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