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 <[email protected]>
Cc: Guenter Roeck <[email protected]>
Cc: [email protected]
Cc: [email protected]
Signed-off-by: Eduardo Valentin <[email protected]>
---
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
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 <[email protected]>
> Cc: Guenter Roeck <[email protected]>
> Cc: [email protected]
> Cc: [email protected]
> Signed-off-by: Eduardo Valentin <[email protected]>
> ---
> 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
>
On Tue, May 28, 2019 at 08:08:21AM -0700, Guenter Roeck wrote:
> 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.
Ok Cool.
Yeah, the patches were copied to the mailing list. Only the cover letter
somehow I forgot to copy the mailing lists while git-sending-email.
I will resend the two patches (and the cover letter) after fixing
the comment on patch 2/2.
>
> Thanks,
> Guenter
>
> > Cc: Jean Delvare <[email protected]>
> > Cc: Guenter Roeck <[email protected]>
> > Cc: [email protected]
> > Cc: [email protected]
> > Signed-off-by: Eduardo Valentin <[email protected]>
> > ---
> > 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
> >
--
All the best,
Eduardo Valentin