drivers/input/keyboard/mpr121_touchkey.c

   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/module.h>
  16 #include <linux/input.h>
  17 #include <linux/i2c.h>
  18 #include <linux/slab.h>
  19 #include <linux/delay.h>
  20 #include <linux/bitops.h>
  21 #include <linux/interrupt.h>
  22 #include <linux/i2c/mpr121_touchkey.h>
  23
  24 /* Register definitions */
  25 #define ELE_TOUCH_STATUS_0_ADDR 0x0
  26 #define ELE_TOUCH_STATUS_1_ADDR 0X1
  27 #define MHD_RISING_ADDR         0x2b
  28 #define NHD_RISING_ADDR         0x2c
  29 #define NCL_RISING_ADDR         0x2d
  30 #define FDL_RISING_ADDR         0x2e
  31 #define MHD_FALLING_ADDR        0x2f
  32 #define NHD_FALLING_ADDR        0x30
  33 #define NCL_FALLING_ADDR        0x31
  34 #define FDL_FALLING_ADDR        0x32
  35 #define ELE0_TOUCH_THRESHOLD_ADDR       0x41
  36 #define ELE0_RELEASE_THRESHOLD_ADDR     0x42
  37 #define AFE_CONF_ADDR                   0x5c
  38 #define FILTER_CONF_ADDR                0x5d
  39
  40 /*
  41  * ELECTRODE_CONF_ADDR: This register configures the number of
  42  * enabled capacitance sensing inputs and its run/suspend mode.
  43  */
  44 #define ELECTRODE_CONF_ADDR             0x5e
  45 #define ELECTRODE_CONF_QUICK_CHARGE     0x80
  46 #define AUTO_CONFIG_CTRL_ADDR           0x7b
  47 #define AUTO_CONFIG_USL_ADDR            0x7d
  48 #define AUTO_CONFIG_LSL_ADDR            0x7e
  49 #define AUTO_CONFIG_TL_ADDR             0x7f
  50
  51 /* Threshold of touch/release trigger */
  52 #define TOUCH_THRESHOLD                 0x08
  53 #define RELEASE_THRESHOLD               0x05
  54 /* Masks for touch and release triggers */
  55 #define TOUCH_STATUS_MASK               0xfff
  56 /* MPR121 has 12 keys */
  57 #define MPR121_MAX_KEY_COUNT            12
  58
  59 struct mpr121_touchkey {
  60         struct i2c_client       *client;
  61         struct input_dev        *input_dev;
  62         unsigned int            key_val;
  63         unsigned int            statusbits;
  64         unsigned int            keycount;
  65         u16                     keycodes[MPR121_MAX_KEY_COUNT];
  66 };
  67
  68 struct mpr121_init_register {
  69         int addr;
  70         u8 val;
  71 };
  72
  73 static const struct mpr121_init_register init_reg_table[] = {
  74         { MHD_RISING_ADDR,      0x1 },
  75         { NHD_RISING_ADDR,      0x1 },
  76         { MHD_FALLING_ADDR,     0x1 },
  77         { NHD_FALLING_ADDR,     0x1 },
  78         { NCL_FALLING_ADDR,     0xff },
  79         { FDL_FALLING_ADDR,     0x02 },
  80         { FILTER_CONF_ADDR,     0x04 },
  81         { AFE_CONF_ADDR,        0x0b },
  82         { AUTO_CONFIG_CTRL_ADDR, 0x0b },
  83 };
  84
  85 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
  86 {
  87         struct mpr121_touchkey *mpr121 = dev_id;
  88         struct i2c_client *client = mpr121->client;
  89         struct input_dev *input = mpr121->input_dev;
  90         unsigned int key_num, key_val, pressed;
  91         int reg;
  92
  93         reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
  94         if (reg < 0) {
  95                 dev_err(&client->dev, "i2c read error [%d]\n", reg);
  96                 goto out;
  97         }
  98
  99         reg <<= 8;
 100         reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
 101         if (reg < 0) {
 102                 dev_err(&client->dev, "i2c read error [%d]\n", reg);
 103                 goto out;
 104         }
 105
 106         reg &= TOUCH_STATUS_MASK;
 107         /* use old press bit to figure out which bit changed */
 108         key_num = ffs(reg ^ mpr121->statusbits) - 1;
 109         pressed = reg & (1 << key_num);
 110         mpr121->statusbits = reg;
 111
 112         key_val = mpr121->keycodes[key_num];
 113
 114         input_event(input, EV_MSC, MSC_SCAN, key_num);
 115         input_report_key(input, key_val, pressed);
 116         input_sync(input);
 117
 118         dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
 119                 pressed ? "pressed" : "released");
 120
 121 out:
 122         return IRQ_HANDLED;
 123 }
 124
 125 static int mpr121_phys_init(const struct mpr121_platform_data *pdata,
 126                                       struct mpr121_touchkey *mpr121,
 127                                       struct i2c_client *client)
 128 {
 129         const struct mpr121_init_register *reg;
 130         unsigned char usl, lsl, tl, eleconf;
 131         int i, t, vdd, ret;
 132
 133         /* Set up touch/release threshold for ele0-ele11 */
 134         for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
 135                 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
 136                 ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
 137                 if (ret < 0)
 138                         goto err_i2c_write;
 139                 ret = i2c_smbus_write_byte_data(client, t + 1,
 140                                                 RELEASE_THRESHOLD);
 141                 if (ret < 0)
 142                         goto err_i2c_write;
 143         }
 144
 145         /* Set up init register */
 146         for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
 147                 reg = &init_reg_table[i];
 148                 ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
 149                 if (ret < 0)
 150                         goto err_i2c_write;
 151         }
 152
 153
 154         /*
 155          * Capacitance on sensing input varies and needs to be compensated.
