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hwmon: (aspeed-pwm-tacho) Poll with short sleeps.

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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>
This commit is contained in:
Patrick Venture 2017-06-23 20:39:56 -07:00 committed by Guenter Roeck
parent ece0c03a9e
commit 44b413661b
1 changed files with 18 additions and 6 deletions
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24
drivers/hwmon/aspeed-pwm-tacho.c
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@ -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;
regmap_read(priv->regmap, ASPEED_PTCR_RESULT, &val);
if (!(val & RESULT_STATUS_MASK))
return -ETIMEDOUT;
ret = regmap_read_poll_timeout(
priv->regmap,
ASPEED_PTCR_RESULT,
val,
(val & RESULT_STATUS_MASK),
ASPEED_RPM_STATUS_SLEEP_USEC,
usec);
/* 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];