linux/drivers/input/keyboard/tca8418_keypad.c
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   1/*
   2 * Driver for TCA8418 I2C keyboard
   3 *
   4 * Copyright (C) 2011 Fuel7, Inc.  All rights reserved.
   5 *
   6 * Author: Kyle Manna <kyle.manna@fuel7.com>
   7 *
   8 * This program is free software; you can redistribute it and/or
   9 * modify it under the terms of the GNU General Public
  10 * License v2 as published by the Free Software Foundation.
  11 *
  12 * This program is distributed in the hope that it will be useful,
  13 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  14 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  15 * General Public License for more details.
  16 *
  17 * You should have received a copy of the GNU General Public
  18 * License along with this program; if not, write to the
  19 * Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  20 * Boston, MA 021110-1307, USA.
  21 *
  22 * If you can't comply with GPLv2, alternative licensing terms may be
  23 * arranged. Please contact Fuel7, Inc. (http://fuel7.com/) for proprietary
  24 * alternative licensing inquiries.
  25 */
  26
  27#include <linux/delay.h>
  28#include <linux/i2c.h>
  29#include <linux/init.h>
  30#include <linux/input.h>
  31#include <linux/input/matrix_keypad.h>
  32#include <linux/interrupt.h>
  33#include <linux/module.h>
  34#include <linux/of.h>
  35#include <linux/property.h>
  36#include <linux/slab.h>
  37#include <linux/types.h>
  38
  39/* TCA8418 hardware limits */
  40#define TCA8418_MAX_ROWS        8
  41#define TCA8418_MAX_COLS        10
  42
  43/* TCA8418 register offsets */
  44#define REG_CFG                 0x01
  45#define REG_INT_STAT            0x02
  46#define REG_KEY_LCK_EC          0x03
  47#define REG_KEY_EVENT_A         0x04
  48#define REG_KEY_EVENT_B         0x05
  49#define REG_KEY_EVENT_C         0x06
  50#define REG_KEY_EVENT_D         0x07
  51#define REG_KEY_EVENT_E         0x08
  52#define REG_KEY_EVENT_F         0x09
  53#define REG_KEY_EVENT_G         0x0A
  54#define REG_KEY_EVENT_H         0x0B
  55#define REG_KEY_EVENT_I         0x0C
  56#define REG_KEY_EVENT_J         0x0D
  57#define REG_KP_LCK_TIMER        0x0E
  58#define REG_UNLOCK1             0x0F
  59#define REG_UNLOCK2             0x10
  60#define REG_GPIO_INT_STAT1      0x11
  61#define REG_GPIO_INT_STAT2      0x12
  62#define REG_GPIO_INT_STAT3      0x13
  63#define REG_GPIO_DAT_STAT1      0x14
  64#define REG_GPIO_DAT_STAT2      0x15
  65#define REG_GPIO_DAT_STAT3      0x16
  66#define REG_GPIO_DAT_OUT1       0x17
  67#define REG_GPIO_DAT_OUT2       0x18
  68#define REG_GPIO_DAT_OUT3       0x19
  69#define REG_GPIO_INT_EN1        0x1A
  70#define REG_GPIO_INT_EN2        0x1B
  71#define REG_GPIO_INT_EN3        0x1C
  72#define REG_KP_GPIO1            0x1D
  73#define REG_KP_GPIO2            0x1E
  74#define REG_KP_GPIO3            0x1F
  75#define REG_GPI_EM1             0x20
  76#define REG_GPI_EM2             0x21
  77#define REG_GPI_EM3             0x22
  78#define REG_GPIO_DIR1           0x23
  79#define REG_GPIO_DIR2           0x24
  80#define REG_GPIO_DIR3           0x25
  81#define REG_GPIO_INT_LVL1       0x26
  82#define REG_GPIO_INT_LVL2       0x27
  83#define REG_GPIO_INT_LVL3       0x28
  84#define REG_DEBOUNCE_DIS1       0x29
  85#define REG_DEBOUNCE_DIS2       0x2A
  86#define REG_DEBOUNCE_DIS3       0x2B
  87#define REG_GPIO_PULL1          0x2C
  88#define REG_GPIO_PULL2          0x2D
  89#define REG_GPIO_PULL3          0x2E
  90
  91/* TCA8418 bit definitions */
  92#define CFG_AI                  BIT(7)
  93#define CFG_GPI_E_CFG           BIT(6)
  94#define CFG_OVR_FLOW_M          BIT(5)
  95#define CFG_INT_CFG             BIT(4)
  96#define CFG_OVR_FLOW_IEN        BIT(3)
  97#define CFG_K_LCK_IEN           BIT(2)
  98#define CFG_GPI_IEN             BIT(1)
  99#define CFG_KE_IEN              BIT(0)
 100
 101#define INT_STAT_CAD_INT        BIT(4)
 102#define INT_STAT_OVR_FLOW_INT   BIT(3)
 103#define INT_STAT_K_LCK_INT      BIT(2)
 104#define INT_STAT_GPI_INT        BIT(1)
 105#define INT_STAT_K_INT          BIT(0)
 106
 107/* TCA8418 register masks */
 108#define KEY_LCK_EC_KEC          0x7
 109#define KEY_EVENT_CODE          0x7f
 110#define KEY_EVENT_VALUE         0x80
 111
 112struct tca8418_keypad {
 113        struct i2c_client *client;
 114        struct input_dev *input;
 115
 116        unsigned int row_shift;
 117};
 118
 119/*
 120 * Write a byte to the TCA8418
 121 */
 122static int tca8418_write_byte(struct tca8418_keypad *keypad_data,
 123                              int reg, u8 val)
 124{
 125        int error;
