[PATCH v2] hwmon: (tc654) Add thermal_cooling device support

[Christian Lamparter <chunkeey@xxxxxxxxx>]

Adds thermal_cooling device support to the tc654/tc655
driver. This make it possible to integrate it into a
device-tree supported thermal-zone node as a
cooling device.

I have been using this patch as part of the Netgear WNDR4700
Centria NAS Router support within OpenWrt since 2016.

Signed-off-by: Christian Lamparter <chunkeey@xxxxxxxxx>
---
v1 -> v2: - Drop imply THERMAL
	  - aligned ( so . everything is lining up
---
 drivers/hwmon/tc654.c | 94 +++++++++++++++++++++++++++++++++++--------
 1 file changed, 77 insertions(+), 17 deletions(-)

diff --git a/drivers/hwmon/tc654.c b/drivers/hwmon/tc654.c
index cf2a3acd5c91..c8f511a60769 100644
--- a/drivers/hwmon/tc654.c
+++ b/drivers/hwmon/tc654.c
@@ -15,6 +15,7 @@
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
+#include <linux/thermal.h>
 #include <linux/util_macros.h>
 
 enum tc654_regs {
@@ -367,36 +368,30 @@ static ssize_t pwm_mode_store(struct device *dev, struct device_attribute *da,
 static const int tc654_pwm_map[16] = { 77,  88, 102, 112, 124, 136, 148, 160,
 				      172, 184, 196, 207, 219, 231, 243, 255};
 
+static int get_pwm(struct tc654_data *data)
+{
+	if (data->config & TC654_REG_CONFIG_SDM)
+		return 0;
+	else
+		return tc654_pwm_map[data->duty_cycle];
+}
+
 static ssize_t pwm_show(struct device *dev, struct device_attribute *da,
 			char *buf)
 {
 	struct tc654_data *data = tc654_update_client(dev);
-	int pwm;
 
 	if (IS_ERR(data))
 		return PTR_ERR(data);
 
-	if (data->config & TC654_REG_CONFIG_SDM)
-		pwm = 0;
-	else
-		pwm = tc654_pwm_map[data->duty_cycle];
-
-	return sprintf(buf, "%d\n", pwm);
+	return sprintf(buf, "%d\n", get_pwm(data));
 }
 
-static ssize_t pwm_store(struct device *dev, struct device_attribute *da,
-			 const char *buf, size_t count)
+static int _set_pwm(struct tc654_data *data, unsigned long val)
 {
-	struct tc654_data *data = dev_get_drvdata(dev);
 	struct i2c_client *client = data->client;
-	unsigned long val;
 	int ret;
 
-	if (kstrtoul(buf, 10, &val))
-		return -EINVAL;
-	if (val > 255)
-		return -EINVAL;
-
 	mutex_lock(&data->update_lock);
 
 	if (val == 0)
@@ -416,6 +411,22 @@ static ssize_t pwm_store(struct device *dev, struct device_attribute *da,
 
 out:
 	mutex_unlock(&data->update_lock);
+	return ret;
+}
+
+static ssize_t pwm_store(struct device *dev, struct device_attribute *da,
+			 const char *buf, size_t count)
+{
+	struct tc654_data *data = dev_get_drvdata(dev);
+	unsigned long val;
+	int ret;
+
+	if (kstrtoul(buf, 10, &val))
+		return -EINVAL;
+	if (val > 255)
+		return -EINVAL;
+
+	ret = _set_pwm(data, val);
 	return ret < 0 ? ret : count;
 }
 
@@ -447,6 +458,44 @@ static struct attribute *tc654_attrs[] = {
 
 ATTRIBUTE_GROUPS(tc654);
 
+/* cooling device */
+
+static int tc654_get_max_state(struct thermal_cooling_device *cdev,
+			       unsigned long *state)
+{
+	*state = 255;
+	return 0;
+}
+
+static int tc654_get_cur_state(struct thermal_cooling_device *cdev,
+			       unsigned long *state)
+{
+	struct tc654_data *data = tc654_update_client(cdev->devdata);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	*state = get_pwm(data);
+	return 0;
+}
+
+static int tc654_set_cur_state(struct thermal_cooling_device *cdev,
+			       unsigned long state)
+{
+	struct tc654_data *data = tc654_update_client(cdev->devdata);
+
+	if (IS_ERR(data))
+		return PTR_ERR(data);
+
+	return _set_pwm(data, clamp_val(state, 0, 255));
+}
+
+static const struct thermal_cooling_device_ops tc654_fan_cool_ops = {
+	.get_max_state = tc654_get_max_state,
+	.get_cur_state = tc654_get_cur_state,
+	.set_cur_state = tc654_set_cur_state,
+};
+
 /*
  * device probe and removal
  */
@@ -477,7 +526,18 @@ static int tc654_probe(struct i2c_client *client)
 	hwmon_dev =
 	    devm_hwmon_device_register_with_groups(dev, client->name, data,
 						   tc654_groups);
-	return PTR_ERR_OR_ZERO(hwmon_dev);
+	if (IS_ERR(hwmon_dev))
+		return PTR_ERR(hwmon_dev);
+
+	if (IS_ENABLED(CONFIG_THERMAL)) {
+		struct thermal_cooling_device *cdev;
+
+		cdev = devm_thermal_of_cooling_device_register(dev, dev->of_node, client->name,
+							       hwmon_dev, &tc654_fan_cool_ops);
+		return PTR_ERR_OR_ZERO(cdev);
+	}
+
+	return 0;
 }
 
 static const struct i2c_device_id tc654_id[] = {
-- 
2.34.1