xref: /linux/drivers/platform/surface/surface3-wmi.c (revision ae22a94997b8a03dcb3c922857c203246711f9d4) 
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 	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 
90 static inline int s3_wmi_query_lid(int *ret)
91 {
92 	return s3_wmi_query_block(SURFACE3_LID_GUID, 0, ret);
93 }
94 
95 static 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 
109 static int s3_wmi_hp_notify(struct acpi_device *adev, u32 value)
110 {
111 	return s3_wmi_send_lid_state();
112 }
113 
114 static 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 = acpi_fetch_acpi_dev(handle);
120 	struct acpi_device **ts_adev = data;
121 
122 	if (!adev || 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 = ACPI_COMPANION(dev);
139 	struct acpi_device *ts_adev = NULL;
140 	acpi_status status;
141 
142 	/* ignore non ACPI devices */
143 	if (!adev)
144 		return 0;
145 
146 	/* check for LID ACPI switch */
147 	if (!strcmp(ACPI_BUTTON_HID_LID, acpi_device_hid(adev))) {
148 		s3_wmi.pnp0c0d_adev = adev;
149 		return 0;
150 	}
151 
152 	/* ignore non SPI controllers */
153 	if (strncmp(acpi_device_bid(adev), SPI_CTL_OBJ_NAME,
154 	    strlen(SPI_CTL_OBJ_NAME)))
155 		return 0;
156 
157 	status = acpi_walk_namespace(ACPI_TYPE_DEVICE, adev->handle, 1,
158 				     s3_wmi_attach_spi_device, NULL,
159 				     &ts_adev, NULL);
160 	if (ACPI_FAILURE(status))
161 		dev_warn(dev, "failed to enumerate SPI slaves\n");
162 
163 	if (!ts_adev)
164 		return 0;
165 
166 	s3_wmi.touchscreen_adev = ts_adev;
167 
168 	return 0;
169 }
170 
171 static int s3_wmi_create_and_register_input(struct platform_device *pdev)
172 {
173 	struct input_dev *input;
174 	int error;
175 
176 	input = devm_input_allocate_device(&pdev->dev);
177 	if (!input)
178 		return -ENOMEM;
179 
180 	input->name = "Lid Switch";
181 	input->phys = "button/input0";
182 	input->id.bustype = BUS_HOST;
183 	input->id.product = 0x0005;
184 
185 	input_set_capability(input, EV_SW, SW_LID);
186 
187 	error = input_register_device(input);
188 	if (error)
189 		return error;
190 
191 	s3_wmi.input = input;
192 
193 	return 0;
194 }
195 
196 static int __init s3_wmi_probe(struct platform_device *pdev)
197 {
198 	int error;
199 
200 	if (!dmi_check_system(surface3_dmi_table))
201 		return -ENODEV;
202 
203 	memset(&s3_wmi, 0, sizeof(s3_wmi));
204 
205 	bus_for_each_dev(&platform_bus_type, NULL, NULL,
206 			 s3_wmi_check_platform_device);
207 
208 	if (!s3_wmi.touchscreen_adev)
209 		return -ENODEV;
210 
211 	acpi_bus_trim(s3_wmi.pnp0c0d_adev);
212 
213 	error = s3_wmi_create_and_register_input(pdev);
214 	if (error)
215 		goto restore_acpi_lid;
216 
217 	acpi_initialize_hp_context(s3_wmi.touchscreen_adev, &s3_wmi.hp,
218 				   s3_wmi_hp_notify, NULL);
219 
220 	s3_wmi_send_lid_state();
221 
222 	return 0;
223 
224  restore_acpi_lid:
225 	acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
226 	return error;
227 }
228 
229 static void s3_wmi_remove(struct platform_device *device)
230 {
231 	/* remove the hotplug context from the acpi device */
232 	s3_wmi.touchscreen_adev->hp = NULL;
233 
234 	/* reinstall the actual PNPC0C0D LID default handle */
235 	acpi_bus_scan(s3_wmi.pnp0c0d_adev->handle);
236 }
237 
238 static int __maybe_unused s3_wmi_resume(struct device *dev)
239 {
240 	s3_wmi_send_lid_state();
241 	return 0;
242 }
243 static SIMPLE_DEV_PM_OPS(s3_wmi_pm, NULL, s3_wmi_resume);
244 
245 static struct platform_driver s3_wmi_driver = {
246 	.driver = {
247 		.name = "surface3-wmi",
248 		.pm = &s3_wmi_pm,
249 	},
250 	.remove_new = s3_wmi_remove,
251 };
252 
253 static int __init s3_wmi_init(void)
254 {
255 	int error;
256 
257 	s3_wmi_pdev = platform_device_alloc("surface3-wmi", -1);
258 	if (!s3_wmi_pdev)
259 		return -ENOMEM;
260 
261 	error = platform_device_add(s3_wmi_pdev);
262 	if (error)
263 		goto err_device_put;
264 
265 	error = platform_driver_probe(&s3_wmi_driver, s3_wmi_probe);
266 	if (error)
267 		goto err_device_del;
268 
269 	pr_info("Surface 3 WMI Extras loaded\n");
270 	return 0;
271 
272  err_device_del:
273 	platform_device_del(s3_wmi_pdev);
274  err_device_put:
275 	platform_device_put(s3_wmi_pdev);
276 	return error;
277 }
278 
279 static void __exit s3_wmi_exit(void)
280 {
281 	platform_device_unregister(s3_wmi_pdev);
282 	platform_driver_unregister(&s3_wmi_driver);
283 }
284 
285 module_init(s3_wmi_init);
286 module_exit(s3_wmi_exit);
287