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