drivers/input/keyboard/tca6416-keypad.c

   1 /*
   2  * Driver for keys on TCA6416 I2C IO expander
   3  *
   4  * Copyright (C) 2010 Texas Instruments
   5  *
   6  * Author : Sriramakrishnan.A.G. <srk@ti.com>
   7  *
   8  * This program is free software; you can redistribute it and/or modify
   9  * it under the terms of the GNU General Public License version 2 as
  10  * published by the Free Software Foundation.
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/module.h>
  15 #include <linux/init.h>
  16 #include <linux/delay.h>
  17 #include <linux/slab.h>
  18 #include <linux/interrupt.h>
  19 #include <linux/workqueue.h>
  20 #include <linux/gpio.h>
  21 #include <linux/i2c.h>
  22 #include <linux/input.h>
  23 #include <linux/tca6416_keypad.h>
  24
  25 #define TCA6416_INPUT          0
  26 #define TCA6416_OUTPUT         1
  27 #define TCA6416_INVERT         2
  28 #define TCA6416_DIRECTION      3
  29
  30 static const struct i2c_device_id tca6416_id[] = {
  31         { "tca6416-keys", 16, },
  32         { "tca6408-keys", 8, },
  33         { }
  34 };
  35 MODULE_DEVICE_TABLE(i2c, tca6416_id);
  36
  37 struct tca6416_drv_data {
  38         struct input_dev *input;
  39         struct tca6416_button data[0];
  40 };
  41
  42 struct tca6416_keypad_chip {
  43         uint16_t reg_output;
  44         uint16_t reg_direction;
  45         uint16_t reg_input;
  46
  47         struct i2c_client *client;
  48         struct input_dev *input;
  49         struct delayed_work dwork;
  50         int io_size;
  51         int irqnum;
  52         u16 pinmask;
  53         bool use_polling;
  54         struct tca6416_button buttons[0];
  55 };
  56
  57 static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
  58 {
  59         int error;
  60
  61         error = chip->io_size > 8 ?
  62                 i2c_smbus_write_word_data(chip->client, reg << 1, val) :
  63                 i2c_smbus_write_byte_data(chip->client, reg, val);
  64         if (error < 0) {
  65                 dev_err(&chip->client->dev,
  66                         "%s failed, reg: %d, val: %d, error: %d\n",
  67                         __func__, reg, val, error);
  68                 return error;
  69         }
  70
  71         return 0;
  72 }
  73
  74 static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
  75 {
  76         int retval;
  77
  78         retval = chip->io_size > 8 ?
  79                  i2c_smbus_read_word_data(chip->client, reg << 1) :
  80                  i2c_smbus_read_byte_data(chip->client, reg);
  81         if (retval < 0) {
  82                 dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
  83                         __func__, reg, retval);
  84                 return retval;
  85         }
  86
  87         *val = (u16)retval;
  88         return 0;
  89 }
  90
  91 static void tca6416_keys_scan(struct tca6416_keypad_chip *chip)
  92 {
  93         struct input_dev *input = chip->input;
  94         u16 reg_val, val;
  95         int error, i, pin_index;
  96
  97         error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
  98         if (error)
  99                 return;
 100
 101         reg_val &= chip->pinmask;
 102
 103         /* Figure out which lines have changed */
 104         val = reg_val ^ chip->reg_input;
 105         chip->reg_input = reg_val;
 106
 107         for (i = 0, pin_index = 0; i < 16; i++) {
 108                 if (val & (1 << i)) {
 109                         struct tca6416_button *button = &chip->buttons[pin_index];
 110                         unsigned int type = button->type ?: EV_KEY;
 111                         int state = ((reg_val & (1 << i)) ? 1 : 0)
 112                                                 ^ button->active_low;
 113
 114                         input_event(input, type, button->code, !!state);
 115                         input_sync(input);
 116                 }
 117
 118                 if (chip->pinmask & (1 << i))
 119                         pin_index++;
 120         }
 121 }
 122
 123 /*
 124  * This is threaded IRQ handler and this can (and will) sleep.
