xref: /linux/drivers/input/touchscreen/msg2638.c (revision 172cdcaefea5c297fdb3d20b7d5aff60ae4fbce6) 
1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3  * Driver for MStar msg2638 touchscreens
4  *
5  * Copyright (c) 2021 Vincent Knecht <vincent.knecht@mailoo.org>
6  *
7  * Checksum and IRQ handler based on mstar_drv_common.c and
8  * mstar_drv_mutual_fw_control.c
9  * Copyright (c) 2006-2012 MStar Semiconductor, Inc.
10  *
11  * Driver structure based on zinitix.c by Michael Srba <Michael.Srba@seznam.cz>
12  */
13 
14 #include <linux/delay.h>
15 #include <linux/gpio/consumer.h>
16 #include <linux/i2c.h>
17 #include <linux/input.h>
18 #include <linux/input/mt.h>
19 #include <linux/input/touchscreen.h>
20 #include <linux/interrupt.h>
21 #include <linux/kernel.h>
22 #include <linux/mod_devicetable.h>
23 #include <linux/module.h>
24 #include <linux/regulator/consumer.h>
25 #include <linux/slab.h>
26 
27 #define MODE_DATA_RAW			0x5A
28 
29 #define MAX_SUPPORTED_FINGER_NUM	5
30 
31 #define CHIP_ON_DELAY_MS		15
32 #define FIRMWARE_ON_DELAY_MS		50
33 #define RESET_DELAY_MIN_US		10000
34 #define RESET_DELAY_MAX_US		11000
35 
36 struct packet {
37 	u8	xy_hi; /* higher bits of x and y coordinates */
38 	u8	x_low;
39 	u8	y_low;
40 	u8	pressure;
41 };
42 
43 struct touch_event {
44 	u8	mode;
45 	struct	packet pkt[MAX_SUPPORTED_FINGER_NUM];
46 	u8	proximity;
47 	u8	checksum;
48 };
49 
50 struct msg2638_ts_data {
51 	struct i2c_client *client;
52 	struct input_dev *input_dev;
53 	struct touchscreen_properties prop;
54 	struct regulator_bulk_data supplies[2];
55 	struct gpio_desc *reset_gpiod;
56 };
57 
58 static u8 msg2638_checksum(u8 *data, u32 length)
59 {
60 	s32 sum = 0;
61 	u32 i;
62 
63 	for (i = 0; i < length; i++)
64 		sum += data[i];
65 
66 	return (u8)((-sum) & 0xFF);
67 }
68 
69 static irqreturn_t msg2638_ts_irq_handler(int irq, void *msg2638_handler)
70 {
71 	struct msg2638_ts_data *msg2638 = msg2638_handler;
72 	struct i2c_client *client = msg2638->client;
73 	struct input_dev *input = msg2638->input_dev;
74 	struct touch_event touch_event;
75 	u32 len = sizeof(touch_event);
76 	struct i2c_msg msg[] = {
77 		{
78 			.addr	= client->addr,
79 			.flags	= I2C_M_RD,
80 			.len	= sizeof(touch_event),
81 			.buf	= (u8 *)&touch_event,
82 		},
83 	};
84 	struct packet *p;
85 	u16 x, y;
86 	int ret;
87 	int i;
88 
89 	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
90 	if (ret != ARRAY_SIZE(msg)) {
91 		dev_err(&client->dev,
92 			"Failed I2C transfer in irq handler: %d\n",
93 			ret < 0 ? ret : -EIO);
94 		goto out;
95 	}
96 
97 	if (touch_event.mode != MODE_DATA_RAW)
98 		goto out;
99 
100 	if (msg2638_checksum((u8 *)&touch_event, len - 1) !=
101 						touch_event.checksum) {
102 		dev_err(&client->dev, "Failed checksum!\n");
103 		goto out;
104 	}
105 
106 	for (i = 0; i < MAX_SUPPORTED_FINGER_NUM; i++) {
107 		p = &touch_event.pkt[i];
108 
109 		/* Ignore non-pressed finger data */
110 		if (p->xy_hi == 0xFF && p->x_low == 0xFF && p->y_low == 0xFF)
111 			continue;
112 
113 		x = (((p->xy_hi & 0xF0) << 4) | p->x_low);
114 		y = (((p->xy_hi & 0x0F) << 8) | p->y_low);
115 
116 		input_mt_slot(input, i);
