[cip-dev] [PATCH 4.4.y-cip 01/11] PM / OPP: Parse clock-latency and voltage-tolerance for v1 bindings

Chen-Yu Tsai (Moxa)
2020-09-09T04:44:45Z

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From: Viresh Kumar <viresh.kumar@linaro.org>

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>
Signed-off-by: Chen-Yu Tsai (Moxa) <wens@csie.org>
---

This patch is needed because the OPPv2 table does not include
clock-latency-ns properties, but instead uses the clock-latency
property from OPPv1.

---
drivers/base/power/opp/core.c | 20 ++++++++++++++++++++
drivers/base/power/opp/opp.h | 6 ++++++
2 files changed, 26 insertions(+)

diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
index 1e0a2ddf73323..f983d5d30fa94 100644
--- a/drivers/base/power/opp/core.c
+++ b/drivers/base/power/opp/core.c
@@ -505,6 +505,7 @@ 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);
@@ -527,6 +528,21 @@ 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);

@@ -759,6 +775,7 @@ 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 */
@@ -772,7 +789,10 @@ 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 690638ef36ee5..7f0d7c8bfef00 100644
--- a/drivers/base/power/opp/opp.h
+++ b/drivers/base/power/opp/opp.h
@@ -135,6 +135,8 @@ 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.
@@ -153,6 +155,10 @@ 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;

--
2.28.0

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