drivers/input/keyboard/mpr121_touchkey.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Touchkey driver for Freescale MPR121 Controllor
   4  *
   5  * Copyright (C) 2011 Freescale Semiconductor, Inc.
   6  * Author: Zhang Jiejing <jiejing.zhang@freescale.com>
   7  *
   8  * Based on mcs_touchkey.c
   9  */
  10
  11 #include <linux/bitops.h>
  12 #include <linux/delay.h>
  13 #include <linux/i2c.h>
  14 #include <linux/input.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/module.h>
  17 #include <linux/of.h>
  18 #include <linux/property.h>
  19 #include <linux/regulator/consumer.h>
  20 #include <linux/slab.h>
  21
  22 /* Register definitions */
  23 #define ELE_TOUCH_STATUS_0_ADDR 0x0
  24 #define ELE_TOUCH_STATUS_1_ADDR 0X1
  25 #define MHD_RISING_ADDR         0x2b
  26 #define NHD_RISING_ADDR         0x2c
  27 #define NCL_RISING_ADDR         0x2d
  28 #define FDL_RISING_ADDR         0x2e
  29 #define MHD_FALLING_ADDR        0x2f
  30 #define NHD_FALLING_ADDR        0x30
  31 #define NCL_FALLING_ADDR        0x31
  32 #define FDL_FALLING_ADDR        0x32
  33 #define ELE0_TOUCH_THRESHOLD_ADDR       0x41
  34 #define ELE0_RELEASE_THRESHOLD_ADDR     0x42
  35 #define AFE_CONF_ADDR                   0x5c
  36 #define FILTER_CONF_ADDR                0x5d
  37
  38 /*
  39  * ELECTRODE_CONF_ADDR: This register configures the number of
  40  * enabled capacitance sensing inputs and its run/suspend mode.
  41  */
  42 #define ELECTRODE_CONF_ADDR             0x5e
  43 #define ELECTRODE_CONF_QUICK_CHARGE     0x80
  44 #define AUTO_CONFIG_CTRL_ADDR           0x7b
  45 #define AUTO_CONFIG_USL_ADDR            0x7d
  46 #define AUTO_CONFIG_LSL_ADDR            0x7e
  47 #define AUTO_CONFIG_TL_ADDR             0x7f
  48
  49 /* Threshold of touch/release trigger */
  50 #define TOUCH_THRESHOLD                 0x08
  51 #define RELEASE_THRESHOLD               0x05
  52 /* Masks for touch and release triggers */
  53 #define TOUCH_STATUS_MASK               0xfff
  54 /* MPR121 has 12 keys */
  55 #define MPR121_MAX_KEY_COUNT            12
  56
  57 #define MPR121_MIN_POLL_INTERVAL        10
  58 #define MPR121_MAX_POLL_INTERVAL        200
  59
  60 struct mpr121_touchkey {
  61         struct i2c_client       *client;
  62         struct input_dev        *input_dev;
  63         unsigned int            statusbits;
  64         unsigned int            keycount;
  65         u32                     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 void mpr121_vdd_supply_disable(void *data)
  86 {
  87         struct regulator *vdd_supply = data;
  88
  89         regulator_disable(vdd_supply);
  90 }
  91
  92 static struct regulator *mpr121_vdd_supply_init(struct device *dev)
  93 {
  94         struct regulator *vdd_supply;
  95         int err;
  96
  97         vdd_supply = devm_regulator_get(dev, "vdd");
  98         if (IS_ERR(vdd_supply)) {
  99                 dev_err(dev, "failed to get vdd regulator: %ld\n",
 100                         PTR_ERR(vdd_supply));
 101                 return vdd_supply;
 102         }
 103
 104         err = regulator_enable(vdd_supply);
 105         if (err) {
 106                 dev_err(dev, "failed to enable vdd regulator: %d\n", err);
 107                 return ERR_PTR(err);
 108         }
 109
 110         err = devm_add_action(dev, mpr121_vdd_supply_disable, vdd_supply);
 111         if (err) {
 112                 regulator_disable(vdd_supply);
 113                 dev_err(dev, "failed to add disable regulator action: %d\n",
 114                         err);
 115                 return ERR_PTR(err);
 116         }
 117
 118         return vdd_supply;
 119 }
 120
 121 static void mpr_touchkey_report(struct input_dev *dev)
 122 {