 126
 127        error = i2c_smbus_write_byte_data(keypad_data->client, reg, val);
 128        if (error < 0) {
 129                dev_err(&keypad_data->client->dev,
 130                        "%s failed, reg: %d, val: %d, error: %d\n",
 131                        __func__, reg, val, error);
 132                return error;
 133        }
 134
 135        return 0;
 136}
 137
 138/*
 139 * Read a byte from the TCA8418
 140 */
 141static int tca8418_read_byte(struct tca8418_keypad *keypad_data,
 142                             int reg, u8 *val)
 143{
 144        int error;
 145
 146        error = i2c_smbus_read_byte_data(keypad_data->client, reg);
 147        if (error < 0) {
 148                dev_err(&keypad_data->client->dev,
 149                                "%s failed, reg: %d, error: %d\n",
 150                                __func__, reg, error);
 151                return error;
 152        }
 153
 154        *val = (u8)error;
 155
 156        return 0;
 157}
 158
 159static void tca8418_read_keypad(struct tca8418_keypad *keypad_data)
 160{
 161        struct input_dev *input = keypad_data->input;
 162        unsigned short *keymap = input->keycode;
 163        int error, col, row;
 164        u8 reg, state, code;
 165
 166        do {
 167                error = tca8418_read_byte(keypad_data, REG_KEY_EVENT_A, &reg);
 168                if (error < 0) {
 169                        dev_err(&keypad_data->client->dev,
 170                                "unable to read REG_KEY_EVENT_A\n");
 171                        break;
 172                }
 173
 174                /* Assume that key code 0 signifies empty FIFO */
 175                if (reg <= 0)
 176                        break;
 177
 178                state = reg & KEY_EVENT_VALUE;
 179                code  = reg & KEY_EVENT_CODE;
 180
 181                row = code / TCA8418_MAX_COLS;
 182                col = code % TCA8418_MAX_COLS;
 183
 184                row = (col) ? row : row - 1;
 185                col = (col) ? col - 1 : TCA8418_MAX_COLS - 1;
 186
 187                code = MATRIX_SCAN_CODE(row, col, keypad_data->row_shift);
 188                input_event(input, EV_MSC, MSC_SCAN, code);
 189                input_report_key(input, keymap[code], state);
 190
 191        } while (1);
 192
 193        input_sync(input);
 194}
 195
 196/*
 197 * Threaded IRQ handler and this can (and will) sleep.
 198 */
 199static irqreturn_t tca8418_irq_handler(int irq, void *dev_id)
 200{
 201        struct tca8418_keypad *keypad_data = dev_id;
 202        u8 reg;
 203        int error;
 204
 205        error = tca8418_read_byte(keypad_data, REG_INT_STAT, &reg);
 206        if (error) {
 207                dev_err(&keypad_data->client->dev,
 208                        "unable to read REG_INT_STAT\n");
 209                return IRQ_NONE;
 210        }
 211
 212        if (!reg)
 213                return IRQ_NONE;
 214
 215        if (reg & INT_STAT_OVR_FLOW_INT)
 216                dev_warn(&keypad_data->client->dev, "overflow occurred\n");
 217
 218        if (reg & INT_STAT_K_INT)
 219                tca8418_read_keypad(keypad_data);
 220
 221        /* Clear all interrupts, even IRQs we didn't check (GPI, CAD, LCK) */
 222        reg = 0xff;
 223        error = tca8418_write_byte(keypad_data, REG_INT_STAT, reg);
 224        if (error)
 225                dev_err(&keypad_data->client->dev,
 226                        "unable to clear REG_INT_STAT\n");
 227
 228        return IRQ_HANDLED;
 229}
 230
 231/*
 232 * Configure the TCA8418 for keypad operation
 233 */
 234static int tca8418_configure(struct tca8418_keypad *keypad_data,
 235                             u32 rows, u32 cols)
 236{
 237        int reg, error = 0;
 238
 239        /* Assemble a mask for row and column registers */
 240        reg  =  ~(~0 << rows);
 241        reg += (~(~0 << cols)) << 8;
 242
 243        /* Set registers to keypad mode */
 244        error |= tca8418_write_byte(keypad_data, REG_KP_GPIO1, reg);
 245        error |= tca8418_write_byte(keypad_data, REG_KP_GPIO2, reg >> 8);
 246        error |= tca8418_write_byte(keypad_data, REG_KP_GPIO3, reg >> 16);
 247
 248        /* Enable column debouncing */
 249        error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS1, reg);
 250        error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS2, reg >> 8);
 251        error |= tca8418_write_byte(keypad_data, REG_DEBOUNCE_DIS3, reg >> 16);
 252
 253        if (error)
 254                return error;
 255
 256        error = tca8418_write_byte(keypad_data, REG_CFG,
