| Message ID | Ynj8lA+bpTR1x2hJ@debian-BULLSEYE-live-builder-AMD64 (mailing list archive) |
|---|---|
| State | Superseded, archived |
| Headers | show |
| Series | [v10] platform/chrome: Add ChromeOS ACPI device driver | expand |
On Mon, May 09, 2022 at 04:35:48PM +0500, Muhammad Usama Anjum wrote: > From: Enric Balletbo i Serra <enric.balletbo@collabora.com> > > The x86 Chromebooks have the ChromeOS ACPI device. This driver attaches > to the ChromeOS ACPI device and exports the values reported by ACPI in a > sysfs directory. This data isn't present in ACPI tables when read > through ACPI tools, hence a driver is needed to do it. The driver gets > data from firmware using the ACPI component of the kernel. The ACPI values > are presented in string form (numbers as decimal values) or binary > blobs, and can be accessed as the contents of the appropriate read only > files in the standard ACPI device's sysfs directory tree. This data is > consumed by the ChromeOS user space. > > Cc: Rafael J. Wysocki <rafael.j.wysocki@intel.com> > Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com> > Cc: Hans de Goede <hdegoede@redhat.com> > Signed-off-by: Enric Balletbo i Serra <enric.balletbo@collabora.com> > Co-developed-by: Muhammad Usama Anjum <usama.anjum@collabora.com> > Signed-off-by: Muhammad Usama Anjum <usama.anjum@collabora.com> > --- > The driver's implementation has been changed completely after Greg's > comment. I've updated the authorship of the module to myself. Enric, > Please let me know if yuo are comfortable with this. > > Changes in v10: > - Remove COMPILE_TEST as driver depends on ACPI component which isn't > enabled by COMPILE_TEST itself. > - Fix build warnings > > Changes in v9: > - Changed the implementation completely > - Move the driver to drivers/platform/chrome > - Remove Acked-by Rafael as driver has changed > - Corrected some typos > - Changed the author of the module > > Changes in v8: > - Change struct platform_driver name from chromeos_acpi_driver to > chromeos_acpi_device_driver > > Changes in v7: > - Rename acpi_chromeos Kconfig option to chromeos_acpi > - Change this acpi driver to platform driver > - Minor cosmetic changes > > There were the following concerns on v4 which have been delt with in > v5/v6: > - Remove BINF.{0,1,4} from sysfs as they are reserved and not used > anymore > - Reword the description of MECK > - Change function name from chromeos_acpi_alloc_name() to > chromeos_acpi_gen_file_name() > - Remove local variable obj in chromeos_acpi_add_method() > - Replace usage of dev_info() to dev_dbg() > - Improve the description of the patch > - Add the firmware interface document which serves as primary > documentation and garantees that this interface will not change > - GGL0001 is valid PNP ID of the Google. PNP ID can be used with the > ACPI devices. Consensus was developed on it in discussion of v4. > > Changes in v6: > - Correct authorship and path email's From > - Add changelog between v4 and v5 in detail > - Add copywrite year 2022 > - Improve the description and add concerns from V4 which have been fixed > > Changes in v5: > - Improve the description of the patch > - Document firmware interface > - Update sysfs interface documentation > - Remove binf{0,1,4} as they have been deprecated > - Update some cleanup logic in case of error > - Remove freeing of chromeos_acpi.root explicitely in > chromeos_acpi_device_remove() as it'll be automatically freed by > chromeos_acpi_remove_groups() > - If sysfs_create_groups() fails in chromeos_acpi_process_mlst(), > cleanup all groups > - Cosmetic changes > > Changes in v4: > https://lore.kernel.org/lkml/20200413134611.478441-1-enric.balletbo@collabora.com/t/ > - Add COMPILE_TEST to increase build coverage. > - Add sysfs ABI documentation. > - Rebased on top of 5.7-rc1 and solve conflicts. > - Cc ACPI maintainers. > > Changes in v3: > - Use attribute groups instead of adding files "by hand". > - Do not use "raw" kobject to create directories. > - Do not abuse of the platform_device interface. Remove it. > > Changes in v2: > - Note that this version is a total rework, with those major changes: > - Use lists to track dinamically allocated attributes and groups. > - Use sysfs binary attributes to store the ACPI contents. > - Remove all the functionalities except the one that creates the sysfs files. > --- > .../ABI/testing/sysfs-driver-chromeos-acpi | 126 ++++++ > .../acpi/chromeos-acpi-device.rst | 363 ++++++++++++++++++ > Documentation/firmware-guide/acpi/index.rst | 1 + > drivers/platform/chrome/Kconfig | 11 + > drivers/platform/chrome/Makefile | 1 + > drivers/platform/chrome/chromeos_acpi.c | 278 ++++++++++++++ > 6 files changed, 780 insertions(+) > create mode 100644 Documentation/ABI/testing/sysfs-driver-chromeos-acpi > create mode 100644 Documentation/firmware-guide/acpi/chromeos-acpi-device.rst > create mode 100644 drivers/platform/chrome/chromeos_acpi.c > > diff --git a/Documentation/ABI/testing/sysfs-driver-chromeos-acpi b/Documentation/ABI/testing/sysfs-driver-chromeos-acpi > new file mode 100644 > index 0000000000000..5b59ef9d7b371 > --- /dev/null > +++ b/Documentation/ABI/testing/sysfs-driver-chromeos-acpi > @@ -0,0 +1,126 @@ > +What: /sys/bus/platform/devices/GGL0001:*/BINF.2 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows information about the current boot of > + the active EC firmware. > + * 0 - Read only (recovery) firmware. > + * 1 - Rewritable firmware. > + > +What: /sys/bus/platform/devices/GGL0001:*/BINF.3 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows information about the current boot of > + the active main firmware type. > + * 0 - Recovery. > + * 1 - Normal. > + * 2 - Developer. > + * 3 - Netboot (factory installation only). > + > +What: /sys/bus/platform/devices/GGL0001:*/CHSW > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the