1 // SPDX-License-Identifier: GPL-2.0-only
2 
3 #include <linux/bits.h>
4 #include <linux/delay.h>
5 #include <linux/i2c.h>
6 #include <linux/input.h>
7 #include <linux/input/mt.h>
8 #include <linux/input/touchscreen.h>
9 #include <linux/kernel.h>
10 #include <linux/module.h>
11 #include <linux/property.h>
12 #include <linux/regulator/consumer.h>
13 
14 #define IST3038C_HIB_ACCESS		(0x800B << 16)
15 #define IST3038C_DIRECT_ACCESS		BIT(31)
16 #define IST3038C_REG_CHIPID		0x40001000
17 #define IST3038C_REG_HIB_BASE		0x30000100
18 #define IST3038C_REG_TOUCH_STATUS	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS)
19 #define IST3038C_REG_TOUCH_COORD	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x8)
20 #define IST3038C_REG_INTR_MESSAGE	(IST3038C_REG_HIB_BASE | IST3038C_HIB_ACCESS | 0x4)
21 #define IST3038C_WHOAMI			0x38c
22 #define IST3038C_CHIP_ON_DELAY_MS	60
23 #define IST3038C_I2C_RETRY_COUNT	3
24 #define IST3038C_MAX_FINGER_NUM		10
25 #define IST3038C_X_MASK			GENMASK(23, 12)
26 #define IST3038C_X_SHIFT		12
27 #define IST3038C_Y_MASK			GENMASK(11, 0)
28 #define IST3038C_AREA_MASK		GENMASK(27, 24)
29 #define IST3038C_AREA_SHIFT		24
30 #define IST3038C_FINGER_COUNT_MASK	GENMASK(15, 12)
31 #define IST3038C_FINGER_COUNT_SHIFT	12
32 #define IST3038C_FINGER_STATUS_MASK	GENMASK(9, 0)
33 
34 struct imagis_ts {
35 	struct i2c_client *client;
36 	struct input_dev *input_dev;
37 	struct touchscreen_properties prop;
38 	struct regulator_bulk_data supplies[2];
39 };
40 
41 static int imagis_i2c_read_reg(struct imagis_ts *ts,
42 			       unsigned int reg, u32 *data)
43 {
44 	__be32 ret_be;
45 	__be32 reg_be = cpu_to_be32(reg);
46 	struct i2c_msg msg[] = {
47 		{
48 			.addr = ts->client->addr,
49 			.flags = 0,
50 			.buf = (unsigned char *)&reg_be,
51 			.len = sizeof(reg_be),
52 		}, {
53 			.addr = ts->client->addr,
54 			.flags = I2C_M_RD,
55 			.buf = (unsigned char *)&ret_be,
56 			.len = sizeof(ret_be),
57 		},
58 	};
59 	int ret, error;
60 	int retry = IST3038C_I2C_RETRY_COUNT;
61 
62 	/* Retry in case the controller fails to respond */
63 	do {
64 		ret = i2c_transfer(ts->client->adapter, msg, ARRAY_SIZE(msg));
65 		if (ret == ARRAY_SIZE(msg)) {
66 			*data = be32_to_cpu(ret_be);
67 			return 0;
68 		}
69 
70 		error = ret < 0 ? ret : -EIO;
71 		dev_err(&ts->client->dev,
72 			"%s - i2c_transfer failed: %d (%d)\n",
73 			__func__, error, ret);
74 	} while (--retry);
75 
76 	return error;
77 }
78 
79 static irqreturn_t imagis_interrupt(int irq, void *dev_id)
80 {
81 	struct imagis_ts *ts = dev_id;
82 	u32 intr_message, finger_status;
83 	unsigned int finger_count, finger_pressed;
84 	int i;
85 	int error;
86 
87 	error = imagis_i2c_read_reg(ts, IST3038C_REG_INTR_MESSAGE,
88 				    &intr_message);
89 	if (error) {
90 		dev_err(&ts->client->dev,
91 			"failed to read the interrupt message: %d\n", error);
92 		goto out;
93 	}
94 
95 	finger_count = (intr_message & IST3038C_FINGER_COUNT_MASK) >>
96 				IST3038C_FINGER_COUNT_SHIFT;
97 	if (finger_count > IST3038C_MAX_FINGER_NUM) {
98 		dev_err(&ts->client->dev,
99 			"finger count %d is more than maximum supported\n",
100 			finger_count);
101 		goto out;
102 	}
103 
104 	finger_pressed = intr_message & IST3038C_FINGER_STATUS_MASK;
105 
106 	for (i = 0; i < finger_count; i++) {
107 		error = imagis_i2c_read_reg(ts,
108 					    IST3038C_REG_TOUCH_COORD + (i * 4),
