1// SPDX-License-Identifier: GPL-2.0-only
  2/*
  3 *  Driver for the LID cover switch of the Surface 3
  4 *
  5 *  Copyright (c) 2016 Red Hat Inc.
  6 */
  7
  8
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/slab.h>
 12
 13#include <linux/acpi.h>
 14#include <linux/dmi.h>
 15#include <linux/input.h>
 16#include <linux/mutex.h>
 17#include <linux/platform_device.h>
 18#include <linux/spi/spi.h>
 19
 20MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
 21MODULE_DESCRIPTION("Surface 3 platform driver");
 22MODULE_LICENSE("GPL");
 23
 24#define ACPI_BUTTON_HID_LID		"PNP0C0D"
 25#define SPI_CTL_OBJ_NAME		"SPI"
 26#define SPI_TS_OBJ_NAME			"NTRG"
 27
 28#define SURFACE3_LID_GUID "F7CC25EC-D20B-404C-8903-0ED4359C18AE"
 29
 30MODULE_ALIAS("wmi:" SURFACE3_LID_GUID);
 31
 32static const struct dmi_system_id surface3_dmi_table[] = {
 33#if defined(CONFIG_X86)
 34	{
 35		.matches = {
 36			DMI_MATCH(DMI_SYS_VENDOR, "Microsoft Corporation"),
 37			DMI_MATCH(DMI_PRODUCT_NAME, "Surface 3"),
 38		},
 39	},
 40#endif
 41	{ }
 42};
 43
 44struct surface3_wmi {
 45	struct acpi_device *touchscreen_adev;
 46	struct acpi_device *pnp0c0d_adev;
 47	struct acpi_hotplug_context hp;
 48	struct input_dev *input;
 49};
 50
 51static struct platform_device *s3_wmi_pdev;
 52
 53static struct surface3_wmi s3_wmi;
 54
 55static DEFINE_MUTEX(s3_wmi_lock);
 56
 57static int s3_wmi_query_block(const char *guid, int instance, int *ret)
 58{
 59	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
 60	acpi_status status;
 61	union acpi_object *obj;
 62	int error = 0;
 63
 64	mutex_lock(&s3_wmi_lock);
 65	status = wmi_query_block(guid, instance, &output);
 66
 67	obj = output.pointer;
 68
 69	if (!obj || obj->type != ACPI_TYPE_INTEGER) {
 70		if (obj) {
 71			pr_err("query block returned object type: %d - buffer length:%d\n",
 72			       obj->type,
 73			       obj->type == ACPI_TYPE_BUFFER ?
 74						obj->buffer.length : 0);
 75		}
 76		error = -EINVAL;
 77		goto out_free_unlock;
 78	}
 79	*ret = obj->integer.value;
 80 out_free_unlock:
 81	kfree(obj);
 82	mutex_unlock(&s3_wmi_lock);
 83	return error;
 84}
 85
 86static inline int s3_wmi_query_lid(int *ret)
 87{
 88	return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
 89}
 90
 91static int s3_wmi_send_lid_state(void)
 92{
 93	int ret, lid_sw;
 94
 95	ret = s3_wmi_query_lid(&lid_sw);
 96	if (ret)
 97		return ret;
 98
 99	input_report_switch(s3_wmi.input, SW_LID, lid_sw);
100	input_sync(s3_wmi.input);
101
102	return 0;
103}
104
105static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
106{
107	return s3_wmi_send_lid_state();
108}
109
110static acpi_status s3_wmi_attach_spi_device(acpi_handle handle,
111					    u32 level,
112					    void *data,
113					    void **return_value)
114{
115	struct acpi_device *adev, **ts_adev;
116
117	if (acpi_bus_get_device(handle, &adev))
118		return AE_OK;
119
120	ts_adev = data;
121
122	if (strncmp(acpi_device_bid(adev), SPI_TS_OBJ_NAME,
123	    strlen(SPI_TS_OBJ_NAME)))
124		return AE_OK;
125
126	if (*ts_adev) {
127		pr_err("duplicate entry %s\n", SPI_TS_OBJ_NAME);
128		return AE_OK;
129	}
130
131	*ts_adev = adev;
132
133	return AE_OK;
134}
135
136static int s3_wmi_check_platform_device(struct device *dev, void *data)
137{
138	struct acpi_device *adev, *ts_adev = NULL;
139	acpi_handle handle;
140	acpi_status status;
141
142	/* ignore non ACPI devices */
143	handle = ACPI_HANDLE(dev);
144	if (!handle || acpi_bus_get_device(handle, &adev))