117 		input_mt_report_slot_state(input, MT_TOOL_FINGER, true);
118 		touchscreen_report_pos(input, &msg2638->prop, x, y, true);
119 	}
120 
121 	input_mt_sync_frame(msg2638->input_dev);
122 	input_sync(msg2638->input_dev);
123 
124 out:
125 	return IRQ_HANDLED;
126 }
127 
128 static void msg2638_reset(struct msg2638_ts_data *msg2638)
129 {
130 	gpiod_set_value_cansleep(msg2638->reset_gpiod, 1);
131 	usleep_range(RESET_DELAY_MIN_US, RESET_DELAY_MAX_US);
132 	gpiod_set_value_cansleep(msg2638->reset_gpiod, 0);
133 	msleep(FIRMWARE_ON_DELAY_MS);
134 }
135 
136 static int msg2638_start(struct msg2638_ts_data *msg2638)
137 {
138 	int error;
139 
140 	error = regulator_bulk_enable(ARRAY_SIZE(msg2638->supplies),
141 				      msg2638->supplies);
142 	if (error) {
143 		dev_err(&msg2638->client->dev,
144 			"Failed to enable regulators: %d\n", error);
145 		return error;
146 	}
147 
148 	msleep(CHIP_ON_DELAY_MS);
149 
150 	msg2638_reset(msg2638);
151 
152 	enable_irq(msg2638->client->irq);
153 
154 	return 0;
155 }
156 
157 static int msg2638_stop(struct msg2638_ts_data *msg2638)
158 {
159 	int error;
160 
161 	disable_irq(msg2638->client->irq);
162 
163 	error = regulator_bulk_disable(ARRAY_SIZE(msg2638->supplies),
164 				       msg2638->supplies);
165 	if (error) {
166 		dev_err(&msg2638->client->dev,
167 			"Failed to disable regulators: %d\n", error);
168 		return error;
169 	}
170 
171 	return 0;
172 }
173 
174 static int msg2638_input_open(struct input_dev *dev)
175 {
176 	struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
177 
178 	return msg2638_start(msg2638);
179 }
180 
181 static void msg2638_input_close(struct input_dev *dev)
182 {
183 	struct msg2638_ts_data *msg2638 = input_get_drvdata(dev);
184 
185 	msg2638_stop(msg2638);
186 }
187 
188 static int msg2638_init_input_dev(struct msg2638_ts_data *msg2638)
189 {
190 	struct device *dev = &msg2638->client->dev;
191 	struct input_dev *input_dev;
192 	int error;
193 
194 	input_dev = devm_input_allocate_device(dev);
195 	if (!input_dev) {
196 		dev_err(dev, "Failed to allocate input device.\n");
197 		return -ENOMEM;
198 	}
199 
200 	input_set_drvdata(input_dev, msg2638);
201 	msg2638->input_dev = input_dev;
202 
203 	input_dev->name = "MStar TouchScreen";
204 	input_dev->phys = "input/ts";
205 	input_dev->id.bustype = BUS_I2C;
206 	input_dev->open = msg2638_input_open;
207 	input_dev->close = msg2638_input_close;
208 
209 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
210 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
211 
212 	touchscreen_parse_properties(input_dev, true, &msg2638->prop);
213 	if (!msg2638->prop.max_x || !msg2638->prop.max_y) {
214 		dev_err(dev, "touchscreen-size-x and/or touchscreen-size-y not set in properties\n");
215 		return -EINVAL;
216 	}
217 
218 	error = input_mt_init_slots(input_dev, MAX_SUPPORTED_FINGER_NUM,
219 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
220 	if (error) {
221 		dev_err(dev, "Failed to initialize MT slots: %d\n", error);
222 		return error;
223 	}
224 
225 	error = input_register_device(input_dev);
226 	if (error) {
227 		dev_err(dev, "Failed to register input device: %d\n", error);
