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 
20 MODULE_AUTHOR("Benjamin Tissoires <benjamin.tissoires@redhat.com>");
21 MODULE_DESCRIPTION("Surface 3 platform driver");
22 MODULE_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 
30 MODULE_ALIAS("wmi:" SURFACE3_LID_GUID);
31 
32 static 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 
44 struct 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 
51 static struct platform_device *s3_wmi_pdev;
52 
53 static struct surface3_wmi s3_wmi;
54 
55 static DEFINE_MUTEX(s3_wmi_lock);
56 
57 static 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 
86 static inline int s3_wmi_query_lid(int *ret)
87 {
88 	return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
89 }
90 
91 static 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 
105 static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
106 {
107 	return s3_wmi_send_lid_state();
108 }
109 
110 static 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 
136 static 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 
172 static 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 
200 static 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 
233 static 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 
243 static int __maybe_unused s3_wmi_resume(struct device *dev)
244 {
245 	s3_wmi_send_lid_state();
246 	return 0;
247 }
248 static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
249 
250 static 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 
258 static 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 
284 static void __exit s3_wmi_exit(void)
285 {
286 	platform_device_unregister(s3_wmi_pdev);
287 	platform_driver_unregister(&s3_wmi_driver);
288 }
289 
290 module_init(s3_wmi_init);
291 module_exit(s3_wmi_exit);
292