4.19-stable review patch. If anyone has any objections, please let me know.
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From: Loic Prylli lprylli@netflix.com
[ Upstream commit 1168491e7f53581ba7b6014a39a49cfbbb722feb ]
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 Fixes: 2d7a548a3eff ("drivers: hwmon: Support for ASPEED PWM/Fan tach") Link: https://lore.kernel.org/r/121d888762a1232ef403cf35230ccf7b3887083a.169900740... Signed-off-by: Guenter Roeck linux@roeck-us.net Signed-off-by: Sasha Levin sashal@kernel.org --- 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 a43fa730a513..4097ae62e9a4 100644 --- a/drivers/hwmon/aspeed-pwm-tacho.c +++ b/drivers/hwmon/aspeed-pwm-tacho.c @@ -197,6 +197,8 @@ 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 }; @@ -531,6 +533,8 @@ 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);
@@ -548,6 +552,8 @@ 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; @@ -938,6 +944,7 @@ 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))