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 <[email protected]> --- drivers/hwmon/aspeed-pwm-tacho.c | 24 ++++++++++++++++++------ 1 file changed, 18 insertions(+), 6 deletions(-) diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c index b2ab5612d8a4..cfcd769175e6 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]; -- 2.13.1.611.g7e3b11ae1-goog -- To unsubscribe from this list: send the line "unsubscribe linux-hwmon" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
