hwmon: (emc2305) Configure PWM channels based on DT properties

Add support for configuring each PWM channel using Device Tree (DT)
properties by parsing the 'pwms' phandle arguments.

Signed-off-by: Florin Leotescu <florin.leotescu@nxp.com>
Link: https://lore.kernel.org/r/20250603113125.3175103-3-florin.leotescu@oss.nxp.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>

Author: Florin Leotescu

drivers/hwmon/emc2305.c

@@ -11,6 +11,9 @@
 #include <linux/module.h>
 #include <linux/platform_data/emc2305.h>
 #include <linux/thermal.h>
+#include <linux/pwm.h>
+#include <linux/of_device.h>
+#include <linux/util_macros.h>
 
 #define EMC2305_REG_DRIVE_FAIL_STATUS	0x27
 #define EMC2305_REG_VENDOR		0xfe
@@ -23,6 +26,8 @@
 #define EMC2305_TACH_REGS_UNUSE_BITS	3
 #define EMC2305_TACH_CNT_MULTIPLIER	0x02
 #define EMC2305_TACH_RANGE_MIN		480
+#define EMC2305_DEFAULT_OUTPUT		0x0
+#define EMC2305_DEFAULT_POLARITY	0x0
 
 #define EMC2305_PWM_DUTY2STATE(duty, max_state, pwm_max) \
 	DIV_ROUND_CLOSEST((duty) * (max_state), (pwm_max))
@@ -39,6 +44,9 @@
 #define EMC2305_REG_FAN_MIN_DRIVE(n)	(0x38 + 0x10 * (n))
 #define EMC2305_REG_FAN_TACH(n)		(0x3e + 0x10 * (n))
 
+/* Supported base PWM frequencies */
+static const unsigned int base_freq_table[] = { 2441, 4882, 19530, 26000 };
+
 enum emc230x_product_id {
 	EMC2305 = 0x34,
 	EMC2303 = 0x35,
@@ -287,7 +295,7 @@ static int emc2305_set_pwm(struct device *dev, long val, int channel)
 	return 0;
 }
 
-static int emc2305_set_single_tz(struct device *dev, int idx)
+static int emc2305_set_single_tz(struct device *dev, struct device_node *fan_node, int idx)
 {
 	struct emc2305_data *data = dev_get_drvdata(dev);
 	long pwm;
@@ -297,7 +305,7 @@ static int emc2305_set_single_tz(struct device *dev, int idx)
 	pwm = data->pwm_min[cdev_idx];
 
 	data->cdev_data[cdev_idx].cdev =
-		devm_thermal_of_cooling_device_register(dev, dev->of_node,
+		devm_thermal_of_cooling_device_register(dev, fan_node,
 							emc2305_fan_name[idx], data,
 							&emc2305_cooling_ops);
 
@@ -332,10 +340,10 @@ static int emc2305_set_tz(struct device *dev)
 	int i, ret;
 
 	if (!data->pwm_separate)
-		return emc2305_set_single_tz(dev, 0);
+		return emc2305_set_single_tz(dev, dev->of_node, 0);
 
 	for (i = 0; i < data->pwm_num; i++) {
-		ret = emc2305_set_single_tz(dev, i + 1);
+		ret = emc2305_set_single_tz(dev, dev->of_node, i + 1);
 		if (ret)
 			return ret;
 	}
@@ -517,15 +525,85 @@ static int emc2305_identify(struct device *dev)
 	return 0;
 }
 
