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From: Eduardo Valentin <>
To: Guenter Roeck <>
Cc: Eduardo Valentin <>,
	Jean Delvare <>, <>,
Subject: [PATCH 1/2] hwmon: core: add thermal sensors only if dev->of_node is present
Date: Fri, 17 May 2019 16:13:36 -0700	[thread overview]
Message-ID: <> (raw)
In-Reply-To: <>

Drivers may register to hwmon and request for also registering
with the thermal subsystem (HWMON_C_REGISTER_TZ). However,
some of these driver, e.g. marvell phy, may be probed from
Device Tree or being dynamically allocated, and in the later
case, it will not have a dev->of_node entry.

Registering with hwmon without the dev->of_node may result in
different outcomes depending on the device tree, which may
be a bit misleading. If the device tree blob has no 'thermal-zones'
node, the *hwmon_device_register*() family functions are going
to gracefully succeed, because of-thermal,
*thermal_zone_of_sensor_register() return -ENODEV in this case,
and the hwmon error path handles this error code as success to
cover for the case where CONFIG_THERMAL_OF is not set.
However, if the device tree blob has the 'thermal-zones'
entry, the *hwmon_device_register*() will always fail on callers
with no dev->of_node, propagating -EINVAL.

If dev->of_node is not present, calling of-thermal does not
make sense. For this reason, this patch checks first if the
device has a of_node before going over the process of registering
with the thermal subsystem of-thermal interface. And in this case,
when a caller of *hwmon_device_register*() with HWMON_C_REGISTER_TZ
and no dev->of_node will still register with hwmon, but not with
the thermal subsystem. If all the hwmon part bits are in place,
the registration will succeed.

Cc: Jean Delvare <>
Cc: Guenter Roeck <>
Signed-off-by: Eduardo Valentin <>
 drivers/hwmon/hwmon.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index fcdbac4a56e3..6b3559f58b67 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -619,7 +619,7 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
 	if (err)
 		goto free_hwmon;
-	if (dev && chip && chip->ops->read &&
+	if (dev && dev->of_node && chip && chip->ops->read &&
 	    chip->info[0]->type == hwmon_chip &&
 	    (chip->info[0]->config[0] & HWMON_C_REGISTER_TZ)) {
 		const struct hwmon_channel_info **info = chip->info;

       reply	other threads:[~2019-05-17 23:13 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
     [not found] <>
2019-05-17 23:13 ` Eduardo Valentin [this message]
2019-05-28 15:08   ` Guenter Roeck
2019-05-29 23:12     ` Eduardo Valentin
2019-05-17 23:13 ` [PATCH 2/2] hwmon: core: fix potential memory leak in *hwmon_device_register* Eduardo Valentin
2019-05-28 15:06   ` Guenter Roeck
2019-05-29 23:14     ` Eduardo Valentin

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