PM / OPP: Parse clock-latency and voltage-tolerance for v1 bindings

V2 bindings have better support for clock-latency and voltage-tolerance
and doesn't need special care. To use callbacks, like
dev_pm_opp_get_max_{transition|volt}_latency(), irrespective of the
bindings, the core needs to know clock-latency/voltage-tolerance for the
earlier bindings.

This patch reads clock-latency/voltage-tolerance from the device node,
irrespective of the bindings (to keep it simple) and use them only for
V1 bindings.

Signed-off-by: Viresh Kumar <viresh.kumar@linaro.org>
Reviewed-by: Stephen Boyd <sboyd@codeaurora.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

2 files changed, 26 insertions, 0 deletions

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index b0f5c72f0fc3..4fafa733a1c7 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -582,6 +582,7 @@ static struct device_opp *_add_device_opp(struct device *dev)
 {
         struct device_opp *dev_opp;
         struct device_list_opp *list_dev;
+        struct device_node *np;
 
         /* Check for existing list for 'dev' first */
         dev_opp = _find_device_opp(dev);
@@ -604,6 +605,21 @@ static struct device_opp *_add_device_opp(struct device *dev)
                 return NULL;
         }
 
+        /*
+         * Only required for backward compatibility with v1 bindings, but isn't
+         * harmful for other cases. And so we do it unconditionally.
+         */
+        np = of_node_get(dev->of_node);
+        if (np) {
+                u32 val;
+
+                if (!of_property_read_u32(np, "clock-latency", &val))
+                        dev_opp->clock_latency_ns_max = val;
+                of_property_read_u32(np, "voltage-tolerance",
+                                     &dev_opp->voltage_tolerance_v1);
+                of_node_put(np);
+        }
+
         srcu_init_notifier_head(&dev_opp->srcu_head);
         INIT_LIST_HEAD(&dev_opp->opp_list);
 
@@ -861,6 +877,7 @@ static int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
 {
         struct device_opp *dev_opp;
         struct dev_pm_opp *new_opp;
+        unsigned long tol;
         int ret;
 
         /* Hold our list modification lock here */
@@ -874,7 +891,10 @@ static int _opp_add_v1(struct device *dev, unsigned long freq, long u_volt,
 
         /* populate the opp table */
         new_opp->rate = freq;
+        tol = u_volt * dev_opp->voltage_tolerance_v1 / 100;
         new_opp->u_volt = u_volt;
+        new_opp->u_volt_min = u_volt - tol;
+        new_opp->u_volt_max = u_volt + tol;
         new_opp->available = true;
         new_opp->dynamic = dynamic;
 
diff --git a/drivers/base/power/opp/opp.h b/drivers/base/power/opp/opp.h
index 416293b7da23..fe44beb404ba 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -138,6 +138,8 @@ struct device_list_opp {
  * @dentry:     debugfs dentry pointer of the real device directory (not links).
  * @dentry_name: Name of the real dentry.
  *
+ * @voltage_tolerance_v1: In percentage, for v1 bindings only.
+ *
  * This is an internal data structure maintaining the link to opps attached to
  * a device. This structure is not meant to be shared to users as it is
  * meant for book keeping and private to OPP library.
@@ -156,6 +158,10 @@ struct device_opp {
 
         struct device_node *np;
         unsigned long clock_latency_ns_max;
+
+        /* For backward compatibility with v1 bindings */
+        unsigned int voltage_tolerance_v1;
+
         bool shared_opp;
         struct dev_pm_opp *suspend_opp;