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 mpr_touchkey_report(struct input_dev *dev)
  86 {
  87         struct mpr121_touchkey *mpr121 = input_get_drvdata(dev);
  88         struct input_dev *input = mpr121->input_dev;
  89         struct i2c_client *client = mpr121->client;
  90         unsigned long bit_changed;
  91         unsigned int key_num;
  92         int reg;
  93
  94         reg = i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_1_ADDR);
  95         if (reg < 0) {
  96                 dev_err(&client->dev, "i2c read error [%d]\n", reg);
  97                 return;
  98         }
  99
 100         reg <<= 8;
 101         reg |= i2c_smbus_read_byte_data(client, ELE_TOUCH_STATUS_0_ADDR);
 102         if (reg < 0) {
 103                 dev_err(&client->dev, "i2c read error [%d]\n", reg);
 104                 return;
 105         }
 106
 107         reg &= TOUCH_STATUS_MASK;
 108         /* use old press bit to figure out which bit changed */
 109         bit_changed = reg ^ mpr121->statusbits;
 110         mpr121->statusbits = reg;
 111         for_each_set_bit(key_num, &bit_changed, mpr121->keycount) {
 112                 unsigned int key_val, pressed;
 113
 114                 pressed = reg & BIT(key_num);
 115                 key_val = mpr121->keycodes[key_num];
 116
 117                 input_event(input, EV_MSC, MSC_SCAN, key_num);
 118                 input_report_key(input, key_val, pressed);
 119
 120                 dev_dbg(&client->dev, "key %d %d %s\n", key_num, key_val,
 121                         pressed ? "pressed" : "released");
 122
 123         }
 124         input_sync(input);
 125 }
 126
 127 static irqreturn_t mpr_touchkey_interrupt(int irq, void *dev_id)
 128 {
 129         struct mpr121_touchkey *mpr121 = dev_id;
 130
 131         mpr_touchkey_report(mpr121->input_dev);
 132
 133         return IRQ_HANDLED;
 134 }
 135
 136 static int mpr121_phys_init(struct mpr121_touchkey *mpr121,
 137                             struct i2c_client *client, int vdd_uv)
 138 {
 139         const struct mpr121_init_register *reg;
 140         unsigned char usl, lsl, tl, eleconf;
 141         int i, t, vdd, ret;
 142
 143         /* Set up touch/release threshold for ele0-ele11 */
 144         for (i = 0; i <= MPR121_MAX_KEY_COUNT; i++) {
 145                 t = ELE0_TOUCH_THRESHOLD_ADDR + (i * 2);
 146                 ret = i2c_smbus_write_byte_data(client, t, TOUCH_THRESHOLD);
 147                 if (ret < 0)
 148                         goto err_i2c_write;
 149                 ret = i2c_smbus_write_byte_data(client, t + 1,
 150                                                 RELEASE_THRESHOLD);
 151                 if (ret < 0)
 152                         goto err_i2c_write;
 153         }
 154
 155         /* Set up init register */
 156         for (i = 0; i < ARRAY_SIZE(init_reg_table); i++) {
 157                 reg = &init_reg_table[i];
 158                 ret = i2c_smbus_write_byte_data(client, reg->addr, reg->val);
 159                 if (ret < 0)
 160                         goto err_i2c_write;
 161         }
 162
 163
 164         /*
 165          * Capacitance on sensing input varies and needs to be compensated.
 166          * The internal MPR121-auto-configuration can do this if it's
 167          * registers are set properly (based on vdd_uv).
 168          */
 169         vdd = vdd_uv / 1000;
 170         usl = ((vdd - 700) * 256) / vdd;
 171         lsl = (usl * 65) / 100;
 172         tl = (usl * 90) / 100;
 173         ret = i2c_smbus_write_byte_data(client, AUTO_CONFIG_USL_ADDR, usl);
 174         ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_LSL_ADDR, lsl);
 175         ret |= i2c_smbus_write_byte_data(client, AUTO_CONFIG_TL_ADDR, tl);
 176
 177         /*
 178          * Quick charge bit will let the capacitive charge to ready
 179          * state quickly, or the buttons may not function after system
 180          * boot.
