A common problem for end users is setting the fan clock divider for
correct operation. This patch removes fan_div sysfs write accessor
and implements an automatic fan clock divider selection strategy.
Two states are possible: if the user specifies a valid minimum low
speed alarm limit that will set an appropriate fan clock divider,
otherwise the driver will seek to a fan clock divider that gives
best resolution for current fan speed.
The auto fan clock divider algorithm received extensive testing
in the adm9240 driver port, this patch is compile tested but needs
hardware test.
Testing: something like this script can be used to verify operation:
#!/bin/bash
#
minpath="/sys/bus/i2c/devices/0-002d/fan1_min"
fanpath="/sys/bus/i2c/devices/0-002d/fan1_input"
read fan < $fanpath
lower=300
upper=13500000
fan_min=123
step=120
#
function test_cycle ()
{
fan_min=$lower
while test $fan_min -lt $upper; do
echo "$fan_min" > "$minpath"
sleep 2
read fan < $fanpath
(( fan_min=($fan_min * $step + 50) / 100 ))
(( fan_min=(($fan_min + 50) / 100) * 100 ))
done
fan_min=$upper
while test $fan_min -gt $lower; do
echo "$fan_min" > "$minpath"
sleep 2
read fan < $fanpath
(( fan_min=($fan_min * 100 + $step / 2) / $step ))
(( fan_min=(($fan_min + 50) / 100) * 100 ))
done
}
test_cycle
Signed-off-by: Grant Coady <gcoady at gmail.com>
---
lm87.c | 107 ++++++++++++++++++++++++++++++++++++-----------------------------
1 files changed, 60 insertions(+), 47 deletions(-)
--- linux-2.6.12-rc2-mm3/drivers/i2c/chips/lm87.c 2005-04-11 20:54:56.000000000 +1000
+++ linux-2.6.12-rc2-mm3h/drivers/i2c/chips/lm87.c 2005-04-15 23:29:37.000000000 +1000
@@ -405,63 +405,62 @@ static DEVICE_ATTR(fan##offset##_input,
show_fan(1);
show_fan(2);
-static void set_fan_min(struct device *dev, const char *buf, int nr)
+/* write new fan_div: callers must hold data->update_lock */
+static void lm87_write_fan_div(struct i2c_client *client, int nr, u8 fan_div)
{
- struct i2c_client *client = to_i2c_client(dev);
- struct lm87_data *data = i2c_get_clientdata(client);
- long val = simple_strtol(buf, NULL, 10);
+ u8 reg, old, shf = (nr + 2) << 1;
- down(&data->update_lock);
- data->fan_min[nr] = FAN_TO_REG(val,
- FAN_DIV_FROM_REG(data->fan_div[nr]));
- lm87_write_value(client, LM87_REG_FAN_MIN(nr), data->fan_min[nr]);
- up(&data->update_lock);
+ reg = lm87_read_value(client, LM87_REG_VID_FAN_DIV);
+ old = (reg >> shf) & 3;
+ reg &= ~(3 << shf);
+ reg |= fan_div << shf;
+ lm87_write_value(client, LM87_REG_VID_FAN_DIV, reg);
+ dev_dbg(&client->dev, "autoX fan%u old %u new %u fan_div changed\n",
+ nr + 1, 1 << old, 1 << fan_div);
}
-/* Note: we save and restore the fan minimum here, because its value is
- determined in part by the fan clock divider. This follows the principle
- of least suprise; the user doesn't expect the fan minimum to change just
- because the divider changed. */
-static ssize_t set_fan_div(struct device *dev, const char *buf,
- size_t count, int nr)
+/* automatic fan clock divider selection when user sets fan_min */
