iio: hid_sensor_hub: Common PM functions

To improvement power and performance, both regular and run time callbacks
are introduced. Because of auto suspend delay, two consecutive read
don't have to go through full power on/off procedure. The auto suspend
time can be adjusted using regular power attributes of PM sysfs.
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/common/hid-sensors/hid-sensor-trigger.c

@@ -22,16 +22,18 @@
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/slab.h>
+#include <linux/delay.h>
 #include <linux/hid-sensor-hub.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/trigger.h>
 #include <linux/iio/sysfs.h>
 #include "hid-sensor-trigger.h"
 
-int hid_sensor_power_state(struct hid_sensor_common *st, bool state)
+static int _hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 {
 	int state_val;
 	int report_val;
+	s32 poll_value = 0;
 
 	if (state) {
 		if (sensor_hub_device_open(st->hsdev))
@@ -47,6 +49,8 @@ int hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 			st->report_state.report_id,
 			st->report_state.index,
 			HID_USAGE_SENSOR_PROP_REPORTING_STATE_ALL_EVENTS_ENUM);
+
+		poll_value = hid_sensor_read_poll_value(st);
 	} else {
 		if (!atomic_dec_and_test(&st->data_ready))
 			return 0;
@@ -78,10 +82,36 @@ int hid_sensor_power_state(struct hid_sensor_common *st, bool state)
 	sensor_hub_get_feature(st->hsdev, st->power_state.report_id,
 					st->power_state.index,
 					&state_val);
+	if (state && poll_value)
+		msleep_interruptible(poll_value * 2);
+
 	return 0;
 }
 EXPORT_SYMBOL(hid_sensor_power_state);
 
+int hid_sensor_power_state(struct hid_sensor_common *st, bool state)
+{
+#ifdef CONFIG_PM
+	int ret;
+
+	if (state)
+		ret = pm_runtime_get_sync(&st->pdev->dev);
+	else {
+		pm_runtime_mark_last_busy(&st->pdev->dev);
+		ret = pm_runtime_put_autosuspend(&st->pdev->dev);
+	}
+	if (ret < 0) {
+		if (state)
+			pm_runtime_put_noidle(&st->pdev->dev);
+		return ret;
+	}
+
+ 	return 0;
+#else
+	return _hid_sensor_power_state(st, state);
+#endif
+}
+
 static int hid_sensor_data_rdy_trigger_set_state(struct iio_trigger *trig,
 						bool state)
 {
@@ -125,8 +155,21 @@ int hid_sensor_setup_trigger(struct iio_dev *indio_dev, const char *name,
 	attrb->trigger = trig;
 	indio_dev->trig = iio_trigger_get(trig);
 
-	return ret;
+	ret = pm_runtime_set_active(&indio_dev->dev);
+	if (ret)
+		goto error_unreg_trigger;
 
+	iio_device_set_drvdata(indio_dev, attrb);
+	pm_suspend_ignore_children(&attrb->pdev->dev, true);
+	pm_runtime_enable(&attrb->pdev->dev);
+	/* Default to 3 seconds, but can be changed from sysfs */
+	pm_runtime_set_autosuspend_delay(&attrb->pdev->dev,
+					 3000);
+	pm_runtime_use_autosuspend(&attrb->pdev->dev);
+
+	return ret;
+error_unreg_trigger:
+	iio_trigger_unregister(trig);
 error_free_trig:
 	iio_trigger_free(trig);
 error_ret:
@@ -134,6 +177,34 @@ int hid_sensor_setup_trigger(struct iio_dev *indio_dev, const char *name,
 }
 EXPORT_SYMBOL(hid_sensor_setup_trigger);
 
+#ifdef CONFIG_PM
+static int hid_sensor_suspend(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct hid_sensor_common *attrb = iio_device_get_drvdata(indio_dev);
+
+	return _hid_sensor_power_state(attrb, false);
+}
+
+static int hid_sensor_resume(struct device *dev)
+{
+	struct platform_device *pdev = to_platform_device(dev);
+	struct iio_dev *indio_dev = platform_get_drvdata(pdev);
+	struct hid_sensor_common *attrb = iio_device_get_drvdata(indio_dev);
+
+	return _hid_sensor_power_state(attrb, true);
+}
+
+#endif
+
+const struct dev_pm_ops hid_sensor_pm_ops = {
+	SET_SYSTEM_SLEEP_PM_OPS(hid_sensor_suspend, hid_sensor_resume)
+	SET_RUNTIME_PM_OPS(hid_sensor_suspend,
+			   hid_sensor_resume, NULL)
+};
+EXPORT_SYMBOL(hid_sensor_pm_ops);
+
 MODULE_AUTHOR("Srinivas Pandruvada <srinivas.pandruvada@intel.com>");
 MODULE_DESCRIPTION("HID Sensor trigger processing");
 MODULE_LICENSE("GPL");

drivers/iio/common/hid-sensors/hid-sensor-trigger.h

@@ -19,6 +19,11 @@
 #ifndef _HID_SENSOR_TRIGGER_H
 #define _HID_SENSOR_TRIGGER_H
 
+#include <linux/pm.h>
+#include <linux/pm_runtime.h>
+
+extern const struct dev_pm_ops hid_sensor_pm_ops;
+
 int hid_sensor_setup_trigger(struct iio_dev *indio_dev, const char *name,
 				struct hid_sensor_common *attrb);
 void hid_sensor_remove_trigger(struct hid_sensor_common *attrb);