hwmon: (aspeed-pwm-tacho) reduce fan_tach period
Subsystems (2)
PATCH v4 1/2 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.
---
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(-)
drivers/hwmon/aspeed-pwm-tacho.c +1 -1
@@ -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 0xFFstruct aspeed_pwm_tacho_data {
Signature · 1 line
2.13.1.611.g7e3b11ae1-goog
Quoted 10 lines · Patrick Venture
Reduce the
fan_tachperiod such that the fan controller uses a shorter period to measure the rpm.The original period of
0x1000was 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 thefan_tach. This value was recently tested and accepted downstream on the IBM Zaius board which uses the ast2500.
Quoted 7 lines
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 <[email protected]>
Applied, thanks.
Guenter
Quoted 22 lines
---
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(-)drivers/hwmon/aspeed-pwm-tacho.c +1
-1@@ -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 0xFFstruct aspeed_pwm_tacho_data {