linux-kernel - [RFC PATCH 1/2] thermal: provide a way to get thermal sensor from a device tree node

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Message-Id: <20210819123215.591593-2-abailon@baylibre.com>
Date:   Thu, 19 Aug 2021 14:32:14 +0200
From:   Alexandre Bailon <abailon@...libre.com>
To:     rui.zhang@...el.com, daniel.lezcano@...aro.org, amitk@...nel.org
Cc:     linux-pm@...r.kernel.org, linux-kernel@...r.kernel.org,
        ben.tseng@...iatek.com, khilman@...libre.com,
        Alexandre Bailon <abailon@...libre.com>
Subject: [RFC PATCH 1/2] thermal: provide a way to get thermal sensor from a device tree node

In order to add support of a virtual thermal sensor,
add a way to get a sensor using the device tree node and sensor id.

Signed-off-by: Alexandre Bailon <abailon@...libre.com>
---
 drivers/thermal/thermal_of.c | 43 ++++++++++++++++++++++++++++++++++++
 include/linux/thermal.h      | 12 ++++++++++
 2 files changed, 55 insertions(+)

diff --git a/drivers/thermal/thermal_of.c b/drivers/thermal/thermal_of.c
index 6379f26a335f6..4d3b07ceef41a 100644
--- a/drivers/thermal/thermal_of.c
+++ b/drivers/thermal/thermal_of.c
@@ -82,6 +82,46 @@ struct __thermal_zone {
 	const struct thermal_zone_of_device_ops *ops;
 };
 
+
+static LIST_HEAD(thermal_sensors);
+
+struct thermal_sensor *thermal_of_get_sensor(struct device_node *np, int id)
+{
+	struct thermal_sensor *sensor;
+	list_for_each_entry(sensor, &thermal_sensors, node) {
+		if (sensor->dev->of_node == np && sensor->id == id) {
+			return sensor;
+		}
+	}
+
+	return NULL;
+}
+
+static int thermal_of_register_sensor(struct device *dev, int id,
+				      void *sensor_data,
+				      const struct thermal_zone_of_device_ops *ops)
+{
+
+	struct thermal_sensor *sensor;
+
+	sensor = thermal_of_get_sensor(dev->of_node, id);
+	if (sensor)
+		return 0;
+
+	sensor = kzalloc(sizeof(*sensor), GFP_KERNEL);
+	sensor->dev = dev;
+	sensor->id = id;
+	sensor->sensor_data = sensor_data;
+	sensor->ops = ops;
+
+	list_add(&sensor->node, &thermal_sensors);
+
+	return 0;
+}
+
+
+
+
 /***   DT thermal zone device callbacks   ***/
 
 static int of_thermal_get_temp(struct thermal_zone_device *tz,
@@ -518,6 +558,9 @@ thermal_zone_of_sensor_register(struct device *dev, int sensor_id, void *data,
 			if (!IS_ERR(tzd))
 				thermal_zone_device_enable(tzd);
 
+			/* TODO handle errors */
+			thermal_of_register_sensor(dev, id, data, ops);
+
 			of_node_put(child);
 			goto exit;
 		}
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 8da5b61070472..3c46b142ebfef 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -104,6 +104,16 @@ struct thermal_cooling_device {
 	struct list_head node;
 };
 
+struct thermal_sensor {
+	struct device *dev;
+	int id;
+
+	void *sensor_data;
+	const struct thermal_zone_of_device_ops *ops;
+
+	struct list_head node;
+};
+
 /**
  * struct thermal_zone_device - structure for a thermal zone
  * @id:		unique id number for each thermal zone
@@ -394,6 +404,8 @@ int thermal_zone_get_offset(struct thermal_zone_device *tz);
 int thermal_zone_device_enable(struct thermal_zone_device *tz);
 int thermal_zone_device_disable(struct thermal_zone_device *tz);
 void thermal_zone_device_critical(struct thermal_zone_device *tz);
+
+struct thermal_sensor *thermal_of_get_sensor(struct device_node *np, int id);
 #else
 static inline struct thermal_zone_device *thermal_zone_device_register(
 	const char *type, int trips, int mask, void *devdata,
-- 
2.31.1