 125  */
 126 static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
 127 {
 128         struct tca6416_keypad_chip *chip = dev_id;
 129
 130         tca6416_keys_scan(chip);
 131
 132         return IRQ_HANDLED;
 133 }
 134
 135 static void tca6416_keys_work_func(struct work_struct *work)
 136 {
 137         struct tca6416_keypad_chip *chip =
 138                 container_of(work, struct tca6416_keypad_chip, dwork.work);
 139
 140         tca6416_keys_scan(chip);
 141         schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
 142 }
 143
 144 static int tca6416_keys_open(struct input_dev *dev)
 145 {
 146         struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
 147
 148         /* Get initial device state in case it has switches */
 149         tca6416_keys_scan(chip);
 150
 151         if (chip->use_polling)
 152                 schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100));
 153         else
 154                 enable_irq(chip->irqnum);
 155
 156         return 0;
 157 }
 158
 159 static void tca6416_keys_close(struct input_dev *dev)
 160 {
 161         struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
 162
 163         if (chip->use_polling)
 164                 cancel_delayed_work_sync(&chip->dwork);
 165         else
 166                 disable_irq(chip->irqnum);
 167 }
 168
 169 static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
 170 {
 171         int error;
 172
 173         error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
 174         if (error)
 175                 return error;
 176
 177         error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
 178         if (error)
 179                 return error;
 180
 181         /* ensure that keypad pins are set to input */
 182         error = tca6416_write_reg(chip, TCA6416_DIRECTION,
 183                                   chip->reg_direction | chip->pinmask);
 184         if (error)
 185                 return error;
 186
 187         error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
 188         if (error)
 189                 return error;
 190
 191         error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
 192         if (error)
 193                 return error;
 194
 195         chip->reg_input &= chip->pinmask;
 196
 197         return 0;
 198 }
 199
 200 static int tca6416_keypad_probe(struct i2c_client *client,
 201                                    const struct i2c_device_id *id)
 202 {
 203         struct tca6416_keys_platform_data *pdata;
 204         struct tca6416_keypad_chip *chip;
 205         struct input_dev *input;
 206         int error;
 207         int i;
 208
 209         /* Check functionality */
 210         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
 211                 dev_err(&client->dev, "%s adapter not supported\n",
 212                         dev_driver_string(&client->adapter->dev));
 213                 return -ENODEV;
 214         }
 215
 216         pdata = dev_get_platdata(&client->dev);
 217         if (!pdata) {
 218                 dev_dbg(&client->dev, "no platform data\n");
 219                 return -EINVAL;
 220         }
 221
 222         chip = kzalloc(struct_size(chip, buttons, pdata->nbuttons), GFP_KERNEL);
 223         input = input_allocate_device();
 224         if (!chip || !input) {
 225                 error = -ENOMEM;
 226                 goto fail1;
 227         }
 228
 229         chip->client = client;
 230         chip->input = input;
 231         chip->io_size = id->driver_data;
 232         chip->pinmask = pdata->pinmask;
 233         chip->use_polling = pdata->use_polling;
 234
 235         INIT_DELAYED_WORK(&chip->dwork, tca6416_keys_work_func);
 236
 237         input->phys = "tca6416-keys/input0";
 238         input->name = client->name;
 239         input->dev.parent = &client->dev;
 240
 241         input->open = tca6416_keys_open;
 242         input->close = tca6416_keys_close;
 243
 244         input->id.bustype = BUS_HOST;
 245         input->id.vendor = 0x0001;
 246         input->id.product = 0x0001;
 247         input->id.version = 0x0100;
 248
 249         /* Enable auto repeat feature of Linux input subsystem */
 250         if (pdata->rep)
 251                 __set_bit(EV_REP, input->evbit);
 252
 253         for (i = 0; i < pdata->nbuttons; i++) {
 254                 unsigned int type;
 255
 256                 chip->buttons[i] = pdata->buttons[i];
 257                 type = (pdata->buttons[i].type) ?: EV_KEY;
 258                 input_set_capability(input, type, pdata->buttons[i].code);
 259         }
 260
 261         input_set_drvdata(input, chip);
 262
 263         /*
 264          * Initialize cached registers from their original values.