switch position for the Chrome OS specific > + hardware switches. > + * 0 - No changes. > + * 2 - Recovery button was pressed when firmware booted. > + * 4 - Recovery button was pressed when EC firmware booted. > + * 32 - Developer switch was enabled when firmware booted. > + * 512 - Firmware write protection was disabled when firmware > + booted. > + > +What: /sys/bus/platform/devices/GGL0001:*/FMAP > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the physical memory address of the start of > + the main processor firmware flashmap. > + > +What: /sys/bus/platform/devices/GGL0001:*/FRID > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the firmware version for the read-only portion > + of the main processor firmware. > + > +What: /sys/bus/platform/devices/GGL0001:*/FWID > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the firmware version for the rewritable portion > + of the main processor firmware. > + > +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.0 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the type of the GPIO signal for the Chrome OS > + specific GPIO assignments. > + * 1 - Recovery button. > + * 2 - Developer mode switch. > + * 3 - Firmware write protection switch. > + * 256 to 511 - Debug header GPIO 0 to GPIO 255. > + > +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.1 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the signal attributes of the GPIO signal. > + * 0 - Signal is active low. > + * 1 - Signal is active high. > + > +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.2 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the GPIO number on the specified GPIO > + controller. > + > +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.3 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the name of the GPIO controller. > + > +What: /sys/bus/platform/devices/GGL0001:*/HWID > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the hardware ID for the Chromebook. > + > +What: /sys/bus/platform/devices/GGL0001:*/MECK > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This binary file returns the SHA-1 or SHA-256 hash that is > + read out of the Management Engine extended registers during > + boot. The hash is exported vi ACPI so the OS can verify that > + the Management Engine firmware has not changed. If Management > + Engine is not present, or if the firmware was unable to read the > + extended registers, this buffer size can be zero. > + > +What: /sys/bus/platform/devices/GGL0001:*/VBNV.0 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the offset in CMOS bank 0 of the verified boot > + non-volatile storage block, counting from the first writable > + CMOS byte (that is, 'offset = 0' is the byte following the 14 > + bytes of clock data). > + > +What: /sys/bus/platform/devices/GGL0001:*/VBNV.1 > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This file shows the size in bytes of the verified boot > + non-volatile storage block. > + > +What: /sys/bus/platform/devices/GGL0001:*/VDAT > +Date: May 2022 > +KernelVersion: 5.19 > +Description: > + This binary file returns the verified boot data block shared > + between the firmware verification step and the kernel > + verification step. > diff --git a/Documentation/firmware-guide/acpi/chromeos-acpi-device.rst b/Documentation/firmware-guide/acpi/chromeos-acpi-device.rst > new file mode 100644 > index 0000000000000..f37fc90ce340e > --- /dev/null > +++ b/Documentation/firmware-guide/acpi/chromeos-acpi-device.rst > @@ -0,0 +1,363 @@ > +.. SPDX-License-Identifier: GPL-2.0 > + > +===================== > +Chrome OS ACPI Device > +===================== > + > +Hardware functionality specific to Chrome OS is exposed through a Chrome OS ACPI device. > +The plug and play ID of a Chrome OS ACPI device is GGL0001. GGL is a valid PNP ID of Google. > +PNP ID can be used with the ACPI devices according to the guidelines. The following ACPI > +objects are supported: > + > +.. flat-table:: Supported ACPI Objects > + :widths: 1 2 > + :header-rows: 1 > + > + * - Object > + - Description > + > + * - CHSW > + - Chrome OS switch positions > + > + * - HWID > + - Chrome OS hardware ID > + > + * - FWID > + - Chrome OS firmware version > + > + * - FRID > + - Chrome OS read-only firmware version > + > + * - BINF > + - Chrome OS boot information > + > + * - GPIO > + - Chrome OS GPIO assignments > + > + * - VBNV > + - Chrome OS NVRAM locations > + > + * - VDTA > + - Chrome OS verified boot data > + > + * - FMAP > + - Chrome OS flashmap base address > + > + * - MLST > + - Chrome OS method list > + > +CHSW (Chrome OS switch positions) > +================================= > +This control method returns the switch positions for Chrome OS specific hardware switches. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +An integer containing the switch positions as bitfields: > + > +.. flat-table:: > + :widths: 1 2 > + > + * - 0x00000002 > + - Recovery button was pressed when x86 firmware booted. > + > + * - 0x00000004 > + - Recovery button was pressed when EC firmware booted. (required if EC EEPROM is > + rewritable; otherwise optional) > + > + * - 0x00000020 > + - Developer switch was enabled when x86 firmware booted. > + > + * - 0x00000200 > + - Firmware write protection was disabled when x86 firmware booted. (required if > + firmware write protection is controlled through x86 BIOS; otherwise optional) > + > +All other bits are reserved and should be set to 0. > + > +HWID (Chrome OS hardware ID) > +============================ > +This control method returns the hardware ID for the Chromebook. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +A null-terminated ASCII string containing the hardware ID from the Model-Specific Data area of > +EEPROM. > + > +Note that the hardware ID can be up to 256 characters long, including the terminating null. > + > +FWID (Chrome OS firmware version) > +================================= > +This control method returns the firmware version for the rewritable portion of the main > +processor firmware. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +A null-terminated ASCII string containing the complete firmware version for the rewritable > +portion of the main processor firmware. > + > +FRID (Chrome OS read-only firmware version) > +=========================================== > +This control method returns the firmware version for the read-only portion of the main > +processor firmware. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +A null-terminated ASCII string containing the complete firmware version for the read-only > +(bootstrap + recovery ) portion of the main processor firmware. > + > +BINF (Chrome OS boot information) > +================================= > +This control method returns information about the current boot. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > + > +.. code-block:: > + > + Package { > + Reserved1 > + Reserved2 > + Active EC Firmware > + Active Main Firmware Type > + Reserved5 > + } > + > +.. flat-table:: > + :widths: 1 1 2 > + :header-rows: 1 > + > + * - Field > + - Format > + - Description > + > + * - Reserved1 > + - DWORD > + - Set to 256 (0x100). This indicates this field is no longer used. > + > + * - Reserved2 > + - DWORD > + - Set to 256 (0x100). This indicates this field is no longer used. > + > + * - Active EC firmware > + - DWORD > + - The EC firmware which was used during boot. > + > + - 0 - Read-only (recovery) firmware > + - 1 - Rewritable firmware. > + > + Set to 0 if EC firmware is always read-only. > + > + * - Active Main Firmware Type > + - DWORD > + - The main firmware type which was used during boot. > + > + - 0 - Recovery > + - 1 - Normal > + - 2 - Developer > + - 3 - netboot (factory installation only) > + > + Other values are reserved. > + > + * - Reserved5 > + - DWORD > + - Set to 256 (0x100). This indicates this field is no longer used. > + > +GPIO (Chrome OS GPIO assignments) > +================================= > +This control method returns information about Chrome OS specific GPIO assignments for > +Chrome OS hardware, so the kernel can directly control that hardware. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +.. code-block:: > + > + Package { > + Package { > + // First GPIO assignment > + Signal Type //DWORD > + Attributes //DWORD > + Controller Offset //DWORD > + Controller Name //ASCIIZ > + }, > + ... > + Package { > + // Last GPIO assignment > + Signal Type //DWORD > + Attributes //DWORD > + Controller Offset //DWORD > + Controller Name //ASCIIZ > + } > + } > + > +Where ASCIIZ means a null-terminated ASCII string. > + > +.. flat-table:: > + :widths: 1 1 2 > + :header-rows: 1 > + > + * - Field > + - Format > + - Description > + > + * - Signal Type > + - DWORD > + - Type of GPIO signal > + > + - 0x00000001 - Recovery button > + - 0x00000002 - Developer mode switch > + - 0x00000003 - Firmware write protection switch > + - 0x00000100 - Debug header GPIO 0 > + - ... > + - 0x000001FF - Debug header GPIO 255 > + > + Other values are reserved. > + > + * - Attributes > + - DWORD > + - Signal attributes as bitfields: > + > + - 0x00000001 - Signal is active-high (for button, a GPIO value > + of 1 means the button is pressed; for switches, a GPIO value > + of 1 means the switch is enabled). If this bit is 0, the signal > + is active low. Set to 0 for debug header GPIOs. > + > + * - Controller Offset > + - DWORD > + - GPIO number on the specified controller. > + > + * - Controller Name > + - ASCIIZ > + - Name of the controller for the GPIO. > + Currently supported names: > + "NM10" - Intel NM10 chip > + > +VBNV (Chrome OS NVRAM locations) > +================================ > +This control method returns information about the NVRAM (CMOS) locations used to > +communicate with the BIOS. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +.. code-block:: > + > + Package { > + NV Storage Block Offset //DWORD > + NV Storage Block Size //DWORD > + } > + > +.. flat-table:: > + :widths: 1 1 2 > + :header-rows: 1 > + > + * - Field > + - Format > + - Description > + > + * - NV Storage Block Offset > + - DWORD > + - Offset in CMOS bank 0 of the verified boot non-volatile storage block, counting from > + the first writable CMOS byte (that is, offset=0 is the byte following the 14 bytes of > + clock data). > + > + * - NV Storage Block Size > + - DWORD > + - Size in bytes of the verified boot non-volatile storage block. > + > +FMAP (Chrome OS flashmap address) > +================================= > +This control method returns the physical memory address of the start of the main processor > +firmware flashmap. > + > +Arguments: > +---------- > +None > + > +NoneResult code: > +---------------- > +A DWORD containing the physical memory address of the start of the main processor firmware > +flashmap. > + > +VDTA (Chrome OS verified boot data) > +=================================== > +This control method returns the verified boot data block shared between the firmware > +verification step and the kernel verification step. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +A buffer containing the verified boot data block. > + > +MECK (Management Engine Checksum) > +================================= > +This control method returns the SHA-1 or SHA-256 hash that is read out of the Management > +Engine extended registers during boot. The hash is exported via ACPI so the OS can verify that > +the ME firmware has not changed. If Management Engine is not present, or if the firmware was > +unable to read the extended registers, this buffer can be zero. