1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3 * Driver for Novatek NT11205 i2c touchscreen controller as found
4 * on the Acer Iconia One 7 B1-750 tablet.
5 *
6 * Copyright (c) 2023 Hans de Goede <hdegoede@redhat.com>
7 */
8
9 #include <linux/delay.h>
10 #include <linux/gpio/consumer.h>
11 #include <linux/interrupt.h>
12 #include <linux/i2c.h>
13 #include <linux/input.h>
14 #include <linux/input/mt.h>
15 #include <linux/input/touchscreen.h>
16 #include <linux/module.h>
17
18 #include <linux/unaligned.h>
19
20 #define NVT_TS_TOUCH_START 0x00
21 #define NVT_TS_TOUCH_SIZE 6
22
23 #define NVT_TS_PARAMETERS_START 0x78
24 /* These are offsets from NVT_TS_PARAMETERS_START */
25 #define NVT_TS_PARAMS_WIDTH 0x04
26 #define NVT_TS_PARAMS_HEIGHT 0x06
27 #define NVT_TS_PARAMS_MAX_TOUCH 0x09
28 #define NVT_TS_PARAMS_MAX_BUTTONS 0x0a
29 #define NVT_TS_PARAMS_IRQ_TYPE 0x0b
30 #define NVT_TS_PARAMS_WAKE_TYPE 0x0c
31 #define NVT_TS_PARAMS_CHIP_ID 0x0e
32 #define NVT_TS_PARAMS_SIZE 0x0f
33
34 #define NVT_TS_MAX_TOUCHES 10
35 #define NVT_TS_MAX_SIZE 4096
36
37 #define NVT_TS_TOUCH_INVALID 0xff
38 #define NVT_TS_TOUCH_SLOT_SHIFT 3
39 #define NVT_TS_TOUCH_TYPE_MASK GENMASK(2, 0)
40 #define NVT_TS_TOUCH_NEW 1
41 #define NVT_TS_TOUCH_UPDATE 2
42 #define NVT_TS_TOUCH_RELEASE 3
43
44 static const int nvt_ts_irq_type[4] = {
45 IRQF_TRIGGER_RISING,
46 IRQF_TRIGGER_FALLING,
47 IRQF_TRIGGER_LOW,
48 IRQF_TRIGGER_HIGH
49 };
50
51 struct nvt_ts_i2c_chip_data {
52 u8 wake_type;
53 u8 chip_id;
54 };
55
56 struct nvt_ts_data {
57 struct i2c_client *client;
58 struct input_dev *input;
59 struct gpio_desc *reset_gpio;
60 struct regulator_bulk_data regulators[2];
61 struct touchscreen_properties prop;
62 int max_touches;
63 u8 buf[NVT_TS_TOUCH_SIZE * NVT_TS_MAX_TOUCHES];
64 };
65
nvt_ts_read_data(struct i2c_client * client,u8 reg,u8 * data,int count)66 static int nvt_ts_read_data(struct i2c_client *client, u8 reg, u8 *data, int count)
67 {
68 struct i2c_msg msg[2] = {
69 {
70 .addr = client->addr,
71 .len = 1,
72 .buf = ®,
73 },
74 {
75 .addr = client->addr,
76 .flags = I2C_M_RD,
77 .len = count,
78 .buf = data,
79 }
80 };
81 int ret;
82
83 ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
84 if (ret != ARRAY_SIZE(msg)) {
85 dev_err(&client->dev, "Error reading from 0x%02x: %d\n", reg, ret);
86 return (ret < 0) ? ret : -EIO;
87 }
88
89 return 0;
90 }
91
nvt_ts_irq(int irq,void * dev_id)92 static irqreturn_t nvt_ts_irq(int irq, void *dev_id)
93 {
94 struct nvt_ts_data *data = dev_id;
95 struct device *dev = &data->client->dev;
96 int i, error, slot, x, y;
97 bool active;
98 u8 *touch;
99
100 error = nvt_ts_read_data(data->client, NVT_TS_TOUCH_START, data->buf,
101 data->max_touches * NVT_TS_TOUCH_SIZE);
102 if (error)
103 return IRQ_HANDLED;
104
105 for (i = 0; i < data->max_touches; i++) {
106 touch = &data->buf[i * NVT_TS_TOUCH_SIZE];
107
108 if (touch[0] == NVT_TS_TOUCH_INVALID)
109 continue;
110
111 slot = touch[0] >> NVT_TS_TOUCH_SLOT_SHIFT;
112 if (slot < 1 || slot > data->max_touches) {
113 dev_warn(dev, "slot %d out of range, ignoring\n", slot);
114 continue;
115 }
116
117 switch (touch[0] & NVT_TS_TOUCH_TYPE_MASK) {
118 case NVT_TS_TOUCH_NEW:
119 case NVT_TS_TOUCH_UPDATE:
120 active = true;
121 break;
122 case NVT_TS_TOUCH_RELEASE:
123 active = false;
124 break;
125 default:
126 dev_warn(dev, "slot %d unknown state %d\n", slot, touch[0] & 7);
127 continue;
128 }
129
130 slot--;
131 x = (touch[1] << 4) | (touch[3] >> 4);