145		return 0;
146
147	/* check for LID ACPI switch */
148	if (!strcmp(ACPI_BUTTON_HID_LID, acpi_device_hid(adev))) {
149		s3_wmi.pnp0c0d_adev = adev;
150		return 0;
151	}
152
153	/* ignore non SPI controllers */
154	if (strncmp(acpi_device_bid(adev), SPI_CTL_OBJ_NAME,
155	    strlen(SPI_CTL_OBJ_NAME)))
156		return 0;
157
158	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
159				     s3_wmi_attach_spi_device, NULL,
160				     &ts_adev, NULL);
161	if (ACPI_FAILURE(status))
162		dev_warn(dev, "failed to enumerate SPI slaves\n");
163
164	if (!ts_adev)
165		return 0;
166
167	s3_wmi.touchscreen_adev = ts_adev;
168
169	return 0;
170}
171
172static int s3_wmi_create_and_register_input(struct platform_device *pdev)
173{
174	struct input_dev *input;
175	int error;
176
177	input = devm_input_allocate_device(&pdev->dev);
178	if (!input)
179		return -ENOMEM;
180
181	input->name = "Lid Switch";
182	input->phys = "button/input0";
183	input->id.bustype = BUS_HOST;
184	input->id.product = 0x0005;
185
186	input_set_capability(input, EV_SW, SW_LID);
187
188	error = input_register_device(input);
189	if (error)
190		goto out_err;
191
192	s3_wmi.input = input;
193
194	return 0;
195 out_err:
196	input_free_device(s3_wmi.input);
197	return error;
198}
199
200static int __init s3_wmi_probe(struct platform_device *pdev)
201{
202	int error;
203
204	if (!dmi_check_system(surface3_dmi_table))
205		return -ENODEV;
206
207	memset(&s3_wmi, 0, sizeof(s3_wmi));
208
209	bus_for_each_dev(&platform_bus_type, NULL, NULL,
210			 s3_wmi_check_platform_device);
211
212	if (!s3_wmi.touchscreen_adev)
213		return -ENODEV;
214
215	acpi_bus_trim(s3_wmi.pnp0c0d_adev);
216
217	error = s3_wmi_create_and_register_input(pdev);
218	if (error)
219		goto restore_acpi_lid;
220
221	acpi_initialize_hp_context(s3_wmi.touchscreen_adev, &s3_wmi.hp,
222				   s3_wmi_hp_notify, NULL);
223
224	s3_wmi_send_lid_state();
225
226	return 0;
227
228 restore_acpi_lid:
229	acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
230	return error;
231}
232
233static int s3_wmi_remove(struct platform_device *device)
234{
235	/* remove the hotplug context from the acpi device */
236	s3_wmi.touchscreen_adev->hp = NULL;
237
238	/* reinstall the actual PNPC0C0D LID default handle */
239	acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
240	return 0;
241}
242
243static int __maybe_unused s3_wmi_resume(struct device *dev)
244{
245	s3_wmi_send_lid_state();
246	return 0;
247}
248static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
249
250static struct platform_driver s3_wmi_driver = {
251	.driver = {
252		.name = "surface3-wmi",
253		.pm = &s3_wmi_pm,
254	},
255	.remove = s3_wmi_remove,
256};
257
258static int __init s3_wmi_init(void)
259{
260	int error;
261
262	s3_wmi_pdev = platform_device_alloc("surface3-wmi", -1);
263	if (!s3_wmi_pdev)
264		return -ENOMEM;
265
266	error = platform_device_add(s3_wmi_pdev);
267	if (error)
268		goto err_device_put;
269
270	error = platform_driver_probe(&s3_wmi_driver, s3_wmi_probe);
271	if (error)
272		goto err_device_del;
273
274	pr_info("Surface 3 WMI Extras loaded\n");
275	return 0;
276
277 err_device_del:
278	platform_device_del(s3_wmi_pdev);
279 err_device_put:
280	platform_device_put(s3_wmi_pdev);
281	return error;
282}
283
284static void __exit s3_wmi_exit(void)
285{
286	platform_device_unregister(s3_wmi_pdev);
287	platform_driver_unregister(&s3_wmi_driver);
288}
289
290module_init(s3_wmi_init);
291module_exit(s3_wmi_exit);