1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * lenovo-ymc.c - Lenovo Yoga Mode Control driver
4  *
5  * Copyright © 2022 Gergo Koteles <soyer@irl.hu>
6  */
7 
8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
9 
10 #include <linux/acpi.h>
11 #include <linux/dmi.h>
12 #include <linux/input.h>
13 #include <linux/input/sparse-keymap.h>
14 #include <linux/wmi.h>
15 #include "ideapad-laptop.h"
16 
17 #define LENOVO_YMC_EVENT_GUID	"06129D99-6083-4164-81AD-F092F9D773A6"
18 #define LENOVO_YMC_QUERY_GUID	"09B0EE6E-C3FD-4243-8DA1-7911FF80BB8C"
19 
20 #define LENOVO_YMC_QUERY_INSTANCE 0
21 #define LENOVO_YMC_QUERY_METHOD 0x01
22 
23 static bool ec_trigger __read_mostly;
24 module_param(ec_trigger, bool, 0444);
25 MODULE_PARM_DESC(ec_trigger, "Enable EC triggering work-around to force emitting tablet mode events");
26 
27 static bool force;
28 module_param(force, bool, 0444);
29 MODULE_PARM_DESC(force, "Force loading on boards without a convertible DMI chassis-type");
30 
31 static const struct dmi_system_id ec_trigger_quirk_dmi_table[] = {
32 	{
33 		/* Lenovo Yoga 7 14ARB7 */
34 		.matches = {
35 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
36 			DMI_MATCH(DMI_PRODUCT_NAME, "82QF"),
37 		},
38 	},
39 	{
40 		/* Lenovo Yoga 7 14ACN6 */
41 		.matches = {
42 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
43 			DMI_MATCH(DMI_PRODUCT_NAME, "82N7"),
44 		},
45 	},
46 	{ }
47 };
48 
49 static const struct dmi_system_id allowed_chasis_types_dmi_table[] = {
50 	{
51 		.matches = {
52 			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "31" /* Convertible */),
53 		},
54 	},
55 	{
56 		.matches = {
57 			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "32" /* Detachable */),
58 		},
59 	},
60 	{ }
61 };
62 
63 struct lenovo_ymc_private {
64 	struct input_dev *input_dev;
65 	struct acpi_device *ec_acpi_dev;
66 };
67 
68 static void lenovo_ymc_trigger_ec(struct wmi_device *wdev, struct lenovo_ymc_private *priv)
69 {
70 	int err;
71 
72 	if (!priv->ec_acpi_dev)
73 		return;
74 
75 	err = write_ec_cmd(priv->ec_acpi_dev->handle, VPCCMD_W_YMC, 1);
76 	if (err)
77 		dev_warn(&wdev->dev, "Could not write YMC: %d\n", err);
78 }
79 
80 static const struct key_entry lenovo_ymc_keymap[] = {
81 	/* Laptop */
82 	{ KE_SW, 0x01, { .sw = { SW_TABLET_MODE, 0 } } },
83 	/* Tablet */
84 	{ KE_SW, 0x02, { .sw = { SW_TABLET_MODE, 1 } } },
85 	/* Drawing Board */
86 	{ KE_SW, 0x03, { .sw = { SW_TABLET_MODE, 1 } } },
87 	/* Tent */
88 	{ KE_SW, 0x04, { .sw = { SW_TABLET_MODE, 1 } } },
89 	{ KE_END },
90 };
91 
92 static void lenovo_ymc_notify(struct wmi_device *wdev, union acpi_object *data)
93 {
94 	struct lenovo_ymc_private *priv = dev_get_drvdata(&wdev->dev);
95 	u32 input_val = 0;
96 	struct acpi_buffer input = { sizeof(input_val), &input_val };
97 	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
98 	union acpi_object *obj;
99 	acpi_status status;
100 	int code;
101 
102 	status = wmi_evaluate_method(LENOVO_YMC_QUERY_GUID,
103 				LENOVO_YMC_QUERY_INSTANCE,
104 				LENOVO_YMC_QUERY_METHOD,
105 				&input, &output);
106 
107 	if (ACPI_FAILURE(status)) {
108 		dev_warn(&wdev->dev,