132 y = (touch[2] << 4) | (touch[3] & 0x0f);
133
134 input_mt_slot(data->input, slot);
135 input_mt_report_slot_state(data->input, MT_TOOL_FINGER, active);
136 touchscreen_report_pos(data->input, &data->prop, x, y, true);
137 }
138
139 input_mt_sync_frame(data->input);
140 input_sync(data->input);
141
142 return IRQ_HANDLED;
143 }
144
nvt_ts_start(struct input_dev * dev)145 static int nvt_ts_start(struct input_dev *dev)
146 {
147 struct nvt_ts_data *data = input_get_drvdata(dev);
148 int error;
149
150 error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
151 if (error) {
152 dev_err(&data->client->dev, "failed to enable regulators\n");
153 return error;
154 }
155
156 enable_irq(data->client->irq);
157 gpiod_set_value_cansleep(data->reset_gpio, 0);
158
159 return 0;
160 }
161
nvt_ts_stop(struct input_dev * dev)162 static void nvt_ts_stop(struct input_dev *dev)
163 {
164 struct nvt_ts_data *data = input_get_drvdata(dev);
165
166 disable_irq(data->client->irq);
167 gpiod_set_value_cansleep(data->reset_gpio, 1);
168 regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
169 }
170
nvt_ts_suspend(struct device * dev)171 static int nvt_ts_suspend(struct device *dev)
172 {
173 struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
174
175 mutex_lock(&data->input->mutex);
176 if (input_device_enabled(data->input))
177 nvt_ts_stop(data->input);
178 mutex_unlock(&data->input->mutex);
179
180 return 0;
181 }
182
nvt_ts_resume(struct device * dev)183 static int nvt_ts_resume(struct device *dev)
184 {
185 struct nvt_ts_data *data = i2c_get_clientdata(to_i2c_client(dev));
186
187 mutex_lock(&data->input->mutex);
188 if (input_device_enabled(data->input))
189 nvt_ts_start(data->input);
190 mutex_unlock(&data->input->mutex);
191
192 return 0;
193 }
194
195 static DEFINE_SIMPLE_DEV_PM_OPS(nvt_ts_pm_ops, nvt_ts_suspend, nvt_ts_resume);
196
nvt_ts_probe(struct i2c_client * client)197 static int nvt_ts_probe(struct i2c_client *client)
198 {
199 struct device *dev = &client->dev;
200 int error, width, height, irq_type;
201 struct nvt_ts_data *data;
202 const struct nvt_ts_i2c_chip_data *chip;
203 struct input_dev *input;
204
205 if (!client->irq) {
206 dev_err(dev, "Error no irq specified\n");
207 return -EINVAL;
208 }
209
210 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL);
211 if (!data)
212 return -ENOMEM;
213
214 chip = device_get_match_data(&client->dev);
215 if (!chip)
216 return -EINVAL;
217
218 data->client = client;
219 i2c_set_clientdata(client, data);
220
221 /*
222 * VCC is the analog voltage supply
223 * IOVCC is the digital voltage supply
224 */
225 data->regulators[0].supply = "vcc";
226 data->regulators[1].supply = "iovcc";
227 error = devm_regulator_bulk_get(dev, ARRAY_SIZE(data->regulators), data->regulators);
228 if (error) {
229 dev_err(dev, "cannot get regulators: %d\n", error);
230 return error;
231 }
232
233 error = regulator_bulk_enable(ARRAY_SIZE(data->regulators), data->regulators);
234 if (error) {
235 dev_err(dev, "failed to enable regulators: %d\n", error);
236 return error;
237 }
238
239 data->reset_gpio = devm_gpiod_get(dev, "reset", GPIOD_OUT_LOW);
240 error = PTR_ERR_OR_ZERO(data->reset_gpio);
241 if (error) {
242 regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
243 dev_err(dev, "failed to request reset GPIO: %d\n", error);
244 return error;
245 }
246
247 /* Wait for controller to come out of reset before params read */
248 msleep(100);
