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
 23static bool force;
 24module_param(force, bool, 0444);
 25MODULE_PARM_DESC(force, "Force loading on boards without a convertible DMI chassis-type");
 26
 27static const struct dmi_system_id allowed_chasis_types_dmi_table[] = {
 28	{
 29		.matches = {
 30			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "31" /* Convertible */),
 31		},
 32	},
 33	{
 34		.matches = {
 35			DMI_EXACT_MATCH(DMI_CHASSIS_TYPE, "32" /* Detachable */),
 36		},
 37	},
 38	{ }
 39};
 40
 41struct lenovo_ymc_private {
 42	struct input_dev *input_dev;
 43};
 44
 45static const struct key_entry lenovo_ymc_keymap[] = {
 46	/* Ignore the uninitialized state */
 47	{ KE_IGNORE, 0x00 },
 48	/* Laptop */
 49	{ KE_SW, 0x01, { .sw = { SW_TABLET_MODE, 0 } } },
 50	/* Tablet */
 51	{ KE_SW, 0x02, { .sw = { SW_TABLET_MODE, 1 } } },
 52	/* Drawing Board */
 53	{ KE_SW, 0x03, { .sw = { SW_TABLET_MODE, 1 } } },
 54	/* Tent */
 55	{ KE_SW, 0x04, { .sw = { SW_TABLET_MODE, 1 } } },
 56	{ KE_END },
 57};
 58
 59static void lenovo_ymc_notify(struct wmi_device *wdev, union acpi_object *data)
 60{
 61	struct lenovo_ymc_private *priv = dev_get_drvdata(&wdev->dev);
 62	u32 input_val = 0;
 63	struct acpi_buffer input = { sizeof(input_val), &input_val };
 64	struct acpi_buffer output = { ACPI_ALLOCATE_BUFFER, NULL };
 65	union acpi_object *obj;
 66	acpi_status status;
 67	int code;
 68
 69	status = wmi_evaluate_method(LENOVO_YMC_QUERY_GUID,
 70				LENOVO_YMC_QUERY_INSTANCE,
 71				LENOVO_YMC_QUERY_METHOD,
 72				&input, &output);
 73
 74	if (ACPI_FAILURE(status)) {
 75		dev_warn(&wdev->dev,
 76			"Failed to evaluate query method: %s\n",
 77			acpi_format_exception(status));
 78		return;
 79	}
 80
 81	obj = output.pointer;
 82
 83	if (obj->type != ACPI_TYPE_INTEGER) {
 84		dev_warn(&wdev->dev,
 85			"WMI event data is not an integer\n");
 86		goto free_obj;
 87	}
 88	code = obj->integer.value;
 89
 90	if (!sparse_keymap_report_event(priv->input_dev, code, 1, true))
 91		dev_warn(&wdev->dev, "Unknown key %d pressed\n", code);
 92
 93free_obj:
 94	kfree(obj);
 95	ideapad_laptop_call_notifier(IDEAPAD_LAPTOP_YMC_EVENT, &code);
 96}
 97
 98static int lenovo_ymc_probe(struct wmi_device *wdev, const void *ctx)
 99{
100	struct lenovo_ymc_private *priv;
101	struct input_dev *input_dev;
102	int err;
103
104	if (!dmi_check_system(allowed_chasis_types_dmi_table)) {
105		if (force)
106			dev_info(&wdev->dev, "Force loading Lenovo YMC support\n");
107		else
108			return -ENODEV;
109	}
110
111	priv = devm_kzalloc(&wdev->dev, sizeof(*priv), GFP_KERNEL);
112	if (!priv)
113		return -ENOMEM;
114
115	input_dev = devm_input_allocate_device(&wdev->dev);
116	if (!input_dev)
117		return -ENOMEM;
118
119	input_dev->name = "Lenovo Yoga Tablet Mode Control switch";
120	input_dev->phys = LENOVO_YMC_EVENT_GUID "/input0";
121	input_dev->id.bustype = BUS_HOST;
122	input_dev->dev.parent = &wdev->dev;
123	err = sparse_keymap_setup(input_dev, lenovo_ymc_keymap, NULL);
124	if (err) {
125		dev_err(&wdev->dev,
126			"Could not set up input device keymap: %d\n", err);
127		return err;
128	}
129
130	err = input_register_device(input_dev);
131	if (err) {
132		dev_err(&wdev->dev,
133			"Could not register input device: %d\n", err);
134		return err;
135	}
136
137	priv->input_dev = input_dev;
138	dev_set_drvdata(&wdev->dev, priv);
139
140	/* Report the state for the first time on probe */
141	lenovo_ymc_notify(wdev, NULL);
142	return 0;
143}
144
145static const struct wmi_device_id lenovo_ymc_wmi_id_table[] = {
146	{ .guid_string = LENOVO_YMC_EVENT_GUID },
147	{ }
148};
149MODULE_DEVICE_TABLE(wmi, lenovo_ymc_wmi_id_table);
150
151static struct wmi_driver lenovo_ymc_driver = {
152	.driver = {
153		.name = "lenovo-ymc",
154	},
155	.id_table = lenovo_ymc_wmi_id_table,
156	.probe = lenovo_ymc_probe,
157	.notify = lenovo_ymc_notify,
158};
159
160module_wmi_driver(lenovo_ymc_driver);
161
162MODULE_AUTHOR("Gergo Koteles <soyer@irl.hu>");
163MODULE_DESCRIPTION("Lenovo Yoga Mode Control driver");
164MODULE_LICENSE("GPL");
165MODULE_IMPORT_NS("IDEAPAD_LAPTOP");