[PATCH] clk: Add is_enabled callback

[Sascha Hauer]

This allows us to better detect whether a clk is enabled or not.

- If we can ask a clk, ask it. If it's enabled, go on and ask parents
- If we can't ask it, but it can be enabled, depend on the enable_count.
  if it's positive, go on and ask parents
- If we can't ask it and it cannot be enabled, assume it is enabled
  and ask parents.

This makes the CLK_ALWAYS_ENABLED unnecessary, since the fixed clk now
always returns 1 in its is_enabled callback.

Signed-off-by: Sascha Hauer <s.hauer at pengutronix.de>
---
 drivers/clk/clk-fixed.c |  2 +-
 drivers/clk/clk-gate.c  | 14 ++++++++++++
 drivers/clk/clk.c       | 61 +++++++++++++++++++++++++++++++++++++------------
 include/linux/clk.h     |  4 ++--
 4 files changed, 63 insertions(+), 18 deletions(-)

diff --git a/drivers/clk/clk-fixed.c b/drivers/clk/clk-fixed.c
index 5e81e72..e5d36b4 100644
--- a/drivers/clk/clk-fixed.c
+++ b/drivers/clk/clk-fixed.c
@@ -34,6 +34,7 @@ static unsigned long clk_fixed_recalc_rate(struct clk *clk,
 
 struct clk_ops clk_fixed_ops = {
 	.recalc_rate = clk_fixed_recalc_rate,
+	.is_enabled = clk_is_enabled_always,
 };
 
 struct clk *clk_fixed(const char *name, int rate)
@@ -44,7 +45,6 @@ struct clk *clk_fixed(const char *name, int rate)
 	fix->rate = rate;
 	fix->clk.ops = &clk_fixed_ops;
 	fix->clk.name = name;
-	fix->clk.flags = CLK_ALWAYS_ENABLED;
 
 	ret = clk_register(&fix->clk);
 	if (ret) {
diff --git a/drivers/clk/clk-gate.c b/drivers/clk/clk-gate.c
index cf1bb1a..a455094 100644
--- a/drivers/clk/clk-gate.c
+++ b/drivers/clk/clk-gate.c
@@ -49,9 +49,23 @@ static void clk_gate_disable(struct clk *clk)
 	writel(val, g->reg);
 }
 
+static int clk_gate_is_enabled(struct clk *clk)
+{
+	struct clk_gate *g = container_of(clk, struct clk_gate, clk);
+	u32 val;
+
+	val = readl(g->reg);
+
+	if (val & (1 << g->shift))
+		return 1;
+	else
+		return 0;
+}
+
 struct clk_ops clk_gate_ops = {
 	.enable = clk_gate_enable,
 	.disable = clk_gate_disable,
+	.is_enabled = clk_gate_is_enabled,
 };
 
 struct clk *clk_gate(const char *name, const char *parent, void __iomem *reg,
diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index cb94755..690a0c6 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -46,9 +46,6 @@ int clk_enable(struct clk *clk)
 	if (IS_ERR(clk))
 		return PTR_ERR(clk);
 
-	if (clk->flags & CLK_ALWAYS_ENABLED)
-		return 0;
-
 	if (!clk->enable_count) {
 		ret = clk_parent_enable(clk);
 		if (ret)
@@ -73,9 +70,6 @@ void clk_disable(struct clk *clk)
 	if (IS_ERR(clk))
 		return;
 
-	if (clk->flags & CLK_ALWAYS_ENABLED)
-		return;
-
 	if (!clk->enable_count)
 		return;
 
@@ -211,23 +205,60 @@ int clk_register(struct clk *clk)
 
 	list_add_tail(&clk->list, &clks);
 
-	if (clk->flags & CLK_ALWAYS_ENABLED) {
-		clk->enable_count = 1;
+	return 0;
+}
+
+int clk_is_enabled(struct clk *clk)
+{
+	int enabled;
+
+	if (IS_ERR(clk))
+		return 0;
+
+	if (clk->ops->is_enabled) {
+		/*
+		 * If we can ask a clk, do it
+		 */
+		enabled = clk->ops->is_enabled(clk);
+	} else {
+		if (clk->ops->enable) {
+			/*
+			 * If we can't ask a clk, but it can be enabled,
+			 * depend on the enable_count.
+			 */
+			enabled = clk->enable_count;
+		} else {
+			/*
+			 * We can't ask a clk, it has no enable op,
+			 * so assume it's enabled and go on and ask
+			 * the parent.
+			 */
+			enabled = 1;
+		}
 	}
 
-	return 0;
+	if (!enabled)
+		return 0;
+
+	clk = clk_get_parent(clk);
+
+	if (IS_ERR(clk))
+		return 1;
+
+	return clk_is_enabled(clk);
+}
+
+int clk_is_enabled_always(struct clk *clk)
+{
+	return 1;
 }
 
 static void dump_one(struct clk *clk, int verbose, int indent)
 {
 	struct clk *c;
-	char *always = "";
-
-	if (clk->flags & CLK_ALWAYS_ENABLED)
-		always = "always ";
 
-	printf("%*s%s (rate %ld, %s%sabled)\n", indent * 4, "", clk->name, clk_get_rate(clk),
-			always, clk->enable_count ? "en" : "dis");
+	printf("%*s%s (rate %ld, %sabled)\n", indent * 4, "", clk->name, clk_get_rate(clk),
+			clk_is_enabled(clk) ? "en" : "dis");
 	if (verbose) {
 
 		if (clk->num_parents > 1) {
diff --git a/include/linux/clk.h b/include/linux/clk.h
index 4389cf8..37a4813 100644
--- a/include/linux/clk.h
+++ b/include/linux/clk.h
@@ -182,8 +182,6 @@ struct clk {
 	unsigned long flags;
 };
 
-#define CLK_ALWAYS_ENABLED	(1 << 0)
-
 struct clk_div_table {
 	unsigned int	val;
 	unsigned int	div;
@@ -202,6 +200,8 @@ struct clk *clk_mux(const char *name, void __iomem *reg,
 struct clk *clk_gate(const char *name, const char *parent, void __iomem *reg,
 		u8 shift);
 
+int clk_is_enabled_always(struct clk *clk);
+
 int clk_register(struct clk *clk);
 
 struct clk *clk_lookup(const char *name);
-- 
1.8.2.rc2