109 			"Failed to evaluate query method: %s\n",
110 			acpi_format_exception(status));
111 		return;
112 	}
113 
114 	obj = output.pointer;
115 
116 	if (obj->type != ACPI_TYPE_INTEGER) {
117 		dev_warn(&wdev->dev,
118 			"WMI event data is not an integer\n");
119 		goto free_obj;
120 	}
121 	code = obj->integer.value;
122 
123 	if (!sparse_keymap_report_event(priv->input_dev, code, 1, true))
124 		dev_warn(&wdev->dev, "Unknown key %d pressed\n", code);
125 
126 free_obj:
127 	kfree(obj);
128 	lenovo_ymc_trigger_ec(wdev, priv);
129 }
130 
131 static void acpi_dev_put_helper(void *p) { acpi_dev_put(p); }
132 
133 static int lenovo_ymc_probe(struct wmi_device *wdev, const void *ctx)
134 {
135 	struct lenovo_ymc_private *priv;
136 	struct input_dev *input_dev;
137 	int err;
138 
139 	if (!dmi_check_system(allowed_chasis_types_dmi_table)) {
140 		if (force)
141 			dev_info(&wdev->dev, "Force loading Lenovo YMC support\n");
142 		else
143 			return -ENODEV;
144 	}
145 
146 	ec_trigger |= dmi_check_system(ec_trigger_quirk_dmi_table);
147 
148 	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
149 	if (!priv)
150 		return -ENOMEM;
151 
152 	if (ec_trigger) {
153 		pr_debug("Lenovo YMC enable EC triggering.\n");
154 		priv->ec_acpi_dev = acpi_dev_get_first_match_dev("VPC2004", NULL, -1);
155 
156 		if (!priv->ec_acpi_dev) {
157 			dev_err(&wdev->dev, "Could not find EC ACPI device.\n");
158 			return -ENODEV;
159 		}
160 		err = devm_add_action_or_reset(&wdev->dev,
161 				acpi_dev_put_helper, priv->ec_acpi_dev);
162 		if (err) {
163 			dev_err(&wdev->dev,
164 				"Could not clean up EC ACPI device: %d\n", err);
165 			return err;
166 		}
167 	}
168 
169 	input_dev = devm_input_allocate_device(&wdev->dev);
170 	if (!input_dev)
171 		return -ENOMEM;
172 
173 	input_dev->name = "Lenovo Yoga Tablet Mode Control switch";
174 	input_dev->phys = LENOVO_YMC_EVENT_GUID "/input0";
175 	input_dev->id.bustype = BUS_HOST;
176 	input_dev->dev.parent = &wdev->dev;
177 	err = sparse_keymap_setup(input_dev, lenovo_ymc_keymap, NULL);
178 	if (err) {
179 		dev_err(&wdev->dev,
180 			"Could not set up input device keymap: %d\n", err);
181 		return err;
182 	}
183 
184 	err = input_register_device(input_dev);
185 	if (err) {
186 		dev_err(&wdev->dev,
187 			"Could not register input device: %d\n", err);
188 		return err;
189 	}
190 
191 	priv->input_dev = input_dev;
192 	dev_set_drvdata(&wdev->dev, priv);
193 
194 	/* Report the state for the first time on probe */
195 	lenovo_ymc_trigger_ec(wdev, priv);
196 	lenovo_ymc_notify(wdev, NULL);
197 	return 0;
198 }
199 
200 static const struct wmi_device_id lenovo_ymc_wmi_id_table[] = {
201 	{ .guid_string = LENOVO_YMC_EVENT_GUID },
202 	{ }
203 };
204 MODULE_DEVICE_TABLE(wmi, lenovo_ymc_wmi_id_table);
205 
206 static struct wmi_driver lenovo_ymc_driver = {
207 	.driver = {
208 		.name = "lenovo-ymc",
209 	},
210 	.id_table = lenovo_ymc_wmi_id_table,
211 	.probe = lenovo_ymc_probe,
212 	.notify = lenovo_ymc_notify,
213 };
214 
215 module_wmi_driver(lenovo_ymc_driver);
216 
217 MODULE_AUTHOR("Gergo Koteles <soyer@irl.hu>");
218 MODULE_DESCRIPTION("Lenovo Yoga Mode Control driver");
219 MODULE_LICENSE("GPL");
220