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, ®_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"); 313