1// SPDX-License-Identifier: GPL-2.0-or-later
2/*
3 * qt2160.c - Atmel AT42QT2160 Touch Sense Controller
4 *
5 * Copyright (C) 2009 Raphael Derosso Pereira <raphaelpereira@gmail.com>
6 */
7
8#include <linux/kernel.h>
9#include <linux/leds.h>
10#include <linux/module.h>
11#include <linux/slab.h>
12#include <linux/jiffies.h>
13#include <linux/i2c.h>
14#include <linux/irq.h>
15#include <linux/interrupt.h>
16#include <linux/input.h>
17
18#define QT2160_VALID_CHIPID 0x11
19
20#define QT2160_CMD_CHIPID 0
21#define QT2160_CMD_CODEVER 1
22#define QT2160_CMD_GSTAT 2
23#define QT2160_CMD_KEYS3 3
24#define QT2160_CMD_KEYS4 4
25#define QT2160_CMD_SLIDE 5
26#define QT2160_CMD_GPIOS 6
27#define QT2160_CMD_SUBVER 7
28#define QT2160_CMD_CALIBRATE 10
29#define QT2160_CMD_DRIVE_X 70
30#define QT2160_CMD_PWMEN_X 74
31#define QT2160_CMD_PWM_DUTY 76
32
33#define QT2160_NUM_LEDS_X 8
34
35#define QT2160_CYCLE_INTERVAL 2000 /* msec - 2 sec */
36
37static unsigned char qt2160_key2code[] = {
38 KEY_0, KEY_1, KEY_2, KEY_3,
39 KEY_4, KEY_5, KEY_6, KEY_7,
40 KEY_8, KEY_9, KEY_A, KEY_B,
41 KEY_C, KEY_D, KEY_E, KEY_F,
42};
43
44#ifdef CONFIG_LEDS_CLASS
45struct qt2160_led {
46 struct qt2160_data *qt2160;
47 struct led_classdev cdev;
48 char name[32];
49 int id;
50 enum led_brightness brightness;
51};
52#endif
53
54struct qt2160_data {
55 struct i2c_client *client;
56 struct input_dev *input;
57 unsigned short keycodes[ARRAY_SIZE(qt2160_key2code)];
58 u16 key_matrix;
59#ifdef CONFIG_LEDS_CLASS
60 struct qt2160_led leds[QT2160_NUM_LEDS_X];
61#endif
62};
63
64static int qt2160_read(struct i2c_client *client, u8 reg);
65static int qt2160_write(struct i2c_client *client, u8 reg, u8 data);
66
67#ifdef CONFIG_LEDS_CLASS
68
69static int qt2160_led_set(struct led_classdev *cdev,
70 enum led_brightness value)
71{
72 struct qt2160_led *led = container_of(cdev, struct qt2160_led, cdev);
73 struct qt2160_data *qt2160 = led->qt2160;
74 struct i2c_client *client = qt2160->client;
75 u32 drive, pwmen;
76
77 if (value != led->brightness) {
78 drive = qt2160_read(client, QT2160_CMD_DRIVE_X);
79 pwmen = qt2160_read(client, QT2160_CMD_PWMEN_X);
80 if (value != LED_OFF) {
81 drive |= BIT(led->id);
82 pwmen |= BIT(led->id);
83
84 } else {
85 drive &= ~BIT(led->id);
86 pwmen &= ~BIT(led->id);
87 }
88 qt2160_write(client, QT2160_CMD_DRIVE_X, data: drive);
89 qt2160_write(client, QT2160_CMD_PWMEN_X, data: pwmen);
90
91 /*
92 * Changing this register will change the brightness
93 * of every LED in the qt2160. It's a HW limitation.
94 */
95 if (value != LED_OFF)
96 qt2160_write(client, QT2160_CMD_PWM_DUTY, data: value);
97
98 led->brightness = value;
99 }
100
101 return 0;
102}
103
104#endif /* CONFIG_LEDS_CLASS */
105
106static int qt2160_read_block(struct i2c_client *client,
107 u8 inireg, u8 *buffer, unsigned int count)
108{
109 int error, idx = 0;
110
111 /*
112 * Can't use SMBus block data read. Check for I2C functionality to speed
113 * things up whenever possible. Otherwise we will be forced to read
114 * sequentially.
