[PATCH 1/1] clk: introduce of_clk_detect_critical helper

[Maxim Kochetkov]

This helper find clock-critiacl property in dts and assign
CLK_IS_CRITICAL flag to the clock.

Signed-off-by: Maxim Kochetkov <fido_max at inbox.ru>
---
 drivers/clk/clk-uclass.c | 17 +++++++++++++++++
 drivers/core/of_access.c | 22 ++++++++++++++++++++++
 include/clk.h            | 28 ++++++++++++++++++++++++++++
 include/dm/of_access.h   | 17 +++++++++++++++++
 4 files changed, 84 insertions(+)

diff --git a/drivers/clk/clk-uclass.c b/drivers/clk/clk-uclass.c
index 7262e89b512..4f35b90382f 100644
--- a/drivers/clk/clk-uclass.c
+++ b/drivers/clk/clk-uclass.c
@@ -835,6 +835,23 @@ struct clk *devm_clk_get(struct udevice *dev, const char *id)
 	return clk;
 }
 
+int of_clk_detect_critical(struct device_node *np, int index,
+			   unsigned long *flags)
+{
+	struct property *prop;
+	const __be32 *cur;
+	uint32_t idx;
+
+	if (!np || !flags)
+		return -EINVAL;
+
+	of_property_for_each_u32(np, "clock-critical", prop, cur, idx)
+		if (index == idx)
+			*flags |= CLK_IS_CRITICAL;
+
+	return 0;
+}
+
 int clk_uclass_post_probe(struct udevice *dev)
 {
 	/*
diff --git a/drivers/core/of_access.c b/drivers/core/of_access.c
index b11e36202c1..59dda3ae152 100644
--- a/drivers/core/of_access.c
+++ b/drivers/core/of_access.c
@@ -666,6 +666,28 @@ int of_property_read_string_helper(const struct device_node *np,
 	return i <= 0 ? -ENODATA : i;
 }
 
+const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
+			       u32 *pu)
+{
+	const void *curv = cur;
+
+	if (!prop)
+		return NULL;
+
+	if (!cur) {
+		curv = prop->value;
+		goto out_val;
+	}
+
+	curv += sizeof(*cur);
+	if (curv >= prop->value + prop->length)
+		return NULL;
+
+out_val:
+	*pu = be32_to_cpup(curv);
+	return curv;
+}
+
 static int __of_root_parse_phandle_with_args(struct device_node *root,
 					     const struct device_node *np,
 					     const char *list_name,
diff --git a/include/clk.h b/include/clk.h
index f94135ff778..ea708f54fd5 100644
--- a/include/clk.h
+++ b/include/clk.h
@@ -589,6 +589,27 @@ bool clk_dev_binded(struct clk *clk);
  */
 ulong clk_get_id(const struct clk *clk);
 
+/**
+ * of_clk_detect_critical() - set CLK_IS_CRITICAL flag from Device Tree
+ * @np: Device node pointer associated with clock provider
+ * @index: clock index
+ * @flags: pointer to top-level framework flags
+ *
+ * Detects if the clock-critical property exists and, if so, sets the
+ * corresponding CLK_IS_CRITICAL flag.
+ *
+ * Do not use this function. It exists only for legacy Device Tree
+ * bindings, such as the one-clock-per-node style that are outdated.
+ * Those bindings typically put all clock data into .dts and the Linux
+ * driver has no clock data, thus making it impossible to set this flag
+ * correctly from the driver. Only those drivers may call
+ * of_clk_detect_critical from their setup functions.
+ *
+ * Return: error code or zero on success
+ */
+int of_clk_detect_critical(struct device_node *np, int index,
+			   unsigned long *flags);
+
 #else /* CONFIG_IS_ENABLED(CLK) */
 
 static inline int clk_request(struct udevice *dev, struct clk *clk)
@@ -665,6 +686,13 @@ static inline ulong clk_get_id(const struct clk *clk)
 {
 	return 0;
 }
+
+int of_clk_detect_critical(struct device_node *np, int index,
+			   unsigned long *flags)
+{
+	return 0;
+}
+
 #endif /* CONFIG_IS_ENABLED(CLK) */
 
 /**
diff --git a/include/dm/of_access.h b/include/dm/of_access.h
index 44143a5a391..dba725498f5 100644
--- a/include/dm/of_access.h
+++ b/include/dm/of_access.h
@@ -405,6 +405,17 @@ int of_property_read_string_helper(const struct device_node *np,
 				   const char *propname, const char **out_strs,
 				   size_t sz, int index);
 
+/*
+ * struct property *prop;
+ * const __be32 *p;
+ * u32 u;
+ *
+ * of_property_for_each_u32(np, "propname", prop, p, u)
+ *         printk("U32 value: %x\n", u);
+ */
+const __be32 *of_prop_next_u32(struct property *prop, const __be32 *cur,
+			       u32 *pu);
+
 /**
  * of_property_read_string_index() - Find and read a string from a multiple
  * strings property.
@@ -701,4 +712,10 @@ int of_remove_property(struct device_node *np, struct property *prop);
  */
 int of_remove_node(struct device_node *to_remove);
 
+#define of_property_for_each_u32(np, propname, prop, p, u)	\
+	for (prop = of_find_property(np, propname, NULL),	\
+		p = of_prop_next_u32(prop, NULL, &u);		\
+		p;						\
+		p = of_prop_next_u32(prop, p, &u))
+
 #endif
-- 
2.50.0