linux/drivers/input/keyboard/mpr121_touchkey.c
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   1/*
   2 * Touchkey driver for Freescale MPR121 Controllor
   3 *
   4 * Copyright (C) 2011 Freescale Semiconductor, Inc.
   5 * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
   6 *
   7 * Based on mcs_touchkey.c
   8 *
   9 * This program is free software; you can redistribute it and/or modify
  10 * it under the terms of the GNU General Public License version 2 as
  11 * published by the Free Software Foundation.
  12 *
  13 */
  14
  15#include <linux/bitops.h>
  16#include <linux/delay.h>
  17#include <linux/i2c.h>
  18#include <linux/input.h>
  19#include <linux/interrupt.h>
  20#include <linux/module.h>
  21#include <linux/of.h>
  22#include <linux/property.h>
  23#include <linux/regulator/consumer.h>
  24#include <linux/slab.h>
  25
  26/* Register definitions */
  27#define ELE_TOUCH_STATUS_0_ADDR 0x0
  28#define ELE_TOUCH_STATUS_1_ADDR 0X1
  29#define MHD_RISING_ADDR         0x2b
  30#define NHD_RISING_ADDR         0x2c
  31#define NCL_RISING_ADDR         0x2d
  32#define FDL_RISING_ADDR         0x2e
  33#define MHD_FALLING_ADDR        0x2f
  34#define NHD_FALLING_ADDR        0x30
  35#define NCL_FALLING_ADDR        0x31
  36#define FDL_FALLING_ADDR        0x32
  37#define ELE0_TOUCH_THRESHOLD_ADDR       0x41
  38#define ELE0_RELEASE_THRESHOLD_ADDR     0x42
  39#define AFE_CONF_ADDR                   0x5c
  40#define FILTER_CONF_ADDR                0x5d
  41
  42/*
  43 * ELECTRODE_CONF_ADDR: This register configures the number of
  44 * enabled capacitance sensing inputs and its run/suspend mode.
  45 */
  46#define ELECTRODE_CONF_ADDR             0x5e
  47#define ELECTRODE_CONF_QUICK_CHARGE     0x80
  48#define AUTO_CONFIG_CTRL_ADDR           0x7b
  49#define AUTO_CONFIG_USL_ADDR            0x7d
  50#define AUTO_CONFIG_LSL_ADDR            0x7e
  51#define AUTO_CONFIG_TL_ADDR             0x7f
  52
  53/* Threshold of touch/release trigger */
  54#define TOUCH_THRESHOLD                 0x08
  55#define RELEASE_THRESHOLD               0x05
  56/* Masks for touch and release triggers */
  57#define TOUCH_STATUS_MASK               0xfff
  58/* MPR121 has 12 keys */
  59#define MPR121_MAX_KEY_COUNT            12
  60
  61struct mpr121_touchkey {
  62        struct i2c_client       *client;
  63        struct input_dev        *input_dev;
  64        unsigned int            statusbits;
  65        unsigned int            keycount;
  66        u32                     keycodes[MPR121_MAX_KEY_COUNT];
  67};
  68
  69struct mpr121_init_register {
  70        int addr;
  71        u8 val;
  72};
  73
  74static const struct mpr121_init_register init_reg_table[] = {
  75        { MHD_RISING_ADDR,      0x1 },
  76        { NHD_RISING_ADDR,      0x1 },
  77        { MHD_FALLING_ADDR,     0x1 },
  78        { NHD_FALLING_ADDR,     0x1 },
  79        { NCL_FALLING_ADDR,     0xff },
  80        { FDL_FALLING_ADDR,     0x02 },
  81        { FILTER_CONF_ADDR,     0x04 },
  82        { AFE_CONF_ADDR,        0x0b },
  83        { AUTO_CONFIG_CTRL_ADDR, 0x0b },
  84};
  85
  86static void mpr121_vdd_supply_disable(void *data)
  87{
  88        struct regulator *vdd_supply = data;
  89
  90        regulator_disable(vdd_supply);
  91}
  92
  93static struct regulator *mpr121_vdd_supply_init(struct device *dev)
  94{
  95        struct regulator *vdd_supply;
  96        int err;
  97
  98        vdd_supply = devm_regulator_get(dev, "vdd");
  99        if (IS_ERR(vdd_supply)) {
 100                dev_err(dev, "failed to get vdd regulator: %ld\n",
 101                        PTR_ERR(vdd_supply));
 102                return vdd_supply;
 103        }
 104
 105        err = regulator_enable(vdd_supply);
 106        if (err) {
 107                dev_err(dev, "failed to enable vdd regulator: %d\n", err);
 108                return ERR_PTR(err);
 109        }
 110