115 */
116 if (i2c_check_functionality(adap: client->adapter, I2C_FUNC_I2C)) {
117
118 error = i2c_smbus_write_byte(client, value: inireg + idx);
119 if (error) {
120 dev_err(&client->dev,
121 "couldn't send request. Returned %d\n", error);
122 return error;
123 }
124
125 error = i2c_master_recv(client, buf: buffer, count);
126 if (error != count) {
127 dev_err(&client->dev,
128 "couldn't read registers. Returned %d bytes\n", error);
129 return error;
130 }
131 } else {
132
133 while (count--) {
134 int data;
135
136 error = i2c_smbus_write_byte(client, value: inireg + idx);
137 if (error) {
138 dev_err(&client->dev,
139 "couldn't send request. Returned %d\n", error);
140 return error;
141 }
142
143 data = i2c_smbus_read_byte(client);
144 if (data < 0) {
145 dev_err(&client->dev,
146 "couldn't read register. Returned %d\n", data);
147 return data;
148 }
149
150 buffer[idx++] = data;
151 }
152 }
153
154 return 0;
155}
156
157static void qt2160_get_key_matrix(struct input_dev *input)
158{
159 struct qt2160_data *qt2160 = input_get_drvdata(dev: input);
160 struct i2c_client *client = qt2160->client;
161 u8 regs[6];
162 u16 old_matrix, new_matrix;
163 int ret, i, mask;
164
165 dev_dbg(&client->dev, "requesting keys...\n");
166
167 /*
168 * Read all registers from General Status Register
169 * to GPIOs register
170 */
171 ret = qt2160_read_block(client, QT2160_CMD_GSTAT, buffer: regs, count: 6);
172 if (ret) {
173 dev_err(&client->dev,
174 "could not perform chip read.\n");
175 return;
176 }
177
178 old_matrix = qt2160->key_matrix;
179 qt2160->key_matrix = new_matrix = (regs[2] << 8) | regs[1];
180
181 mask = 0x01;
182 for (i = 0; i < 16; ++i, mask <<= 1) {
183 int keyval = new_matrix & mask;
184
185 if ((old_matrix & mask) != keyval) {
186 input_report_key(dev: input, code: qt2160->keycodes[i], value: keyval);
187 dev_dbg(&client->dev, "key %d %s\n",
188 i, keyval ? "pressed" : "released");
189 }
190 }
191
192 input_sync(dev: input);
193}
194
195static irqreturn_t qt2160_irq(int irq, void *data)
196{
197 struct input_dev *input = data;
198
199 qt2160_get_key_matrix(input);
200
201 return IRQ_HANDLED;
202}
203
204static int qt2160_read(struct i2c_client *client, u8 reg)
205{
206 int ret;
207
208 ret = i2c_smbus_write_byte(client, value: reg);
209 if (ret) {
210 dev_err(&client->dev,
211 "couldn't send request. Returned %d\n", ret);
212 return ret;
213 }
214
215 ret = i2c_smbus_read_byte(client);
216 if (ret < 0) {
217 dev_err(&client->dev,
218 "couldn't read register. Returned %d\n", ret);
219 return ret;
220 }
221
222 return ret;
223}
224
225static int qt2160_write(struct i2c_client *client, u8 reg, u8 data)
226{
227 int ret;
228
229 ret = i2c_smbus_write_byte_data(client, command: reg, value: data);
230 if (ret < 0)
231 dev_err(&client->dev,
232 "couldn't write data. Returned %d\n", ret);
233
234 return ret;
235}
236
237#ifdef CONFIG_LEDS_CLASS
238
239static int qt2160_register_leds(struct qt2160_data *qt2160)
240{
241 struct i2c_client *client = qt2160->client;
242 int error;
243 int i;
244
245 for (i = 0; i < QT2160_NUM_LEDS_X; i++) {
246 struct qt2160_led *led = &qt2160->leds[i];
247
248 snprintf(buf: led->name, size: sizeof(led->name), fmt: "qt2160:x%d", i);
249 led->cdev.name = led->name;
250 led->cdev.brightness_set_blocking = qt2160_led_set;
251 led->cdev.brightness = LED_OFF;
252 led->id = i;
253 led->qt2160 = qt2160;
254
255 error = devm_led_classdev_register(parent: &client->dev, led_cdev: &led->cdev);
256 if (error)
257 return error;
258 }
259
260 /* Tur off LEDs */
261 qt2160_write(client, QT2160_CMD_DRIVE_X, data: 0);
262 qt2160_write(client, QT2160_CMD_PWMEN_X, data: 0);
263 qt2160_write(client, QT2160_CMD_PWM_DUTY, data: 0);
264
265 return 0;
266}
267
268#else
269
270static inline int qt2160_register_leds(struct qt2160_data *qt2160)
271{
272 return 0;
273}
