clk: Introduce of_clk_get_hw_from_clkspec()

We want to get struct clk_hw pointers from a DT clk specifier (i.e. a
clocks property) so that we can find parent clks without searching for
globally unique clk names. This should save time by avoiding the global
string search for clks that are external to the clock controller
providing the clk and let us move away from string comparisons in
general.

Introduce of_clk_get_hw_from_clkspec() which is largely the DT parsing
part of finding clks implemented in clkdev.c and have that return a
clk_hw pointer instead of converting that into a clk pointer. This lets
us push up the clk pointer creation to the caller in clk_get() and
avoids the need to push the dev_id and con_id throughout the DT parsing
code.

Cc: Miquel Raynal <miquel.raynal@bootlin.com>
Cc: Jerome Brunet <jbrunet@baylibre.com>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Michael Turquette <mturquette@baylibre.com>
Cc: Jeffrey Hugo <jhugo@codeaurora.org>
Cc: Chen-Yu Tsai <wens@csie.org>
Signed-off-by: Stephen Boyd <sboyd@kernel.org>

1 files changed, 41 insertions, 5 deletions

diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c
index d46e8b9b9c9f..04288063847b 100644
--- a/drivers/clk/clk.c
+++ b/drivers/clk/clk.c
@@ -4065,6 +4065,42 @@ void devm_of_clk_del_provider(struct device *dev)
 }
 EXPORT_SYMBOL(devm_of_clk_del_provider);
 
+int of_parse_clkspec(const struct device_node *np, int index, const char *name,
+		     struct of_phandle_args *out_args)
+{
+	int ret = -ENOENT;
+
+	/* Walk up the tree of devices looking for a clock property that matches */
+	while (np) {
+		/*
+		 * For named clocks, first look up the name in the
+		 * "clock-names" property.  If it cannot be found, then index
+		 * will be an error code and of_parse_phandle_with_args() will
+		 * return -EINVAL.
+		 */
+		if (name)
+			index = of_property_match_string(np, "clock-names", name);
+		ret = of_parse_phandle_with_args(np, "clocks", "#clock-cells",
+						 index, out_args);
+		if (!ret)
+			break;
+		if (name && index >= 0)
+			break;
+
+		/*
+		 * No matching clock found on this node.  If the parent node
+		 * has a "clock-ranges" property, then we can try one of its
+		 * clocks.
+		 */
+		np = np->parent;
+		if (np && !of_get_property(np, "clock-ranges", NULL))
+			break;
+		index = 0;
+	}
+
+	return ret;
+}
+
 static struct clk_hw *
 __of_clk_get_hw_from_provider(struct of_clk_provider *provider,
 			      struct of_phandle_args *clkspec)
@@ -4080,8 +4116,7 @@ __of_clk_get_hw_from_provider(struct of_clk_provider *provider,
 	return __clk_get_hw(clk);
 }
 
-struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
-				       const char *dev_id, const char *con_id)
+struct clk_hw *of_clk_get_hw_from_clkspec(struct of_phandle_args *clkspec)
 {
 	struct of_clk_provider *provider;
 	struct clk_hw *hw = ERR_PTR(-EPROBE_DEFER);
@@ -4089,7 +4124,6 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 	if (!clkspec)
 		return ERR_PTR(-EINVAL);
 
-	/* Check if we have such a provider in our array */
 	mutex_lock(&of_clk_mutex);
 	list_for_each_entry(provider, &of_clk_providers, link) {
 		if (provider->node == clkspec->np) {
@@ -4100,7 +4134,7 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
 	}
 	mutex_unlock(&of_clk_mutex);
 
-	return clk_hw_create_clk(hw, dev_id, con_id);
+	return hw;
 }
 
 /**
@@ -4113,7 +4147,9 @@ struct clk *__of_clk_get_from_provider(struct of_phandle_args *clkspec,
  */
 struct clk *of_clk_get_from_provider(struct of_phandle_args *clkspec)
 {
-	return __of_clk_get_from_provider(clkspec, NULL, __func__);
+	struct clk_hw *hw = of_clk_get_hw_from_clkspec(clkspec);
+
+	return clk_hw_create_clk(hw, NULL, __func__);
 }
 EXPORT_SYMBOL_GPL(of_clk_get_from_provider);