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, ®_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"); 312