Re: [PATCH v3 1/5] hwmon: (core) Inherit power properties to hdev

From: linux
Date: Wed Oct 24 2018 - 20:13:04 EST

Quoting Nicolin Chen <nicoleotsuka@xxxxxxxxx>:

The new hdev is a child device related to the original parent
hwmon driver and its device. However, it doesn't support the
power features, typically being defined in the parent driver.

So this patch inherits three necessary power properties from
the parent dev to hdev: power, pm_domain and driver pointers.

Note that the dev->driver pointer is the place that contains
a dev_pm_ops pointer defined in the parent device driver and
the pm runtime core also checks this pointer:
if (!cb && dev->driver && dev->driver->pm)

Signed-off-by: Nicolin Chen <nicoleotsuka@xxxxxxxxx>
* N/A
* Added device pointers

drivers/hwmon/hwmon.c | 7 ++++++-
1 file changed, 6 insertions(+), 1 deletion(-)

diff --git a/drivers/hwmon/hwmon.c b/drivers/hwmon/hwmon.c
index 975c95169884..14cfab64649f 100644
--- a/drivers/hwmon/hwmon.c
+++ b/drivers/hwmon/hwmon.c
@@ -625,7 +625,12 @@ __hwmon_device_register(struct device *dev, const char *name, void *drvdata,
hwdev->name = name;
hdev->class = &hwmon_class;
hdev->parent = dev;
- hdev->of_node = dev ? dev->of_node : NULL;
+ if (dev) {
+ hdev->driver = dev->driver;
+ hdev->power = dev->power;
+ hdev->pm_domain = dev->pm_domain;
+ hdev->of_node = dev->of_node;
+ }

We'l need to dig into this more; I suspect it may be inappropriate to do this.
With this change, every hwmon driver supporting (runtime ?) suspend/resume
will have the problem worked around in #5, and that just seems wrong.


hwdev->chip = chip;
dev_set_drvdata(hdev, drvdata);
dev_set_name(hdev, HWMON_ID_FORMAT, id);