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/gpio.h>
  18 #include <linux/i2c.h>
  19 #include <linux/input.h>
  20 #include <linux/tca6416_keypad.h>
  21
  22 #define TCA6416_INPUT          0
  23 #define TCA6416_OUTPUT         1
  24 #define TCA6416_INVERT         2
  25 #define TCA6416_DIRECTION      3
  26
  27 #define TCA6416_POLL_INTERVAL   100 /* msec */
  28
  29 static const struct i2c_device_id tca6416_id[] = {
  30         { "tca6416-keys", 16, },
  31         { "tca6408-keys", 8, },
  32         { }
  33 };
  34 MODULE_DEVICE_TABLE(i2c, tca6416_id);
  35
  36 struct tca6416_drv_data {
  37         struct input_dev *input;
  38         struct tca6416_button data[];
  39 };
  40
  41 struct tca6416_keypad_chip {
  42         uint16_t reg_output;
  43         uint16_t reg_direction;
  44         uint16_t reg_input;
  45
  46         struct i2c_client *client;
  47         struct input_dev *input;
  48         int io_size;
  49         int irqnum;
  50         u16 pinmask;
  51         bool use_polling;
  52         struct tca6416_button buttons[];
  53 };
  54
  55 static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val)
  56 {
  57         int error;
  58
  59         error = chip->io_size > 8 ?
  60                 i2c_smbus_write_word_data(chip->client, reg << 1, val) :
  61                 i2c_smbus_write_byte_data(chip->client, reg, val);
  62         if (error < 0) {
  63                 dev_err(&chip->client->dev,
  64                         "%s failed, reg: %d, val: %d, error: %d\n",
  65                         __func__, reg, val, error);
  66                 return error;
  67         }
  68
  69         return 0;
  70 }
  71
  72 static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val)
  73 {
  74         int retval;
  75
  76         retval = chip->io_size > 8 ?
  77                  i2c_smbus_read_word_data(chip->client, reg << 1) :
  78                  i2c_smbus_read_byte_data(chip->client, reg);
  79         if (retval < 0) {
  80                 dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n",
  81                         __func__, reg, retval);
  82                 return retval;
  83         }
  84
  85         *val = (u16)retval;
  86         return 0;
  87 }
  88
  89 static void tca6416_keys_scan(struct input_dev *input)
  90 {
  91         struct tca6416_keypad_chip *chip = input_get_drvdata(input);
  92         u16 reg_val, val;
  93         int error, i, pin_index;
  94
  95         error = tca6416_read_reg(chip, TCA6416_INPUT, &reg_val);
  96         if (error)
  97                 return;
  98
  99         reg_val &= chip->pinmask;
 100
 101         /* Figure out which lines have changed */
 102         val = reg_val ^ chip->reg_input;
 103         chip->reg_input = reg_val;
 104
 105         for (i = 0, pin_index = 0; i < 16; i++) {
 106                 if (val & (1 << i)) {
 107                         struct tca6416_button *button = &chip->buttons[pin_index];
 108                         unsigned int type = button->type ?: EV_KEY;
 109                         int state = ((reg_val & (1 << i)) ? 1 : 0)
 110                                                 ^ button->active_low;
 111
 112                         input_event(input, type, button->code, !!state);
 113                         input_sync(input);
 114                 }
 115
 116                 if (chip->pinmask & (1 << i))
 117                         pin_index++;
 118         }
 119 }
 120
 121 /*
 122  * This is threaded IRQ handler and this can (and will) sleep.
