[PATCH v2] hwmon: (cros_ec) register thermal sensors to thermal framework

[Sung-Chi <lschyi@chromium.org>]

From: "Sung-Chi, Li" <lschyi@chromium.org>

cros_ec hwmon driver probes available thermal sensors when probing the
driver.  Register these thermal sensors to the thermal framework, such
that thermal framework can adopt these sensors as well.

To make cros_ec registrable to thermal framework, the cros_ec dts need
the corresponding changes:

&cros_ec {
	#thermal-sensor-cells = <1>;
};

Change-Id: I29b638427c715cb44391496881fc61ad53abccaf
Signed-off-by: Sung-Chi, Li <lschyi@chromium.org>
---
 Changes in v2:
   - Rename `cros_ec_sensor_data` to `cros_ec_hwmon_thermal_zone_data`.
   - Rename `addr` in struct `cros_ec_hwmon_thermal_zone_data` to `idx`.
   - Use `cros_ec_hwmon_temp_to_millicelsius` to do value conversion in 
     `cros_ec_thermal_get_temp` function.
   - Rename `cros_ec_thermal_get_temp` to `cros_ec_hwmon_thermal_get_temp` to
     make `cros_ec_hwmon` a prefix.
   - Use `%pe` in `cros_ec_hwmon_probe_temp_sensors` when printing out
     `data->tz_dev` if failed register thermal device.
   - Remove `cros_ec_hwmon_remove`, and the `.remove` value in
     `cros_ec_hwmon_driver` since there is no need to call
     `devm_thermal_of_zone_unregister` for clean up.
   - Revert function signature of `cros_ec_hwmon_probe_temp_sensors` since all
     needed parameters are presented.
   - Revert include of `linux/list.h` because no list data structure is used.
---
 drivers/hwmon/cros_ec_hwmon.c | 41 +++++++++++++++++++++++++++++++++++
 1 file changed, 41 insertions(+)

diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
index 5514cf780b8b..81e563e0455f 100644
--- a/drivers/hwmon/cros_ec_hwmon.c
+++ b/drivers/hwmon/cros_ec_hwmon.c
@@ -12,6 +12,7 @@
 #include <linux/platform_device.h>
 #include <linux/platform_data/cros_ec_commands.h>
 #include <linux/platform_data/cros_ec_proto.h>
+#include <linux/thermal.h>
 #include <linux/types.h>
 #include <linux/units.h>
 
@@ -23,6 +24,12 @@ struct cros_ec_hwmon_priv {
 	u8 usable_fans;
 };
 
+struct cros_ec_hwmon_thermal_zone_data {
+	struct cros_ec_device *cros_ec;
+	struct thermal_zone_device *tz_dev;
+	int idx;
+};
+
 static int cros_ec_hwmon_read_fan_speed(struct cros_ec_device *cros_ec, u8 index, u16 *speed)
 {
 	int ret;
@@ -185,11 +192,30 @@ static const struct hwmon_chip_info cros_ec_hwmon_chip_info = {
 	.info = cros_ec_hwmon_info,
 };
 
+static int cros_ec_hwmon_thermal_get_temp(struct thermal_zone_device *tz, int *temp)
+{
+	struct cros_ec_hwmon_thermal_zone_data *data =
+		thermal_zone_device_priv(tz);
+	int ret;
+	u8 val;
+
+	ret = cros_ec_hwmon_read_temp(data->cros_ec, data->idx, &val);
+	if (ret || cros_ec_hwmon_is_error_temp(temp))
+		return -ENODATA;
+	*temp = cros_ec_hwmon_temp_to_millicelsius(val);
+	return 0;
+}
+
+static const struct thermal_zone_device_ops thermal_ops = {
+	.get_temp = cros_ec_hwmon_thermal_get_temp,
+};
+
 static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_hwmon_priv *priv,
 					     u8 thermal_version)
 {
 	struct ec_params_temp_sensor_get_info req = {};
 	struct ec_response_temp_sensor_get_info resp;
+	struct cros_ec_hwmon_thermal_zone_data *data;
 	size_t candidates, i, sensor_name_size;
 	int ret;
 	u8 temp;
@@ -216,6 +242,21 @@ static void cros_ec_hwmon_probe_temp_sensors(struct device *dev, struct cros_ec_
 		priv->temp_sensor_names[i] = devm_kasprintf(dev, GFP_KERNEL, "%.*s",
 							    (int)sensor_name_size,
 							    resp.sensor_name);
+
+		data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
+		if (!data)
+			continue;
+
+		data->idx = i;
+		data->cros_ec = priv->cros_ec;
+		data->tz_dev = devm_thermal_of_zone_register(
+			priv->cros_ec->dev, i, data, &thermal_ops);
+		if (IS_ERR_VALUE(data->tz_dev)) {
+			dev_err(dev,
+				"failed to register %zu thermal sensor, err = %pe",
+				i, data->tz_dev);
+			continue;
+		}
 	}
 }
 
-- 
2.47.0.277.g8800431eea-goog