drivers/hwmon: pwm-fan: support automatic and changing cooling levels via sysfs

drivers/hwmon/pwm-fan.c

@@ -8,6 +8,7 @@
  */
 
 #include <linux/hwmon.h>
+#include <linux/hwmon-sysfs.h>
 #include <linux/interrupt.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
@@ -59,6 +60,8 @@ struct pwm_fan_ctx {
 
 	struct hwmon_chip_info info;
 	struct hwmon_channel_info fan_channel;
+
+	bool automatic;
 };
 
 /* This handler assumes self resetting edge triggered interrupt. */
@@ -332,12 +335,12 @@ static int pwm_fan_read(struct device *dev, enum hwmon_sensor_types type,
 		case hwmon_pwm_enable:
 			*val = ctx->enable_mode;
 			return 0;
+	
 		}
 		return -EOPNOTSUPP;
 	case hwmon_fan:
 		*val = ctx->tachs[channel].rpm;
 		return 0;
-
 	default:
 		return -ENOTSUPP;
 	}
@@ -404,10 +407,12 @@ pwm_fan_set_cur_state(struct thermal_cooling_device *cdev, unsigned long state)
 	if (state == ctx->pwm_fan_state)
 		return 0;
 
-	ret = set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
-	if (ret) {
-		dev_err(&cdev->device, "Cannot set pwm!\n");
-		return ret;
+	if(ctx->automatic) {
+		ret = set_pwm(ctx, ctx->pwm_fan_cooling_levels[state]);
+		if (ret) {
+			dev_err(&cdev->device, "Cannot set pwm!\n");
+			return ret;
+		}
 	}
 
 	ctx->pwm_fan_state = state;
@@ -472,6 +477,121 @@ static void pwm_fan_cleanup(void *__ctx)
 	pwm_fan_power_off(ctx);
 }
 
+static ssize_t fan_speed_store(struct device *dev, struct device_attribute *attr,
+			     const char *buf, size_t count)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	unsigned int speed_0, speed_1, speed_2, speed_3;
+
+	if(sscanf(buf, "%u %u %u %u\n", &speed_0, &speed_1, &speed_2, &speed_3) != 4) {
+		dev_err(dev, "invalid speed input");
+		return  -EINVAL;
+	}
+
+	if(!(speed_0 < speed_1 && speed_1 < speed_2 && speed_2 < speed_3)){
+		dev_err(dev, "fan speeds must be increasing in value");
+		return count;
+	}
+
+	dev_info(dev, "fan_speeds : %s [%d %d %d %d] \n",
+			__func__, speed_0, speed_1, speed_2, speed_3);
+
+	mutex_lock(&ctx->lock);
+	ctx->pwm_fan_cooling_levels[0] = speed_0;
+	ctx->pwm_fan_cooling_levels[1] = speed_1;
+	ctx->pwm_fan_cooling_levels[2] = speed_2;
+	ctx->pwm_fan_cooling_levels[3] = speed_3;
+	mutex_unlock(&ctx->lock);
+
+	return count;
+}
+
+static ssize_t fan_speed_show(struct device *dev, struct device_attribute *attr,
+			      char *buf)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	int lenght = 0, i;
+
+	mutex_lock(&ctx->lock);
+	for (i = 0; i <= ctx->pwm_fan_max_state; i++)
+                lenght += sprintf(buf+lenght, "%u ", ctx->pwm_fan_cooling_levels[i]);
+	mutex_unlock(&ctx->lock);
+
+	return lenght;
+}
+
+static ssize_t automatic_show(struct device *dev,
+                                     struct device_attribute *attr, char *buf)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", ctx->automatic);}
+
+static ssize_t automatic_store(struct device *dev,
+                                     struct device_attribute *attr,
+                                     const char *buf, size_t count)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	bool automatic;
+	int ret;
+
+	if (kstrtobool(buf, &automatic))
+		return -EINVAL;
+
+	mutex_lock(&ctx->lock);
+	ctx->automatic = automatic;
+	mutex_unlock(&ctx->lock);
+
+	if (automatic) {
+		ret = __set_pwm(ctx, ctx->pwm_fan_cooling_levels[ctx->pwm_fan_state]);
+		if (ret)
+			return ret;
+	}
+
+	return count;
+}
+
+static ssize_t pwm_store(struct device *dev, struct device_attribute *attr,
+			 const char *buf, size_t count)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+	unsigned long pwm;
+	int ret;
+
+	if (kstrtoul(buf, 10, &pwm) || pwm > MAX_PWM)
+		return -EINVAL;
+
+	ret = __set_pwm(ctx, pwm);
+	if (ret)
+		return ret;
+
+	pwm_fan_update_state(ctx, pwm);
+	return count;
+}
+
+static ssize_t pwm_show(struct device *dev, struct device_attribute *attr,
+			char *buf)
+{
+	struct pwm_fan_ctx *ctx = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", ctx->pwm_value);
+}
+
+static DEVICE_ATTR(automatic, 0664, automatic_show, automatic_store);
+static DEVICE_ATTR(fan_speed, 0664, fan_speed_show, fan_speed_store);
+static DEVICE_ATTR(pwm1, 0664, pwm_show, pwm_store);
+
+static struct attribute *pwm_fan_attributes[] = {
+	&dev_attr_automatic.attr,
+	&dev_attr_fan_speed.attr,
+	&dev_attr_pwm1.attr,
+	NULL
+};
+
+static const struct attribute_group pwm_fan_attr_group = {
+	.attrs = pwm_fan_attributes,
+};
+
 static int pwm_fan_probe(struct platform_device *pdev)
 {
 	struct thermal_cooling_device *cdev;
@@ -527,6 +647,8 @@ static int pwm_fan_probe(struct platform_device *pdev)
 
 	ctx->enable_mode = pwm_disable_reg_enable;
 
+	ctx->automatic = true;
+
 	/*
 	 * Set duty cycle to maximum allowed and enable PWM output as well as
 	 * the regulator. In case of error nothing is changed
@@ -640,6 +762,12 @@ static int pwm_fan_probe(struct platform_device *pdev)
 		ctx->cdev = cdev;
 	}
 
+	/* add sysfs interface */
+	ret = sysfs_create_group(&dev->kobj, &pwm_fan_attr_group);
+	if(ret) {
+		dev_err(dev, "failed to register sysfs");
+	}
+
 	return 0;
 }