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +A buffer containing the ME hash. > + > +MLST (Chrome OS method list) > +============================ > +This control method returns a list of the other control methods supported by the Chrome OS > +hardware device. > + > +Arguments: > +---------- > +None > + > +Result code: > +------------ > +A package containing a list of null-terminated ASCII strings, one for each control method > +supported by the Chrome OS hardware device, not including the MLST method itself. > +For this version of the specification, the result is: > + > +.. code-block:: > + > + Package { > + "CHSW", > + "FWID", > + "HWID", > + "FRID", > + "BINF", > + "GPIO", > + "VBNV", > + "FMAP", > + "VDTA", > + "MECK" > + } > diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst > index b053b0c3d6969..b6a42f4ffe032 100644 > --- a/Documentation/firmware-guide/acpi/index.rst > +++ b/Documentation/firmware-guide/acpi/index.rst > @@ -29,3 +29,4 @@ ACPI Support > non-d0-probe > extcon-intel-int3496 > intel-pmc-mux > + chromeos-acpi-device > diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig > index 75e93efd669f0..717299cbccac6 100644 > --- a/drivers/platform/chrome/Kconfig > +++ b/drivers/platform/chrome/Kconfig > @@ -15,6 +15,17 @@ menuconfig CHROME_PLATFORMS > > if CHROME_PLATFORMS > > +config CHROMEOS_ACPI > + tristate "ChromeOS specific ACPI extensions" > + depends on ACPI > + help > + This driver provides the firmware interface for the services > + exported through the ChromeOS interfaces when using ChromeOS > + ACPI firmware. > + > + If you have an ACPI-compatible Chromebook, say Y or M here. > + The module will be called chromeos_acpi. > + > config CHROMEOS_LAPTOP > tristate "Chrome OS Laptop" > depends on I2C && DMI && X86 > diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile > index 6420ca129548e..52f5a2dde8b81 100644 > --- a/drivers/platform/chrome/Makefile > +++ b/drivers/platform/chrome/Makefile > @@ -4,6 +4,7 @@ > CFLAGS_cros_ec_trace.o:= -I$(src) > CFLAGS_cros_ec_sensorhub_ring.o:= -I$(src) > > +obj-$(CONFIG_CHROMEOS_ACPI) += chromeos_acpi.o > obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o > obj-$(CONFIG_CHROMEOS_PRIVACY_SCREEN) += chromeos_privacy_screen.o > obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o > diff --git a/drivers/platform/chrome/chromeos_acpi.c b/drivers/platform/chrome/chromeos_acpi.c > new file mode 100644 > index 0000000000000..cb7b6d326803d > --- /dev/null > +++ b/drivers/platform/chrome/chromeos_acpi.c > @@ -0,0 +1,278 @@ > +// SPDX-License-Identifier: GPL-2.0-only > +/* > + * ChromeOS specific ACPI extensions > + * > + * Copyright 2022 Google LLC > + * > + * This driver attaches to the ChromeOS ACPI device and then exports the > + * values reported by the ACPI in a sysfs directory. All values are > + * presented in the string form (numbers as decimal values) and can be > + * accessed as the contents of the appropriate read only files in the > + * sysfs directory tree. > + */ > +#include <linux/acpi.h> > +#include <linux/platform_device.h> > +#include <linux/kernel.h> > +#include <linux/list.h> > +#include <linux/module.h> > + > +#define ACPI_ATTR_NAME_LEN 4 > + > +#define DEV_ATTR(_var, _name) \ > + static struct device_attribute dev_attr_##_var = { \ > + .attr = { .name = _name, .mode = 0444 }, \ > + .show = chromeos_first_level_attr_show \ > + }; Why do you really need to define your own macro here? What's wrong with DEVICE_ATTR_RO()? At the very least, use __ATTR() please, to ensure you get the read-only mode correct, but really, just use the macros we have already today. I see you want only one show function, so please use __ATTR(). > + > +#define GPIO_ATTR_GROUP(_group, _name, _num) \ > + static umode_t attr_is_visible_gpio_##_num(struct kobject *kobj, \ > + struct attribute *attr, int n) \ > + { \ > + if (_num < chromeos_acpi_gpio_groups) \ > + return attr->mode; \ > + else \ > + return 0; \ > + } \ > + static ssize_t chromeos_attr_show_gpio_##_num(struct device *dev, \ > + struct device_attribute *attr, \ > + char *buf) \ > + { \ > + char name[ACPI_ATTR_NAME_LEN + 1]; \ > + int ret, num; \ > + \ > + ret = parse_attr_name(attr->attr.name, name, &num); \ > + if (ret) \ > + return ret; \ > + ret = chromeos_acpi_evaluate_method(dev, _num, num, name, buf); \ > + if (ret < 0) \ > + ret = 0; \ > + return ret; \ > + } \ > + static struct device_attribute dev_attr_0_##_group = { \ > + .attr = { .name = "GPIO.0", .mode = 0444 }, \ > + .show = chromeos_attr_show_gpio_##_num \ > + }; \ > + static struct device_attribute dev_attr_1_##_group = { \ > + .attr = { .name = "GPIO.1", .mode = 0444 }, \ > + .show = chromeos_attr_show_gpio_##_num \ > + }; \ > + static struct device_attribute dev_attr_2_##_group = { \ > + .attr = { .name = "GPIO.2", .mode = 0444 }, \ > + .show = chromeos_attr_show_gpio_##_num \ > + }; \ > + static struct device_attribute dev_attr_3_##_group = { \ > + .attr = { .name = "GPIO.3", .mode = 0444 }, \ > + .show = chromeos_attr_show_gpio_##_num \ > + }; \ Same for the above, __ATTR() please. > + static struct attribute *attrs_##_group[] = { \ > + &dev_attr_0_##_group.attr, \ > + &dev_attr_1_##_group.attr, \ > + &dev_attr_2_##_group.attr, \ > + &dev_attr_3_##_group.attr, \ > + NULL \ > + }; \ > + static const struct attribute_group attr_group_##_group = { \ > + .name = _name, \ > + .is_visible = attr_is_visible_gpio_##_num, \ > + .attrs = attrs_##_group \ > + }; > + > +static unsigned int chromeos_acpi_gpio_groups; > + > +/* Parse the ACPI package and return the data related to that attribute */ > +static int chromeos_acpi_handle_package(struct device *dev, union acpi_object *obj, > + int pkg_num, int sub_pkg_num, char *name, char *buf) > +{ > + union acpi_object *element = obj->package.elements; > + int length = -EINVAL; > + > + if (pkg_num >= obj->package.count) > + return -EINVAL; > + element += pkg_num; > + > + if (element->type == ACPI_TYPE_PACKAGE) { > + if (sub_pkg_num >= element->package.count) > + return -EINVAL; > + // select sub element inside this package > + element = element->package.elements; > + element += sub_pkg_num; > + } > + > + switch (element->type) { > + case ACPI_TYPE_INTEGER: > + length = sysfs_emit(buf, "%d", (int)element->integer.value); Why not just: return sysfs_emit(....) here and below? That allows you to drop the length variable entirely. > + break; > + case ACPI_TYPE_STRING: > + length = sysfs_emit(buf, "%s", element->string.pointer); > + break; > + case ACPI_TYPE_BUFFER: > + length = sysfs_emit(buf, "%s", element->buffer.pointer); > + break; > + default: > + dev_err(dev, "element type %d not supported\n", element->type); > + break; > + } > + > + return length; > +} But that all is just minor tweaks, your call if you want to do that or not. Otherwise looks much better than originally, nice work: Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/Documentation/ABI/testing/sysfs-driver-chromeos-acpi b/Documentation/ABI/testing/sysfs-driver-chromeos-acpi new file mode 100644 index 0000000000000..5b59ef9d7b371 --- /dev/null +++ b/Documentation/ABI/testing/sysfs-driver-chromeos-acpi @@ -0,0 +1,126 @@ +What: /sys/bus/platform/devices/GGL0001:*/BINF.2 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows information about the current boot of + the active EC firmware. + * 0 - Read only (recovery) firmware. + * 1 - Rewritable firmware. + +What: /sys/bus/platform/devices/GGL0001:*/BINF.3 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows information about the current boot of + the active main firmware type. + * 0 - Recovery. + * 1 - Normal. + * 2 - Developer. + * 3 - Netboot (factory installation only). + +What: /sys/bus/platform/devices/GGL0001:*/CHSW +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the switch position for the Chrome OS specific + hardware switches. + * 0 - No changes. + * 2 - Recovery button was pressed when firmware booted. + * 4 - Recovery button was pressed when EC firmware booted. + * 32 - Developer switch was enabled when firmware booted. + * 512 - Firmware write protection was disabled when firmware + booted. + +What: /sys/bus/platform/devices/GGL0001:*/FMAP +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the physical memory address of the start of + the main processor firmware flashmap. + +What: /sys/bus/platform/devices/GGL0001:*/FRID +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the firmware version for the read-only portion + of the main processor firmware. + +What: /sys/bus/platform/devices/GGL0001:*/FWID +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the firmware version for the rewritable portion + of the main processor firmware. + +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.0 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the type of the GPIO signal for the Chrome OS + specific GPIO assignments. + * 1 - Recovery button. + * 2 - Developer mode switch. + * 3 - Firmware write protection switch. + * 256 to 511 - Debug header GPIO 0 to GPIO 255. + +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.1 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the signal attributes of the GPIO signal. + * 0 - Signal is active low. + * 1 - Signal is active high. + +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.2 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the GPIO number on the specified GPIO + controller. + +What: /sys/bus/platform/devices/GGL0001:*/GPIO.X/GPIO.3 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the name of the GPIO controller. + +What: /sys/bus/platform/devices/GGL0001:*/HWID +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the hardware ID for the Chromebook. + +What: /sys/bus/platform/devices/GGL0001:*/MECK +Date: May 2022 +KernelVersion: 5.19 +Description: + This binary file returns the SHA-1 or SHA-256 hash that is + read out of the Management Engine extended registers during + boot. The hash is exported vi ACPI so the OS can verify that + the Management Engine firmware has not changed. If Management + Engine is not present, or if the firmware was unable to read the + extended registers, this buffer size can be zero. + +What: /sys/bus/platform/devices/GGL0001:*/VBNV.0 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the offset in CMOS bank 0 of the verified boot + non-volatile storage block, counting from the first writable + CMOS byte (that is, 'offset = 0' is the byte following the 14 + bytes of clock data). + +What: /sys/bus/platform/devices/GGL0001:*/VBNV.1 +Date: May 2022 +KernelVersion: 5.19 +Description: + This file shows the size in bytes of the verified boot + non-volatile storage block. + +What: /sys/bus/platform/devices/GGL0001:*/VDAT +Date: May 2022 +KernelVersion: 5.19 +Description: + This binary file returns the verified boot data block shared + between the firmware verification step and the kernel + verification step. diff --git a/Documentation/firmware-guide/acpi/chromeos-acpi-device.rst b/Documentation/firmware-guide/acpi/chromeos-acpi-device.rst new file mode 100644 index 0000000000000..f37fc90ce340e --- /dev/null +++ b/Documentation/firmware-guide/acpi/chromeos-acpi-device.rst @@ -0,0 +1,363 @@ +.. SPDX-License-Identifier: GPL-2.0 + +===================== +Chrome OS ACPI Device +===================== + +Hardware functionality specific to Chrome OS is exposed through a Chrome OS ACPI device. +The plug and play ID of a Chrome OS ACPI device is GGL0001. GGL is a valid PNP ID of Google. +PNP ID can be used with the ACPI devices according to the guidelines. The following ACPI +objects are supported: + +.. flat-table:: Supported ACPI Objects + :widths: 1 2 + :header-rows: 1 + + * - Object + - Description + + * - CHSW + - Chrome OS switch positions + + * - HWID + - Chrome OS hardware ID + + * - FWID + - Chrome OS