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
imagis_i2c_read_reg(struct imagis_ts * ts,unsigned int reg,u32 * data)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 *)®_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
imagis_interrupt(int irq,void * dev_id)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
imagis_power_off(void * _ts)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
imagis_power_on(struct imagis_ts * ts)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
imagis_start(struct imagis_ts * ts)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
imagis_stop(struct imagis_ts * ts)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
imagis_input_open(struct input_dev * dev)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
imagis_input_close(struct input_dev * dev)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
imagis_init_input_dev(struct imagis_ts * ts)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
imagis_init_regulators(struct imagis_ts * ts)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
imagis_probe(struct i2c_client * i2c)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
imagis_suspend(struct device * dev)312 static int 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
imagis_resume(struct device * dev)328 static int 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 DEFINE_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 = pm_sleep_ptr(&imagis_pm_ops),
358 .of_match_table = of_match_ptr(imagis_of_match),
359 },
360 .probe = 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