From: Anson Huang <anson.hu...@nxp.com>

On some platforms like i.MX8QXP, the thermal driver needs a
real HW sensor ID from DT thermal zone, the HW sensor ID is
used to get temperature from SCU firmware, and the virtual
sensor ID starting from 0 to N is NOT used at all, this patch
adds new API thermal_zone_of_get_sensor_id() to provide the
feature of getting sensor ID from DT thermal zone's node.

Signed-off-by: Anson Huang <anson.hu...@nxp.com>
---
Changes since V13:
        - add new API into the thermal API doc.
---
 Documentation/thermal/sysfs-api.txt |  8 +++++
 drivers/thermal/of-thermal.c        | 66 ++++++++++++++++++++++++++++---------
 include/linux/thermal.h             | 10 ++++++
 3 files changed, 68 insertions(+), 16 deletions(-)

diff --git a/Documentation/thermal/sysfs-api.txt 
b/Documentation/thermal/sysfs-api.txt
index c3fa500..8d7f1b1 100644
--- a/Documentation/thermal/sysfs-api.txt
+++ b/Documentation/thermal/sysfs-api.txt
@@ -159,6 +159,14 @@ temperature) and throttle appropriate devices.
        for the thermal zone device, which might be useful for platform
        drivers for temperature calculations.
 
+1.1.9 int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
+               struct device_node *sensor_np,
+               u32 *id)
+
+       This interface is used to get the sensor id from thermal sensor's
+       phandle argument, it might be necessary for some platforms which
+       have specific sensor ID rather than virtual ID from 0 - N.
+
 1.2 thermal cooling device interface
 1.2.1 struct thermal_cooling_device *thermal_cooling_device_register(char 
*name,
                void *devdata, struct thermal_cooling_device_ops *)
diff --git a/drivers/thermal/of-thermal.c b/drivers/thermal/of-thermal.c
index dc5093b..a53792b 100644
--- a/drivers/thermal/of-thermal.c
+++ b/drivers/thermal/of-thermal.c
@@ -449,6 +449,54 @@ thermal_zone_of_add_sensor(struct device_node *zone,
 }
 
 /**
+ * thermal_zone_of_get_sensor_id - get sensor ID from a DT thermal zone
+ * @tz_np: a valid thermal zone device node.
+ * @sensor_np: a sensor node of a valid sensor device.
+ * @id: a sensor ID pointer will be passed back.
+ *
+ * This function will get sensor ID from a given thermal zone node, use
+ * "thermal-sensors" as list name, and get sensor ID from first phandle's
+ * argument.
+ *
+ * Return: 0 on success, proper error code otherwise.
+ */
+
+int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
+                                 struct device_node *sensor_np,
+                                 u32 *id)
+{
+       struct of_phandle_args sensor_specs;
+       int ret;
+
+       ret = of_parse_phandle_with_args(tz_np,
+                                        "thermal-sensors",
+                                        "#thermal-sensor-cells",
+                                        0,
+                                        &sensor_specs);
+       if (ret)
+               return ret;
+
+       if (sensor_specs.np != sensor_np) {
+               of_node_put(sensor_specs.np);
+               return -ENODEV;
+       }
+
+       if (sensor_specs.args_count >= 1) {
+               *id = sensor_specs.args[0];
+               WARN(sensor_specs.args_count > 1,
+                    "%pOFn: too many cells in sensor specifier %d\n",
+                    sensor_specs.np, sensor_specs.args_count);
+       } else {
+               *id = 0;
+       }
+
+       of_node_put(sensor_specs.np);
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(thermal_zone_of_get_sensor_id);
+
+/**
  * thermal_zone_of_sensor_register - registers a sensor to a DT thermal zone
  * @dev: a valid struct device pointer of a sensor device. Must contain
  *       a valid .of_node, for the sensor node.
@@ -499,36 +547,22 @@ thermal_zone_of_sensor_register(struct device *dev, int 
sensor_id, void *data,
        sensor_np = of_node_get(dev->of_node);
 
        for_each_available_child_of_node(np, child) {
-               struct of_phandle_args sensor_specs;
                int ret, id;
 
                /* For now, thermal framework supports only 1 sensor per zone */
-               ret = of_parse_phandle_with_args(child, "thermal-sensors",
-                                                "#thermal-sensor-cells",
-                                                0, &sensor_specs);
+               ret = thermal_zone_of_get_sensor_id(child, sensor_np, &id);
                if (ret)
                        continue;
 
-               if (sensor_specs.args_count >= 1) {
-                       id = sensor_specs.args[0];
-                       WARN(sensor_specs.args_count > 1,
-                            "%pOFn: too many cells in sensor specifier %d\n",
-                            sensor_specs.np, sensor_specs.args_count);
-               } else {
-                       id = 0;
-               }
-
-               if (sensor_specs.np == sensor_np && id == sensor_id) {
+               if (id == sensor_id) {
                        tzd = thermal_zone_of_add_sensor(child, sensor_np,
                                                         data, ops);
                        if (!IS_ERR(tzd))
                                tzd->ops->set_mode(tzd, THERMAL_DEVICE_ENABLED);
 
-                       of_node_put(sensor_specs.np);
                        of_node_put(child);
                        goto exit;
                }
-               of_node_put(sensor_specs.np);
        }
 exit:
        of_node_put(sensor_np);
diff --git a/include/linux/thermal.h b/include/linux/thermal.h
index 15a4ca5..5edffe6 100644
--- a/include/linux/thermal.h
+++ b/include/linux/thermal.h
@@ -375,6 +375,9 @@ struct thermal_trip {
 
 /* Function declarations */
 #ifdef CONFIG_THERMAL_OF
+int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
+                                 struct device_node *sensor_np,
+                                 u32 *id);
 struct thermal_zone_device *
 thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
                                const struct thermal_zone_of_device_ops *ops);
@@ -386,6 +389,13 @@ struct thermal_zone_device 
*devm_thermal_zone_of_sensor_register(
 void devm_thermal_zone_of_sensor_unregister(struct device *dev,
                                            struct thermal_zone_device *tz);
 #else
+
+static int thermal_zone_of_get_sensor_id(struct device_node *tz_np,
+                                        struct device_node *sensor_np,
+                                        u32 *id)
+{
+       return -ENOENT;
+}
 static inline struct thermal_zone_device *
 thermal_zone_of_sensor_register(struct device *dev, int id, void *data,
                                const struct thermal_zone_of_device_ops *ops)
-- 
2.7.4

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