1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  * Copyright (C) 2016, Jelle van der Waa <jelle@vdwaa.nl>
4  */
5 
6 #include <linux/delay.h>
7 #include <linux/i2c.h>
8 #include <linux/input.h>
9 #include <linux/input/mt.h>
10 #include <linux/input/touchscreen.h>
11 #include <linux/interrupt.h>
12 #include <linux/module.h>
13 #include <linux/regulator/consumer.h>
14 #include <asm/unaligned.h>
15 
16 #define ZET6223_MAX_FINGERS		16
17 #define ZET6223_MAX_PKT_SIZE		(3 + 4 * ZET6223_MAX_FINGERS)
18 
19 #define ZET6223_CMD_INFO		0xB2
20 #define ZET6223_CMD_INFO_LENGTH		17
21 #define ZET6223_VALID_PACKET		0x3c
22 
23 #define ZET6223_POWER_ON_DELAY_MSEC	30
24 
25 struct zet6223_ts {
26 	struct i2c_client *client;
27 	struct input_dev *input;
28 	struct regulator *vcc;
29 	struct regulator *vio;
30 	struct touchscreen_properties prop;
31 	struct regulator_bulk_data supplies[2];
32 	u16 max_x;
33 	u16 max_y;
34 	u8 fingernum;
35 };
36 
37 static int zet6223_start(struct input_dev *dev)
38 {
39 	struct zet6223_ts *ts = input_get_drvdata(dev);
40 
41 	enable_irq(ts->client->irq);
42 
43 	return 0;
44 }
45 
46 static void zet6223_stop(struct input_dev *dev)
47 {
48 	struct zet6223_ts *ts = input_get_drvdata(dev);
49 
50 	disable_irq(ts->client->irq);
51 }
52 
53 static irqreturn_t zet6223_irq(int irq, void *dev_id)
54 {
55 	struct zet6223_ts *ts = dev_id;
56 	u16 finger_bits;
57 
58 	/*
59 	 * First 3 bytes are an identifier, two bytes of finger data.
60 	 * X, Y data per finger is 4 bytes.
61 	 */
62 	u8 bufsize = 3 + 4 * ts->fingernum;
63 	u8 buf[ZET6223_MAX_PKT_SIZE];
64 	int i;
65 	int ret;
66 	int error;
67 
68 	ret = i2c_master_recv(ts->client, buf, bufsize);
69 	if (ret != bufsize) {
70 		error = ret < 0 ? ret : -EIO;
71 		dev_err_ratelimited(&ts->client->dev,
72 				    "Error reading input data: %d\n", error);
73 		return IRQ_HANDLED;
74 	}
75 
76 	if (buf[0] != ZET6223_VALID_PACKET)
77 		return IRQ_HANDLED;
78 
79 	finger_bits = get_unaligned_be16(buf + 1);
80 	for (i = 0; i < ts->fingernum; i++) {
81 		if (!(finger_bits & BIT(15 - i)))
82 			continue;
83 
84 		input_mt_slot(ts->input, i);
85 		input_mt_report_slot_state(ts->input, MT_TOOL_FINGER, true);
86 		input_event(ts->input, EV_ABS, ABS_MT_POSITION_X,
87 				((buf[i + 3] >> 4) << 8) + buf[i + 4]);
88 		input_event(ts->input, EV_ABS, ABS_MT_POSITION_Y,
89 				((buf[i + 3] & 0xF) << 8) + buf[i + 5]);
90 	}
91 
92 	input_mt_sync_frame(ts->input);
93 	input_sync(ts->input);
94 
95 	return IRQ_HANDLED;
96 }
97 
98 static void zet6223_power_off(void *_ts)
99 {
100 	struct zet6223_ts *ts = _ts;
101 
102 	regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies);
103 }
104 
105 static int zet6223_power_on(struct zet6223_ts *ts)
106 {
107 	struct device *dev = &ts->client->dev;
108 	int error;
109 
110 	ts->supplies[0].supply = "vio";
111 	ts->supplies[1].supply = "vcc";
112 
113 	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(ts->supplies),
114 					ts->supplies);
115 	if (error)
116 		return error;
117 
118 	error = regulator_bulk_enable(ARRAY_SIZE(ts->supplies), ts->supplies);
119 	if (error)
120 		return error;
121 
122 	msleep(ZET6223_POWER_ON_DELAY_MSEC);
123 
124 	error = devm_add_action_or_reset(dev, zet6223_power_off, ts);
125 	if (error) {
126 		dev_err(dev, "failed to install poweroff action: %d\n", error);
127 		return error;
128 	}
129 
130 	return 0;
131 }
132 
