1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Wacom Penabled Driver for I2C
4  *
5  * Copyright (c) 2011 - 2013 Tatsunosuke Tobita, Wacom.
6  * <tobita.tatsunosuke@wacom.co.jp>
7  */
8 
9 #include <linux/bits.h>
10 #include <linux/module.h>
11 #include <linux/input.h>
12 #include <linux/i2c.h>
13 #include <linux/slab.h>
14 #include <linux/irq.h>
15 #include <linux/interrupt.h>
16 #include <asm/unaligned.h>
17 
18 /* Bitmasks (for data[3]) */
19 #define WACOM_TIP_SWITCH	BIT(0)
20 #define WACOM_BARREL_SWITCH	BIT(1)
21 #define WACOM_ERASER		BIT(2)
22 #define WACOM_INVERT		BIT(3)
23 #define WACOM_BARREL_SWITCH_2	BIT(4)
24 #define WACOM_IN_PROXIMITY	BIT(5)
25 
26 /* Registers */
27 #define WACOM_COMMAND_LSB	0x04
28 #define WACOM_COMMAND_MSB	0x00
29 
30 #define WACOM_DATA_LSB		0x05
31 #define WACOM_DATA_MSB		0x00
32 
33 /* Report types */
34 #define REPORT_FEATURE		0x30
35 
36 /* Requests / operations */
37 #define OPCODE_GET_REPORT	0x02
38 
39 #define WACOM_QUERY_REPORT	3
40 #define WACOM_QUERY_SIZE	19
41 
42 struct wacom_features {
43 	int x_max;
44 	int y_max;
45 	int pressure_max;
46 	char fw_version;
47 };
48 
49 struct wacom_i2c {
50 	struct i2c_client *client;
51 	struct input_dev *input;
52 	u8 data[WACOM_QUERY_SIZE];
53 	bool prox;
54 	int tool;
55 };
56 
57 static int wacom_query_device(struct i2c_client *client,
58 			      struct wacom_features *features)
59 {
60 	u8 get_query_data_cmd[] = {
61 		WACOM_COMMAND_LSB,
62 		WACOM_COMMAND_MSB,
63 		REPORT_FEATURE | WACOM_QUERY_REPORT,
64 		OPCODE_GET_REPORT,
65 		WACOM_DATA_LSB,
66 		WACOM_DATA_MSB,
67 	};
68 	u8 data[WACOM_QUERY_SIZE];
69 	int ret;
70 
71 	struct i2c_msg msgs[] = {
72 		/* Request reading of feature ReportID: 3 (Pen Query Data) */
73 		{
74 			.addr = client->addr,
75 			.flags = 0,
76 			.len = sizeof(get_query_data_cmd),
77 			.buf = get_query_data_cmd,
78 		},
79 		{
80 			.addr = client->addr,
81 			.flags = I2C_M_RD,
82 			.len = sizeof(data),
83 			.buf = data,
84 		},
85 	};
86 
87 	ret = i2c_transfer(client->adapter, msgs, ARRAY_SIZE(msgs));
88 	if (ret < 0)
89 		return ret;
90 	if (ret != ARRAY_SIZE(msgs))
91 		return -EIO;
92 
93 	features->x_max = get_unaligned_le16(&data[3]);
94 	features->y_max = get_unaligned_le16(&data[5]);
95 	features->pressure_max = get_unaligned_le16(&data[11]);
96 	features->fw_version = get_unaligned_le16(&data[13]);
97 
98 	dev_dbg(&client->dev,
99 		"x_max:%d, y_max:%d, pressure:%d, fw:%d\n",
100 		features->x_max, features->y_max,
101 		features->pressure_max, features->fw_version);
102 
103 	return 0;
104 }
105 
106 static irqreturn_t wacom_i2c_irq(int irq, void *dev_id)
107 {
108 	struct wacom_i2c *wac_i2c = dev_id;
109 	struct input_dev *input = wac_i2c->input;
110 	u8 *data = wac_i2c->data;
111 	unsigned int x, y, pressure;
112 	unsigned char tsw, f1, f2, ers;
113 	int error;
114 
115 	error = i2c_master_recv(wac_i2c->client,
116 				wac_i2c->data, sizeof(wac_i2c->data));
117 	if (error < 0)
118 		goto out;
119 
120 	tsw = data[3] & WACOM_TIP_SWITCH;
121 	ers = data[3] & WACOM_ERASER;
122 	f1 = data[3] & WACOM_BARREL_SWITCH;
123 	f2 = data[3] & WACOM_BARREL_SWITCH_2;
124 	x = le16_to_cpup((__le16 *)&data[4]);
125 	y = le16_to_cpup((__le16 *)&data[6]);
126 	pressure = le16_to_cpup((__le16 *)&data[8]);
127 
128 	if (!wac_i2c->prox)
129 		wac_i2c->tool = (data[3] & (WACOM_ERASER | WACOM_INVERT)) ?