 257                                CFG_INT_CFG | CFG_OVR_FLOW_IEN | CFG_KE_IEN);
 258
 259        return error;
 260}
 261
 262static int tca8418_keypad_probe(struct i2c_client *client,
 263                                const struct i2c_device_id *id)
 264{
 265        struct device *dev = &client->dev;
 266        struct tca8418_keypad *keypad_data;
 267        struct input_dev *input;
 268        u32 rows = 0, cols = 0;
 269        int error, row_shift;
 270        u8 reg;
 271
 272        /* Check i2c driver capabilities */
 273        if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
 274                dev_err(dev, "%s adapter not supported\n",
 275                        dev_driver_string(&client->adapter->dev));
 276                return -ENODEV;
 277        }
 278
 279        error = matrix_keypad_parse_properties(dev, &rows, &cols);
 280        if (error)
 281                return error;
 282
 283        if (!rows || rows > TCA8418_MAX_ROWS) {
 284                dev_err(dev, "invalid rows\n");
 285                return -EINVAL;
 286        }
 287
 288        if (!cols || cols > TCA8418_MAX_COLS) {
 289                dev_err(dev, "invalid columns\n");
 290                return -EINVAL;
 291        }
 292
 293        row_shift = get_count_order(cols);
 294
 295        /* Allocate memory for keypad_data and input device */
 296        keypad_data = devm_kzalloc(dev, sizeof(*keypad_data), GFP_KERNEL);
 297        if (!keypad_data)
 298                return -ENOMEM;
 299
 300        keypad_data->client = client;
 301        keypad_data->row_shift = row_shift;
 302
 303        /* Read key lock register, if this fails assume device not present */
 304        error = tca8418_read_byte(keypad_data, REG_KEY_LCK_EC, &reg);
 305        if (error)
 306                return -ENODEV;
 307
 308        /* Configure input device */
 309        input = devm_input_allocate_device(dev);
 310        if (!input)
 311                return -ENOMEM;
 312
 313        keypad_data->input = input;
 314
 315        input->name = client->name;
 316        input->id.bustype = BUS_I2C;
 317        input->id.vendor  = 0x0001;
 318        input->id.product = 0x001;
 319        input->id.version = 0x0001;
 320
 321        error = matrix_keypad_build_keymap(NULL, NULL, rows, cols, NULL, input);
 322        if (error) {
 323                dev_err(dev, "Failed to build keymap\n");
 324                return error;
 325        }
 326
 327        if (device_property_read_bool(dev, "keypad,autorepeat"))
 328                __set_bit(EV_REP, input->evbit);
 329
 330        input_set_capability(input, EV_MSC, MSC_SCAN);
 331
 332        error = devm_request_threaded_irq(dev, client->irq,
 333                                          NULL, tca8418_irq_handler,
 334                                          IRQF_SHARED | IRQF_ONESHOT,
 335                                          client->name, keypad_data);
 336        if (error) {
 337                dev_err(dev, "Unable to claim irq %d; error %d\n",
 338                        client->irq, error);
 339                return error;
 340        }
 341
 342        /* Initialize the chip */
 343        error = tca8418_configure(keypad_data, rows, cols);
 344        if (error < 0)
 345                return error;
 346
 347        error = input_register_device(input);
 348        if (error) {
 349                dev_err(dev, "Unable to register input device, error: %d\n",
 350                        error);
 351                return error;
 352        }
 353
 354        return 0;
 355}
 356
 357static const struct i2c_device_id tca8418_id[] = {
 358        { "tca8418", 8418, },
 359        { }
 360};
 361MODULE_DEVICE_TABLE(i2c, tca8418_id);
 362
 363static const struct of_device_id tca8418_dt_ids[] = {
 364        { .compatible = "ti,tca8418", },
 365        { }
 366};
 367MODULE_DEVICE_TABLE(of, tca8418_dt_ids);
 368
 369static struct i2c_driver tca8418_keypad_driver = {
 370        .driver = {
 371                .name   = "tca8418_keypad",
 372                .of_match_table = tca8418_dt_ids,
 373        },
 374        .probe          = tca8418_keypad_probe,
 375        .id_table       = tca8418_id,
 376};
 377
 378static int __init tca8418_keypad_init(void)
 379{
 380        return i2c_add_driver(&tca8418_keypad_driver);
 381}
 382subsys_initcall(tca8418_keypad_init);
 383
 384static void __exit tca8418_keypad_exit(void)
 385{
 386        i2c_del_driver(&tca8418_keypad_driver);
 387}
 388module_exit(tca8418_keypad_exit);
 389
 390MODULE_AUTHOR("Kyle Manna <kyle.manna@fuel7.com>");
 391MODULE_DESCRIPTION("Keypad driver for TCA8418");
 392MODULE_LICENSE("GPL");
 393