133 static int zet6223_query_device(struct zet6223_ts *ts)
134 {
135 	u8 buf[ZET6223_CMD_INFO_LENGTH];
136 	u8 cmd = ZET6223_CMD_INFO;
137 	int ret;
138 	int error;
139 
140 	ret = i2c_master_send(ts->client, &cmd, sizeof(cmd));
141 	if (ret != sizeof(cmd)) {
142 		error = ret < 0 ? ret : -EIO;
143 		dev_err(&ts->client->dev,
144 			"touchpanel info cmd failed: %d\n", error);
145 		return error;
146 	}
147 
148 	ret = i2c_master_recv(ts->client, buf, sizeof(buf));
149 	if (ret != sizeof(buf)) {
150 		error = ret < 0 ? ret : -EIO;
151 		dev_err(&ts->client->dev,
152 			"failed to retrieve touchpanel info: %d\n", error);
153 		return error;
154 	}
155 
156 	ts->fingernum = buf[15] & 0x7F;
157 	if (ts->fingernum > ZET6223_MAX_FINGERS) {
158 		dev_warn(&ts->client->dev,
159 			 "touchpanel reports %d fingers, limiting to %d\n",
160 			 ts->fingernum, ZET6223_MAX_FINGERS);
161 		ts->fingernum = ZET6223_MAX_FINGERS;
162 	}
163 
164 	ts->max_x = get_unaligned_le16(&buf[8]);
165 	ts->max_y = get_unaligned_le16(&buf[10]);
166 
167 	return 0;
168 }
169 
170 static int zet6223_probe(struct i2c_client *client,
171 			 const struct i2c_device_id *id)
172 {
173 	struct device *dev = &client->dev;
174 	struct zet6223_ts *ts;
175 	struct input_dev *input;
176 	int error;
177 
178 	if (!client->irq) {
179 		dev_err(dev, "no irq specified\n");
180 		return -EINVAL;
181 	}
182 
183 	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
184 	if (!ts)
185 		return -ENOMEM;
186 
187 	ts->client = client;
188 
189 	error = zet6223_power_on(ts);
190 	if (error)
191 		return error;
192 
193 	error = zet6223_query_device(ts);
194 	if (error)
195 		return error;
196 
197 	ts->input = input = devm_input_allocate_device(dev);
198 	if (!input)
199 		return -ENOMEM;
200 
201 	input_set_drvdata(input, ts);
202 
203 	input->name = client->name;
204 	input->id.bustype = BUS_I2C;
205 	input->open = zet6223_start;
206 	input->close = zet6223_stop;
207 
208 	input_set_abs_params(input, ABS_MT_POSITION_X, 0, ts->max_x, 0, 0);
209 	input_set_abs_params(input, ABS_MT_POSITION_Y, 0, ts->max_y, 0, 0);
210 
211 	touchscreen_parse_properties(input, true, &ts->prop);
212 
213 	error = input_mt_init_slots(input, ts->fingernum,
214 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
215 	if (error)
216 		return error;
217 
218 	error = devm_request_threaded_irq(dev, client->irq, NULL, zet6223_irq,
219 					  IRQF_ONESHOT, client->name, ts);
220 	if (error) {
221 		dev_err(dev, "failed to request irq %d: %d\n",
222 			client->irq, error);
223 		return error;
224 	}
225 
226 	zet6223_stop(input);
227 
228 	error = input_register_device(input);
229 	if (error)
230 		return error;
231 
232 	return 0;
233 }
234 
235 static const struct of_device_id zet6223_of_match[] = {
236 	{ .compatible = "zeitec,zet6223" },
237 	{ }
238 };
239 MODULE_DEVICE_TABLE(of, zet6223_of_match);
240 
241 static const struct i2c_device_id zet6223_id[] = {
242 	{ "zet6223", 0},
243 	{ }
244 };
245 MODULE_DEVICE_TABLE(i2c, zet6223_id);
246 
247 static struct i2c_driver zet6223_driver = {
248 	.driver = {
249 		.name = "zet6223",
250 		.of_match_table = zet6223_of_match,
251 	},
252 	.probe = zet6223_probe,
253 	.id_table = zet6223_id
254 };
255 module_i2c_driver(zet6223_driver);
256 
257 MODULE_AUTHOR("Jelle van der Waa <jelle@vdwaa.nl>");
258 MODULE_DESCRIPTION("ZEITEC zet622x I2C touchscreen driver");
259 MODULE_LICENSE("GPL");
260