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 const struct dmi_system_id ec_trigger_quirk_dmi_table[] = {
28 	{
29 		/* Lenovo Yoga 7 14ARB7 */
30 		.matches = {
31 			DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
32 			DMI_MATCH(DMI_PRODUCT_NAME, "82QF"),
33 		},
34 	},
35 	{ }
36 };
37 
38 struct lenovo_ymc_private {
39 	struct input_dev *input_dev;
40 	struct acpi_device *ec_acpi_dev;
41 };
42 
43 static void lenovo_ymc_trigger_ec(struct wmi_device *wdev, struct lenovo_ymc_private *priv)
44 {
45 	int err;
46 
47 	if (!priv->ec_acpi_dev)
48 		return;
49 
50 	err = write_ec_cmd(priv->ec_acpi_dev->handle, VPCCMD_W_YMC, 1);
51 	if (err)
52 		dev_warn(&wdev->dev, "Could not write YMC: %d\n", err);
53 }
54 
55 static const struct key_entry lenovo_ymc_keymap[] = {
56 	/* Laptop */
57 	{ KE_SW, 0x01, { .sw = { SW_TABLET_MODE, 0 } } },
58 	/* Tablet */
59 	{ KE_SW, 0x02, { .sw = { SW_TABLET_MODE, 1 } } },
60 	/* Drawing Board */
61 	{ KE_SW, 0x03, { .sw = { SW_TABLET_MODE, 1 } } },
62 	/* Tent */
63 	{ KE_SW, 0x04, { .sw = { SW_TABLET_MODE, 1 } } },
64 	{ KE_END },
65 };
66 
67 static void lenovo_ymc_notify(struct wmi_device *wdev, union acpi_object *data)
68 {
69 	struct lenovo_ymc_private *priv = dev_get_drvdata(&wdev->dev);
70 	u32 input_val = 0;
71 	struct acpi_buffer input = { sizeof(input_val), &input_val };
72 	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
73 	union acpi_object *obj;
74 	acpi_status status;
75 	int code;
76 
77 	status = wmi_evaluate_method(LENOVO_YMC_QUERY_GUID,
78 				LENOVO_YMC_QUERY_INSTANCE,
79 				LENOVO_YMC_QUERY_METHOD,
80 				&input, &output);
81 
82 	if (ACPI_FAILURE(status)) {
83 		dev_warn(&wdev->dev,
84 			"Failed to evaluate query method: %s\n",
85 			acpi_format_exception(status));
86 		return;
87 	}
88 
89 	obj = output.pointer;
90 
91 	if (obj->type != ACPI_TYPE_INTEGER) {
92 		dev_warn(&wdev->dev,
93 			"WMI event data is not an integer\n");
94 		goto free_obj;
95 	}
96 	code = obj->integer.value;
97 
98 	if (!sparse_keymap_report_event(priv->input_dev, code, 1, true))
99 		dev_warn(&wdev->dev, "Unknown key %d pressed\n", code);
100 
101 free_obj:
102 	kfree(obj);
103 	lenovo_ymc_trigger_ec(wdev, priv);
104 }
105 
106 static void acpi_dev_put_helper(void *p) { acpi_dev_put(p); }
107 
108 static int lenovo_ymc_probe(struct wmi_device *wdev, const void *ctx)
109 {
110 	struct lenovo_ymc_private *priv;
111 	struct input_dev *input_dev;
112 	int err;
113 
114 	ec_trigger |= dmi_check_system(ec_trigger_quirk_dmi_table);
115 
116 	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
117 	if (!priv)
118 		return -ENOMEM;
119 
120 	if (ec_trigger) {
121 		pr_debug("Lenovo YMC enable EC triggering.\n");
122 		priv->ec_acpi_dev = acpi_dev_get_first_match_dev("VPC2004", NULL, -1);
123 
124 		if (!priv->ec_acpi_dev) {
125 			dev_err(&wdev->dev, "Could not find EC ACPI device.\n");
126 			return -ENODEV;
127 		}
128 		err = devm_add_action_or_reset(&wdev->dev,
129 				acpi_dev_put_helper, priv->ec_acpi_dev);
130 		if (err) {
131 			dev_err(&wdev->dev,
132 				"Could not clean up EC ACPI device: %d\n", err);
133 			return err;
134 		}
135 	}
136 
137 	input_dev = devm_input_allocate_device(&wdev->dev);
138 	if (!input_dev)
139 		return -ENOMEM;
140 
141 	input_dev->name = "Lenovo Yoga Tablet Mode Control switch";
142 	input_dev->phys = LENOVO_YMC_EVENT_GUID "/input0";
143 	input_dev->id.bustype = BUS_HOST;
144 	input_dev->dev.parent = &wdev->dev;
145 	err = sparse_keymap_setup(input_dev, lenovo_ymc_keymap, NULL);
146 	if (err) {
147 		dev_err(&wdev->dev,
148 			"Could not set up input device keymap: %d\n", err);
149 		return err;
150 	}
151 
152 	err = input_register_device(input_dev);
153 	if (err) {
154 		dev_err(&wdev->dev,
155 			"Could not register input device: %d\n", err);
156 		return err;
157 	}
158 
159 	priv->input_dev = input_dev;
160 	dev_set_drvdata(&wdev->dev, priv);
161 
162 	/* Report the state for the first time on probe */
163 	lenovo_ymc_trigger_ec(wdev, priv);
164 	lenovo_ymc_notify(wdev, NULL);
165 	return 0;
166 }
167 
168 static const struct wmi_device_id lenovo_ymc_wmi_id_table[] = {
169 	{ .guid_string = LENOVO_YMC_EVENT_GUID },
170 	{ }
171 };
172 MODULE_DEVICE_TABLE(wmi, lenovo_ymc_wmi_id_table);
173 
174 static struct wmi_driver lenovo_ymc_driver = {
175 	.driver = {
176 		.name = "lenovo-ymc",
177 	},
178 	.id_table = lenovo_ymc_wmi_id_table,
179 	.probe = lenovo_ymc_probe,
180 	.notify = lenovo_ymc_notify,
181 };
182 
183 module_wmi_driver(lenovo_ymc_driver);
184 
185 MODULE_AUTHOR("Gergo Koteles <soyer@irl.hu>");
186 MODULE_DESCRIPTION("Lenovo Yoga Mode Control driver");
187 MODULE_LICENSE("GPL");
188