From: Cumulus Networks <support@xxxxxxxxxxxxxxxxxxx>
The driver only fills the most significant 8 bits of the fan tach
count (11 bit value). Fixing the driver to use all of 11 bits for
more accuracy.
---
drivers/hwmon/max6620.c | 105 ++++++++++++++++++----------------------
1 file changed, 46 insertions(+), 59 deletions(-)
diff --git a/drivers/hwmon/max6620.c b/drivers/hwmon/max6620.c
index 3c337c7b0f4d..2cd3b0beb6b4 100644
--- a/drivers/hwmon/max6620.c
+++ b/drivers/hwmon/max6620.c
@@ -46,6 +46,8 @@
/* clock: The clock frequency of the chip the driver should assume */
static int clock = 8192;
+static u32 sr = 2;
+static u32 np = 2;
module_param(clock, int, S_IRUGO);
@@ -213,22 +215,22 @@ static ssize_t get_fan(struct device *dev, struct device_attribute *devattr, cha
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct max6620_data *data = max6620_update_device(dev);
- int rpm;
-
- /*
- * Calculation details:
- *
- * Each tachometer counts over an interval given by the "count"
- * register (0.25, 0.5, 1 or 2 seconds). This module assumes
- * that the fans produce two pulses per revolution (this seems
- * to be the most common).
- */
- if(data->tach[attr->index] == 0 || data->tach[attr->index] == 255) {
+ struct i2c_client *client = to_i2c_client(dev);
+ u32 rpm = 0;
+ u32 tach = 0;
+ u32 tach1 = 0;
+ u32 tach2 = 0;
+
+ tach1 = i2c_smbus_read_byte_data(client, tach_reg[attr->index]);
+ tach1 = (tach1 << 3) & 0x7f8;
+ tach2 = i2c_smbus_read_byte_data(client, tach_reg[attr->index] + 1);
+ tach2 = (tach2 >> 5) & 0x7;
+ tach = tach1 | tach2;
+ if (tach == 0) {
rpm = 0;
} else {
- rpm = ((clock / (data->tach[attr->index] << 3)) * 30 * DIV_FROM_REG(data->fandyn[attr->index]));
+ rpm = (60 * DIV_FROM_REG(data->fandyn[attr->index]) * clock)/(tach * np);
}
-
return sprintf(buf, "%d\n", rpm);
}
@@ -236,22 +238,21 @@ static ssize_t get_target(struct device *dev, struct device_attribute *devattr,
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct max6620_data *data = max6620_update_device(dev);
- int kscale, ktach, rpm;
-
- /*
- * Use the datasheet equation:
- *
- * FanSpeed = KSCALE x fCLK / [256 x (KTACH + 1)]
- *
- * then multiply by 60 to give rpm.
- */
-
- kscale = DIV_FROM_REG(data->fandyn[attr->index]);
- ktach = data->target[attr->index];
- if(ktach == 0) {
+ struct i2c_client *client = to_i2c_client(dev);
+ u32 rpm;
+ u32 target;
+ u32 target1;
+ u32 target2;
+
+ target1 = i2c_smbus_read_byte_data(client, target_reg[attr->index]);
+ target1 = (target1 << 3) & 0x7f8;
+ target2 = i2c_smbus_read_byte_data(client, target_reg[attr->index] + 1);
+ target2 = (target2 >> 5) & 0x7;
+ target = target1 | target2;
+ if (target == 0) {
rpm = 0;
} else {
- rpm = ((60 * kscale * clock) / (ktach << 3));
+ rpm = (60 * DIV_FROM_REG(data->fandyn[attr->index]) * clock)/(target * np);
}
return sprintf(buf, "%d\n", rpm);
}
@@ -261,9 +262,11 @@ static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
struct i2c_client *client = to_i2c_client(dev);
struct sensor_device_attribute *attr = to_sensor_dev_attr(devattr);
struct max6620_data *data = i2c_get_clientdata(client);
- int kscale, ktach;
- unsigned long rpm;
+ u32 rpm;
int err;
+ u32 target;
+ u32 target1;
+ u32 target2;
err = kstrtoul(buf, 10, &rpm);
if (err)
@@ -271,25 +274,13 @@ static ssize_t set_target(struct device *dev, struct device_attribute *devattr,
rpm = SENSORS_LIMIT(rpm, FAN_RPM_MIN, FAN_RPM_MAX);
- /*
- * Divide the required speed by 60 to get from rpm to rps, then
- * use the datasheet equation:
- *
- * KTACH = [(fCLK x KSCALE) / (256 x FanSpeed)] - 1
- */
-
mutex_lock(&data->update_lock);
- kscale = DIV_FROM_REG(data->fandyn[attr->index]);
- ktach = ((60 * kscale * clock) / rpm);
- if (ktach < 0)
- ktach = 0;
- if (ktach > 255)
- ktach = 255;
- data->target[attr->index] = ktach;
-
- i2c_smbus_write_byte_data(client, target_reg[attr->index], data->target[attr->index]);
- i2c_smbus_write_byte_data(client, target_reg[attr->index]+0x01, 0x00);
+ target = (60 * DIV_FROM_REG(data->fandyn[attr->index]) * clock)/(rpm * np);
+ target1 = (target >> 3) & 0xff;
+ target2 = (target << 5) & 0xe0;
+ i2c_smbus_write_byte_data(client, target_reg[attr->index], target1);
+ i2c_smbus_write_byte_data(client, target_reg[attr->index] + 1, target2);
mutex_unlock(&data->update_lock);
@@ -609,8 +600,11 @@ static int max6620_init_client(struct i2c_client *client) {
}
-
- if (i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config)) {
+ /*
+ * Set bit 4, disable other fans from going full speed on a fail
+ * failure.
+ */
+ if (i2c_smbus_write_byte_data(client, MAX6620_REG_CONFIG, config | 0x10)) {
dev_err(&client->dev, "Config write error, aborting.\n");
return err;
}
@@ -618,28 +612,21 @@ static int max6620_init_client(struct i2c_client *client) {
data->config = config;
for (i = 0; i < 4; i++) {
data->fancfg[i] = i2c_smbus_read_byte_data(client, config_reg[i]);
- data->fancfg[i] |= 0x80; // enable TACH monitoring
+ data->fancfg[i] |= 0xa8; // enable TACH monitoring
i2c_smbus_write_byte_data(client, config_reg[i], data->fancfg[i]);
data->fandyn[i] = i2c_smbus_read_byte_data(client, dyn_reg[i]);
- data-> fandyn[i] |= 0x1C;
+ /* 2 counts (001) and Rate change 100 (0.125 secs) */
+ data-> fandyn[i] = 0x30;
i2c_smbus_write_byte_data(client, dyn_reg[i], data->fandyn[i]);
data->tach[i] = i2c_smbus_read_byte_data(client, tach_reg[i]);
data->volt[i] = i2c_smbus_read_byte_data(client, volt_reg[i]);
data->target[i] = i2c_smbus_read_byte_data(client, target_reg[i]);
data->dac[i] = i2c_smbus_read_byte_data(client, dac_reg[i]);
-
-
}
-
-
-
return 0;
}
-
-
-
static struct max6620_data *max6620_update_device(struct device *dev)
{
int i;
@@ -678,7 +665,7 @@ static struct max6620_data *max6620_update_device(struct device *dev)
return data;
}
-module_i2c_driver(max6620_driver);
+// module_i2c_driver(max6620_driver);
static int __init max6620_init(void)
{
--
2.32.0
