/* individual register bits */
 #define FAN_CTRL_SKIP                  0x80
+#define FAN_CTRL_DC_MODE               0x10
 #define FAN_CTRL_MODE_MASK             0x03
 #define FAN_CTRL_MODE_SPEED            0x00
 #define FAN_CTRL_MODE_TEMPERATURE      0x01
                return 1000000UL / (val << 8);
 }
 
+static inline int pwm_mode_from_reg(u8 reg)
+{
+       return !(reg & FAN_CTRL_DC_MODE);
+}
+
 static inline long temp_from_reg(u8 reg)
 {
        return (reg * 1000);
        return sprintf(buf, "%lu\n", pwm_freq_from_reg(data->pwm_freq[nr]));
 }
 
+static ssize_t show_pwm_mode(struct device *dev, struct device_attribute
+                            *devattr, char *buf)
+{
+       struct f71805f_data *data = f71805f_update_device(dev);
+       struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
+       int nr = attr->index;
+
+       return sprintf(buf, "%d\n", pwm_mode_from_reg(data->fan_ctrl[nr]));
+}
+
 static ssize_t set_pwm(struct device *dev, struct device_attribute *devattr,
                       const char *buf, size_t count)
 {
                          show_pwm_enable, set_pwm_enable, 0);
 static SENSOR_DEVICE_ATTR(pwm1_freq, S_IRUGO | S_IWUSR,
                          show_pwm_freq, set_pwm_freq, 0);
+static SENSOR_DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL, 0);
 static SENSOR_DEVICE_ATTR(pwm2, S_IRUGO, show_pwm, set_pwm, 1);
 static SENSOR_DEVICE_ATTR(pwm2_enable, S_IRUGO | S_IWUSR,
                          show_pwm_enable, set_pwm_enable, 1);
 static SENSOR_DEVICE_ATTR(pwm2_freq, S_IRUGO | S_IWUSR,
                          show_pwm_freq, set_pwm_freq, 1);
+static SENSOR_DEVICE_ATTR(pwm2_mode, S_IRUGO, show_pwm_mode, NULL, 1);
 static SENSOR_DEVICE_ATTR(pwm3, S_IRUGO, show_pwm, set_pwm, 2);
 static SENSOR_DEVICE_ATTR(pwm3_enable, S_IRUGO | S_IWUSR,
                          show_pwm_enable, set_pwm_enable, 2);
 static SENSOR_DEVICE_ATTR(pwm3_freq, S_IRUGO | S_IWUSR,
                          show_pwm_freq, set_pwm_freq, 2);
+static SENSOR_DEVICE_ATTR(pwm3_mode, S_IRUGO, show_pwm_mode, NULL, 2);
 
 static SENSOR_DEVICE_ATTR(in0_alarm, S_IRUGO, show_alarm, NULL, 0);
 static SENSOR_DEVICE_ATTR(in1_alarm, S_IRUGO, show_alarm, NULL, 1);
                &sensor_dev_attr_fan1_alarm.dev_attr.attr,
                &sensor_dev_attr_pwm1.dev_attr.attr,
                &sensor_dev_attr_pwm1_enable.dev_attr.attr,
-               &sensor_dev_attr_pwm1_freq.dev_attr.attr,
+               &sensor_dev_attr_pwm1_mode.dev_attr.attr,
                NULL
        }, {
                &sensor_dev_attr_fan2_input.dev_attr.attr,
                &sensor_dev_attr_fan2_alarm.dev_attr.attr,
                &sensor_dev_attr_pwm2.dev_attr.attr,
                &sensor_dev_attr_pwm2_enable.dev_attr.attr,
-               &sensor_dev_attr_pwm2_freq.dev_attr.attr,
+               &sensor_dev_attr_pwm2_mode.dev_attr.attr,
                NULL
        }, {
                &sensor_dev_attr_fan3_input.dev_attr.attr,
                &sensor_dev_attr_fan3_alarm.dev_attr.attr,
                &sensor_dev_attr_pwm3.dev_attr.attr,
                &sensor_dev_attr_pwm3_enable.dev_attr.attr,
-               &sensor_dev_attr_pwm3_freq.dev_attr.attr,
+               &sensor_dev_attr_pwm3_mode.dev_attr.attr,
                NULL
        }
 };
        { .attrs = f71805f_attributes_fan[2] },
 };
 
+/* We don't include pwm_freq files in the arrays above, because they must be
+   created conditionally (only if pwm_mode is 1 == PWM) */
+static struct attribute *f71805f_attributes_pwm_freq[] = {
+       &sensor_dev_attr_pwm1_freq.dev_attr.attr,
+       &sensor_dev_attr_pwm2_freq.dev_attr.attr,
+       &sensor_dev_attr_pwm3_freq.dev_attr.attr,
+       NULL
+};
+
+static const struct attribute_group f71805f_group_pwm_freq = {
+       .attrs = f71805f_attributes_pwm_freq,
+};
+
 /* We also need an indexed access to pwmN files to toggle writability */
 static struct attribute *f71805f_attr_pwm[] = {
        &sensor_dev_attr_pwm1.dev_attr.attr,
                if ((err = sysfs_create_group(&pdev->dev.kobj,
                                              &f71805f_group_fan[i])))
                        goto exit_remove_files;
+               /* If control mode is PWM, create pwm_freq file */
+               if (!(data->fan_ctrl[i] & FAN_CTRL_DC_MODE)) {
+                       if ((err = sysfs_create_file(&pdev->dev.kobj,
+                                       f71805f_attributes_pwm_freq[i])))
+                               goto exit_remove_files;
+               }
                /* If PWM is in manual mode, add write permission */
                if (data->fan_ctrl[i] & FAN_CTRL_MODE_MANUAL) {
                        if ((err = sysfs_chmod_file(&pdev->dev.kobj,
        sysfs_remove_group(&pdev->dev.kobj, &f71805f_group);
        for (i = 0; i < 3; i++)
                sysfs_remove_group(&pdev->dev.kobj, &f71805f_group_fan[i]);
+       sysfs_remove_group(&pdev->dev.kobj, &f71805f_group_pwm_freq);
 exit_free:
        platform_set_drvdata(pdev, NULL);
        kfree(data);
        sysfs_remove_group(&pdev->dev.kobj, &f71805f_group);
        for (i = 0; i < 3; i++)
                sysfs_remove_group(&pdev->dev.kobj, &f71805f_group_fan[i]);
+       sysfs_remove_group(&pdev->dev.kobj, &f71805f_group_pwm_freq);
        kfree(data);
 
        return 0;