This is a note to let you know that I've just added the patch titled
hwmon: (aspeed-pwm-tacho) mutex for tach reading
to the 4.19-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
hwmon-aspeed-pwm-tacho-mutex-for-tach-reading.patch
and it can be found in the queue-4.19 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit aa6b4787d76a4305db76dc7421b88a866bd269e3
Author: Loic Prylli <lprylli@xxxxxxxxxxx>
Date: Fri Nov 3 11:30:55 2023 +0100
hwmon: (aspeed-pwm-tacho) mutex for tach reading
[ 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@xxxxxxxxxxx>
Signed-off-by: Alexander Hansen <alexander.hansen@xxxxxxxxxxxxx>
Fixes: 2d7a548a3eff ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Link: https://lore.kernel.org/r/121d888762a1232ef403cf35230ccf7b3887083a.1699007401.git.alexander.hansen@xxxxxxxxxxxxx
Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
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))
