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| author | Patrick Venture <venture@google.com> | 2017-06-24 08:39:32 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2017-06-24 08:57:42 -0700 |
| commit | ece0c03a9e5f727435d19754411e59c3ae28cbb8 (patch) | |
| tree | 6418c244170741841c65ff1b9a61238e25054bb4 /drivers/hwmon | |
| parent | 3a2b3d37e1eecb75d792db2588b9eb7a471632cd (diff) | |
| download | linux-ece0c03a9e5f727435d19754411e59c3ae28cbb8.tar.gz linux-ece0c03a9e5f727435d19754411e59c3ae28cbb8.tar.bz2 linux-ece0c03a9e5f727435d19754411e59c3ae28cbb8.zip | |
hwmon: (aspeed-pwm-tacho) reduce fan_tach period
Reduce the fan_tach period such that the fan controller uses a shorter
period to measure the rpm.
The original period of 0x1000 was chosen as a conversative value from the
reference implementation. Through experimentation on the quanta-q71l
board, I was able to drive the number down which ultimately reduced the
time the controller would use to determine the fan_tach. This value was
recently tested and accepted downstream on the IBM Zaius board which uses
the ast2500.
Future work: It may be worthwhile as this is a tunable parameter to the
system, to allow overriding it through the device tree.
Testing: Tested on an ast2400 sitting on a quanta-q71l and ast2500 on
power9.
Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon')
| -rw-r--r-- | drivers/hwmon/aspeed-pwm-tacho.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c index 86e2ea8287a7..b2ab5612d8a4 100644 --- a/drivers/hwmon/aspeed-pwm-tacho.c +++ b/drivers/hwmon/aspeed-pwm-tacho.c @@ -160,7 +160,7 @@ * 11: reserved. */ #define M_TACH_MODE 0x02 /* 10b */ -#define M_TACH_UNIT 0x1000 +#define M_TACH_UNIT 0x00c0 #define INIT_FAN_CTRL 0xFF struct aspeed_pwm_tacho_data { |