109 					    &finger_status);
110 		if (error) {
111 			dev_err(&ts->client->dev,
112 				"failed to read coordinates for finger %d: %d\n",
113 				i, error);
114 			goto out;
115 		}
116 
117 		input_mt_slot(ts->input_dev, i);
118 		input_mt_report_slot_state(ts->input_dev, MT_TOOL_FINGER,
119 					   finger_pressed & BIT(i));
120 		touchscreen_report_pos(ts->input_dev, &ts->prop,
121 				       (finger_status & IST3038C_X_MASK) >>
122 						IST3038C_X_SHIFT,
123 				       finger_status & IST3038C_Y_MASK, 1);
124 		input_report_abs(ts->input_dev, ABS_MT_TOUCH_MAJOR,
125 				 (finger_status & IST3038C_AREA_MASK) >>
126 					IST3038C_AREA_SHIFT);
127 	}
128 
129 	input_mt_sync_frame(ts->input_dev);
130 	input_sync(ts->input_dev);
131 
132 out:
133 	return IRQ_HANDLED;
134 }
135 
136 static void imagis_power_off(void *_ts)
137 {
138 	struct imagis_ts *ts = _ts;
139 
140 	regulator_bulk_disable(ARRAY_SIZE(ts->supplies), ts->supplies);
141 }
142 
143 static int imagis_power_on(struct imagis_ts *ts)
144 {
145 	int error;
146 
147 	error = regulator_bulk_enable(ARRAY_SIZE(ts->supplies), ts->supplies);
148 	if (error)
149 		return error;
150 
151 	msleep(IST3038C_CHIP_ON_DELAY_MS);
152 
153 	return 0;
154 }
155 
156 static int imagis_start(struct imagis_ts *ts)
157 {
158 	int error;
159 
160 	error = imagis_power_on(ts);
161 	if (error)
162 		return error;
163 
164 	enable_irq(ts->client->irq);
165 
166 	return 0;
167 }
168 
169 static int imagis_stop(struct imagis_ts *ts)
170 {
171 	disable_irq(ts->client->irq);
172 
173 	imagis_power_off(ts);
174 
175 	return 0;
176 }
177 
178 static int imagis_input_open(struct input_dev *dev)
179 {
180 	struct imagis_ts *ts = input_get_drvdata(dev);
181 
182 	return imagis_start(ts);
183 }
184 
185 static void imagis_input_close(struct input_dev *dev)
186 {
187 	struct imagis_ts *ts = input_get_drvdata(dev);
188 
189 	imagis_stop(ts);
190 }
191 
192 static int imagis_init_input_dev(struct imagis_ts *ts)
193 {
194 	struct input_dev *input_dev;
195 	int error;
196 
197 	input_dev = devm_input_allocate_device(&ts->client->dev);
198 	if (!input_dev)
199 		return -ENOMEM;
200 
201 	ts->input_dev = input_dev;
202 
203 	input_dev->name = "Imagis capacitive touchscreen";
204 	input_dev->phys = "input/ts";
205 	input_dev->id.bustype = BUS_I2C;
206 	input_dev->open = imagis_input_open;
207 	input_dev->close = imagis_input_close;
208 
209 	input_set_drvdata(input_dev, ts);
210 
211 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_X);
212 	input_set_capability(input_dev, EV_ABS, ABS_MT_POSITION_Y);
213 	input_set_abs_params(input_dev, ABS_MT_TOUCH_MAJOR, 0, 255, 0, 0);
214 
215 	touchscreen_parse_properties(input_dev, true, &ts->prop);
216 	if (!ts->prop.max_x || !ts->prop.max_y) {
217 		dev_err(&ts->client->dev,
218 			"Touchscreen-size-x and/or touchscreen-size-y not set in dts\n");
219 		return -EINVAL;
220 	}
221 
222 	error = input_mt_init_slots(input_dev,
223 				    IST3038C_MAX_FINGER_NUM,
224 				    INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
225 	if (error) {
226 		dev_err(&ts->client->dev,
227 			"Failed to initialize MT slots: %d", error);
228 		return error;
229 	}
230 
231 	error = input_register_device(input_dev);
232 	if (error) {
233 		dev_err(&ts->client->dev,
234 			"Failed to register input device: %d", error);
235 		return error;
236 	}
237 
238 	return 0;
239 }
