diff options
| author | Patrick Venture <venture@google.com> | 2017-06-23 20:39:56 -0700 |
|---|---|---|
| committer | Guenter Roeck <linux@roeck-us.net> | 2017-06-24 08:58:06 -0700 |
| commit | 44b413661b57cbbb7e4c3adf7b087fada42a443e (patch) | |
| tree | 24b07c51801aa75770ab8c92266472215d899e51 /drivers/hwmon/aspeed-pwm-tacho.c | |
| parent | ece0c03a9e5f727435d19754411e59c3ae28cbb8 (diff) | |
| download | linux-44b413661b57cbbb7e4c3adf7b087fada42a443e.tar.bz2 | |
hwmon: (aspeed-pwm-tacho) Poll with short sleeps.
The reference driver polled but mentioned it was possible to sleep
for a computed period to know when it's ready to read. However, polling
with minimal sleeps is quick and works. This also improves responsiveness
from the driver.
Testing: tested on ast2400 on quanta-q71l
Signed-off-by: Patrick Venture <venture@google.com>
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Diffstat (limited to 'drivers/hwmon/aspeed-pwm-tacho.c')
| -rw-r--r-- | drivers/hwmon/aspeed-pwm-tacho.c | 24 |
1 files changed, 18 insertions, 6 deletions
diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c index b2ab5612d8a4..ddfe66bdff86 100644 --- a/drivers/hwmon/aspeed-pwm-tacho.c +++ b/drivers/hwmon/aspeed-pwm-tacho.c @@ -163,6 +163,9 @@ #define M_TACH_UNIT 0x00c0 #define INIT_FAN_CTRL 0xFF +/* How long we sleep in us while waiting for an RPM result. */ +#define ASPEED_RPM_STATUS_SLEEP_USEC 500 + struct aspeed_pwm_tacho_data { struct regmap *regmap; unsigned long clk_freq; @@ -508,8 +511,9 @@ static u32 aspeed_get_fan_tach_ch_measure_period(struct aspeed_pwm_tacho_data static int aspeed_get_fan_tach_ch_rpm(struct aspeed_pwm_tacho_data *priv, u8 fan_tach_ch) { - u32 raw_data, tach_div, clk_source, sec, val; + u32 raw_data, tach_div, clk_source, msec, usec, val; u8 fan_tach_ch_source, type, mode, both; + int ret; regmap_write(priv->regmap, ASPEED_PTCR_TRIGGER, 0); regmap_write(priv->regmap, ASPEED_PTCR_TRIGGER, 0x1 << fan_tach_ch); @@ -517,12 +521,20 @@ static int aspeed_get_fan_tach_ch_rpm(struct aspeed_pwm_tacho_data *priv, fan_tach_ch_source = priv->fan_tach_ch_source[fan_tach_ch]; type = priv->pwm_port_type[fan_tach_ch_source]; - sec = (1000 / aspeed_get_fan_tach_ch_measure_period(priv, type)); - msleep(sec); + msec = (1000 / aspeed_get_fan_tach_ch_measure_period(priv, type)); + usec = msec * 1000; + + ret = regmap_read_poll_timeout( + priv->regmap, + ASPEED_PTCR_RESULT, + val, + (val & RESULT_STATUS_MASK), + ASPEED_RPM_STATUS_SLEEP_USEC, + usec); - regmap_read(priv->regmap, ASPEED_PTCR_RESULT, &val); - if (!(val & RESULT_STATUS_MASK)) - return -ETIMEDOUT; + /* return -ETIMEDOUT if we didn't get an answer. */ + if (ret) + return ret; raw_data = val & RESULT_VALUE_MASK; tach_div = priv->type_fan_tach_clock_division[type]; |