249 error = nvt_ts_read_data(data->client, NVT_TS_PARAMETERS_START,
250 data->buf, NVT_TS_PARAMS_SIZE);
251 gpiod_set_value_cansleep(data->reset_gpio, 1); /* Put back in reset */
252 regulator_bulk_disable(ARRAY_SIZE(data->regulators), data->regulators);
253 if (error)
254 return error;
255
256 width = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_WIDTH]);
257 height = get_unaligned_be16(&data->buf[NVT_TS_PARAMS_HEIGHT]);
258 data->max_touches = data->buf[NVT_TS_PARAMS_MAX_TOUCH];
259 irq_type = data->buf[NVT_TS_PARAMS_IRQ_TYPE];
260
261 if (width > NVT_TS_MAX_SIZE || height >= NVT_TS_MAX_SIZE ||
262 data->max_touches > NVT_TS_MAX_TOUCHES ||
263 irq_type >= ARRAY_SIZE(nvt_ts_irq_type) ||
264 data->buf[NVT_TS_PARAMS_WAKE_TYPE] != chip->wake_type ||
265 data->buf[NVT_TS_PARAMS_CHIP_ID] != chip->chip_id) {
266 dev_err(dev, "Unsupported touchscreen parameters: %*ph\n",
267 NVT_TS_PARAMS_SIZE, data->buf);
268 return -EIO;
269 }
270
271 dev_dbg(dev, "Detected %dx%d touchscreen with %d max touches\n",
272 width, height, data->max_touches);
273
274 if (data->buf[NVT_TS_PARAMS_MAX_BUTTONS])
275 dev_warn(dev, "Touchscreen buttons are not supported\n");
276
277 input = devm_input_allocate_device(dev);
278 if (!input)
279 return -ENOMEM;
280
281 input->name = client->name;
282 input->id.bustype = BUS_I2C;
283 input->open = nvt_ts_start;
284 input->close = nvt_ts_stop;
285
286 input_set_abs_params(input, ABS_MT_POSITION_X, 0, width - 1, 0, 0);
287 input_set_abs_params(input, ABS_MT_POSITION_Y, 0, height - 1, 0, 0);
288 touchscreen_parse_properties(input, true, &data->prop);
289
290 error = input_mt_init_slots(input, data->max_touches,
291 INPUT_MT_DIRECT | INPUT_MT_DROP_UNUSED);
292 if (error)
293 return error;
294
295 data->input = input;
296 input_set_drvdata(input, data);
297
298 error = devm_request_threaded_irq(dev, client->irq, NULL, nvt_ts_irq,
299 IRQF_ONESHOT | IRQF_NO_AUTOEN |
300 nvt_ts_irq_type[irq_type],
301 client->name, data);
302 if (error) {
303 dev_err(dev, "failed to request irq: %d\n", error);
304 return error;
305 }
306
307 error = input_register_device(input);
308 if (error) {
309 dev_err(dev, "failed to register input device: %d\n", error);
310 return error;
311 }
312
313 return 0;
314 }
315
316 static const struct nvt_ts_i2c_chip_data nvt_nt11205_ts_data = {
317 .wake_type = 0x05,
318 .chip_id = 0x05,
319 };
320
321 static const struct nvt_ts_i2c_chip_data nvt_nt36672a_ts_data = {
322 .wake_type = 0x01,
323 .chip_id = 0x08,
324 };
325
326 static const struct of_device_id nvt_ts_of_match[] = {
327 { .compatible = "novatek,nt11205-ts", .data = &nvt_nt11205_ts_data },
328 { .compatible = "novatek,nt36672a-ts", .data = &nvt_nt36672a_ts_data },
329 { }
330 };
331 MODULE_DEVICE_TABLE(of, nvt_ts_of_match);
332
333 static const struct i2c_device_id nvt_ts_i2c_id[] = {
334 { "nt11205-ts", (unsigned long) &nvt_nt11205_ts_data },
335 { "nt36672a-ts", (unsigned long) &nvt_nt36672a_ts_data },
336 { }
337 };
338 MODULE_DEVICE_TABLE(i2c, nvt_ts_i2c_id);
339
340 static struct i2c_driver nvt_ts_driver = {
341 .driver = {
342 .name = "novatek-nvt-ts",
343 .pm = pm_sleep_ptr(&nvt_ts_pm_ops),
344 .of_match_table = nvt_ts_of_match,
345 },
346 .probe = nvt_ts_probe,
347 .id_table = nvt_ts_i2c_id,
348 };
349
350 module_i2c_driver(nvt_ts_driver);
351
352 MODULE_DESCRIPTION("Novatek NT11205 touchscreen driver");
353 MODULE_AUTHOR("Hans de Goede <hdegoede@redhat.com>");
354 MODULE_LICENSE("GPL");
355