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Message-ID: <121d888762a1232ef403cf35230ccf7b3887083a.1699007401.git.alexander.hansen@9elements.com>
Date: Fri, 3 Nov 2023 11:30:55 +0100
From: Alexander Hansen <alexander.hansen@...ements.com>
To: Jean Delvare <jdelvare@...e.com>,
Guenter Roeck <linux@...ck-us.net>,
Joel Stanley <joel@....id.au>, Andrew Jeffery <andrew@...id.au>
Cc: Loic Prylli <lprylli@...flix.com>,
Alexander Hansen <alexander.hansen@...ements.com>,
linux-hwmon@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-aspeed@...ts.ozlabs.org, linux-kernel@...r.kernel.org
Subject: [PATCH v1 1/1] hwmon: (aspeed-pwm-tacho) mutex for tach reading
From: Loic Prylli <lprylli@...flix.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@...flix.com>
Signed-off-by: Alexander Hansen <alexander.hansen@...ements.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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