 181          */
 182         eleconf = mpr121->keycount | ELECTRODE_CONF_QUICK_CHARGE;
 183         ret |= i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 184                                          eleconf);
 185         if (ret != 0)
 186                 goto err_i2c_write;
 187
 188         dev_dbg(&client->dev, "set up with %x keys.\n", mpr121->keycount);
 189
 190         return 0;
 191
 192 err_i2c_write:
 193         dev_err(&client->dev, "i2c write error: %d\n", ret);
 194         return ret;
 195 }
 196
 197 static int mpr_touchkey_probe(struct i2c_client *client)
 198 {
 199         struct device *dev = &client->dev;
 200         int vdd_uv;
 201         struct mpr121_touchkey *mpr121;
 202         struct input_dev *input_dev;
 203         u32 poll_interval = 0;
 204         int error;
 205         int i;
 206
 207         vdd_uv = devm_regulator_get_enable_read_voltage(dev, "vdd");
 208         if (vdd_uv < 0)
 209                 return dev_err_probe(dev, vdd_uv, "failed to get vdd voltage\n");
 210
 211         mpr121 = devm_kzalloc(dev, sizeof(*mpr121), GFP_KERNEL);
 212         if (!mpr121)
 213                 return -ENOMEM;
 214
 215         input_dev = devm_input_allocate_device(dev);
 216         if (!input_dev)
 217                 return -ENOMEM;
 218
 219         mpr121->client = client;
 220         mpr121->input_dev = input_dev;
 221         mpr121->keycount = device_property_count_u32(dev, "linux,keycodes");
 222         if (mpr121->keycount > MPR121_MAX_KEY_COUNT) {
 223                 dev_err(dev, "too many keys defined (%d)\n", mpr121->keycount);
 224                 return -EINVAL;
 225         }
 226
 227         error = device_property_read_u32_array(dev, "linux,keycodes",
 228                                                mpr121->keycodes,
 229                                                mpr121->keycount);
 230         if (error) {
 231                 dev_err(dev,
 232                         "failed to read linux,keycode property: %d\n", error);
 233                 return error;
 234         }
 235
 236         input_dev->name = "Freescale MPR121 Touchkey";
 237         input_dev->id.bustype = BUS_I2C;
 238         input_dev->dev.parent = dev;
 239         if (device_property_read_bool(dev, "autorepeat"))
 240                 __set_bit(EV_REP, input_dev->evbit);
 241         input_set_capability(input_dev, EV_MSC, MSC_SCAN);
 242         input_set_drvdata(input_dev, mpr121);
 243
 244         input_dev->keycode = mpr121->keycodes;
 245         input_dev->keycodesize = sizeof(mpr121->keycodes[0]);
 246         input_dev->keycodemax = mpr121->keycount;
 247
 248         for (i = 0; i < mpr121->keycount; i++)
 249                 input_set_capability(input_dev, EV_KEY, mpr121->keycodes[i]);
 250
 251         error = mpr121_phys_init(mpr121, client, vdd_uv);
 252         if (error) {
 253                 dev_err(dev, "Failed to init register\n");
 254                 return error;
 255         }
 256
 257         device_property_read_u32(dev, "poll-interval", &poll_interval);
 258
 259         if (client->irq) {
 260                 error = devm_request_threaded_irq(dev, client->irq, NULL,
 261                                                   mpr_touchkey_interrupt,
 262                                                   IRQF_TRIGGER_FALLING |
 263                                                   IRQF_ONESHOT,
 264                                                   dev->driver->name, mpr121);
 265                 if (error) {
 266                         dev_err(dev, "Failed to register interrupt\n");
 267                         return error;
 268                 }
 269         } else if (poll_interval) {
 270                 if (poll_interval < MPR121_MIN_POLL_INTERVAL)
 271                         return -EINVAL;
 272
 273                 if (poll_interval > MPR121_MAX_POLL_INTERVAL)
 274                         return -EINVAL;
 275
 276                 error = input_setup_polling(input_dev, mpr_touchkey_report);
 277                 if (error) {
 278                         dev_err(dev, "Failed to setup polling\n");
 279                         return error;
 280                 }
 281
 282                 input_set_poll_interval(input_dev, poll_interval);
 283                 input_set_min_poll_interval(input_dev,
 284                                             MPR121_MIN_POLL_INTERVAL);
 285                 input_set_max_poll_interval(input_dev,
 286                                             MPR121_MAX_POLL_INTERVAL);
 287         } else {
 288                 dev_err(dev,
 289                         "invalid IRQ number and polling not configured\n");
 290                 return -EINVAL;
 291         }
 292
 293         error = input_register_device(input_dev);
 294         if (error)
 295                 return error;
 296
 297         i2c_set_clientdata(client, mpr121);
 298         device_init_wakeup(dev,
 299                         device_property_read_bool(dev, "wakeup-source"));
 300
 301         return 0;
 302 }
 303
 304 static int mpr_suspend(struct device *dev)
 305 {
 306         struct i2c_client *client = to_i2c_client(dev);
 307
 308         if (device_may_wakeup(&client->dev))
 309                 enable_irq_wake(client->irq);
 310
 311         i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR, 0x00);
 312
 313         return 0;
 314 }
 315
 316 static int mpr_resume(struct device *dev)
 317 {
 318         struct i2c_client *client = to_i2c_client(dev);
 319         struct mpr121_touchkey *mpr121 = i2c_get_clientdata(client);
 320
 321         if (device_may_wakeup(&client->dev))
 322                 disable_irq_wake(client->irq);
 323
 324         i2c_smbus_write_byte_data(client, ELECTRODE_CONF_ADDR,
 325                                   mpr121->keycount);
 326
 327         return 0;
 328 }
 329
 330 static DEFINE_SIMPLE_DEV_PM_OPS(mpr121_touchkey_pm_ops, mpr_suspend, mpr_resume);
 331
 332 static const struct i2c_device_id mpr121_id[] = {
 333         { "mpr121_touchkey" },
 334         { }
 335 };
 336 MODULE_DEVICE_TABLE(i2c, mpr121_id);
 337
 338 #ifdef CONFIG_OF
 339 static const struct of_device_id mpr121_touchkey_dt_match_table[] = {
 340         { .compatible = "fsl,mpr121-touchkey" },
 341         { },
 342 };
 343 MODULE_DEVICE_TABLE(of, mpr121_touchkey_dt_match_table);
 344 #endif
 345
 346 static struct i2c_driver mpr_touchkey_driver = {
 347         .driver = {
 348                 .name   = "mpr121",
 349                 .pm     = pm_sleep_ptr(&mpr121_touchkey_pm_ops),
 350                 .of_match_table = of_match_ptr(mpr121_touchkey_dt_match_table),
 351         },
 352         .id_table       = mpr121_id,
 353         .probe          = mpr_touchkey_probe,
 354 };
 355
 356 module_i2c_driver(mpr_touchkey_driver);
 357
 358 MODULE_LICENSE("GPL");
 359 MODULE_AUTHOR("Zhang Jiejing <jiejing.zhang@freescale.com>");
 360 MODULE_DESCRIPTION("Touch Key driver for Freescale MPR121 Chip");