[lm-sensors] [PATCH] Use fan divisor bits from vbat register of w83791d

Marc Hulsman m.hulsman at tudelft.nl
Thu May 15 00:52:13 CEST 2008


Hi all,

I will take over maintenance of the w83791d driver. Thanks Charles for you 
work on it until now, I found it really useful!

Also thanks for your help with finalizing the following patch. It takes into 
account an extra bit for the fan divisor of fans 1-3, enabling them to have 
fan divisors higher than 8. This also solves a bug where the reported fan 
speed is too high if the chip is initialized with a fan divisor larger than 
8. 

Marc

---
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 at tudelft.nl>

---
 drivers/hwmon/w83791d.c     |   26 ++++++++++++++++++++++----
 Documentation/hwmon/w83791d |    6 +++---
 2 files changed, 25 insertions(+), 7 deletions(-)
---
diff -uNrp linux-2.6.26-rc1-git6/drivers/hwmon/w83791d.c 
linux-2.6.26-rc1-git6-modified/drivers/hwmon/w83791d.c
--- linux-2.6.26-rc1-git6/drivers/hwmon/w83791d.c	2008-05-03 
20:59:44.000000000 +0200
+++ linux-2.6.26-rc1-git6-modified/drivers/hwmon/w83791d.c	2008-05-08 
19:08:55.000000000 +0200
@@ -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;
@@ -519,6 +517,7 @@ static ssize_t store_fan_div(struct devi
 	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;
@@ -570,6 +569,16 @@ static ssize_t store_fan_div(struct devi
 	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]);
@@ -1245,6 +1254,7 @@ static struct w83791d_data *w83791d_upda
 	struct w83791d_data *data = i2c_get_clientdata(client);
 	int i, j;
 	u8 reg_array_tmp[3];
+	u8 vbat_reg;
 
 	mutex_lock(&data->update_lock);
 
@@ -1288,6 +1298,14 @@ static struct w83791d_data *w83791d_upda
 						W83791D_REG_TEMP1[i]);
 		}
 
+		/* 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 &
+						(1 << (5 + i))) >> (3 + i));
+		}
+
 		/* Update the rest of the temperature sensors */
 		for (i = 0; i < 2; i++) {
 			for (j = 0; j < 3; j++) {
diff -uNrp linux-2.6.26-rc1-git6/Documentation/hwmon/w83791d 
linux-2.6.26-rc1-git6-modified/Documentation/hwmon/w83791d
--- linux-2.6.26-rc1-git6/Documentation/hwmon/w83791d	2008-05-03 
20:59:44.000000000 +0200
+++ linux-2.6.26-rc1-git6-modified/Documentation/hwmon/w83791d	2008-05-08 
18:52:46.000000000 +0200
@@ -22,6 +22,7 @@ Credits:
 
 Additional contributors:
     Sven Anders <anders at anduras.de>
+    Marc Hulsman <m.hulsman at tudelft.nl>
 
 Module Parameters
 -----------------
@@ -67,9 +68,8 @@ on until the temperature falls below the
 
 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





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