surface3-wmi.c
// SPDX-License-Identifier: GPL-2.0-only
/*
* Driver for the LID cover switch of the Surface 3
*
* Copyright (c) 2016 Red Hat Inc.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/acpi.h>
#include <linux/dmi.h>
#include <linux/input.h>
#include <linux/mutex.h>
#include <linux/platform_device.h>
#include <linux/spi/spi.h>
MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
MODULE_DESCRIPTION("Surface 3 platform driver");
MODULE_LICENSE("GPL");
#define ACPI_BUTTON_HID_LID "PNP0C0D"
#define SPI_CTL_OBJ_NAME "SPI"
#define SPI_TS_OBJ_NAME "NTRG"
#define SURFACE3_LID_GUID "F7CC25EC-D20B-404C-8903-0ED4359C18AE"
MODULE_ALIAS("wmi:" SURFACE3_LID_GUID);
static const struct dmi_system_id surface3_dmi_table[] = {
#if defined(CONFIG_X86)
{
.matches = {
DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
DMI_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
},
},
#endif
{ }
};
struct surface3_wmi {
struct acpi_device *touchscreen_adev;
struct acpi_device *pnp0c0d_adev;
struct acpi_hotplug_context hp;
struct input_dev *input;
};
static struct platform_device *s3_wmi_pdev;
static struct surface3_wmi s3_wmi;
static DEFINE_MUTEX(s3_wmi_lock);
static int s3_wmi_query_block(const char *guid, int instance, int *ret)
{
struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
acpi_status status;
union acpi_object *obj;
int error = 0;
mutex_lock(&s3_wmi_lock);
status = wmi_query_block(guid, instance, &output);
obj = output.pointer;
if (!obj || obj->type != ACPI_TYPE_INTEGER) {
if (obj) {
pr_err("query block returned object type: %d - buffer length:%d\n",
obj->type,
obj->type == ACPI_TYPE_BUFFER ?
obj->buffer.length : 0);
}
error = -EINVAL;
goto out_free_unlock;
}
*ret = obj->integer.value;
out_free_unlock:
kfree(obj);
mutex_unlock(&s3_wmi_lock);
return error;
}
static inline int s3_wmi_query_lid(int *ret)
{
return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
}
static int s3_wmi_send_lid_state(void)
{
int ret, lid_sw;
ret = s3_wmi_query_lid(&lid_sw);
if (ret)
return ret;
input_report_switch(s3_wmi.input, SW_LID, lid_sw);
input_sync(s3_wmi.input);
return 0;
}
static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
{
return s3_wmi_send_lid_state();
}
static acpi_status s3_wmi_attach_spi_device(acpi_handle handle,
u32 level,
void *data,
void **return_value)
{
struct acpi_device *adev, **ts_adev;
if (acpi_bus_get_device(handle, &adev))
return AE_OK;
ts_adev = data;
if (strncmp(acpi_device_bid(adev), SPI_TS_OBJ_NAME,
strlen(SPI_TS_OBJ_NAME)))
return AE_OK;
if (*ts_adev) {
pr_err("duplicate entry %s\n", SPI_TS_OBJ_NAME);
return AE_OK;
}
*ts_adev = adev;
return AE_OK;
}
static int s3_wmi_check_platform_device(struct device *dev, void *data)
{
struct acpi_device *adev, *ts_adev = NULL;
acpi_handle handle;
acpi_status status;
/* ignore non ACPI devices */
handle = ACPI_HANDLE(dev);
if (!handle || acpi_bus_get_device(handle, &adev))
return 0;
/* check for LID ACPI switch */
if (!strcmp(ACPI_BUTTON_HID_LID, acpi_device_hid(adev))) {
s3_wmi.pnp0c0d_adev = adev;
return 0;
}
/* ignore non SPI controllers */
if (strncmp(acpi_device_bid(adev), SPI_CTL_OBJ_NAME,
strlen(SPI_CTL_OBJ_NAME)))
return 0;
status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
s3_wmi_attach_spi_device, NULL,
&ts_adev, NULL);
if (ACPI_FAILURE(status))
dev_warn(dev, "failed to enumerate SPI slaves\n");
if (!ts_adev)
return 0;
s3_wmi.touchscreen_adev = ts_adev;
return 0;
}
static int s3_wmi_create_and_register_input(struct platform_device *pdev)
{
struct input_dev *input;
int error;
input = devm_input_allocate_device(&pdev->dev);
if (!input)
return -ENOMEM;
input->name = "Lid Switch";
input->phys = "button/input0";
input->id.bustype = BUS_HOST;
input->id.product = 0x0005;
input_set_capability(input, EV_SW, SW_LID);
error = input_register_device(input);
if (error)
goto out_err;
s3_wmi.input = input;
return 0;
out_err:
input_free_device(s3_wmi.input);
return error;
}
static int __init s3_wmi_probe(struct platform_device *pdev)
{
int error;
if (!dmi_check_system(surface3_dmi_table))
return -ENODEV;
memset(&s3_wmi, 0, sizeof(s3_wmi));
bus_for_each_dev(&platform_bus_type, NULL, NULL,
s3_wmi_check_platform_device);
if (!s3_wmi.touchscreen_adev)
return -ENODEV;
acpi_bus_trim(s3_wmi.pnp0c0d_adev);
error = s3_wmi_create_and_register_input(pdev);
if (error)
goto restore_acpi_lid;
acpi_initialize_hp_context(s3_wmi.touchscreen_adev, &s3_wmi.hp,
s3_wmi_hp_notify, NULL);
s3_wmi_send_lid_state();
return 0;
restore_acpi_lid:
acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
return error;
}
static int s3_wmi_remove(struct platform_device *device)
{
/* remove the hotplug context from the acpi device */
s3_wmi.touchscreen_adev->hp = NULL;
/* reinstall the actual PNPC0C0D LID default handle */
acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
return 0;
}
static int __maybe_unused s3_wmi_resume(struct device *dev)
{
s3_wmi_send_lid_state();
return 0;
}
static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
static struct platform_driver s3_wmi_driver = {
.driver = {
.name = "surface3-wmi",
.pm = &s3_wmi_pm,
},
.remove = s3_wmi_remove,
};
static int __init s3_wmi_init(void)
{
int error;
s3_wmi_pdev = platform_device_alloc("surface3-wmi", -1);
if (!s3_wmi_pdev)
return -ENOMEM;
error = platform_device_add(s3_wmi_pdev);
if (error)
goto err_device_put;
error = platform_driver_probe(&s3_wmi_driver, s3_wmi_probe);
if (error)
goto err_device_del;
pr_info("Surface 3 WMI Extras loaded\n");
return 0;
err_device_del:
platform_device_del(s3_wmi_pdev);
err_device_put:
platform_device_put(s3_wmi_pdev);
return error;
}
static void __exit s3_wmi_exit(void)
{
platform_device_unregister(s3_wmi_pdev);
platform_driver_unregister(&s3_wmi_driver);
}
module_init(s3_wmi_init);
module_exit(s3_wmi_exit);