hwmon/w83627ehf: Preserve speed reading when changing fan min
The w83627ehf driver changes the fan clock divider automatically when
a new min fan speed is set. It is supposed to preserve the fan speed
reading while doing so, bug doesn't really. Fix it.
Signed-off-by: Jean Delvare <khali@linux-fr.org>
Signed-off-by: Mark M. Hoffman <mhoffman@lightlink.com>
diff --git a/drivers/hwmon/w83627ehf.c b/drivers/hwmon/w83627ehf.c
index 30a7640..f4d850c 100644
--- a/drivers/hwmon/w83627ehf.c
+++ b/drivers/hwmon/w83627ehf.c
@@ -716,10 +716,15 @@
/* Write both the fan clock divider (if it changed) and the new
fan min (unconditionally) */
if (new_div != data->fan_div[nr]) {
- if (new_div > data->fan_div[nr])
- data->fan[nr] >>= (data->fan_div[nr] - new_div);
- else
- data->fan[nr] <<= (new_div - data->fan_div[nr]);
+ /* Preserve the fan speed reading */
+ if (data->fan[nr] != 0xff) {
+ if (new_div > data->fan_div[nr])
+ data->fan[nr] >>= new_div - data->fan_div[nr];
+ else if (data->fan[nr] & 0x80)
+ data->fan[nr] = 0xff;
+ else
+ data->fan[nr] <<= data->fan_div[nr] - new_div;
+ }
dev_dbg(dev, "fan%u clock divider changed from %u to %u\n",
nr + 1, div_from_reg(data->fan_div[nr]),