 265          * we can't share this chip with another i2c master.
 266          */
 267         error = tca6416_setup_registers(chip);
 268         if (error)
 269                 goto fail1;
 270
 271         if (!chip->use_polling) {
 272                 if (pdata->irq_is_gpio)
 273                         chip->irqnum = gpio_to_irq(client->irq);
 274                 else
 275                         chip->irqnum = client->irq;
 276
 277                 error = request_threaded_irq(chip->irqnum, NULL,
 278                                              tca6416_keys_isr,
 279                                              IRQF_TRIGGER_FALLING |
 280                                                 IRQF_ONESHOT,
 281                                              "tca6416-keypad", chip);
 282                 if (error) {
 283                         dev_dbg(&client->dev,
 284                                 "Unable to claim irq %d; error %d\n",
 285                                 chip->irqnum, error);
 286                         goto fail1;
 287                 }
 288                 disable_irq(chip->irqnum);
 289         }
 290
 291         error = input_register_device(input);
 292         if (error) {
 293                 dev_dbg(&client->dev,
 294                         "Unable to register input device, error: %d\n", error);
 295                 goto fail2;
 296         }
 297
 298         i2c_set_clientdata(client, chip);
 299         device_init_wakeup(&client->dev, 1);
 300
 301         return 0;
 302
 303 fail2:
 304         if (!chip->use_polling) {
 305                 free_irq(chip->irqnum, chip);
 306                 enable_irq(chip->irqnum);
 307         }
 308 fail1:
 309         input_free_device(input);
 310         kfree(chip);
 311         return error;
 312 }
 313
 314 static int tca6416_keypad_remove(struct i2c_client *client)
 315 {
 316         struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
 317
 318         if (!chip->use_polling) {
 319                 free_irq(chip->irqnum, chip);
 320                 enable_irq(chip->irqnum);
 321         }
 322
 323         input_unregister_device(chip->input);
 324         kfree(chip);
 325
 326         return 0;
 327 }
 328
 329 #ifdef CONFIG_PM_SLEEP
 330 static int tca6416_keypad_suspend(struct device *dev)
 331 {
 332         struct i2c_client *client = to_i2c_client(dev);
 333         struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
 334
 335         if (device_may_wakeup(dev))
 336                 enable_irq_wake(chip->irqnum);
 337
 338         return 0;
 339 }
 340
 341 static int tca6416_keypad_resume(struct device *dev)
 342 {
 343         struct i2c_client *client = to_i2c_client(dev);
 344         struct tca6416_keypad_chip *chip = i2c_get_clientdata(client);
 345
 346         if (device_may_wakeup(dev))
 347                 disable_irq_wake(chip->irqnum);
 348
 349         return 0;
 350 }
 351 #endif
 352
 353 static SIMPLE_DEV_PM_OPS(tca6416_keypad_dev_pm_ops,
 354                          tca6416_keypad_suspend, tca6416_keypad_resume);
 355
 356 static struct i2c_driver tca6416_keypad_driver = {
 357         .driver = {
 358                 .name   = "tca6416-keypad",
 359                 .pm     = &tca6416_keypad_dev_pm_ops,
 360         },
 361         .probe          = tca6416_keypad_probe,
 362         .remove         = tca6416_keypad_remove,
 363         .id_table       = tca6416_id,
 364 };
 365
 366 static int __init tca6416_keypad_init(void)
 367 {
 368         return i2c_add_driver(&tca6416_keypad_driver);
 369 }
 370
 371 subsys_initcall(tca6416_keypad_init);
 372
 373 static void __exit tca6416_keypad_exit(void)
 374 {
 375         i2c_del_driver(&tca6416_keypad_driver);
 376 }
 377 module_exit(tca6416_keypad_exit);
 378
 379 MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
 380 MODULE_DESCRIPTION("Keypad driver over tca6146 IO expander");
 381 MODULE_LICENSE("GPL");