+static int emc2305_of_parse_pwm_child(struct device *dev,
+				      struct device_node *child,
+				      struct emc2305_data *data)
+{	u32 ch;
+	int ret;
+	struct of_phandle_args args;
+
+	ret = of_property_read_u32(child, "reg", &ch);
+	if (ret) {
+		dev_err(dev, "missing reg property of %pOFn\n", child);
+		return ret;
+	}
+
+	ret = of_parse_phandle_with_args(child, "pwms", "#pwm-cells", 0, &args);
+
+	if (ret)
+		return ret;
+
+	if (args.args_count > 0) {
+		data->pwm_freq[ch] = find_closest(args.args[0], base_freq_table,
+						  ARRAY_SIZE(base_freq_table));
+	} else {
+		data->pwm_freq[ch] = base_freq_table[3];
+	}
+
+	if (args.args_count > 1) {
+		if (args.args[1] == PWM_POLARITY_NORMAL || args.args[1] == PWM_POLARITY_INVERSED)
+			data->pwm_polarity_mask |= args.args[1] << ch;
+		else
+			dev_err(dev, "Wrong PWM polarity config provided: %d\n", args.args[0]);
+	} else {
+		data->pwm_polarity_mask |= PWM_POLARITY_NORMAL << ch;
+	}
+
+	if (args.args_count > 2) {
+		if (args.args[2] == EMC2305_PUSH_PULL || args.args[2] <= EMC2305_OPEN_DRAIN)
+			data->pwm_output_mask |= args.args[2] << ch;
+		else
+			dev_err(dev, "Wrong PWM output config provided: %d\n", args.args[1]);
+	} else {
+		data->pwm_output_mask |= EMC2305_OPEN_DRAIN << ch;
+	}
+
+	return 0;
+}
+
+static int emc2305_probe_childs_from_dt(struct device *dev)
+{
+	struct emc2305_data *data = dev_get_drvdata(dev);
+	struct device_node *child;
+	int ret, count = 0;
+
+	data->pwm_output_mask = 0x0;
+	data->pwm_polarity_mask = 0x0;
+
+	for_each_child_of_node(dev->of_node, child) {
+		if (of_property_present(child, "reg")) {
+			ret = emc2305_of_parse_pwm_child(dev, child, data);
+			if (ret) {
+				of_node_put(child);
+				continue;
+			}
+			count++;
+		}
+	}
+	return count;
+}
+
 static int emc2305_probe(struct i2c_client *client)
 {
 	struct i2c_adapter *adapter = client->adapter;
 	struct device *dev = &client->dev;
+	struct device_node *child;
 	struct emc2305_data *data;
 	struct emc2305_platform_data *pdata;
 	int vendor;
 	int ret;
 	int i;
+	int pwm_childs;
 
 	if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_BYTE_DATA | I2C_FUNC_SMBUS_WORD_DATA))
 		return -ENODEV;
@@ -545,22 +623,40 @@ static int emc2305_probe(struct i2c_client *client)
 	if (ret)
 		return ret;
 
+	pwm_childs = emc2305_probe_childs_from_dt(dev);
+
 	pdata = dev_get_platdata(&client->dev);
-	if (pdata) {
-		if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE)
-			return -EINVAL;
-		data->max_state = pdata->max_state;
-		/*
-		 * Validate a number of active PWM channels. Note that
-		 * configured number can be less than the actual maximum
-		 * supported by the device.
-		 */
-		if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX)
-			return -EINVAL;
-		data->pwm_num = pdata->pwm_num;
-		data->pwm_separate = pdata->pwm_separate;
-		for (i = 0; i < EMC2305_PWM_MAX; i++)
-			data->pwm_min[i] = pdata->pwm_min[i];
+
+	if (!pwm_childs) {
+		if (pdata) {
+			if (!pdata->max_state || pdata->max_state > EMC2305_FAN_MAX_STATE)
+				return -EINVAL;
+			data->max_state = pdata->max_state;
+			/*
+			 * Validate a number of active PWM channels. Note that
+			 * configured number can be less than the actual maximum
+			 * supported by the device.
+			 */
+			if (!pdata->pwm_num || pdata->pwm_num > EMC2305_PWM_MAX)
+				return -EINVAL;
+			data->pwm_num = pdata->pwm_num;
+			data->pwm_output_mask = pdata->pwm_output_mask;
+			data->pwm_polarity_mask = pdata->pwm_polarity_mask;
+			data->pwm_separate = pdata->pwm_separate;
+			for (i = 0; i < EMC2305_PWM_MAX; i++) {
+				data->pwm_min[i] = pdata->pwm_min[i];
+				data->pwm_freq[i] = pdata->pwm_freq[i];
+			}
+		} else {
+			data->max_state = EMC2305_FAN_MAX_STATE;
+			data->pwm_separate = false;
+			data->pwm_output_mask = EMC2305_DEFAULT_OUTPUT;
+			data->pwm_polarity_mask = EMC2305_DEFAULT_POLARITY;
+			for (i = 0; i < EMC2305_PWM_MAX; i++) {
+				data->pwm_min[i] = EMC2305_FAN_MIN;
+				data->pwm_freq[i] = base_freq_table[3];
+			}
+		}
 	} else {
 		data->max_state = EMC2305_FAN_MAX_STATE;
 		data->pwm_separate = false;
@@ -574,9 +670,20 @@ static int emc2305_probe(struct i2c_client *client)
 		return PTR_ERR(data->hwmon_dev);
 
 	if (IS_REACHABLE(CONFIG_THERMAL)) {
-		ret = emc2305_set_tz(dev);
-		if (ret != 0)
-			return ret;
+		/* Parse and check for the available PWM child nodes */
+		if (pwm_childs > 0) {
+			i = 0;
+			for_each_child_of_node(dev->of_node, child) {
+				ret = emc2305_set_single_tz(dev, child, i);
+				if (ret != 0)
+					return ret;
+				i++;
+			}
+		} else {
+			ret = emc2305_set_tz(dev);
+			if (ret != 0)
+				return ret;
+		}
 	}
 
 	for (i = 0; i < data->pwm_num; i++) {