 156          * The internal MPR121-auto-configuration can do this if it's
 157          * registers are set properly (based on pdata->vdd_uv).
 158          */
 159         vdd = pdata->vdd_uv / 1000;
 160         usl = ((vdd - 700) * 256) / vdd;
 161         lsl = (usl * 65) / 100;
 162         tl = (usl * 90) / 100;
 163         ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
 164         ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
 165         ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
 166
 167         /*
 168          * Quick charge bit will let the capacitive charge to ready
 169          * state quickly, or the buttons may not function after system
 170          * boot.
 171          */
 172         eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
 173         ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 174                                          eleconf);
 175         if (ret != 0)
 176                 goto err_i2c_write;
 177
 178         dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
 179
 180         return 0;
 181
 182 err_i2c_write:
 183         dev_err(&client->dev, "i2c write error: %d\n", ret);
 184         return ret;
 185 }
 186
 187 static int mpr_touchkey_probe(struct i2c_client *client,
 188                               const struct i2c_device_id *id)
 189 {
 190         const struct mpr121_platform_data *pdata =
 191                         dev_get_platdata(&client->dev);
 192         struct mpr121_touchkey *mpr121;
 193         struct input_dev *input_dev;
 194         int error;
 195         int i;
 196
 197         if (!pdata) {
 198                 dev_err(&client->dev, "no platform data defined\n");
 199                 return -EINVAL;
 200         }
 201
 202         if (!pdata->keymap || !pdata->keymap_size) {
 203                 dev_err(&client->dev, "missing keymap data\n");
 204                 return -EINVAL;
 205         }
 206
 207         if (pdata->keymap_size > MPR121_MAX_KEY_COUNT) {
 208                 dev_err(&client->dev, "too many keys defined\n");
 209                 return -EINVAL;
 210         }
 211
 212         if (!client->irq) {
 213                 dev_err(&client->dev, "irq number should not be zero\n");
 214                 return -EINVAL;
 215         }
 216
 217         mpr121 = devm_kzalloc(&client->dev, sizeof(*mpr121),
 218                               GFP_KERNEL);
 219         if (!mpr121)
 220                 return -ENOMEM;
 221
 222         input_dev = devm_input_allocate_device(&client->dev);
 223         if (!input_dev)
 224                 return -ENOMEM;
 225
 226         mpr121->client = client;
 227         mpr121->input_dev = input_dev;
 228         mpr121->keycount = pdata->keymap_size;
 229
 230         input_dev->name = "Freescale MPR121 Touchkey";
 231         input_dev->id.bustype = BUS_I2C;
 232         input_dev->dev.parent = &client->dev;
 233         input_dev->evbit[0] = BIT_MASK(EV_KEY) | BIT_MASK(EV_REP);
 234
 235         input_dev->keycode = mpr121->keycodes;
 236         input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
 237         input_dev->keycodemax = mpr121->keycount;
 238
 239         for (i = 0; i < pdata->keymap_size; i++) {
 240                 input_set_capability(input_dev, EV_KEY, pdata->keymap[i]);
 241                 mpr121->keycodes[i] = pdata->keymap[i];
 242         }
 243
 244         error = mpr121_phys_init(pdata, mpr121, client);
 245         if (error) {
 246                 dev_err(&client->dev, "Failed to init register\n");
 247                 return error;
 248         }
 249
 250         error = devm_request_threaded_irq(&client->dev, client->irq, NULL,
 251                                      mpr_touchkey_interrupt,
 252                                      IRQF_TRIGGER_FALLING | IRQF_ONESHOT,
 253                                      client->dev.driver->name, mpr121);
 254         if (error) {
 255                 dev_err(&client->dev, "Failed to register interrupt\n");
 256                 return error;
 257         }
 258
 259         error = input_register_device(input_dev);
 260         if (error)
 261                 return error;
 262
 263         i2c_set_clientdata(client, mpr121);
 264         device_init_wakeup(&client->dev, pdata->wakeup);
 265
 266         return 0;
 267 }
 268
 269 #ifdef CONFIG_PM_SLEEP
 270 static int mpr_suspend(struct device *dev)
 271 {
 272         struct i2c_client *client = to_i2c_client(dev);
 273
 274         if (device_may_wakeup(&client->dev))
 275                 enable_irq_wake(client->irq);
 276
 277         i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
 278
 279         return 0;
 280 }
 281
 282 static int mpr_resume(struct device *dev)
 283 {
 284         struct i2c_client *client = to_i2c_client(dev);
 285         struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
 286
 287         if (device_may_wakeup(&client->dev))
 288                 disable_irq_wake(client->irq);
 289
 290         i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 291                                   mpr121->keycount);
 292
 293         return 0;
 294 }
 295 #endif
 296
 297 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
 298
 299 static const struct i2c_device_id mpr121_id[] = {
 300         { "mpr121_touchkey", 0 },
 301         { }
 302 };
 303 MODULE_DEVICE_TABLE(i2c, mpr121_id);
 304
 305 static struct i2c_driver mpr_touchkey_driver = {
 306         .driver = {
 307                 .name   = "mpr121",
 308                 .pm     = &mpr121_touchkey_pm_ops,
 309         },
 310         .id_table       = mpr121_id,
 311         .probe          = mpr_touchkey_probe,
 312 };
 313
 314 module_i2c_driver(mpr_touchkey_driver);
 315
 316 MODULE_LICENSE("GPL");
 317 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 318 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");