240 
241 static int imagis_init_regulators(struct imagis_ts *ts)
242 {
243 	struct i2c_client *client = ts->client;
244 
245 	ts->supplies[0].supply = "vdd";
246 	ts->supplies[1].supply = "vddio";
247 	return devm_regulator_bulk_get(&client->dev,
248 				       ARRAY_SIZE(ts->supplies),
249 				       ts->supplies);
250 }
251 
252 static int imagis_probe(struct i2c_client *i2c)
253 {
254 	struct device *dev = &i2c->dev;
255 	struct imagis_ts *ts;
256 	int chip_id, error;
257 
258 	ts = devm_kzalloc(dev, sizeof(*ts), GFP_KERNEL);
259 	if (!ts)
260 		return -ENOMEM;
261 
262 	ts->client = i2c;
263 
264 	error = imagis_init_regulators(ts);
265 	if (error) {
266 		dev_err(dev, "regulator init error: %d\n", error);
267 		return error;
268 	}
269 
270 	error = imagis_power_on(ts);
271 	if (error) {
272 		dev_err(dev, "failed to enable regulators: %d\n", error);
273 		return error;
274 	}
275 
276 	error = devm_add_action_or_reset(dev, imagis_power_off, ts);
277 	if (error) {
278 		dev_err(dev, "failed to install poweroff action: %d\n", error);
279 		return error;
280 	}
281 
282 	error = imagis_i2c_read_reg(ts,
283 			IST3038C_REG_CHIPID | IST3038C_DIRECT_ACCESS,
284 			&chip_id);
285 	if (error) {
286 		dev_err(dev, "chip ID read failure: %d\n", error);
287 		return error;
288 	}
289 
290 	if (chip_id != IST3038C_WHOAMI) {
291 		dev_err(dev, "unknown chip ID: 0x%x\n", chip_id);
292 		return -EINVAL;
293 	}
294 
295 	error = devm_request_threaded_irq(dev, i2c->irq,
296 					  NULL, imagis_interrupt,
297 					  IRQF_ONESHOT | IRQF_NO_AUTOEN,
298 					  "imagis-touchscreen", ts);
299 	if (error) {
300 		dev_err(dev, "IRQ %d allocation failure: %d\n",
301 			i2c->irq, error);
302 		return error;
303 	}
304 
305 	error = imagis_init_input_dev(ts);
306 	if (error)
307 		return error;
308 
309 	return 0;
310 }
311 
312 static int __maybe_unused imagis_suspend(struct device *dev)
313 {
314 	struct i2c_client *client = to_i2c_client(dev);
315 	struct imagis_ts *ts = i2c_get_clientdata(client);
316 	int retval = 0;
317 
318 	mutex_lock(&ts->input_dev->mutex);
319 
320 	if (input_device_enabled(ts->input_dev))
321 		retval = imagis_stop(ts);
322 
323 	mutex_unlock(&ts->input_dev->mutex);
324 
325 	return retval;
326 }
327 
328 static int __maybe_unused imagis_resume(struct device *dev)
329 {
330 	struct i2c_client *client = to_i2c_client(dev);
331 	struct imagis_ts *ts = i2c_get_clientdata(client);
332 	int retval = 0;
333 
334 	mutex_lock(&ts->input_dev->mutex);
335 
336 	if (input_device_enabled(ts->input_dev))
337 		retval = imagis_start(ts);
338 
339 	mutex_unlock(&ts->input_dev->mutex);
340 
341 	return retval;
342 }
343 
344 static SIMPLE_DEV_PM_OPS(imagis_pm_ops, imagis_suspend, imagis_resume);
345 
346 #ifdef CONFIG_OF
347 static const struct of_device_id imagis_of_match[] = {
348 	{ .compatible = "imagis,ist3038c", },
349 	{ },
350 };
351 MODULE_DEVICE_TABLE(of, imagis_of_match);
352 #endif
353 
354 static struct i2c_driver imagis_ts_driver = {
355 	.driver = {
356 		.name = "imagis-touchscreen",
357 		.pm = &imagis_pm_ops,
358 		.of_match_table = of_match_ptr(imagis_of_match),
359 	},
360 	.probe_new = imagis_probe,
361 };
362 
363 module_i2c_driver(imagis_ts_driver);
364 
365 MODULE_DESCRIPTION("Imagis IST3038C Touchscreen Driver");
366 MODULE_AUTHOR("Markuss Broks <markuss.broks@gmail.com>");
367 MODULE_LICENSE("GPL");
368