 111        err = devm_add_action(dev, mpr121_vdd_supply_disable, vdd_supply);
 112        if (err) {
 113                regulator_disable(vdd_supply);
 114                dev_err(dev, "failed to add disable regulator action: %d\n",
 115                        err);
 116                return ERR_PTR(err);
 117        }
 118
 119        return vdd_supply;
 120}
 121
 122static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
 123{
 124        struct mpr121_touchkey *mpr121 = dev_id;
 125        struct i2c_client *client = mpr121->client;
 126        struct input_dev *input = mpr121->input_dev;
 127        unsigned long bit_changed;
 128        unsigned int key_num;
 129        int reg;
 130
 131        reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
 132        if (reg < 0) {
 133                dev_err(&client->dev, "i2c read error [%d]\n", reg);
 134                goto out;
 135        }
 136
 137        reg <<= 8;
 138        reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
 139        if (reg < 0) {
 140                dev_err(&client->dev, "i2c read error [%d]\n", reg);
 141                goto out;
 142        }
 143
 144        reg &= TOUCH_STATUS_MASK;
 145        /* use old press bit to figure out which bit changed */
 146        bit_changed = reg ^ mpr121->statusbits;
 147        mpr121->statusbits = reg;
 148        for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
 149                unsigned int key_val, pressed;
 150
 151                pressed = reg & BIT(key_num);
 152                key_val = mpr121->keycodes[key_num];
 153
 154                input_event(input, EV_MSC, MSC_SCAN, key_num);
 155                input_report_key(input, key_val, pressed);
 156
 157                dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
 158                        pressed ? "pressed" : "released");
 159
 160        }
 161        input_sync(input);
 162
 163out:
 164        return IRQ_HANDLED;
 165}
 166
 167static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
 168                            struct i2c_client *client, int vdd_uv)
 169{
 170        const struct mpr121_init_register *reg;
 171        unsigned char usl, lsl, tl, eleconf;
 172        int i, t, vdd, ret;
 173
 174        /* Set up touch/release threshold for ele0-ele11 */
 175        for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
 176                t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
 177                ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
 178                if (ret < 0)
 179                        goto err_i2c_write;
 180                ret = i2c_smbus_write_byte_data(client, t + 1,
 181                                                RELEASE_THRESHOLD);
 182                if (ret < 0)
 183                        goto err_i2c_write;
 184        }
 185
 186        /* Set up init register */
 187        for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
 188                reg = &init_reg_table[i];
 189                ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
 190                if (ret < 0)
 191                        goto err_i2c_write;
 192        }
 193
 194
 195        /*
 196         * Capacitance on sensing input varies and needs to be compensated.
 197         * The internal MPR121-auto-configuration can do this if it's
 198         * registers are set properly (based on vdd_uv).
 199         */
 200        vdd = vdd_uv / 1000;
 201        usl = ((vdd - 700) * 256) / vdd;
 202        lsl = (usl * 65) / 100;
 203        tl = (usl * 90) / 100;
 204        ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
 205        ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
 206        ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
 207
 208        /*
 209         * Quick charge bit will let the capacitive charge to ready
 210         * state quickly, or the buttons may not function after system
 211         * boot.
