[PATCH V2] thermal/drivers/hisi: Switch to interrupt mode

[Daniel Lezcano <daniel.lezcano@linaro.org>]

At this moment, we have both the interrupt setup and the polling enabled. The
interrupt does nothing more than forcing an update while the temperature is
polled every second.

We can do much better than that, threshold is set to 65C in the DT and the
passive cooling device enters in the dance when 75C is reached. We need to
sample the temperature at 65C in order to let the IPA gather enough values for
the PID computation. If the SoC is running at a temperature below 65C, we will
be constantly polling for nothing.

This patch disables the sensor when the temperature is below 65C and enables it
when passing the threshold. It results the thermal sensor driver will have no
activity most of the time.

Cc: Keerthy <j-keerthy@ti.com>
Cc: Leo Yang <leo.yan@linaro.org>
Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org>
---
 drivers/thermal/hisi_thermal.c | 24 ++++++++++++++----------
 1 file changed, 14 insertions(+), 10 deletions(-)

diff --git a/drivers/thermal/hisi_thermal.c b/drivers/thermal/hisi_thermal.c
index 39f4627..74ea70d 100644
--- a/drivers/thermal/hisi_thermal.c
+++ b/drivers/thermal/hisi_thermal.c
@@ -218,6 +218,15 @@ static int hisi_thermal_get_temp(void *__data, int *temp)
 	return 0;
 }
 
+static void hisi_thermal_toggle_sensor(struct hisi_thermal_sensor *sensor,
+				       bool on)
+{
+	struct thermal_zone_device *tzd = sensor->tzd;
+
+	tzd->ops->set_mode(tzd,
+		on ? THERMAL_DEVICE_ENABLED : THERMAL_DEVICE_DISABLED);
+}
+
 static const struct thermal_zone_of_device_ops hisi_of_thermal_ops = {
 	.get_temp = hisi_thermal_get_temp,
 };
@@ -236,12 +245,16 @@ static irqreturn_t hisi_thermal_alarm_irq_thread(int irq, void *dev)
 		dev_crit(&data->pdev->dev, "THERMAL ALARM: %d > %d\n",
 			 temp, sensor->thres_temp);
 
+		hisi_thermal_toggle_sensor(&data->sensor, true);
+
 		thermal_zone_device_update(data->sensor.tzd,
 					   THERMAL_EVENT_UNSPECIFIED);
 
 	} else if (temp < sensor->thres_temp) {
 		dev_crit(&data->pdev->dev, "THERMAL ALARM stopped: %d < %d\n",
 			 temp, sensor->thres_temp);
+
+		hisi_thermal_toggle_sensor(&data->sensor, false);
 	}
 
 	return IRQ_HANDLED;
@@ -286,15 +299,6 @@ static const struct of_device_id of_hisi_thermal_match[] = {
 };
 MODULE_DEVICE_TABLE(of, of_hisi_thermal_match);
 
-static void hisi_thermal_toggle_sensor(struct hisi_thermal_sensor *sensor,
-				       bool on)
-{
-	struct thermal_zone_device *tzd = sensor->tzd;
-
-	tzd->ops->set_mode(tzd,
-		on ? THERMAL_DEVICE_ENABLED : THERMAL_DEVICE_DISABLED);
-}
-
 static int hisi_thermal_setup(struct hisi_thermal_data *data)
 {
 	struct hisi_thermal_sensor *sensor;
@@ -393,7 +397,7 @@ static int hisi_thermal_probe(struct platform_device *pdev)
 		return ret;
 	}
 
-	hisi_thermal_toggle_sensor(&data->sensor, true);
+	hisi_thermal_toggle_sensor(&data->sensor, false);
 
 	return 0;
 }
-- 
2.7.4