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