> > ACPI devices are glued with physical devices through _ADR object, ACPI
> > enumerated devices are identified with _UID object. Currently we can
> > observe _HID/_CID through sysfs interfaces (hid/modalias), but there's
> > no mean for us to check _ADR/_UID from user space. This patch fix
> > this gap for ACPI developers and users.
> >
> why do we need to get this information from userspace?
Developers may want to check _ADR from user land to see whether the glue implementation is correct.
Same situation may be encountered on _UID.
We may discuss here to see whether the two files are required for ACPI users.
Thus this optional feature hasn't been combined with the former _UID enabling one.
Best regards/Lv Zheng
> > Signed-off-by: Lv Zheng <lv.zheng@xxxxxxxxx>
> > ---
> > drivers/acpi/scan.c | 25 +++++++++++++++++++++++++
> > 1 file changed, 25 insertions(+)
> >
> > diff --git a/drivers/acpi/scan.c b/drivers/acpi/scan.c index
> > bb7fe47..df53190 100644
> > --- a/drivers/acpi/scan.c
> > +++ b/drivers/acpi/scan.c
> > @@ -216,6 +216,22 @@ acpi_device_hid_show(struct device *dev, struct
> > device_attribute *attr, char *bu static DEVICE_ATTR(hid, 0444,
> > acpi_device_hid_show, NULL);
> >
> > static ssize_t
> > +acpi_device_uid_show(struct device *dev, struct device_attribute *attr,
> char *buf) {
> > + struct acpi_device *acpi_dev = to_acpi_device(dev);
> > +
> > + return sprintf(buf, "%s\n", acpi_dev->pnp.unique_id); } static
> > +DEVICE_ATTR(uid, 0444, acpi_device_uid_show, NULL);
> > +
> > +static ssize_t
> > +acpi_device_adr_show(struct device *dev, struct device_attribute *attr,
> char *buf) {
> > + struct acpi_device *acpi_dev = to_acpi_device(dev);
> > +
> > + return sprintf(buf, "0x%08x\n", (unsigned
> > +int)(acpi_dev->pnp.bus_address)); } static DEVICE_ATTR(adr, 0444,
> > +acpi_device_adr_show, NULL);
> > +
> > +static ssize_t
> > acpi_device_path_show(struct device *dev, struct device_attribute *attr,
> char *buf) {
> > struct acpi_device *acpi_dev = to_acpi_device(dev);
> > struct acpi_buffer path = {ACPI_ALLOCATE_BUFFER, NULL}; @@ -257,6
> > +273,11 @@ static int acpi_device_setup_files(struct acpi_device *dev)
> > goto end;
> > }
> >
> > + if (dev->flags.bus_address)
> > + result = device_create_file(&dev->dev, &dev_attr_adr);
> > + if (dev->pnp.unique_id)
> > + result = device_create_file(&dev->dev, &dev_attr_uid);
> > +
> > /*
> > * If device has _EJ0, 'eject' file is created that is used to trigger
> > * hot-removal function from userland.
> > @@ -281,6 +302,10 @@ static void acpi_device_remove_files(struct
> acpi_device *dev)
> > if (ACPI_SUCCESS(status))
> > device_remove_file(&dev->dev, &dev_attr_eject);
> >
> > + if (dev->pnp.unique_id)
> > + device_remove_file(&dev->dev, &dev_attr_uid);
> > + if (dev->flags.bus_address)
> > + device_remove_file(&dev->dev, &dev_attr_adr);
> > device_remove_file(&dev->dev, &dev_attr_modalias);
> > device_remove_file(&dev->dev, &dev_attr_hid);
> > if (dev->handle)
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