228 		return error;
229 	}
230 
231 	return 0;
232 }
233 
234 static int msg2638_ts_probe(struct i2c_client *client)
235 {
236 	struct device *dev = &client->dev;
237 	struct msg2638_ts_data *msg2638;
238 	int error;
239 
240 	if (!i2c_check_functionality(client->adapter, I2C_FUNC_I2C)) {
241 		dev_err(dev, "Failed to assert adapter's support for plain I2C.\n");
242 		return -ENXIO;
243 	}
244 
245 	msg2638 = devm_kzalloc(dev, sizeof(*msg2638), GFP_KERNEL);
246 	if (!msg2638)
247 		return -ENOMEM;
248 
249 	msg2638->client = client;
250 	i2c_set_clientdata(client, msg2638);
251 
252 	msg2638->supplies[0].supply = "vdd";
253 	msg2638->supplies[1].supply = "vddio";
254 	error = devm_regulator_bulk_get(dev, ARRAY_SIZE(msg2638->supplies),
255 					msg2638->supplies);
256 	if (error) {
257 		dev_err(dev, "Failed to get regulators: %d\n", error);
258 		return error;
259 	}
260 
261 	msg2638->reset_gpiod = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
262 	if (IS_ERR(msg2638->reset_gpiod)) {
263 		error = PTR_ERR(msg2638->reset_gpiod);
264 		dev_err(dev, "Failed to request reset GPIO: %d\n", error);
265 		return error;
266 	}
267 
268 	error = msg2638_init_input_dev(msg2638);
269 	if (error) {
270 		dev_err(dev, "Failed to initialize input device: %d\n", error);
271 		return error;
272 	}
273 
274 	error = devm_request_threaded_irq(dev, client->irq,
275 					  NULL, msg2638_ts_irq_handler,
276 					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
277 					  client->name, msg2638);
278 	if (error) {
279 		dev_err(dev, "Failed to request IRQ: %d\n", error);
280 		return error;
281 	}
282 
283 	return 0;
284 }
285 
286 static int __maybe_unused msg2638_suspend(struct device *dev)
287 {
288 	struct i2c_client *client = to_i2c_client(dev);
289 	struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
290 
291 	mutex_lock(&msg2638->input_dev->mutex);
292 
293 	if (input_device_enabled(msg2638->input_dev))
294 		msg2638_stop(msg2638);
295 
296 	mutex_unlock(&msg2638->input_dev->mutex);
297 
298 	return 0;
299 }
300 
301 static int __maybe_unused msg2638_resume(struct device *dev)
302 {
303 	struct i2c_client *client = to_i2c_client(dev);
304 	struct msg2638_ts_data *msg2638 = i2c_get_clientdata(client);
305 	int ret = 0;
306 
307 	mutex_lock(&msg2638->input_dev->mutex);
308 
309 	if (input_device_enabled(msg2638->input_dev))
310 		ret = msg2638_start(msg2638);
311 
312 	mutex_unlock(&msg2638->input_dev->mutex);
313 
314 	return ret;
315 }
316 
317 static SIMPLE_DEV_PM_OPS(msg2638_pm_ops, msg2638_suspend, msg2638_resume);
318 
319 static const struct of_device_id msg2638_of_match[] = {
320 	{ .compatible = "mstar,msg2638" },
321 	{ }
322 };
323 MODULE_DEVICE_TABLE(of, msg2638_of_match);
324 
325 static struct i2c_driver msg2638_ts_driver = {
326 	.probe_new = msg2638_ts_probe,
327 	.driver = {
328 		.name = "MStar-TS",
329 		.pm = &msg2638_pm_ops,
330 		.of_match_table = msg2638_of_match,
331 	},
332 };
333 module_i2c_driver(msg2638_ts_driver);
334 
335 MODULE_AUTHOR("Vincent Knecht <vincent.knecht@mailoo.org>");
336 MODULE_DESCRIPTION("MStar MSG2638 touchscreen driver");
337 MODULE_LICENSE("GPL v2");
338