Skip to content

Commit

Permalink
acpi: allow usage of acpi_tad on HW-reduced platforms
Browse files Browse the repository at this point in the history
The specification [1] allows so-called HW-reduced platforms,
which do not implement everything, especially the wakeup related stuff.

In that case, it is still usable as a RTC. This is helpful for [2]
and [3], which is about a device with no other working RTC,
but it does have an HW-reduced TAD, which can be used as a RTC instead.

[1]: https://uefi.org/specs/ACPI/6.5/09_ACPI_Defined_Devices_and_Device_Specific_Objects.html#time-and-alarm-device
[2]: https://bugzilla.kernel.org/show_bug.cgi?id=212313
[3]: linux-surface/linux-surface#415

Signed-off-by: Bart Groeneveld | GPX Solutions B.V. <bart@gpxbv.nl>
Patchset: rtc
  • Loading branch information
groengpx authored and qzed committed Apr 20, 2023
1 parent c4b8d0e commit c3f3a7a
Showing 1 changed file with 24 additions and 11 deletions.
35 changes: 24 additions & 11 deletions drivers/acpi/acpi_tad.c
Original file line number Diff line number Diff line change
Expand Up @@ -432,6 +432,14 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,

static DEVICE_ATTR_RO(caps);

static struct attribute *acpi_tad_attrs[] = {
&dev_attr_caps.attr,
NULL,
};
static const struct attribute_group acpi_tad_attr_group = {
.attrs = acpi_tad_attrs,
};

static ssize_t ac_alarm_store(struct device *dev, struct device_attribute *attr,
const char *buf, size_t count)
{
Expand Down Expand Up @@ -480,15 +488,14 @@ static ssize_t ac_status_show(struct device *dev, struct device_attribute *attr,

static DEVICE_ATTR_RW(ac_status);

static struct attribute *acpi_tad_attrs[] = {
&dev_attr_caps.attr,
static struct attribute *acpi_tad_ac_attrs[] = {
&dev_attr_ac_alarm.attr,
&dev_attr_ac_policy.attr,
&dev_attr_ac_status.attr,
NULL,
};
static const struct attribute_group acpi_tad_attr_group = {
.attrs = acpi_tad_attrs,
static const struct attribute_group acpi_tad_ac_attr_group = {
.attrs = acpi_tad_ac_attrs,
};

static ssize_t dc_alarm_store(struct device *dev, struct device_attribute *attr,
Expand Down Expand Up @@ -563,13 +570,18 @@ static int acpi_tad_remove(struct platform_device *pdev)

pm_runtime_get_sync(dev);

if (dd->capabilities & ACPI_TAD_AC_WAKE)
sysfs_remove_group(&dev->kobj, &acpi_tad_ac_attr_group);

if (dd->capabilities & ACPI_TAD_DC_WAKE)
sysfs_remove_group(&dev->kobj, &acpi_tad_dc_attr_group);

sysfs_remove_group(&dev->kobj, &acpi_tad_attr_group);

acpi_tad_disable_timer(dev, ACPI_TAD_AC_TIMER);
acpi_tad_clear_status(dev, ACPI_TAD_AC_TIMER);
if (dd->capabilities & ACPI_TAD_AC_WAKE) {
acpi_tad_disable_timer(dev, ACPI_TAD_AC_TIMER);
acpi_tad_clear_status(dev, ACPI_TAD_AC_TIMER);
}
if (dd->capabilities & ACPI_TAD_DC_WAKE) {
acpi_tad_disable_timer(dev, ACPI_TAD_DC_TIMER);
acpi_tad_clear_status(dev, ACPI_TAD_DC_TIMER);
Expand Down Expand Up @@ -604,11 +616,6 @@ static int acpi_tad_probe(struct platform_device *pdev)
return -ENODEV;
}

if (!acpi_has_method(handle, "_PRW")) {
dev_info(dev, "Missing _PRW\n");
return -ENODEV;
}

dd = devm_kzalloc(dev, sizeof(*dd), GFP_KERNEL);
if (!dd)
return -ENOMEM;
Expand Down Expand Up @@ -637,6 +644,12 @@ static int acpi_tad_probe(struct platform_device *pdev)
if (ret)
goto fail;

if (caps & ACPI_TAD_AC_WAKE) {
ret = sysfs_create_group(&dev->kobj, &acpi_tad_ac_attr_group);
if (ret)
goto fail;
}

if (caps & ACPI_TAD_DC_WAKE) {
ret = sysfs_create_group(&dev->kobj, &acpi_tad_dc_attr_group);
if (ret)
Expand Down

0 comments on commit c3f3a7a

Please sign in to comment.