+static void set_fan_min(struct device *dev, const char *buf, int nr)
{
struct i2c_client *client = to_i2c_client(dev);
struct lm87_data *data = i2c_get_clientdata(client);
long val = simple_strtol(buf, NULL, 10);
- unsigned long min;
- u8 reg;
down(&data->update_lock);
- min = FAN_FROM_REG(data->fan_min[nr],
- FAN_DIV_FROM_REG(data->fan_div[nr]));
- switch (val) {
- case 1: data->fan_div[nr] = 0; break;
- case 2: data->fan_div[nr] = 1; break;
- case 4: data->fan_div[nr] = 2; break;
- case 8: data->fan_div[nr] = 3; break;
- default:
- up(&data->update_lock);
- return -EINVAL;
- }
+ dev_dbg(&client->dev, "auto? fan%u div %u min %3u val %5ld spd %u\n",
+ nr + 1, 1 << data->fan_div[nr],
+ data->fan_min[nr],val,data->fan[nr]);
+
+ if (val <= 1350000 / (8 * 254)) {
+ data->fan_min[nr] = 255; /* too low, disable alarm */
+ dev_dbg(&client->dev, "auto! fan%u div %u min %3u too low\n",
+ nr + 1, 1 << data->fan_div[nr],
+ data->fan_min[nr]);
+ } else {
+ /* calculate optimum fan clock divider to suit fan_min */
+ unsigned int new_min = 1350000U / val;
+ u8 new_div = 0;
+
+ while (new_min > 192 && new_div < 3) {
+ new_div++;
+ new_min++;
+ new_min >>= 1;
+ }
+ dev_dbg(&client->dev, "auto- fan%u div %u min %3u\n",
+ nr + 1, 1 << new_div, new_min);
- reg = lm87_read_value(client, LM87_REG_VID_FAN_DIV);
- switch (nr) {
- case 0:
- reg = (reg & 0xCF) | (data->fan_div[0] << 4);
- break;
- case 1:
- reg = (reg & 0x3F) | (data->fan_div[1] << 6);
- break;
+ data->fan_min[nr] = new_min;
+
+ if (new_div != data->fan_div[nr]) {
+ data->fan_div[nr] = new_div;
+ lm87_write_fan_div(client, nr, new_div);
+ }
}
- lm87_write_value(client, LM87_REG_VID_FAN_DIV, reg);
- data->fan_min[nr] = FAN_TO_REG(min, val);
lm87_write_value(client, LM87_REG_FAN_MIN(nr),
data->fan_min[nr]);
up(&data->update_lock);
-
- return count;
}
#define set_fan(offset) \
@@ -471,15 +470,10 @@ static ssize_t set_fan##offset##_min(str
set_fan_min(dev, buf, offset-1); \
return count; \
} \
-static ssize_t set_fan##offset##_div(struct device *dev, const char *buf, \
- size_t count) \
-{ \
- return set_fan_div(dev, buf, count, offset-1); \
-} \
static DEVICE_ATTR(fan##offset##_min, S_IRUGO | S_IWUSR, \
show_fan##offset##_min, set_fan##offset##_min); \
-static DEVICE_ATTR(fan##offset##_div, S_IRUGO | S_IWUSR, \
- show_fan##offset##_div, set_fan##offset##_div);
+static DEVICE_ATTR(fan##offset##_div, S_IRUGO, \
+ show_fan##offset##_div, NULL);
set_fan(1);
set_fan(2);
@@ -767,6 +761,25 @@ static struct lm87_data *lm87_update_dev
} else {
data->fan[i] = lm87_read_value(client,
LM87_REG_FAN(i));
+
+ /* if fan_min off: auto fan clock divider */
+ if (data->fan_min[i] == 255) {
+ int x = 0;
+
+ if (data->fan[i] > 192 &&
+ data->fan_div[i] < 3) {
+ x++;
+ }
+ if (data->fan[i] < 96 &&
+ data->fan_div[i] > 0) {
+ x--;
+ }
+ if (x != 0) {
+ data->fan_div[i] += x;
+ lm87_write_fan_div(client, i,
+ data->fan_div[i]);
+ }
+ }
data->fan_min[i] = lm87_read_value(client,
LM87_REG_FAN_MIN(i));
}
