[PATCH 3/3] hwmon: (cros_ec) Synchronize EC access from the thermal device callbacks

[Thomas Weißschuh]

To guarantee consistency for the read-modify-write access in
cros_ec_hwmon_cooling_set_cur_state(), locking is necessary.

Use the existing hwmon device lock to do so.

Fixes: 5798b62867b4 ("hwmon: (cros_ec) register fans into thermal framework cooling devices")
Signed-off-by: Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
---
 drivers/hwmon/cros_ec_hwmon.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/hwmon/cros_ec_hwmon.c b/drivers/hwmon/cros_ec_hwmon.c
index fb5daa9f80d1..76d83e1c68cf 100644
--- a/drivers/hwmon/cros_ec_hwmon.c
+++ b/drivers/hwmon/cros_ec_hwmon.c
@@ -5,6 +5,7 @@
  *  Copyright (C) 2024 Thomas Weißschuh <linux@xxxxxxxxxxxxxx>
  */
 
+#include <linux/cleanup.h>
 #include <linux/device.h>
 #include <linux/hwmon.h>
 #include <linux/math.h>
@@ -411,6 +412,8 @@ static int cros_ec_hwmon_cooling_get_cur_state(struct thermal_cooling_device *cd
 	u8 read_val;
 	int ret;
 
+	guard(hwmon_lock)(priv->hwmon_priv->hwmon_dev);
+
 	ret = cros_ec_hwmon_read_pwm_value(priv->hwmon_priv->cros_ec, priv->index, &read_val);
 	if (ret)
 		return ret;
@@ -424,6 +427,8 @@ static int cros_ec_hwmon_cooling_set_cur_state(struct thermal_cooling_device *cd
 {
 	const struct cros_ec_hwmon_cooling_priv *priv = cdev->devdata;
 
+	guard(hwmon_lock)(priv->hwmon_priv->hwmon_dev);
+
 	return cros_ec_hwmon_write_pwm_input(priv->hwmon_priv->cros_ec, priv->index, val);
 }
 

-- 
2.55.0