firmware version + + * - FRID + - Chrome OS read-only firmware version + + * - BINF + - Chrome OS boot information + + * - GPIO + - Chrome OS GPIO assignments + + * - VBNV + - Chrome OS NVRAM locations + + * - VDTA + - Chrome OS verified boot data + + * - FMAP + - Chrome OS flashmap base address + + * - MLST + - Chrome OS method list + +CHSW (Chrome OS switch positions) +================================= +This control method returns the switch positions for Chrome OS specific hardware switches. + +Arguments: +---------- +None + +Result code: +------------ +An integer containing the switch positions as bitfields: + +.. flat-table:: + :widths: 1 2 + + * - 0x00000002 + - Recovery button was pressed when x86 firmware booted. + + * - 0x00000004 + - Recovery button was pressed when EC firmware booted. (required if EC EEPROM is + rewritable; otherwise optional) + + * - 0x00000020 + - Developer switch was enabled when x86 firmware booted. + + * - 0x00000200 + - Firmware write protection was disabled when x86 firmware booted. (required if + firmware write protection is controlled through x86 BIOS; otherwise optional) + +All other bits are reserved and should be set to 0. + +HWID (Chrome OS hardware ID) +============================ +This control method returns the hardware ID for the Chromebook. + +Arguments: +---------- +None + +Result code: +------------ +A null-terminated ASCII string containing the hardware ID from the Model-Specific Data area of +EEPROM. + +Note that the hardware ID can be up to 256 characters long, including the terminating null. + +FWID (Chrome OS firmware version) +================================= +This control method returns the firmware version for the rewritable portion of the main +processor firmware. + +Arguments: +---------- +None + +Result code: +------------ +A null-terminated ASCII string containing the complete firmware version for the rewritable +portion of the main processor firmware. + +FRID (Chrome OS read-only firmware version) +=========================================== +This control method returns the firmware version for the read-only portion of the main +processor firmware. + +Arguments: +---------- +None + +Result code: +------------ +A null-terminated ASCII string containing the complete firmware version for the read-only +(bootstrap + recovery ) portion of the main processor firmware. + +BINF (Chrome OS boot information) +================================= +This control method returns information about the current boot. + +Arguments: +---------- +None + +Result code: +------------ + +.. code-block:: + + Package { + Reserved1 + Reserved2 + Active EC Firmware + Active Main Firmware Type + Reserved5 + } + +.. flat-table:: + :widths: 1 1 2 + :header-rows: 1 + + * - Field + - Format + - Description + + * - Reserved1 + - DWORD + - Set to 256 (0x100). This indicates this field is no longer used. + + * - Reserved2 + - DWORD + - Set to 256 (0x100). This indicates this field is no longer used. + + * - Active EC firmware + - DWORD + - The EC firmware which was used during boot. + + - 0 - Read-only (recovery) firmware + - 1 - Rewritable firmware. + + Set to 0 if EC firmware is always read-only. + + * - Active Main Firmware Type + - DWORD + - The main firmware type which was used during boot. + + - 0 - Recovery + - 1 - Normal + - 2 - Developer + - 3 - netboot (factory installation only) + + Other values are reserved. + + * - Reserved5 + - DWORD + - Set to 256 (0x100). This indicates this field is no longer used. + +GPIO (Chrome OS GPIO assignments) +================================= +This control method returns information about Chrome OS specific GPIO assignments for +Chrome OS hardware, so the kernel can directly control that hardware. + +Arguments: +---------- +None + +Result code: +------------ +.. code-block:: + + Package { + Package { + // First GPIO assignment + Signal Type //DWORD + Attributes //DWORD + Controller Offset //DWORD + Controller Name //ASCIIZ + }, + ... + Package { + // Last GPIO assignment + Signal Type //DWORD + Attributes //DWORD + Controller Offset //DWORD + Controller Name //ASCIIZ + } + } + +Where ASCIIZ means a null-terminated ASCII string. + +.. flat-table:: + :widths: 1 1 2 + :header-rows: 1 + + * - Field + - Format + - Description + + * - Signal Type + - DWORD + - Type of GPIO signal + + - 0x00000001 - Recovery button + - 0x00000002 - Developer mode switch + - 0x00000003 - Firmware write protection switch + - 0x00000100 - Debug header GPIO 0 + - ... + - 0x000001FF - Debug header GPIO 255 + + Other values are reserved. + + * - Attributes + - DWORD + - Signal attributes as bitfields: + + - 0x00000001 - Signal is active-high (for button, a GPIO value + of 1 means the button is pressed; for switches, a GPIO value + of 1 means the switch is enabled). If this bit is 0, the signal + is active low. Set to 0 for debug header GPIOs. + + * - Controller Offset + - DWORD + - GPIO number on the specified controller. + + * - Controller Name + - ASCIIZ + - Name of the controller for the GPIO. + Currently supported names: + "NM10" - Intel NM10 chip + +VBNV (Chrome OS NVRAM locations) +================================ +This control method returns information about the NVRAM (CMOS) locations used to +communicate with the BIOS. + +Arguments: +---------- +None + +Result code: +------------ +.. code-block:: + + Package { + NV Storage Block Offset //DWORD + NV Storage Block Size //DWORD + } + +.. flat-table:: + :widths: 1 1 2 + :header-rows: 1 + + * - Field + - Format + - Description + + * - NV Storage Block Offset + - DWORD + - Offset in CMOS bank 0 of the verified boot non-volatile storage block, counting from + the first writable CMOS byte (that is, offset=0 is the byte following the 14 bytes of + clock data). + + * - NV Storage Block Size + - DWORD + - Size in bytes of the verified boot