 123         struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
 124         struct input_dev *input = mpr121->input_dev;
 125         struct i2c_client *client = mpr121->client;
 126         unsigned long bit_changed;
 127         unsigned int key_num;
 128         int reg;
 129
 130         reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
 131         if (reg < 0) {
 132                 dev_err(&client->dev, "i2c read error [%d]\n", reg);
 133                 return;
 134         }
 135
 136         reg <<= 8;
 137         reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
 138         if (reg < 0) {
 139                 dev_err(&client->dev, "i2c read error [%d]\n", reg);
 140                 return;
 141         }
 142
 143         reg &= TOUCH_STATUS_MASK;
 144         /* use old press bit to figure out which bit changed */
 145         bit_changed = reg ^ mpr121->statusbits;
 146         mpr121->statusbits = reg;
 147         for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
 148                 unsigned int key_val, pressed;
 149
 150                 pressed = reg & BIT(key_num);
 151                 key_val = mpr121->keycodes[key_num];
 152
 153                 input_event(input, EV_MSC, MSC_SCAN, key_num);
 154                 input_report_key(input, key_val, pressed);
 155
 156                 dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
 157                         pressed ? "pressed" : "released");
 158
 159         }
 160         input_sync(input);
 161 }
 162
 163 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
 164 {
 165         struct mpr121_touchkey *mpr121 = dev_id;
 166
 167         mpr_touchkey_report(mpr121->input_dev);
 168
 169         return IRQ_HANDLED;
 170 }
 171
 172 static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
 173                             struct i2c_client *client, int vdd_uv)
 174 {
 175         const struct mpr121_init_register *reg;
 176         unsigned char usl, lsl, tl, eleconf;
 177         int i, t, vdd, ret;
 178
 179         /* Set up touch/release threshold for ele0-ele11 */
 180         for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
 181                 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
 182                 ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
 183                 if (ret < 0)
 184                         goto err_i2c_write;
 185                 ret = i2c_smbus_write_byte_data(client, t + 1,
 186                                                 RELEASE_THRESHOLD);
 187                 if (ret < 0)
 188                         goto err_i2c_write;
 189         }
 190
 191         /* Set up init register */
 192         for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
 193                 reg = &init_reg_table[i];
 194                 ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
 195                 if (ret < 0)
 196                         goto err_i2c_write;
 197         }
 198
 199
 200         /*
 201          * Capacitance on sensing input varies and needs to be compensated.
 202          * The internal MPR121-auto-configuration can do this if it's
 203          * registers are set properly (based on vdd_uv).
 204          */
 205         vdd = vdd_uv / 1000;
 206         usl = ((vdd - 700) * 256) / vdd;
 207         lsl = (usl * 65) / 100;
 208         tl = (usl * 90) / 100;
 209         ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
 210         ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
 211         ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
 212
 213         /*
 214          * Quick charge bit will let the capacitive charge to ready
 215          * state quickly, or the buttons may not function after system
 216          * boot.
