drivers/input/keyboard/tca6416-keypad.c

   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * Driver for keys on TCA6416 I2C IO expander
   4  *
   5  * Copyright (C) 2010 Texas Instruments
   6  *
   7  * Author : Sriramakrishnan.A.G. <srk@ti.com>
   8  */
   9
  10 #include <linux/types.h>
  11 #include <linux/module.h>
  12 #include <linux/init.h>
  13 #include <linux/delay.h>
  14 #include <linux/slab.h>
  15 #include <linux/interrupt.h>
  16 #include <linux/workqueue.h>
  17 #include <linux/i2c.h>
  18 #include <linux/input.h>
  19 #include <linux/tca6416_keypad.h>
  20
  21 #define TCA6416_INPUT          0
  22 #define TCA6416_OUTPUT         1
  23 #define TCA6416_INVERT         2
  24 #define TCA6416_DIRECTION      3
  25
  26 #define TCA6416_POLL_INTERVAL   100 /* msec */
  27
  28 static const struct i2c_device_id tca6416_id[] = {
  29         { "tca6416-keys", 16, },
  30         { "tca6408-keys", 8, },
  31         { }
  32 };
  33 MODULE_DEVICE_TABLE(i2c, tca6416_id);
  34
  35 struct tca6416_keypad_chip {
  36         uint16_t reg_output;
  37         uint16_t reg_direction;
  38         uint16_t reg_input;
  39
  40         struct i2c_client *client;
  41         struct input_dev *input;
  42         int io_size;
  43         u16 pinmask;
  44         bool use_polling;
  45         struct tca6416_button buttons[];
  46 };
  47
  48 static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
  49 {
  50         int error;
  51
  52         error = chip->io_size > 8 ?
  53                 i2c_smbus_write_word_data(chip->client, reg << 1, val) :
  54                 i2c_smbus_write_byte_data(chip->client, reg, val);
  55         if (error < 0) {
  56                 dev_err(&chip->client->dev,
  57                         "%s failed, reg: %d, val: %d, error: %d\n",
  58                         __func__, reg, val, error);
  59                 return error;
  60         }
  61
  62         return 0;
  63 }
  64
  65 static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
  66 {
  67         int retval;
  68
  69         retval = chip->io_size > 8 ?
  70                  i2c_smbus_read_word_data(chip->client, reg << 1) :
  71                  i2c_smbus_read_byte_data(chip->client, reg);
  72         if (retval < 0) {
  73                 dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
  74                         __func__, reg, retval);
  75                 return retval;
  76         }
  77
  78         *val = (u16)retval;
  79         return 0;
  80 }
  81
  82 static void tca6416_keys_scan(struct input_dev *input)
  83 {
  84         struct tca6416_keypad_chip *chip = input_get_drvdata(input);
  85         u16 reg_val, val;
  86         int error, i, pin_index;
  87
  88         error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
  89         if (error)
  90                 return;
  91
  92         reg_val &= chip->pinmask;
  93
  94         /* Figure out which lines have changed */
  95         val = reg_val ^ chip->reg_input;
  96         chip->reg_input = reg_val;
  97
  98         for (i = 0, pin_index = 0; i < 16; i++) {
  99                 if (val & (1 << i)) {
 100                         struct tca6416_button *button = &chip->buttons[pin_index];
 101                         unsigned int type = button->type ?: EV_KEY;
 102                         int state = ((reg_val & (1 << i)) ? 1 : 0)
 103                                                 ^ button->active_low;
 104
 105                         input_event(input, type, button->code, !!state);
 106                         input_sync(input);
 107                 }
 108
 109                 if (chip->pinmask & (1 << i))
 110                         pin_index++;
 111         }
 112 }
 113
 114 /*
 115  * This is threaded IRQ handler and this can (and will) sleep.
