1/* 2 * Driver for keys on TCA6416 I2C IO expander 3 * 4 * Copyright (C) 2010 Texas Instruments 5 * 6 * Author : Sriramakrishnan.A.G. <srk@ti.com> 7 * 8 * This program is free software; you can redistribute it and/or modify 9 * it under the terms of the GNU General Public License version 2 as 10 * published by the Free Software Foundation. 11 */ 12 13#include <linux/types.h> 14#include <linux/module.h> 15#include <linux/init.h> 16#include <linux/delay.h> 17#include <linux/slab.h> 18#include <linux/interrupt.h> 19#include <linux/workqueue.h> 20#include <linux/gpio.h> 21#include <linux/i2c.h> 22#include <linux/input.h> 23#include <linux/tca6416_keypad.h> 24 25#define TCA6416_INPUT 0 26#define TCA6416_OUTPUT 1 27#define TCA6416_INVERT 2 28#define TCA6416_DIRECTION 3 29 30static const struct i2c_device_id tca6416_id[] = { 31 { "tca6416-keys", 16, }, 32 { } 33}; 34MODULE_DEVICE_TABLE(i2c, tca6416_id); 35 36struct tca6416_drv_data { 37 struct input_dev *input; 38 struct tca6416_button data[0]; 39}; 40 41struct 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 struct delayed_work dwork; 49 u16 pinmask; 50 int irqnum; 51 bool use_polling; 52 struct tca6416_button buttons[0]; 53}; 54 55static int tca6416_write_reg(struct tca6416_keypad_chip *chip, int reg, u16 val) 56{ 57 int error; 58 59 error = i2c_smbus_write_word_data(chip->client, reg << 1, val); 60 if (error < 0) { 61 dev_err(&chip->client->dev, 62 "%s failed, reg: %d, val: %d, error: %d\n", 63 __func__, reg, val, error); 64 return error; 65 } 66 67 return 0; 68} 69 70static int tca6416_read_reg(struct tca6416_keypad_chip *chip, int reg, u16 *val) 71{ 72 int retval; 73 74 retval = i2c_smbus_read_word_data(chip->client, reg << 1); 75 if (retval < 0) { 76 dev_err(&chip->client->dev, "%s failed, reg: %d, error: %d\n", 77 __func__, reg, retval); 78 return retval; 79 } 80 81 *val = (u16)retval; 82 return 0; 83} 84 85static void tca6416_keys_scan(struct tca6416_keypad_chip *chip) 86{ 87 struct input_dev *input = chip->input; 88 u16 reg_val, val; 89 int error, i, pin_index; 90 91 error = tca6416_read_reg(chip, TCA6416_INPUT, ®_val); 92 if (error) 93 return; 94 95 reg_val &= chip->pinmask; 96 97 /* Figure out which lines have changed */ 98 val = reg_val ^ chip->reg_input; 99 chip->reg_input = reg_val; 100 101 for (i = 0, pin_index = 0; i < 16; i++) { 102 if (val & (1 << i)) { 103 struct tca6416_button *button = &chip->buttons[pin_index]; 104 unsigned int type = button->type ?: EV_KEY; 105 int state = ((reg_val & (1 << i)) ? 1 : 0) 106 ^ button->active_low; 107 108 input_event(input, type, button->code, !!state); 109 input_sync(input); 110 } 111 112 if (chip->pinmask & (1 << i)) 113 pin_index++; 114 } 115} 116 117/* 118 * This is threaded IRQ handler and this can (and will) sleep. 119 */ 120static irqreturn_t tca6416_keys_isr(int irq, void *dev_id) 121{ 122 struct tca6416_keypad_chip *chip = dev_id; 123 124 tca6416_keys_scan(chip); 125 126 return IRQ_HANDLED; 127} 128 129static void tca6416_keys_work_func(struct work_struct *work) 130{ 131 struct tca6416_keypad_chip *chip = 132 container_of(work, struct tca6416_keypad_chip, dwork.work); 133 134 tca6416_keys_scan(chip); 135 schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100)); 136} 137 138static int tca6416_keys_open(struct input_dev *dev) 139{ 140 struct tca6416_keypad_chip *chip = input_get_drvdata(dev); 141 142 /* Get initial device state in case it has switches */ 143 tca6416_keys_scan(chip); 144 145 if (chip->use_polling) 146 schedule_delayed_work(&chip->dwork, msecs_to_jiffies(100)); 147 else 148 enable_irq(chip->irqnum); 149 150 return 0; 151} 152 153static void tca6416_keys_close(struct input_dev *dev) 154{ 155 struct tca6416_keypad_chip *chip = input_get_drvdata(dev); 156 157 if (chip->use_polling) 158 cancel_delayed_work_sync(&chip->dwork); 159 else 160 disable_irq(chip->irqnum); 161} 162 163static int __devinit tca6416_setup_registers(struct tca6416_keypad_chip *chip) 164{ 165 int error; 166 167 error = tca6416_read_reg(chip, TCA6416_OUTPUT, &chip->reg_output); 168 if (error) 169 return error; 170 171 error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction); 172 if (error) 173 return error; 174 175 /* ensure that keypad pins are set to input */ 176 error = tca6416_write_reg(chip, TCA6416_DIRECTION, 