drivers/input/keyboard/qt2160.c

   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
  37 static 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
  45 struct 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
  54 struct 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
  64 static int qt2160_read(struct i2c_client *client, u8 reg);
  65 static int qt2160_write(struct i2c_client *client, u8 reg, u8 data);
  66
  67 #ifdef CONFIG_LEDS_CLASS
  68
  69 static 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, drive);
  89                 qt2160_write(client, QT2160_CMD_PWMEN_X, 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, value);
  97
  98                 led->brightness = value;
  99         }
 100
 101         return 0;
 102 }
 103
 104 #endif /* CONFIG_LEDS_CLASS */
 105
 106 static 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(client->adapter, I2C_FUNC_I2C))     {
 117
 118                 error = i2c_smbus_write_byte(client, 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, 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, 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
 157 static void qt2160_get_key_matrix(struct input_dev *input)
 158 {
 159         struct qt2160_data *qt2160 = input_get_drvdata(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, regs, 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(input, qt2160->keycodes[i], keyval);
 187                         dev_dbg(&client->dev, "key %d %s\n",
 188                                 i, keyval ? "pressed" : "released");
 189                 }
 190         }
 191
 192         input_sync(input);
 193 }
 194
 195 static 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
 204 static int qt2160_read(struct i2c_client *client, u8 reg)
 205 {
 206         int ret;
 207
 208         ret = i2c_smbus_write_byte(client, 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
 225 static int qt2160_write(struct i2c_client *client, u8 reg, u8 data)
 226 {
 227         int ret;
 228
 229         ret = i2c_smbus_write_byte_data(client, reg, 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
 239 static 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(led->name, sizeof(led->name), "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(&client->dev, &led->cdev);
 256                 if (error)
 257                         return error;
 258         }
 259
 260         /* Tur off LEDs */
 261         qt2160_write(client, QT2160_CMD_DRIVE_X, 0);
 262         qt2160_write(client, QT2160_CMD_PWMEN_X, 0);
 263         qt2160_write(client, QT2160_CMD_PWM_DUTY, 0);
 264
 265         return 0;
 266 }
 267
 268 #else
 269
 270 static inline int qt2160_register_leds(struct qt2160_data *qt2160)
 271 {
 272         return 0;
 273 }
 274
 275 #endif
 276
 277 static 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
 308 static 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(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(&client->dev, 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(input, qt2160);
 352
 353         /* Calibrate device */
 354         error = qt2160_write(client, QT2160_CMD_CALIBRATE, 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(&client->dev, client->irq,
 362                                                   NULL, qt2160_irq,
 363                                                   IRQF_ONESHOT,
 364                                                   "qt2160", 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(input, 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(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
 395 static const struct i2c_device_id qt2160_idtable[] = {
 396         { "qt2160", 0, },
 397         { }
 398 };
 399
 400 MODULE_DEVICE_TABLE(i2c, qt2160_idtable);
 401
 402 static struct i2c_driver qt2160_driver = {
 403         .driver = {
 404                 .name   = "qt2160",
 405         },
 406
 407         .id_table       = qt2160_idtable,
 408         .probe          = qt2160_probe,
 409 };
 410
 411 module_i2c_driver(qt2160_driver);
 412
 413 MODULE_AUTHOR("Raphael Derosso Pereira <raphaelpereira@gmail.com>");
 414 MODULE_DESCRIPTION("Driver for AT42QT2160 Touch Sensor");
 415 MODULE_LICENSE("GPL");