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	union acpi_object *obj = NULL;
 61	acpi_status status;
 62	int error = 0;
 63
 64	mutex_lock(&s3_wmi_lock);
 65	status = wmi_query_block(guid, instance, &output);
 66	if (ACPI_FAILURE(status)) {
 67		error = -EIO;
 68		goto out_free_unlock;
 69	}
 70
 71	obj = output.pointer;
 72
 73	if (!obj || obj->type != ACPI_TYPE_INTEGER) {
 74		if (obj) {
 75			pr_err("query block returned object type: %d - buffer length:%d\n",
 76			       obj->type,
 77			       obj->type == ACPI_TYPE_BUFFER ?
 78						obj->buffer.length : 0);
 79		}
 80		error = -EINVAL;
 81		goto out_free_unlock;
 82	}
 83	*ret = obj->integer.value;
 84 out_free_unlock:
 85	kfree(obj);
 86	mutex_unlock(&s3_wmi_lock);
 87	return error;
 88}
 89
 90static inline int s3_wmi_query_lid(int *ret)
 91{
 92	return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
 93}
 94
 95static int s3_wmi_send_lid_state(void)
 96{
 97	int ret, lid_sw;
 98
 99	ret = s3_wmi_query_lid(&lid_sw);
100	if (ret)
101		return ret;
102
103	input_report_switch(s3_wmi.input, SW_LID, lid_sw);
104	input_sync(s3_wmi.input);
105
106	return 0;
107}
108
109static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
110{
111	return s3_wmi_send_lid_state();
112}
113
114static acpi_status s3_wmi_attach_spi_device(acpi_handle handle,
115					    u32 level,
116					    void *data,
117					    void **return_value)
118{
119	struct acpi_device *adev, **ts_adev;
120
121	if (acpi_bus_get_device(handle, &adev))
122		return AE_OK;
123
124	ts_adev = data;
125
126	if (strncmp(acpi_device_bid(adev), SPI_TS_OBJ_NAME,
127	    strlen(SPI_TS_OBJ_NAME)))
128		return AE_OK;
129
130	if (*ts_adev) {
131		pr_err("duplicate entry %s\n", SPI_TS_OBJ_NAME);
132		return AE_OK;
133	}
134
135	*ts_adev = adev;
136
137	return AE_OK;
138}
139
140static int s3_wmi_check_platform_device(struct device *dev, void *data)
141{
142	struct acpi_device *adev, *ts_adev = NULL;
143	acpi_handle handle;
144	acpi_status status;
145
146	/* ignore non ACPI devices */
147	handle = ACPI_HANDLE(dev);
148	if (!handle || acpi_bus_get_device(handle, &adev))
149		return 0;
150
151	/* check for LID ACPI switch */
152	if (!strcmp(ACPI_BUTTON_HID_LID, acpi_device_hid(adev))) {
153		s3_wmi.pnp0c0d_adev = adev;
154		return 0;
155	}
156
157	/* ignore non SPI controllers */
158	if (strncmp(acpi_device_bid(adev), SPI_CTL_OBJ_NAME,
159	    strlen(SPI_CTL_OBJ_NAME)))
160		return 0;
161
162	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, handle, 1,
163				     s3_wmi_attach_spi_device, NULL,
164				     &ts_adev, NULL);
165	if (ACPI_FAILURE(status))
166		dev_warn(dev, "failed to enumerate SPI slaves\n");
167
168	if (!ts_adev)
169		return 0;
170
171	s3_wmi.touchscreen_adev = ts_adev;
172
173	return 0;
174}
175
176static int s3_wmi_create_and_register_input(struct platform_device *pdev)
177{
178	struct input_dev *input;
179	int error;
180
181	input = devm_input_allocate_device(&pdev->dev);
182	if (!input)
183		return -ENOMEM;
184
185	input->name = "Lid Switch";
186	input->phys = "button/input0";
187	input->id.bustype = BUS_HOST;
188	input->id.product = 0x0005;
189
190	input_set_capability(input, EV_SW, SW_LID);
191
192	error = input_register_device(input);
193	if (error)
194		goto out_err;
195
196	s3_wmi.input = input;
197
198	return 0;
199 out_err:
200	input_free_device(s3_wmi.input);
201	return error;
202}
203
204static int __init s3_wmi_probe(struct platform_device *pdev)
205{
206	int error;
207
208	if (!dmi_check_system(surface3_dmi_table))
209		return -ENODEV;
210
211	memset(&s3_wmi, 0, sizeof(s3_wmi));
212
213	bus_for_each_dev(&platform_bus_type, NULL, NULL,
214			 s3_wmi_check_platform_device);
215
216	if (!s3_wmi.touchscreen_adev)
217		return -ENODEV;
218
219	acpi_bus_trim(s3_wmi.pnp0c0d_adev);
220
221	error = s3_wmi_create_and_register_input(pdev);
222	if (error)
223		goto restore_acpi_lid;
224
225	acpi_initialize_hp_context(s3_wmi.touchscreen_adev, &s3_wmi.hp,
226				   s3_wmi_hp_notify, NULL);
227
228	s3_wmi_send_lid_state();
229
230	return 0;
231
232 restore_acpi_lid:
233	acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
234	return error;
235}
236
237static int s3_wmi_remove(struct platform_device *device)
238{
239	/* remove the hotplug context from the acpi device */
240	s3_wmi.touchscreen_adev->hp = NULL;
241
242	/* reinstall the actual PNPC0C0D LID default handle */
243	acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
244	return 0;
245}
246
247static int __maybe_unused s3_wmi_resume(struct device *dev)
248{
249	s3_wmi_send_lid_state();
250	return 0;
251}
252static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
253
254static struct platform_driver s3_wmi_driver = {
255	.driver = {
256		.name = "surface3-wmi",
257		.pm = &s3_wmi_pm,
258	},
259	.remove = s3_wmi_remove,
260};
261
262static int __init s3_wmi_init(void)
263{
264	int error;
265
266	s3_wmi_pdev = platform_device_alloc("surface3-wmi", -1);
267	if (!s3_wmi_pdev)
268		return -ENOMEM;
269
270	error = platform_device_add(s3_wmi_pdev);
271	if (error)
272		goto err_device_put;
273
274	error = platform_driver_probe(&s3_wmi_driver, s3_wmi_probe);
275	if (error)
276		goto err_device_del;
277
278	pr_info("Surface 3 WMI Extras loaded\n");
279	return 0;
280
281 err_device_del:
282	platform_device_del(s3_wmi_pdev);
283 err_device_put:
284	platform_device_put(s3_wmi_pdev);
285	return error;
286}
287
288static void __exit s3_wmi_exit(void)
289{
290	platform_device_unregister(s3_wmi_pdev);
291	platform_driver_unregister(&s3_wmi_driver);
292}
293
294module_init(s3_wmi_init);
295module_exit(s3_wmi_exit);