177 chip->reg_direction | chip->pinmask); 178 if (error) 179 return error; 180 181 error = tca6416_read_reg(chip, TCA6416_DIRECTION, &chip->reg_direction); 182 if (error) 183 return error; 184 185 error = tca6416_read_reg(chip, TCA6416_INPUT, &chip->reg_input); 186 if (error) 187 return error; 188 189 chip->reg_input &= chip->pinmask; 190 191 return 0; 192} 193 194static int __devinit tca6416_keypad_probe(struct i2c_client *client, 195 const struct i2c_device_id *id) 196{ 197 struct tca6416_keys_platform_data *pdata; 198 struct tca6416_keypad_chip *chip; 199 struct input_dev *input; 200 int error; 201 int i; 202 203 /* Check functionality */ 204 if (!i2c_check_functionality(client->adapter, I2C_FUNC_SMBUS_BYTE)) { 205 dev_err(&client->dev, "%s adapter not supported\n", 206 dev_driver_string(&client->adapter->dev)); 207 return -ENODEV; 208 } 209 210 pdata = client->dev.platform_data; 211 if (!pdata) { 212 dev_dbg(&client->dev, "no platform data\n"); 213 return -EINVAL; 214 } 215 216 chip = kzalloc(sizeof(struct tca6416_keypad_chip) + 217 pdata->nbuttons * sizeof(struct tca6416_button), 218 GFP_KERNEL); 219 input = input_allocate_device(); 220 if (!chip || !input) { 221 error = -ENOMEM; 222 goto fail1; 223 } 224 225 chip->client = client; 226 chip->input = input; 227 chip->pinmask = pdata->pinmask; 228 chip->use_polling = pdata->use_polling; 229 230 INIT_DELAYED_WORK(&chip->dwork, tca6416_keys_work_func); 231 232 input->phys = "tca6416-keys/input0"; 233 input->name = client->name; 234 input->dev.parent = &client->dev; 235 236 input->open = tca6416_keys_open; 237 input->close = tca6416_keys_close; 238 239 input->id.bustype = BUS_HOST; 240 input->id.vendor = 0x0001; 241 input->id.product = 0x0001; 242 input->id.version = 0x0100; 243 244 /* Enable auto repeat feature of Linux input subsystem */ 245 if (pdata->rep) 246 __set_bit(EV_REP, input->evbit); 247 248 for (i = 0; i < pdata->nbuttons; i++) { 249 unsigned int type; 250 251 chip->buttons[i] = pdata->buttons[i]; 252 type = (pdata->buttons[i].type) ?: EV_KEY; 253 input_set_capability(input, type, pdata->buttons[i].code); 254 } 255 256 input_set_drvdata(input, chip); 257 258 /* 259 * Initialize cached registers from their original values. 260 * we can't share this chip with another i2c master. 261 */ 262 error = tca6416_setup_registers(chip); 263 if (error) 264 goto fail1; 265 266 if (!chip->use_polling) { 267 if (pdata->irq_is_gpio) 268 chip->irqnum = gpio_to_irq(client->irq); 269 else 270 chip->irqnum = client->irq; 271 272 error = request_threaded_irq(chip->irqnum, NULL, 273 tca6416_keys_isr, 274 IRQF_TRIGGER_FALLING, 275 "tca6416-keypad", chip); 276 if (error) { 277 dev_dbg(&client->dev, 278 "Unable to claim irq %d; error %d\n", 279 chip->irqnum, error); 280 goto fail1; 281 } 282 disable_irq(chip->irqnum); 283 } 284 285 error = input_register_device(input); 286 if (error) { 287 dev_dbg(&client->dev, 288 "Unable to register input device, error: %d\n", error); 289 goto fail2; 290 } 291 292 i2c_set_clientdata(client, chip); 293 294 return 0; 295 296fail2: 297 if (!chip->use_polling) { 298 free_irq(chip->irqnum, chip); 299 enable_irq(chip->irqnum); 300 } 301fail1: 302 input_free_device(input); 303 kfree(chip); 304 return error; 305} 306 307static int __devexit tca6416_keypad_remove(struct i2c_client *client) 308{ 309 struct tca6416_keypad_chip *chip = i2c_get_clientdata(client); 310 311 if (!chip->use_polling) { 312 free_irq(chip->irqnum, chip); 313 enable_irq(chip->irqnum); 314 } 315 316 input_unregister_device(chip->input); 317 kfree(chip); 318 319 return 0; 320} 321 322 323static struct i2c_driver tca6416_keypad_driver = { 324 .driver = { 325 .name = "tca6416-keypad", 326 }, 327 .probe = tca6416_keypad_probe, 328 .remove = __devexit_p(tca6416_keypad_remove), 329 .id_table = tca6416_id, 330}; 331 332static int __init tca6416_keypad_init(void) 333{ 334 return i2c_add_driver(&tca6416_keypad_driver); 335} 336 337subsys_initcall(tca6416_keypad_init); 338 339static void __exit tca6416_keypad_exit(void) 340{ 341 i2c_del_driver(&tca6416_keypad_driver); 342} 343module_exit(tca6416_keypad_exit); 344 345MODULE_AUTHOR("Sriramakrishnan <srk@ti.com>"); 346MODULE_DESCRIPTION("Keypad driver over tca6146 IO expander"); 347MODULE_LICENSE("GPL"); 348