Messages in this thread Patch in this message | | | From | Alexander Hansen <> | Subject | [PATCH v1 1/1] hwmon: (aspeed-pwm-tacho) mutex for tach reading | Date | Fri, 3 Nov 2023 11:30:55 +0100 |
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From: Loic Prylli <lprylli@netflix.com>
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@netflix.com> Signed-off-by: Alexander Hansen <alexander.hansen@9elements.com> --- 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
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