non-volatile storage block. + +FMAP (Chrome OS flashmap address) +================================= +This control method returns the physical memory address of the start of the main processor +firmware flashmap. + +Arguments: +---------- +None + +NoneResult code: +---------------- +A DWORD containing the physical memory address of the start of the main processor firmware +flashmap. + +VDTA (Chrome OS verified boot data) +=================================== +This control method returns the verified boot data block shared between the firmware +verification step and the kernel verification step. + +Arguments: +---------- +None + +Result code: +------------ +A buffer containing the verified boot data block. + +MECK (Management Engine Checksum) +================================= +This control method returns the SHA-1 or SHA-256 hash that is read out of the Management +Engine extended registers during boot. The hash is exported via ACPI so the OS can verify that +the ME firmware has not changed. If Management Engine is not present, or if the firmware was +unable to read the extended registers, this buffer can be zero. + +Arguments: +---------- +None + +Result code: +------------ +A buffer containing the ME hash. + +MLST (Chrome OS method list) +============================ +This control method returns a list of the other control methods supported by the Chrome OS +hardware device. + +Arguments: +---------- +None + +Result code: +------------ +A package containing a list of null-terminated ASCII strings, one for each control method +supported by the Chrome OS hardware device, not including the MLST method itself. +For this version of the specification, the result is: + +.. code-block:: + + Package { + "CHSW", + "FWID", + "HWID", + "FRID", + "BINF", + "GPIO", + "VBNV", + "FMAP", + "VDTA", + "MECK" + } diff --git a/Documentation/firmware-guide/acpi/index.rst b/Documentation/firmware-guide/acpi/index.rst index b053b0c3d6969..b6a42f4ffe032 100644 --- a/Documentation/firmware-guide/acpi/index.rst +++ b/Documentation/firmware-guide/acpi/index.rst @@ -29,3 +29,4 @@ ACPI Support non-d0-probe extcon-intel-int3496 intel-pmc-mux + chromeos-acpi-device diff --git a/drivers/platform/chrome/Kconfig b/drivers/platform/chrome/Kconfig index 75e93efd669f0..717299cbccac6 100644 --- a/drivers/platform/chrome/Kconfig +++ b/drivers/platform/chrome/Kconfig @@ -15,6 +15,17 @@ menuconfig CHROME_PLATFORMS if CHROME_PLATFORMS +config CHROMEOS_ACPI + tristate "ChromeOS specific ACPI extensions" + depends on ACPI + help + This driver provides the firmware interface for the services + exported through the ChromeOS interfaces when using ChromeOS + ACPI firmware. + + If you have an ACPI-compatible Chromebook, say Y or M here. + The module will be called chromeos_acpi. + config CHROMEOS_LAPTOP tristate "Chrome OS Laptop" depends on I2C && DMI && X86 diff --git a/drivers/platform/chrome/Makefile b/drivers/platform/chrome/Makefile index 6420ca129548e..52f5a2dde8b81 100644 --- a/drivers/platform/chrome/Makefile +++ b/drivers/platform/chrome/Makefile @@ -4,6 +4,7 @@ CFLAGS_cros_ec_trace.o:= -I$(src) CFLAGS_cros_ec_sensorhub_ring.o:= -I$(src) +obj-$(CONFIG_CHROMEOS_ACPI) += chromeos_acpi.o obj-$(CONFIG_CHROMEOS_LAPTOP) += chromeos_laptop.o obj-$(CONFIG_CHROMEOS_PRIVACY_SCREEN) += chromeos_privacy_screen.o obj-$(CONFIG_CHROMEOS_PSTORE) += chromeos_pstore.o diff --git a/drivers/platform/chrome/chromeos_acpi.c b/drivers/platform/chrome/chromeos_acpi.c new file mode 100644 index 0000000000000..cb7b6d326803d --- /dev/null +++ b/drivers/platform/chrome/chromeos_acpi.c @@ -0,0 +1,278 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * ChromeOS specific ACPI extensions + * + * Copyright 2022 Google LLC + * + * This driver attaches to the ChromeOS ACPI device and then exports the + * values reported by the ACPI in a sysfs directory. All values are + * presented in the string form (numbers as decimal values) and can be + * accessed as the contents of the appropriate read only files in the + * sysfs directory tree. + */ +#include <linux/acpi.h> +#include <linux/platform_device.h> +#include <linux/kernel.h> +#include <linux/list.h> +#include <linux/module.h> + +#define ACPI_ATTR_NAME_LEN 4 + +#define DEV_ATTR(_var, _name) \ + static struct device_attribute dev_attr_##_var = { \ + .attr = { .name = _name, .mode = 0444 }, \ + .show = chromeos_first_level_attr_show \ + }; + +#define GPIO_ATTR_GROUP(_group, _name, _num) \ + static umode_t attr_is_visible_gpio_##_num(struct kobject *kobj, \ + struct attribute *attr, int n) \ + { \ + if (_num < chromeos_acpi_gpio_groups) \ + return attr->mode; \ + else \ + return 0; \ + } \ + static ssize_t chromeos_attr_show_gpio_##_num(struct device *dev, \ + struct device_attribute *attr, \ + char *buf) \ + { \ + char name[ACPI_ATTR_NAME_LEN + 1]; \ + int ret, num; \ + \ + ret = parse_attr_name(attr->attr.name, name, &num); \ + if (ret) \ + return ret; \ + ret = chromeos_acpi_evaluate_method(dev, _num, num, name, buf); \ + if (ret < 0) \ + ret = 0; \ + return ret; \ + } \ + static struct device_attribute dev_attr_0_##_group = { \ + .attr = { .name = "GPIO.0", .mode = 0444 }, \ + .show = chromeos_attr_show_gpio_##_num \ + }; \ + static struct device_attribute dev_attr_1_##_group = { \ + .attr = { .name = "GPIO.1", .mode = 0444 }, \ + .show = chromeos_attr_show_gpio_##_num \ + }; \ + static struct device_attribute dev_attr_2_##_group = { \ + .attr = { .name = "GPIO.2", .mode = 0444 }, \ + .show = chromeos_attr_show_gpio_##_num \ + }; \ + static struct device_attribute dev_attr_3_##_group = { \ + .attr = { .name = "GPIO.3", .mode = 0444 }, \ + .show = chromeos_attr_show_gpio_##_num \ + }; \ + static struct attribute *attrs_##_group[] = { \ + &dev_attr_0_##_group.attr, \ + &dev_attr_1_##_group.attr, \ + &dev_attr_2_##_group.attr, \ + &dev_attr_3_##_group.attr, \ + NULL \ + }; \ + static const struct attribute_group attr_group_##_group = { \ + .name = _name, \ + .is_visible = attr_is_visible_gpio_##_num, \ + .attrs = attrs_##_group \ + }; + +static unsigned int chromeos_acpi_gpio_groups; + +/* Parse the ACPI package and return the data related to that attribute */ +static int chromeos_acpi_handle_package(struct device *dev, union acpi_object *obj, + int pkg_num, int sub_pkg_num, char *name, char *buf) +{ + union acpi_object *element = obj->package.elements; + int length = -EINVAL; + + if (pkg_num >= obj->package.count) + return -EINVAL; + element += pkg_num; + + if (element->type == ACPI_TYPE_PACKAGE) { + if (sub_pkg_num >= element->package.count) + return -EINVAL; + // select sub element inside this package + element = element->package.elements; + element += sub_pkg_num; + } + + switch (element->type) { + case ACPI_TYPE_INTEGER: + length = sysfs_emit(buf, "%d", (int)element->integer.value); + break; + case ACPI_TYPE_STRING: + length = sysfs_emit(buf, "%s", element->string.pointer); + break; + case ACPI_TYPE_BUFFER: + length = sysfs_emit(buf, "%s", element->buffer.pointer); + break; + default: + dev_err(dev, "element type %d not supported\n", element->type); + break; + } + + return length; +} + +static int chromeos_acpi_evaluate_method(struct device *dev, int pkg_num, int sub_pkg_num, + char *name, char *buf) +{ + struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; + acpi_status status; + int ret = -EINVAL; + + status = acpi_evaluate_object(ACPI_HANDLE(dev), name, NULL, &output); + if (ACPI_FAILURE(status)) { + dev_err(dev, "failed to retrieve %s. %s\n", name, acpi_format_exception(status)); + return ret; + } + + if (((union acpi_object *)output.pointer)->type == ACPI_TYPE_PACKAGE) + ret = chromeos_acpi_handle_package(dev, output.pointer, pkg_num, sub_pkg_num, + name, buf); + + kfree(output.pointer); + return ret; +} + +static int parse_attr_name(const char *name, char *attr_name, int *attr_num) +{ + int ret = 0; + + strscpy(attr_name, name, ACPI_ATTR_NAME_LEN + 1); + + if (strlen(name) > ACPI_ATTR_NAME_LEN) + ret = kstrtoint(&name[ACPI_ATTR_NAME_LEN + 1], 0, attr_num); + + return ret; +} + +static ssize_t chromeos_first_level_attr_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + char attr_name[ACPI_ATTR_NAME_LEN + 1]; + int ret, attr_num = 0; + + ret = parse_attr_name(attr->attr.name, attr_name, &attr_num); + if (ret) + return 0; + ret = chromeos_acpi_evaluate_method(dev, attr_num, 0, attr_name, buf); + if (ret < 0) + ret = 0; + return ret; +} + +static unsigned int get_gpio_pkg_num(struct device *dev) +{ + struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL }; + acpi_status status; + unsigned int count = 0; + char *name = "GPIO"; + + status = acpi_evaluate_object(ACPI_HANDLE(dev), name, NULL, &output); + if (ACPI_FAILURE(status)) { + dev_err(dev, "failed to retrieve %s. %s\n", name, acpi_format_exception(status)); + return count; + } + + if (((union acpi_object *)output.pointer)->type == ACPI_TYPE_PACKAGE) + count = ((union acpi_object *)output.pointer)->package.count; + + kfree(output.pointer); + return count; +} + +DEV_ATTR(binf2, "BINF.2") +DEV_ATTR(binf3, "BINF.3") +DEV_ATTR(chsw, "CHSW") +DEV_ATTR(fmap, "FMAP") +DEV_ATTR(frid, "FRID") +DEV_ATTR(fwid, "FWID") +DEV_ATTR(hwid, "HWID") +DEV_ATTR(meck, "MECK") +DEV_ATTR(vbnv0, "VBNV.0") +DEV_ATTR(vbnv1, "VBNV.1") +DEV_ATTR(vdat, "VDAT") + +static struct attribute *first_level_attrs[] = { + &dev_attr_binf2.attr, + &dev_attr_binf3.attr, + &dev_attr_chsw.attr, + &dev_attr_fmap.attr, + &dev_attr_frid.attr, + &dev_attr_fwid.attr, + &dev_attr_hwid.attr, + &dev_attr_meck.attr, + &dev_attr_vbnv0.attr, + &dev_attr_vbnv1.attr, + &dev_attr_vdat.attr, + NULL +}; + +static const struct attribute_group first_level_attr_group = { + .attrs = first_level_attrs, +}; + +/* Every platform can have different number of GPIO attribute groups. + * Define upper limit groups. At run time, the platform decides to show + * the present number of groups only, others are hidden. + */ +GPIO_ATTR_GROUP(gpio0, "GPIO.0", 0) +GPIO_ATTR_GROUP(gpio1, "GPIO.1", 1) +GPIO_ATTR_GROUP(gpio2, "GPIO.2", 2) +GPIO_ATTR_GROUP(gpio3, "GPIO.3", 3) +GPIO_ATTR_GROUP(gpio4, "GPIO.4", 4) +GPIO_ATTR_GROUP(gpio5, "GPIO.5", 5) +GPIO_ATTR_GROUP(gpio6, "GPIO.6", 6) +GPIO_ATTR_GROUP(gpio7, "GPIO.7", 7) + +static const struct attribute_group *chromeos_acpi_all_groups[] = { + &first_level_attr_group, + &attr_group_gpio0, + &attr_group_gpio1, + &attr_group_gpio2, + &attr_group_gpio3, + &attr_group_gpio4, + &attr_group_gpio5, + &attr_group_gpio6, + &attr_group_gpio7, + NULL +}; + +static int chromeos_acpi_device_probe(struct platform_device *pdev) +{ + chromeos_acpi_gpio_groups = get_gpio_pkg_num(&pdev->dev); + + /* If platform has more GPIO attribute groups than the number of + * groups this driver supports, give out a warning message. + */ + if (chromeos_acpi_gpio_groups > (ARRAY_SIZE(chromeos_acpi_all_groups) - 2)) + dev_warn(&(pdev->dev), "Only %u GPIO attr groups supported by the driver out of total %u.\n", + (unsigned int)(ARRAY_SIZE(chromeos_acpi_all_groups) - 2), + chromeos_acpi_gpio_groups); + return 0; +} + +/* GGL is valid PNP ID of Google. PNP ID can be used with the ACPI devices. */ +static const struct acpi_device_id chromeos_device_ids[] = { + { "GGL0001", 0 }, + {} +}; +MODULE_DEVICE_TABLE(acpi, chromeos_device_ids); + +static struct platform_driver chromeos_acpi_device_driver = { + .probe = chromeos_acpi_device_probe, + .driver = { + .name = KBUILD_MODNAME, + .dev_groups = chromeos_acpi_all_groups, + .acpi_match_table = ACPI_PTR(chromeos_device_ids) + } +}; +module_platform_driver(chromeos_acpi_device_driver); + +MODULE_AUTHOR("Muhammad Usama Anjum <usama.anjum@collabora.com>"); +MODULE_LICENSE("GPL"); +MODULE_DESCRIPTION("ChromeOS specific ACPI extensions");