130 			BTN_TOOL_RUBBER : BTN_TOOL_PEN;
131 
132 	wac_i2c->prox = data[3] & WACOM_IN_PROXIMITY;
133 
134 	input_report_key(input, BTN_TOUCH, tsw || ers);
135 	input_report_key(input, wac_i2c->tool, wac_i2c->prox);
136 	input_report_key(input, BTN_STYLUS, f1);
137 	input_report_key(input, BTN_STYLUS2, f2);
138 	input_report_abs(input, ABS_X, x);
139 	input_report_abs(input, ABS_Y, y);
140 	input_report_abs(input, ABS_PRESSURE, pressure);
141 	input_sync(input);
142 
143 out:
144 	return IRQ_HANDLED;
145 }
146 
147 static int wacom_i2c_open(struct input_dev *dev)
148 {
149 	struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
150 	struct i2c_client *client = wac_i2c->client;
151 
152 	enable_irq(client->irq);
153 
154 	return 0;
155 }
156 
157 static void wacom_i2c_close(struct input_dev *dev)
158 {
159 	struct wacom_i2c *wac_i2c = input_get_drvdata(dev);
160 	struct i2c_client *client = wac_i2c->client;
161 
162 	disable_irq(client->irq);
163 }
164 
165 static int wacom_i2c_probe(struct i2c_client *client)
166 {
167 	struct device *dev = &client->dev;
168 	struct wacom_i2c *wac_i2c;
169 	struct input_dev *input;
170 	struct wacom_features features = { 0 };
171 	int error;
172 
173 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
174 		dev_err(dev, "i2c_check_functionality error\n");
175 		return -EIO;
176 	}
177 
178 	error = wacom_query_device(client, &features);
179 	if (error)
180 		return error;
181 
182 	wac_i2c = devm_kzalloc(dev, sizeof(*wac_i2c), GFP_KERNEL);
183 	if (!wac_i2c)
184 		return -ENOMEM;
185 
186 	wac_i2c->client = client;
187 
188 	input = devm_input_allocate_device(dev);
189 	if (!input)
190 		return -ENOMEM;
191 
192 	wac_i2c->input = input;
193 
194 	input->name = "Wacom I2C Digitizer";
195 	input->id.bustype = BUS_I2C;
196 	input->id.vendor = 0x56a;
197 	input->id.version = features.fw_version;
198 	input->open = wacom_i2c_open;
199 	input->close = wacom_i2c_close;
200 
201 	input->evbit[0] |= BIT_MASK(EV_KEY) | BIT_MASK(EV_ABS);
202 
203 	__set_bit(BTN_TOOL_PEN, input->keybit);
204 	__set_bit(BTN_TOOL_RUBBER, input->keybit);
205 	__set_bit(BTN_STYLUS, input->keybit);
206 	__set_bit(BTN_STYLUS2, input->keybit);
207 	__set_bit(BTN_TOUCH, input->keybit);
208 
209 	input_set_abs_params(input, ABS_X, 0, features.x_max, 0, 0);
210 	input_set_abs_params(input, ABS_Y, 0, features.y_max, 0, 0);
211 	input_set_abs_params(input, ABS_PRESSURE,
212 			     0, features.pressure_max, 0, 0);
213 
214 	input_set_drvdata(input, wac_i2c);
215 
216 	error = devm_request_threaded_irq(dev, client->irq, NULL, wacom_i2c_irq,
217 					  IRQF_ONESHOT, "wacom_i2c", wac_i2c);
218 	if (error) {
219 		dev_err(dev, "Failed to request IRQ: %d\n", error);
220 		return error;
221 	}
222 
223 	/* Disable the IRQ, we'll enable it in wac_i2c_open() */
224 	disable_irq(client->irq);
225 
226 	error = input_register_device(wac_i2c->input);
227 	if (error) {
228 		dev_err(dev, "Failed to register input device: %d\n", error);
229 		return error;
230 	}
231 
232 	return 0;
233 }
234 
235 static int wacom_i2c_suspend(struct device *dev)
236 {
237 	struct i2c_client *client = to_i2c_client(dev);
238 
239 	disable_irq(client->irq);
240 
241 	return 0;
242 }
243 
244 static int wacom_i2c_resume(struct device *dev)
245 {
246 	struct i2c_client *client = to_i2c_client(dev);
247 
248 	enable_irq(client->irq);
249 
250 	return 0;
251 }
252 
253 static DEFINE_SIMPLE_DEV_PM_OPS(wacom_i2c_pm, wacom_i2c_suspend, wacom_i2c_resume);
254 
255 static const struct i2c_device_id wacom_i2c_id[] = {
256 	{ "WAC_I2C_EMR", 0 },
257 	{ },
258 };
259 MODULE_DEVICE_TABLE(i2c, wacom_i2c_id);
260 
261 static struct i2c_driver wacom_i2c_driver = {
262 	.driver	= {
263 		.name	= "wacom_i2c",
264 		.pm	= pm_sleep_ptr(&wacom_i2c_pm),
265 	},
266 
267 	.probe		= wacom_i2c_probe,
268 	.id_table	= wacom_i2c_id,
269 };
270 module_i2c_driver(wacom_i2c_driver);
271 
272 MODULE_AUTHOR("Tatsunosuke Tobita <tobita.tatsunosuke@wacom.co.jp>");
273 MODULE_DESCRIPTION("WACOM EMR I2C Driver");
274 MODULE_LICENSE("GPL");
275