| Message ID | 20170624153932.8895-1-venture@google.com (mailing list archive) |
|---|---|
| State | Accepted |
| Headers | show |
On 06/24/2017 08:39 AM, Patrick Venture wrote: > 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> Applied, thanks. Guenter > --- > v4: Added explanation for value. > v3: Added missing change log > v2: Updated commit message language > --- > drivers/hwmon/aspeed-pwm-tacho.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > 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 { > -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html
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 {
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> --- v4: Added explanation for value. v3: Added missing change log v2: Updated commit message language --- drivers/hwmon/aspeed-pwm-tacho.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)