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path: root/drivers/base/power/opp.c
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Diffstat (limited to 'drivers/base/power/opp.c')
-rw-r--r--drivers/base/power/opp.c47
1 files changed, 47 insertions, 0 deletions
diff --git a/drivers/base/power/opp.c b/drivers/base/power/opp.c
index ac993eafec82..d9468642fc41 100644
--- a/drivers/base/power/opp.c
+++ b/drivers/base/power/opp.c
@@ -22,6 +22,7 @@
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/opp.h>
+#include <linux/of.h>
/*
* Internal data structure organization with the OPP layer library is as
@@ -674,3 +675,49 @@ struct srcu_notifier_head *opp_get_notifier(struct device *dev)
return &dev_opp->head;
}
+
+#ifdef CONFIG_OF
+/**
+ * of_init_opp_table() - Initialize opp table from device tree
+ * @dev: device pointer used to lookup device OPPs.
+ *
+ * Register the initial OPP table with the OPP library for given device.
+ */
+int of_init_opp_table(struct device *dev)
+{
+ const struct property *prop;
+ const __be32 *val;
+ int nr;
+
+ prop = of_find_property(dev->of_node, "operating-points", NULL);
+ if (!prop)
+ return -ENODEV;
+ if (!prop->value)
+ return -ENODATA;
+
+ /*
+ * Each OPP is a set of tuples consisting of frequency and
+ * voltage like <freq-kHz vol-uV>.
+ */
+ nr = prop->length / sizeof(u32);
+ if (nr % 2) {
+ dev_err(dev, "%s: Invalid OPP list\n", __func__);
+ return -EINVAL;
+ }
+
+ val = prop->value;
+ while (nr) {
+ unsigned long freq = be32_to_cpup(val++) * 1000;
+ unsigned long volt = be32_to_cpup(val++);
+
+ if (opp_add(dev, freq, volt)) {
+ dev_warn(dev, "%s: Failed to add OPP %ld\n",
+ __func__, freq);
+ continue;
+ }
+ nr -= 2;
+ }
+
+ return 0;
+}
+#endif