The LM85 and compatible chips only support 8 arbitrary PWM frequencies.
The algorithm to pick one of them based on the user input is not
optimum. Improve it to always pick the closest supported frequency.
Signed-off-by: Jean Delvare <khali at linux-fr.org>
---
The new algorithm is exactly the same as the one used in
RANGE_TO_REG().
drivers/hwmon/lm85.c | 16 ++++++++++++----
1 file changed, 12 insertions(+), 4 deletions(-)
--- linux-2.6.25-rc8.orig/drivers/hwmon/lm85.c 2008-04-03 18:16:31.000000000 +0200
+++ linux-2.6.25-rc8/drivers/hwmon/lm85.c 2008-04-03 18:45:54.000000000 +0200
@@ -202,10 +202,18 @@ static int FREQ_TO_REG(int freq)
if (freq >= lm85_freq_map[7])
return 7;
- for (i = 0; i < 7; ++i)
- if (freq <= lm85_freq_map[i])
- break;
- return i;
+
+ /* Find the closest match */
+ for (i = 6; i >= 0; --i) {
+ if (freq >= lm85_freq_map[i]) {
+ if ((lm85_freq_map[i + 1] - freq) <
+ (freq - lm85_freq_map[i]))
+ return i + 1;
+ return i;
+ }
+ }
+
+ return 0;
}
#define FREQ_FROM_REG(val) lm85_freq_map[(val) & 0x07]
--
Jean Delvare
