In all cases in which a struct acpi_driver is used for binding a driver
to an ACPI device object, a corresponding platform device is created by
the ACPI core and that device is regarded as a proper representation of
underlying hardware. Accordingly, a struct platform_driver should be
used by driver code to bind to that device. There are multiple reasons
why drivers should not bind directly to ACPI device objects [1].
Overall, it is better to bind drivers to platform devices than to their
ACPI companions, so convert the ChromeOS privacy-screen ACPI driver
to a platform one.
While this is not expected to alter functionality, it changes sysfs
layout and so it will be visible to user space.
Link: https://lore.kernel.org/all/2396510.ElGaqSPkdT@rafael.j.wysocki/ [1]
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Link: https://lore.kernel.org/r/1963835.tdWV9SEqCh@rafael.j.wysocki
Signed-off-by: Tzung-Bi Shih <tzungbi@kernel.org>
For bus-based driver, device removal is implemented as:
1 device_remove()->
2 bus->remove()->
3 driver->remove()
Driver core needs no inform from callee(bus driver) about the
result of remove callback. In that case, commit fc7a6209d5
("bus: Make remove callback return void") forces bus_type::remove
be void-returned.
Now we have the situation that both 1 & 2 of calling chain are
void-returned, so it does not make much sense for 3(driver->remove)
to return non-void to its caller.
So the basic idea behind this change is making remove() callback of
any bus-based driver to be void-returned.
This change, for itself, is for device drivers based on acpi-bus.
Acked-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Acked-by: Lee Jones <lee@kernel.org>
Acked-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Dawei Li <set_pte_at@outlook.com>
Reviewed-by: Maximilian Luz <luzmaximilian@gmail.com> # for drivers/platform/surface/*
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
This adds the ACPI driver for the ChromeOS privacy screen that is
present on some chromeos devices.
Note that ideally, we'd want this privacy screen driver to be probed
BEFORE the drm probe in order to avoid a drm probe deferral:
https://hansdegoede.livejournal.com/25948.html
In practise, I found that ACPI drivers are bound to their devices AFTER
the drm probe on chromebooks. So on chromebooks with privacy-screen,
this patch along with the other one in this series results in a probe
deferral of about 250ms for i915 driver. However, it did not result in
any user noticeable delay of splash screen in my personal experience.
In future if this probe deferral turns out to be an issue, we can
consider turning this ACPI driver into something that is probed
earlier than the drm drivers.
Signed-off-by: Rajat Jain <rajatja@google.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Acked-by: Benson Leung <bleung@chromium.org>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20220107190208.95479-2-rajatja@google.com
