hwmon: (w83791d) Use fan divisor bits from vbat register

Update w83791d with fan bits in vbat mon register (7.48 of the
datasheet). This change allows all fans to have a divisor of 128,
and fixes a problem with incorrectly reported fan speeds.

Signed-off-by: Marc Hulsman <m.hulsman@tudelft.nl>
Signed-off-by: Jean Delvare <khali@linux-fr.org>

diff --git a/Documentation/hwmon/w83791d b/Documentation/hwmon/w83791d
index f153b2f6d62ca76958c2e80eb42efc3aa4c830be..a67d3b7a709831bb0f32f70ab30c1695693a2606 100644 (file)
--- a/Documentation/hwmon/w83791d
+++ b/Documentation/hwmon/w83791d
@@ -22,6 +22,7 @@ Credits:
 
 Additional contributors:
     Sven Anders <anders@anduras.de>
+    Marc Hulsman <m.hulsman@tudelft.nl>
 
 Module Parameters
 -----------------
@@ -67,9 +68,8 @@ on until the temperature falls below the Hysteresis value.
 
 Fan rotation speeds are reported in RPM (rotations per minute). An alarm is
 triggered if the rotation speed has dropped below a programmable limit. Fan
-readings can be divided by a programmable divider (1, 2, 4, 8 for fan 1/2/3
-and 1, 2, 4, 8, 16, 32, 64 or 128 for fan 4/5) to give the readings more
-range or accuracy.
+readings can be divided by a programmable divider (1, 2, 4, 8, 16,
+32, 64 or 128 for all fans) to give the readings more range or accuracy.
 
 Voltage sensors (also known as IN sensors) report their values in millivolts.
 An alarm is triggered if the voltage has crossed a programmable minimum

diff --git a/drivers/hwmon/w83791d.c b/drivers/hwmon/w83791d.c
index e4e91c9d480a5dd8b1965ff4e6a3c789ef00887d..daa7d121483bdd042c4396ec62e903e6a9b46cb8 100644 (file)
--- a/drivers/hwmon/w83791d.c
+++ b/drivers/hwmon/w83791d.c
@@ -233,11 +233,9 @@ static u8 fan_to_reg(long rpm, int div)
 static u8 div_to_reg(int nr, long val)
 {
        int i;
-       int max;
 
-       /* first three fan's divisor max out at 8, rest max out at 128 */
-       max = (nr < 3) ? 8 : 128;
-       val = SENSORS_LIMIT(val, 1, max) >> 1;
+       /* fan divisors max out at 128 */
+       val = SENSORS_LIMIT(val, 1, 128) >> 1;
        for (i = 0; i < 7; i++) {
                if (val == 0)
                        break;
@@ -530,6 +528,7 @@ static ssize_t store_fan_div(struct device *dev, struct device_attribute *attr,
        unsigned long min;
        u8 tmp_fan_div;
        u8 fan_div_reg;
+       u8 vbat_reg;
        int indx = 0;
        u8 keep_mask = 0;
        u8 new_shift = 0;
@@ -581,6 +580,16 @@ static ssize_t store_fan_div(struct device *dev, struct device_attribute *attr,
        w83791d_write(client, W83791D_REG_FAN_DIV[indx],
                                fan_div_reg | tmp_fan_div);
 
+       /* Bit 2 of fans 0-2 is stored in the vbat register (bits 5-7) */
+       if (nr < 3) {
+               keep_mask = ~(1 << (nr + 5));
+               vbat_reg = w83791d_read(client, W83791D_REG_VBAT)
+                               & keep_mask;
+               tmp_fan_div = (data->fan_div[nr] << (3 + nr)) & ~keep_mask;
+               w83791d_write(client, W83791D_REG_VBAT,
+                               vbat_reg | tmp_fan_div);
+       }
+
        /* Restore fan_min */
        data->fan_min[nr] = fan_to_reg(min, DIV_FROM_REG(data->fan_div[nr]));
        w83791d_write(client, W83791D_REG_FAN_MIN[nr], data->fan_min[nr]);
@@ -1182,6 +1191,7 @@ static struct w83791d_data *w83791d_update_device(struct device *dev)
        struct w83791d_data *data = i2c_get_clientdata(client);
        int i, j;
        u8 reg_array_tmp[3];
+       u8 vbat_reg;
 
        mutex_lock(&data->update_lock);
 
@@ -1219,6 +1229,12 @@ static struct w83791d_data *w83791d_update_device(struct device *dev)
                data->fan_div[3] = reg_array_tmp[2] & 0x07;
                data->fan_div[4] = (reg_array_tmp[2] >> 4) & 0x07;
 
+               /* The fan divisor for fans 0-2 get bit 2 from
+                  bits 5-7 respectively of vbat register */
+               vbat_reg = w83791d_read(client, W83791D_REG_VBAT);
+               for (i = 0; i < 3; i++)
+                       data->fan_div[i] |= (vbat_reg >> (3 + i)) & 0x04;
+
                /* Update the first temperature sensor */
                for (i = 0; i < 3; i++) {
                        data->temp1[i] = w83791d_read(client,