 123  */
 124 static irqreturn_t tca6416_keys_isr(int irq, void *dev_id)
 125 {
 126         tca6416_keys_scan(dev_id);
 127
 128         return IRQ_HANDLED;
 129 }
 130
 131 static int tca6416_keys_open(struct input_dev *dev)
 132 {
 133         struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
 134
 135         if (!chip->use_polling) {
 136                 /* Get initial device state in case it has switches */
 137                 tca6416_keys_scan(dev);
 138                 enable_irq(chip->client->irq);
 139         }
 140
 141         return 0;
 142 }
 143
 144 static void tca6416_keys_close(struct input_dev *dev)
 145 {
 146         struct tca6416_keypad_chip *chip = input_get_drvdata(dev);
 147
 148         if (!chip->use_polling)
 149                 disable_irq(chip->client->irq);
 150 }
 151
 152 static int tca6416_setup_registers(struct tca6416_keypad_chip *chip)
 153 {
 154         int error;
 155
 156         error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output);
 157         if (error)
 158                 return error;
 159
 160         error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
 161         if (error)
 162                 return error;
 163
 164         /* ensure that keypad pins are set to input */
 165         error = tca6416_write_reg(chip, TCA6416_DIRECTION,
 166                                   chip->reg_direction | chip->pinmask);
 167         if (error)
 168                 return error;
 169
 170         error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction);
 171         if (error)
 172                 return error;
 173
 174         error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input);
 175         if (error)
 176                 return error;
 177
 178         chip->reg_input &= chip->pinmask;
 179
 180         return 0;
 181 }
 182
 183 static int tca6416_keypad_probe(struct i2c_client *client)
 184 {
 185         const struct i2c_device_id *id = i2c_client_get_device_id(client);
 186         struct tca6416_keys_platform_data *pdata;
 187         struct tca6416_keypad_chip *chip;
 188         struct input_dev *input;
 189         int error;
 190         int i;
 191
 192         /* Check functionality */
 193         if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) {
 194                 dev_err(&client->dev, "%s adapter not supported\n",
 195                         dev_driver_string(&client->adapter->dev));
 196                 return -ENODEV;
 197         }
 198
 199         pdata = dev_get_platdata(&client->dev);
 200         if (!pdata) {
 201                 dev_dbg(&client->dev, "no platform data\n");
 202                 return -EINVAL;
 203         }
 204
 205         chip = devm_kzalloc(&client->dev,
 206                             struct_size(chip, buttons, pdata->nbuttons),
 207                             GFP_KERNEL);
 208         if (!chip)
 209                 return -ENOMEM;
 210
 211         input = devm_input_allocate_device(&client->dev);
 212         if (!input)
 213                 return -ENOMEM;
 214
 215         chip->client = client;
 216         chip->input = input;
 217         chip->io_size = id->driver_data;
 218         chip->pinmask = pdata->pinmask;
 219         chip->use_polling = pdata->use_polling;
 220
 221         input->phys = "tca6416-keys/input0";
 222         input->name = client->name;
 223
 224         input->open = tca6416_keys_open;
 225         input->close = tca6416_keys_close;
 226
 227         input->id.bustype = BUS_HOST;
 228         input->id.vendor = 0x0001;
 229         input->id.product = 0x0001;
 230         input->id.version = 0x0100;
 231
 232         /* Enable auto repeat feature of Linux input subsystem */
 233         if (pdata->rep)
 234                 __set_bit(EV_REP, input->evbit);
 235
 236         for (i = 0; i < pdata->nbuttons; i++) {
 237                 unsigned int type;
 238
 239                 chip->buttons[i] = pdata->buttons[i];
 240                 type = (pdata->buttons[i].type) ?: EV_KEY;
 241                 input_set_capability(input, type, pdata->buttons[i].code);
 242         }
 243
 244         input_set_drvdata(input, chip);
 245
 246         /*
 247          * Initialize cached registers from their original values.
 248          * we can't share this chip with another i2c master.
 249          */
 250         error = tca6416_setup_registers(chip);
 251         if (error)
 252                 return error;
 253
 254         if (chip->use_polling) {
 255                 error = input_setup_polling(input, tca6416_keys_scan);
 256                 if (error) {
 257                         dev_err(&client->dev, "Failed to setup polling\n");
 258                         return error;
 259                 }
 260
 261                 input_set_poll_interval(input, TCA6416_POLL_INTERVAL);
 262         } else {
 263                 error = devm_request_threaded_irq(&client->dev, client->irq,
 264                                                   NULL, tca6416_keys_isr,
 265                                                   IRQF_TRIGGER_FALLING |
 266                                                         IRQF_ONESHOT |
 267                                                         IRQF_NO_AUTOEN,
 268                                                   "tca6416-keypad", input);
 269                 if (error) {
 270                         dev_dbg(&client->dev,
 271                                 "Unable to claim irq %d; error %d\n",
 272                                 client->irq, error);
 273                         return error;
 274                 }
 275         }
 276
 277         error = input_register_device(input);
 278         if (error) {
 279                 dev_dbg(&client->dev,
 280                         "Unable to register input device, error: %d\n", error);
 281                 return error;
 282         }
 283
 284         i2c_set_clientdata(client, chip);
 285
 286         return 0;
 287 }
 288
 289 static struct i2c_driver tca6416_keypad_driver = {
 290         .driver = {
 291                 .name   = "tca6416-keypad",
 292         },
 293         .probe          = tca6416_keypad_probe,
 294         .id_table       = tca6416_id,
 295 };
 296
 297 static int __init tca6416_keypad_init(void)
 298 {
 299         return i2c_add_driver(&tca6416_keypad_driver);
 300 }
 301
 302 subsys_initcall(tca6416_keypad_init);
 303
 304 static void __exit tca6416_keypad_exit(void)
 305 {
 306         i2c_del_driver(&tca6416_keypad_driver);
 307 }
 308 module_exit(tca6416_keypad_exit);
 309
 310 MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>");
 311 MODULE_DESCRIPTION("Keypad driver over tca6416 IO expander");
 312 MODULE_LICENSE("GPL");