From: Loic Prylli <lprylli@xxxxxxxxxxx>
the ASPEED_PTCR_RESULT Register can only hold the result for a
single fan input. Adding a mutex to protect the register until the
reading is done.
Signed-off-by: Loic Prylli <lprylli@xxxxxxxxxxx>
Signed-off-by: Alexander Hansen <alexander.hansen@xxxxxxxxxxxxx>
---
drivers/hwmon/aspeed-pwm-tacho.c | 7 +++++++
1 file changed, 7 insertions(+)
diff --git a/drivers/hwmon/aspeed-pwm-tacho.c b/drivers/hwmon/aspeed-pwm-tacho.c
index 997df4b40509..b2ae2176f11f 100644
--- a/drivers/hwmon/aspeed-pwm-tacho.c
+++ b/drivers/hwmon/aspeed-pwm-tacho.c
@@ -193,6 +193,8 @@ struct aspeed_pwm_tacho_data {
u8 fan_tach_ch_source[16];
struct aspeed_cooling_device *cdev[8];
const struct attribute_group *groups[3];
+ /* protects access to shared ASPEED_PTCR_RESULT */
+ struct mutex tach_lock;
};
enum type { TYPEM, TYPEN, TYPEO };
@@ -527,6 +529,8 @@ static int aspeed_get_fan_tach_ch_rpm(struct aspeed_pwm_tacho_data *priv,
u8 fan_tach_ch_source, type, mode, both;
int ret;
+ mutex_lock(&priv->tach_lock);
+
regmap_write(priv->regmap, ASPEED_PTCR_TRIGGER, 0);
regmap_write(priv->regmap, ASPEED_PTCR_TRIGGER, 0x1 << fan_tach_ch);
@@ -544,6 +548,8 @@ static int aspeed_get_fan_tach_ch_rpm(struct aspeed_pwm_tacho_data *priv,
ASPEED_RPM_STATUS_SLEEP_USEC,
usec);
+ mutex_unlock(&priv->tach_lock);
+
/* return -ETIMEDOUT if we didn't get an answer. */
if (ret)
return ret;
@@ -903,6 +909,7 @@ static int aspeed_pwm_tacho_probe(struct platform_device *pdev)
priv = devm_kzalloc(dev, sizeof(*priv), GFP_KERNEL);
if (!priv)
return -ENOMEM;
+ mutex_init(&priv->tach_lock);
priv->regmap = devm_regmap_init(dev, NULL, (__force void *)regs,
&aspeed_pwm_tacho_regmap_config);
if (IS_ERR(priv->regmap))
--
2.42.0