274
275#endif
276
277static bool qt2160_identify(struct i2c_client *client)
278{
279 int id, ver, rev;
280
281 /* Read Chid ID to check if chip is valid */
282 id = qt2160_read(client, QT2160_CMD_CHIPID);
283 if (id != QT2160_VALID_CHIPID) {
284 dev_err(&client->dev, "ID %d not supported\n", id);
285 return false;
286 }
287
288 /* Read chip firmware version */
289 ver = qt2160_read(client, QT2160_CMD_CODEVER);
290 if (ver < 0) {
291 dev_err(&client->dev, "could not get firmware version\n");
292 return false;
293 }
294
295 /* Read chip firmware revision */
296 rev = qt2160_read(client, QT2160_CMD_SUBVER);
297 if (rev < 0) {
298 dev_err(&client->dev, "could not get firmware revision\n");
299 return false;
300 }
301
302 dev_info(&client->dev, "AT42QT2160 firmware version %d.%d.%d\n",
303 ver >> 4, ver & 0xf, rev);
304
305 return true;
306}
307
308static int qt2160_probe(struct i2c_client *client)
309{
310 struct qt2160_data *qt2160;
311 struct input_dev *input;
312 int i;
313 int error;
314
315 if (!i2c_check_functionality(adap: client->adapter, I2C_FUNC_SMBUS_BYTE)) {
316 dev_err(&client->dev, "%s adapter not supported\n",
317 dev_driver_string(&client->adapter->dev));
318 return -ENODEV;
319 }
320
321 if (!qt2160_identify(client))
322 return -ENODEV;
323
324 /* Chip is valid and active. Allocate structure */
325 qt2160 = devm_kzalloc(dev: &client->dev, size: sizeof(*qt2160), GFP_KERNEL);
326 if (!qt2160)
327 return -ENOMEM;
328
329 input = devm_input_allocate_device(&client->dev);
330 if (!input)
331 return -ENOMEM;
332
333 qt2160->client = client;
334 qt2160->input = input;
335
336 input->name = "AT42QT2160 Touch Sense Keyboard";
337 input->id.bustype = BUS_I2C;
338
339 input->keycode = qt2160->keycodes;
340 input->keycodesize = sizeof(qt2160->keycodes[0]);
341 input->keycodemax = ARRAY_SIZE(qt2160_key2code);
342
343 __set_bit(EV_KEY, input->evbit);
344 __clear_bit(EV_REP, input->evbit);
345 for (i = 0; i < ARRAY_SIZE(qt2160_key2code); i++) {
346 qt2160->keycodes[i] = qt2160_key2code[i];
347 __set_bit(qt2160_key2code[i], input->keybit);
348 }
349 __clear_bit(KEY_RESERVED, input->keybit);
350
351 input_set_drvdata(dev: input, data: qt2160);
352
353 /* Calibrate device */
354 error = qt2160_write(client, QT2160_CMD_CALIBRATE, data: 1);
355 if (error) {
356 dev_err(&client->dev, "failed to calibrate device\n");
357 return error;
358 }
359
360 if (client->irq) {
361 error = devm_request_threaded_irq(dev: &client->dev, irq: client->irq,
362 NULL, thread_fn: qt2160_irq,
363 IRQF_ONESHOT,
364 devname: "qt2160", dev_id: input);
365 if (error) {
366 dev_err(&client->dev,
367 "failed to allocate irq %d\n", client->irq);
368 return error;
369 }
370 } else {
371 error = input_setup_polling(dev: input, poll_fn: qt2160_get_key_matrix);
372 if (error) {
373 dev_err(&client->dev, "Failed to setup polling\n");
374 return error;
375 }
376 input_set_poll_interval(dev: input, QT2160_CYCLE_INTERVAL);
377 }
378
379 error = qt2160_register_leds(qt2160);
380 if (error) {
381 dev_err(&client->dev, "Failed to register leds\n");
382 return error;
383 }
384
385 error = input_register_device(qt2160->input);
386 if (error) {
387 dev_err(&client->dev,
388 "Failed to register input device\n");
389 return error;
390 }
391
392 return 0;
393}
394
395static const struct i2c_device_id qt2160_idtable[] = {
396 { "qt2160" },
397 { }
398};
399
400MODULE_DEVICE_TABLE(i2c, qt2160_idtable);
401
402static struct i2c_driver qt2160_driver = {
403 .driver = {
404 .name = "qt2160",
405 },
406
407 .id_table = qt2160_idtable,
408 .probe = qt2160_probe,
409};
410
411module_i2c_driver(qt2160_driver);
412
413MODULE_AUTHOR("Raphael Derosso Pereira <raphaelpereira@gmail.com>");
414MODULE_DESCRIPTION("Driver for AT42QT2160 Touch Sensor");
415MODULE_LICENSE("GPL");
416

source code of linux/drivers/input/keyboard/qt2160.c