hwmon/w83793: Hide invalid VID readings

Ignore the VID readings when the motherboard has not designed
the function.  

Signed-off-by: Gong Jun <jgong@winbond.com>
Signed-off-by: Rudolf Marek <r.marek@assembler.cz>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

1 files changed, 30 insertions, 3 deletions

diff --git a/drivers/hwmon/w83793.c b/drivers/hwmon/w83793.c
index 7cadef8cd87d..253ffaf1568a 100644
--- a/drivers/hwmon/w83793.c
+++ b/drivers/hwmon/w83793.c
@@ -205,6 +205,7 @@ struct w83793_data {
 
         u8 has_pwm;
         u8 has_temp;
+        u8 has_vid;
         u8 pwm_enable;          /* Register value, each Temp has 1 bit */
         u8 pwm_uptime;          /* Register value */
         u8 pwm_downtime;        /* Register value */
@@ -1025,9 +1026,12 @@ static struct sensor_device_attribute_2 w83793_left_pwm[] = {
         SENSOR_ATTR_PWM(8),
 };
 
-static struct sensor_device_attribute_2 sda_single_files[] = {
+static struct sensor_device_attribute_2 w83793_vid[] = {
         SENSOR_ATTR_2(cpu0_vid, S_IRUGO, show_vid, NULL, NOT_USED, 0),
         SENSOR_ATTR_2(cpu1_vid, S_IRUGO, show_vid, NULL, NOT_USED, 1),
+};
+
+static struct sensor_device_attribute_2 sda_single_files[] = {
         SENSOR_ATTR_2(vrm, S_IWUSR | S_IRUGO, show_vrm, store_vrm,
                       NOT_USED, NOT_USED),
         SENSOR_ATTR_2(chassis, S_IWUSR | S_IRUGO, show_alarm_beep,
@@ -1080,6 +1084,9 @@ static int w83793_detach_client(struct i2c_client *client)
                 for (i = 0; i < ARRAY_SIZE(sda_single_files); i++)
                         device_remove_file(dev, &sda_single_files[i].dev_attr);
 
+                for (i = 0; i < ARRAY_SIZE(w83793_vid); i++)
+                        device_remove_file(dev, &w83793_vid[i].dev_attr);
+
                 for (i = 0; i < ARRAY_SIZE(w83793_left_fan); i++)
                         device_remove_file(dev, &w83793_left_fan[i].dev_attr);
 
@@ -1358,6 +1365,13 @@ static int w83793_detect(struct i2c_adapter *adapter, int address, int kind)
         if (tmp & 0x02)
                 data->has_temp |= 0x20;
 
+        /* Detect the VID usage and ignore unused input */
+        tmp = w83793_read_value(client, W83793_REG_MFC);
+        if (!(tmp & 0x29))
+                data->has_vid |= 0x1;   /* has VIDA */
+        if (tmp & 0x80)
+                data->has_vid |= 0x2;   /* has VIDB */
+
         /* Register sysfs hooks */
         for (i = 0; i < ARRAY_SIZE(w83793_sensor_attr_2); i++) {
                 err = device_create_file(dev,
@@ -1366,6 +1380,14 @@ static int w83793_detect(struct i2c_adapter *adapter, int address, int kind)
                         goto exit_remove;
         }
 
+        for (i = 0; i < ARRAY_SIZE(w83793_vid); i++) {
+                if (!(data->has_vid & (1 << i)))
+                        continue;
+                err = device_create_file(dev, &w83793_vid[i].dev_attr);
+                if (err)
+                        goto exit_remove;
+        }
+
         for (i = 0; i < ARRAY_SIZE(sda_single_files); i++) {
                 err = device_create_file(dev, &sda_single_files[i].dev_attr);
                 if (err)
@@ -1429,6 +1451,9 @@ exit_remove:
         for (i = 0; i < ARRAY_SIZE(sda_single_files); i++)
                 device_remove_file(dev, &sda_single_files[i].dev_attr);
 
+        for (i = 0; i < ARRAY_SIZE(w83793_vid); i++)
+                device_remove_file(dev, &w83793_vid[i].dev_attr);
+
         for (i = 0; i < ARRAY_SIZE(w83793_left_fan); i++)
                 device_remove_file(dev, &w83793_left_fan[i].dev_attr);
 
@@ -1593,8 +1618,10 @@ static struct w83793_data *w83793_update_device(struct device *dev)
         for (i = 0; i < ARRAY_SIZE(data->alarms); i++)
                 data->alarms[i] =
                     w83793_read_value(client, W83793_REG_ALARM(i));
-        data->vid[0] = w83793_read_value(client, W83793_REG_VID_INA);
-        data->vid[1] = w83793_read_value(client, W83793_REG_VID_INB);
+        if (data->has_vid & 0x01)
+                data->vid[0] = w83793_read_value(client, W83793_REG_VID_INA);
+        if (data->has_vid & 0x02)
+                data->vid[1] = w83793_read_value(client, W83793_REG_VID_INB);
         w83793_update_nonvolatile(dev);
         data->last_updated = jiffies;
         data->valid = 1;