core *core)
 	clk_pm_runtime_put(core);
 
 	trace_clk_unprepare_complete(core);
+
+	if (core->flags & CLK_OPS_PARENT_ENABLE)
+		clk_core_disable_lock(core->parent);
 	clk_core_unprepare(core->parent);
 }
 
@@ -891,6 +913,9 @@ static int clk_core_prepare(struct clk_core *core)
 		if (ret)
 			goto runtime_put;
 
+		if (core->flags & CLK_OPS_PARENT_ENABLE)
+			clk_core_enable_lock(core->parent);
+
 		trace_clk_prepare(core);
 
 		if (core->ops->prepare)
@@ -898,6 +923,9 @@ static int clk_core_prepare(struct clk_core *core)
 
 		trace_clk_prepare_complete(core);
 
+		if (core->flags & CLK_OPS_PARENT_ENABLE)
+			clk_core_disable_lock(core->parent);
+
 		if (ret)
 			goto unprepare;
 	}