Hi Eduardo, On Fri, May 17, 2019 at 04:13:36PM -0700, Eduardo Valentin wrote: > 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. > Makes sense. I'd apply it as-is, but it would be better if you resend it to the list to give others a chance to comment. Thanks, Guenter > Cc: Jean Delvare <jdelvare@xxxxxxxx> > Cc: Guenter Roeck <linux@xxxxxxxxxxxx> > Cc: linux-hwmon@xxxxxxxxxxxxxxx > Cc: linux-kernel@xxxxxxxxxxxxxxx > Signed-off-by: Eduardo Valentin <eduval@xxxxxxxxxx> > --- > 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; > -- > 2.21.0 >