 116  */
 117 static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
 118 {
 119         tca6416_keys_scan(dev_id);
 120
 121         return IRQ_HANDLED;
 122 }
 123
 124 static int tca6416_keys_open(struct input_dev *dev)
 125 {
 126         struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
 127
 128         if (!chip->use_polling) {
 129                 /* Get initial device state in case it has switches */
 130                 tca6416_keys_scan(dev);
 131                 enable_irq(chip->client->irq);
 132         }
 133
 134         return 0;
 135 }
 136
 137 static void tca6416_keys_close(struct input_dev *dev)
 138 {
 139         struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
 140
 141         if (!chip->use_polling)
 142                 disable_irq(chip->client->irq);
 143 }
 144
 145 static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
 146 {
 147         int error;
 148
 149         error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
 150         if (error)
 151                 return error;
 152
 153         error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
 154         if (error)
 155                 return error;
 156
 157         /* ensure that keypad pins are set to input */
 158         error = tca6416_write_reg(chip, TCA6416_DIRECTION,
 159                                   chip->reg_direction | chip->pinmask);
 160         if (error)
 161                 return error;
 162
 163         error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
 164         if (error)
 165                 return error;
 166
 167         error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
 168         if (error)
 169                 return error;
 170
 171         chip->reg_input &= chip->pinmask;
 172
 173         return 0;
 174 }
 175
 176 static int tca6416_keypad_probe(struct i2c_client *client)
 177 {
 178         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 179         struct tca6416_keys_platform_data *pdata;
 180         struct tca6416_keypad_chip *chip;
 181         struct input_dev *input;
 182         int error;
 183         int i;
 184
 185         /* Check functionality */
 186         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
 187                 dev_err(&client->dev, "%s adapter not supported\n",
 188                         dev_driver_string(&client->adapter->dev));
 189                 return -ENODEV;
 190         }
 191
 192         pdata = dev_get_platdata(&client->dev);
 193         if (!pdata) {
 194                 dev_dbg(&client->dev, "no platform data\n");
 195                 return -EINVAL;
 196         }
 197
 198         chip = devm_kzalloc(&client->dev,
 199                             struct_size(chip, buttons, pdata->nbuttons),
 200                             GFP_KERNEL);
 201         if (!chip)
 202                 return -ENOMEM;
 203
 204         input = devm_input_allocate_device(&client->dev);
 205         if (!input)
 206                 return -ENOMEM;
 207
 208         chip->client = client;
 209         chip->input = input;
 210         chip->io_size = id->driver_data;
 211         chip->pinmask = pdata->pinmask;
 212         chip->use_polling = pdata->use_polling;
 213
 214         input->phys = "tca6416-keys/input0";
 215         input->name = client->name;
 216
 217         input->open = tca6416_keys_open;
 218         input->close = tca6416_keys_close;
 219
 220         input->id.bustype = BUS_HOST;
 221         input->id.vendor = 0x0001;
 222         input->id.product = 0x0001;
 223         input->id.version = 0x0100;
 224
 225         /* Enable auto repeat feature of Linux input subsystem */
 226         if (pdata->rep)
 227                 __set_bit(EV_REP, input->evbit);
 228
 229         for (i = 0; i < pdata->nbuttons; i++) {
 230                 unsigned int type;
 231
 232                 chip->buttons[i] = pdata->buttons[i];
 233                 type = (pdata->buttons[i].type) ?: EV_KEY;
 234                 input_set_capability(input, type, pdata->buttons[i].code);
 235         }
 236
 237         input_set_drvdata(input, chip);
 238
 239         /*
 240          * Initialize cached registers from their original values.
 241          * we can't share this chip with another i2c master.
 242          */
 243         error = tca6416_setup_registers(chip);
 244         if (error)
 245                 return error;
 246
 247         if (chip->use_polling) {
 248                 error = input_setup_polling(input, tca6416_keys_scan);
 249                 if (error) {
 250                         dev_err(&client->dev, "Failed to setup polling\n");
 251                         return error;
 252                 }
 253
 254                 input_set_poll_interval(input, TCA6416_POLL_INTERVAL);
 255         } else {
 256                 error = devm_request_threaded_irq(&client->dev, client->irq,
 257                                                   NULL, tca6416_keys_isr,
 258                                                   IRQF_TRIGGER_FALLING |
 259                                                         IRQF_ONESHOT |
 260                                                         IRQF_NO_AUTOEN,
 261                                                   "tca6416-keypad", input);
 262                 if (error) {
 263                         dev_dbg(&client->dev,
 264                                 "Unable to claim irq %d; error %d\n",
 265                                 client->irq, error);
 266                         return error;
 267                 }
 268         }
 269
 270         error = input_register_device(input);
 271         if (error) {
 272                 dev_dbg(&client->dev,
 273                         "Unable to register input device, error: %d\n", error);
 274                 return error;
 275         }
 276
 277         i2c_set_clientdata(client, chip);
 278
 279         return 0;
 280 }
 281
 282 static struct i2c_driver tca6416_keypad_driver = {
 283         .driver = {
 284                 .name   = "tca6416-keypad",
 285         },
 286         .probe          = tca6416_keypad_probe,
 287         .id_table       = tca6416_id,
 288 };
 289
 290 static int __init tca6416_keypad_init(void)
 291 {
 292         return i2c_add_driver(&tca6416_keypad_driver);
 293 }
 294
 295 subsys_initcall(tca6416_keypad_init);
 296
 297 static void __exit tca6416_keypad_exit(void)
 298 {
 299         i2c_del_driver(&tca6416_keypad_driver);
 300 }
 301 module_exit(tca6416_keypad_exit);
 302
 303 MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
 304 MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
 305 MODULE_LICENSE("GPL");