hwmon: (w83627ehf) Permit enabling SmartFan IV mode if configured at startup

If SmartFan IV mode was configured at startup, it should be possible
to re-enable it later on.

Signed-off-by: Guenter Roeck <guenter.roeck@ericsson.com>
Acked-by: Ian Dobson <i.dobson@planet-ian.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/hwmon/w83627ehf.c b/drivers/hwmon/w83627ehf.c
index 2420f1c6f4e9..2f17f99e0ae1 100644
--- a/drivers/hwmon/w83627ehf.c
+++ b/drivers/hwmon/w83627ehf.c
@@ -346,7 +346,10 @@ struct w83627ehf_data {
                              2->thermal cruise mode (also called SmartFan I)
                              3->fan speed cruise mode
                              4->variable thermal cruise (also called
-                                SmartFan III) */
+                                SmartFan III)
+                             5->enhanced variable thermal cruise (also called
+                                SmartFan IV) */
+        u8 pwm_enable_orig[4];  /* original value of pwm_enable */
         u8 pwm_num;             /* number of pwm */
         u8 pwm[4];
         u8 target_temp[4];
@@ -1055,7 +1058,7 @@ store_pwm_enable(struct device *dev, struct device_attribute *attr,
         if (err < 0)
                 return err;
 
-        if (!val || (val > 4))
+        if (!val || (val > 4 && val != data->pwm_enable_orig[nr]))
                 return -EINVAL;
         mutex_lock(&data->update_lock);
         reg = w83627ehf_read_value(data, W83627EHF_REG_PWM_ENABLE[nr]);
@@ -1617,6 +1620,11 @@ static int __devinit w83627ehf_probe(struct platform_device *pdev)
         /* Read fan clock dividers immediately */
         w83627ehf_update_fan_div(data);
 
+        /* Read pwm data to save original values */
+        w83627ehf_update_pwm_common(dev, data);
+        for (i = 0; i < data->pwm_num; i++)
+                data->pwm_enable_orig[i] = data->pwm_enable[i];
+
         /* Register sysfs hooks */
         for (i = 0; i < ARRAY_SIZE(sda_sf3_arrays); i++) {
                 err = device_create_file(dev, &sda_sf3_arrays[i].dev_attr);