[PATCH 1/3] clk: initially enable critical clocks

[PATCH 1/3] clk: initially enable critical clocks

[Sascha Hauer]

Critical clocks have to be enabled initially. We have to do this not
only to enable the clock itself, but also to make sure its parents
stay enabled and also to correctly enable the new parents during
reparenting of the clock.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/clk/clk.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index ea3304bc7c..05bc21a6d4 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -282,6 +282,9 @@ int clk_register(struct clk *clk)
 
 	list_add_tail(&clk->list, &clks);
 
+	if (clk->flags & CLK_IS_CRITICAL)
+		clk_enable(clk);
+
 	return 0;
 }
 
-- 
2.25.0


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[PATCH 2/3] clk: Do not let the enable count of critical clocks go below 1

[Sascha Hauer]

The enable count of critical clocks may not drop below 1. Otherwise
the new parent during a reparenting of a critical clock will not
be enabled.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/clk/clk.c | 8 +++++---
 1 file changed, 5 insertions(+), 3 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 05bc21a6d4..5777c9c58e 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -84,12 +84,14 @@ void clk_disable(struct clk *clk)
 	if (!clk->enable_count)
 		return;
 
+	if (clk->enable_count == 1 && clk->flags & CLK_IS_CRITICAL) {
+		pr_warn("Disabling critical clock %s\n", clk->name);
+		return;
+	}
+
 	clk->enable_count--;
 
 	if (!clk->enable_count) {
-		if (clk->flags & CLK_IS_CRITICAL)
-			return;
-
 		if (clk->ops->disable)
 			clk->ops->disable(clk);
 
-- 
2.25.0


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[PATCH 3/3] clk: print more consistent clock states

[Sascha Hauer]

In clk_dump we only print the state of clk_is_enabled(). Depending on
the clock this can mean different things. When the clock provides an
is_enabled() callback it will print its result, so the enabled state
matches the hardware state of that clock, but doesn't necessarily mean
its parents are enabled. If a clock does not provide an is_enabled()
callback then we rely on our internal enable_count tracker.

Change this to always print the hardware state of the current clock. It
can be:

- disabled: The clock is disabled (as provided by is_enabled())
- enabled: The clock is enabled (as provided by is_enabled())
- always enabled: The clock can't be disabled (no is_enabled callback
                  and can't be enabled/disabled)
- unknown: no is_enabled callback but can be enabled/disabled

Additionally we print the enable_count variable, so from enable_count !=
0 we can know that barebox has enabled the clock.

Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
---
 drivers/clk/clk.c | 32 ++++++++++++++++++++++++++++++--
 1 file changed, 30 insertions(+), 2 deletions(-)

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index 5777c9c58e..b27ad6d249 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -632,12 +632,40 @@ int of_clk_init(struct device_node *root, const struct of_device_id *matches)
 }
 #endif
 
+static const char *clk_hw_stat(struct clk *clk)
+{
+	if (clk->ops->is_enabled) {
+		if (clk->ops->is_enabled(clk))
+			return "enabled";
+		else
+			return "disabled";
+	}
+
+	if (!clk->ops->enable)
+		return "always enabled";
+
+	return "unknown";
+}
+
 static void dump_one(struct clk *clk, int verbose, int indent)
 {
 	struct clk *c;
+	int enabled = clk_is_enabled(clk);
+	const char *hwstat, *stat;
+
+	hwstat = clk_hw_stat(clk);
+
+	if (enabled == 0)
+		stat = "disabled";
+	else
+		stat = "enabled";
+
+	printf("%*s%s (rate %lu, enable_count: %d, %s)\n", indent * 4, "",
+	       clk->name,
+	       clk_get_rate(clk),
+	       clk->enable_count,
+	       hwstat);
 
-	printf("%*s%s (rate %lu, %sabled)\n", indent * 4, "", clk->name, clk_get_rate(clk),
-			clk_is_enabled(clk) ? "en" : "dis");
 	if (verbose) {
 
 		if (clk->num_parents > 1) {
-- 
2.25.0


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