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hwmon: (aspeed-pwm-tacho) mutex for tach reading 

[ Upstream commit 1168491e7f ]

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: 2d7a548a3e ("drivers: hwmon: Support for ASPEED PWM/Fan tach")
Link: https://lore.kernel.org/r/121d888762a1232ef403cf35230ccf7b3887083a.1699007401.git.alexander.hansen@9elements.com
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
Loic Prylli 2023-11-03 11:30:55 +01:00 committed by Greg Kroah-Hartman
parent 4065746686
commit a3156be201
1 changed files with 7 additions and 0 deletions
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7
drivers/hwmon/aspeed-pwm-tacho.c
View File

@ -194,6 +194,8 @@ 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 };
@ -528,6 +530,8 @@ 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);
@ -545,6 +549,8 @@ 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;
@ -904,6 +910,7 @@ 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))