 217          */
 218         eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
 219         ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 220                                          eleconf);
 221         if (ret != 0)
 222                 goto err_i2c_write;
 223
 224         dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
 225
 226         return 0;
 227
 228 err_i2c_write:
 229         dev_err(&client->dev, "i2c write error: %d\n", ret);
 230         return ret;
 231 }
 232
 233 static int mpr_touchkey_probe(struct i2c_client *client,
 234                               const struct i2c_device_id *id)
 235 {
 236         struct device *dev = &client->dev;
 237         struct regulator *vdd_supply;
 238         int vdd_uv;
 239         struct mpr121_touchkey *mpr121;
 240         struct input_dev *input_dev;
 241         u32 poll_interval = 0;
 242         int error;
 243         int i;
 244
 245         vdd_supply = mpr121_vdd_supply_init(dev);
 246         if (IS_ERR(vdd_supply))
 247                 return PTR_ERR(vdd_supply);
 248
 249         vdd_uv = regulator_get_voltage(vdd_supply);
 250
 251         mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
 252         if (!mpr121)
 253                 return -ENOMEM;
 254
 255         input_dev = devm_input_allocate_device(dev);
 256         if (!input_dev)
 257                 return -ENOMEM;
 258
 259         mpr121->client = client;
 260         mpr121->input_dev = input_dev;
 261         mpr121->keycount = device_property_count_u32(dev, "linux,keycodes");
 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         input_set_drvdata(input_dev, mpr121);
 283
 284         input_dev->keycode = mpr121->keycodes;
 285         input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
 286         input_dev->keycodemax = mpr121->keycount;
 287
 288         for (i = 0; i < mpr121->keycount; i++)
 289                 input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);
 290
 291         error = mpr121_phys_init(mpr121, client, vdd_uv);
 292         if (error) {
 293                 dev_err(dev, "Failed to init register\n");
 294                 return error;
 295         }
 296
 297         device_property_read_u32(dev, "poll-interval", &poll_interval);
 298
 299         if (client->irq) {
 300                 error = devm_request_threaded_irq(dev, client->irq, NULL,
 301                                                   mpr_touchkey_interrupt,
 302                                                   IRQF_TRIGGER_FALLING |
 303                                                   IRQF_ONESHOT,
 304                                                   dev->driver->name, mpr121);
 305                 if (error) {
 306                         dev_err(dev, "Failed to register interrupt\n");
 307                         return error;
 308                 }
 309         } else if (poll_interval) {
 310                 if (poll_interval < MPR121_MIN_POLL_INTERVAL)
 311                         return -EINVAL;
 312
 313                 if (poll_interval > MPR121_MAX_POLL_INTERVAL)
 314                         return -EINVAL;
 315
 316                 error = input_setup_polling(input_dev, mpr_touchkey_report);
 317                 if (error) {
 318                         dev_err(dev, "Failed to setup polling\n");
 319                         return error;
 320                 }
 321
 322                 input_set_poll_interval(input_dev, poll_interval);
 323                 input_set_min_poll_interval(input_dev,
 324                                             MPR121_MIN_POLL_INTERVAL);
 325                 input_set_max_poll_interval(input_dev,
 326                                             MPR121_MAX_POLL_INTERVAL);
 327         } else {
 328                 dev_err(dev,
 329                         "invalid IRQ number and polling not configured\n");
 330                 return -EINVAL;
 331         }
 332
 333         error = input_register_device(input_dev);
 334         if (error)
 335                 return error;
 336
 337         i2c_set_clientdata(client, mpr121);
 338         device_init_wakeup(dev,
 339                         device_property_read_bool(dev, "wakeup-source"));
 340
 341         return 0;
 342 }
 343
 344 static int __maybe_unused mpr_suspend(struct device *dev)
 345 {
 346         struct i2c_client *client = to_i2c_client(dev);
 347
 348         if (device_may_wakeup(&client->dev))
 349                 enable_irq_wake(client->irq);
 350
 351         i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
 352
 353         return 0;
 354 }
 355
 356 static int __maybe_unused mpr_resume(struct device *dev)
 357 {
 358         struct i2c_client *client = to_i2c_client(dev);
 359         struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
 360
 361         if (device_may_wakeup(&client->dev))
 362                 disable_irq_wake(client->irq);
 363
 364         i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 365                                   mpr121->keycount);
 366
 367         return 0;
 368 }
 369
 370 static SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
 371
 372 static const struct i2c_device_id mpr121_id[] = {
 373         { "mpr121_touchkey", 0 },
 374         { }
 375 };
 376 MODULE_DEVICE_TABLE(i2c, mpr121_id);
 377
 378 #ifdef CONFIG_OF
 379 static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
 380         { .compatible = "fsl,mpr121-touchkey" },
 381         { },
 382 };
 383 MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
 384 #endif
 385
 386 static struct i2c_driver mpr_touchkey_driver = {
 387         .driver = {
 388                 .name   = "mpr121",
 389                 .pm     = &mpr121_touchkey_pm_ops,
 390                 .of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
 391         },
 392         .id_table       = mpr121_id,
 393         .probe          = mpr_touchkey_probe,
 394 };
 395
 396 module_i2c_driver(mpr_touchkey_driver);
 397
 398 MODULE_LICENSE("GPL");
 399 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 400 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");