 212         */
 213        eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
 214        ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 215                                         eleconf);
 216        if (ret != 0)
 217                goto err_i2c_write;
 218
 219        dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
 220
 221        return 0;
 222
 223err_i2c_write:
 224        dev_err(&client->dev, "i2c write error: %d\n", ret);
 225        return ret;
 226}
 227
 228static int mpr_touchkey_probe(struct i2c_client *client,
 229                              const struct i2c_device_id *id)
 230{
 231        struct device *dev = &client->dev;
 232        struct regulator *vdd_supply;
 233        int vdd_uv;
 234        struct mpr121_touchkey *mpr121;
 235        struct input_dev *input_dev;
 236        int error;
 237        int i;
 238
 239        if (!client->irq) {
 240                dev_err(dev, "irq number should not be zero\n");
 241                return -EINVAL;
 242        }
 243
 244        vdd_supply = mpr121_vdd_supply_init(dev);
 245        if (IS_ERR(vdd_supply))
 246                return PTR_ERR(vdd_supply);
 247
 248        vdd_uv = regulator_get_voltage(vdd_supply);
 249
 250        mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
 251        if (!mpr121)
 252                return -ENOMEM;
 253
 254        input_dev = devm_input_allocate_device(dev);
 255        if (!input_dev)
 256                return -ENOMEM;
 257
 258        mpr121->client = client;
 259        mpr121->input_dev = input_dev;
 260        mpr121->keycount = device_property_read_u32_array(dev, "linux,keycodes",
 261                                                          NULL, 0);
 262        if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
 263                dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
 264                return -EINVAL;
 265        }
 266
 267        error = device_property_read_u32_array(dev, "linux,keycodes",
 268                                               mpr121->keycodes,
 269                                               mpr121->keycount);
 270        if (error) {
 271                dev_err(dev,
 272                        "failed to read linux,keycode property: %d\n", error);
 273                return error;
 274        }
 275
 276        input_dev->name = "Freescale MPR121 Touchkey";
 277        input_dev->id.bustype = BUS_I2C;
 278        input_dev->dev.parent = dev;
 279        if (device_property_read_bool(dev, "autorepeat"))
 280                __set_bit(EV_REP, input_dev->evbit);
 281        input_set_capability(input_dev, EV_MSC, MSC_SCAN);
 282
 283        input_dev->keycode = mpr121->keycodes;
 284        input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
 285        input_dev->keycodemax = mpr121->keycount;
 286
 287        for (i = 0; i < mpr121->keycount; i++)
 288                input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);
 289
 290        error = mpr121_phys_init(mpr121, client, vdd_uv);
 291        if (error) {
 292                dev_err(dev, "Failed to init register\n");
 293                return error;
 294        }
 295
 296        error = devm_request_threaded_irq(dev, client->irq, NULL,
 297                                          mpr_touchkey_interrupt,
 298                                          IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 299                                          dev->driver->name, mpr121);
 300        if (error) {
 301                dev_err(dev, "Failed to register interrupt\n");
 302                return error;
 303        }
 304
 305        error = input_register_device(input_dev);
 306        if (error)
 307                return error;
 308
 309        i2c_set_clientdata(client, mpr121);
 310        device_init_wakeup(dev,
 311                        device_property_read_bool(dev, "wakeup-source"));
 312
 313        return 0;
 314}
 315
 316static int __maybe_unused mpr_suspend(struct device *dev)
 317{
 318        struct i2c_client *client = to_i2c_client(dev);
 319
 320        if (device_may_wakeup(&client->dev))
 321                enable_irq_wake(client->irq);
 322
 323        i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
 324
 325        return 0;
 326}
 327
 328static int __maybe_unused mpr_resume(struct device *dev)
 329{
 330        struct i2c_client *client = to_i2c_client(dev);
 331        struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
 332
 333        if (device_may_wakeup(&client->dev))
 334                disable_irq_wake(client->irq);
 335
 336        i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 337                                  mpr121->keycount);
 338
 339        return 0;
 340}
 341
 342static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
 343
 344static const struct i2c_device_id mpr121_id[] = {
 345        { "mpr121_touchkey", 0 },
 346        { }
 347};
 348MODULE_DEVICE_TABLE(i2c, mpr121_id);
 349
 350#ifdef CONFIG_OF
 351static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
 352        { .compatible = "fsl,mpr121-touchkey" },
 353        { },
 354};
 355MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
 356#endif
 357
 358static struct i2c_driver mpr_touchkey_driver = {
 359        .driver = {
 360                .name   = "mpr121",
 361                .pm     = &mpr121_touchkey_pm_ops,
 362                .of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
 363        },
 364        .id_table       = mpr121_id,
 365        .probe          = mpr_touchkey_probe,
 366};
 367
 368module_i2c_driver(mpr_touchkey_driver);
 369
 370MODULE_LICENSE("GPL");
 371MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 372MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");
 373