1 /* 2 * Copyright (C) 2013 Capella Microsystems Inc. 3 * Author: Kevin Tsai <ktsai@capellamicro.com> 4 * 5 * This program is free software; you can redistribute it and/or modify it 6 * under the terms of the GNU General Public License version 2, as published 7 * by the Free Software Foundation. 8 */ 9 10 #include <linux/delay.h> 11 #include <linux/err.h> 12 #include <linux/i2c.h> 13 #include <linux/mutex.h> 14 #include <linux/module.h> 15 #include <linux/interrupt.h> 16 #include <linux/regulator/consumer.h> 17 #include <linux/iio/iio.h> 18 #include <linux/iio/sysfs.h> 19 #include <linux/iio/events.h> 20 #include <linux/init.h> 21 22 /* Registers Address */ 23 #define CM32181_REG_ADDR_CMD 0x00 24 #define CM32181_REG_ADDR_ALS 0x04 25 #define CM32181_REG_ADDR_STATUS 0x06 26 #define CM32181_REG_ADDR_ID 0x07 27 28 /* Number of Configurable Registers */ 29 #define CM32181_CONF_REG_NUM 0x01 30 31 /* CMD register */ 32 #define CM32181_CMD_ALS_ENABLE 0x00 33 #define CM32181_CMD_ALS_DISABLE 0x01 34 #define CM32181_CMD_ALS_INT_EN 0x02 35 36 #define CM32181_CMD_ALS_IT_SHIFT 6 37 #define CM32181_CMD_ALS_IT_MASK (0x0F << CM32181_CMD_ALS_IT_SHIFT) 38 #define CM32181_CMD_ALS_IT_DEFAULT (0x00 << CM32181_CMD_ALS_IT_SHIFT) 39 40 #define CM32181_CMD_ALS_SM_SHIFT 11 41 #define CM32181_CMD_ALS_SM_MASK (0x03 << CM32181_CMD_ALS_SM_SHIFT) 42 #define CM32181_CMD_ALS_SM_DEFAULT (0x01 << CM32181_CMD_ALS_SM_SHIFT) 43 44 #define CM32181_MLUX_PER_BIT 5 /* ALS_SM=01 IT=800ms */ 45 #define CM32181_MLUX_PER_BIT_BASE_IT 800000 /* Based on IT=800ms */ 46 #define CM32181_CALIBSCALE_DEFAULT 1000 47 #define CM32181_CALIBSCALE_RESOLUTION 1000 48 #define MLUX_PER_LUX 1000 49 50 static const u8 cm32181_reg[CM32181_CONF_REG_NUM] = { 51 CM32181_REG_ADDR_CMD, 52 }; 53 54 static const int als_it_bits[] = {12, 8, 0, 1, 2, 3}; 55 static const int als_it_value[] = {25000, 50000, 100000, 200000, 400000, 56 800000}; 57 58 struct cm32181_chip { 59 struct i2c_client *client; 60 struct mutex lock; 61 u16 conf_regs[CM32181_CONF_REG_NUM]; 62 int calibscale; 63 }; 64 65 /** 66 * cm32181_reg_init() - Initialize CM32181 registers 67 * @cm32181: pointer of struct cm32181. 68 * 69 * Initialize CM32181 ambient light sensor register to default values. 70 * 71 * Return: 0 for success; otherwise for error code. 72 */ 73 static int cm32181_reg_init(struct cm32181_chip *cm32181) 74 { 75 struct i2c_client *client = cm32181->client; 76 int i; 77 s32 ret; 78 79 ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ID); 80 if (ret < 0) 81 return ret; 82 83 /* check device ID */ 84 if ((ret & 0xFF) != 0x81) 85 return -ENODEV; 86 87 /* Default Values */ 88 cm32181->conf_regs[CM32181_REG_ADDR_CMD] = CM32181_CMD_ALS_ENABLE | 89 CM32181_CMD_ALS_IT_DEFAULT | CM32181_CMD_ALS_SM_DEFAULT; 90 cm32181->calibscale = CM32181_CALIBSCALE_DEFAULT; 91 92 /* Initialize registers*/ 93 for (i = 0; i < CM32181_CONF_REG_NUM; i++) { 94 ret = i2c_smbus_write_word_data(client, cm32181_reg[i], 95 cm32181->conf_regs[i]); 96 if (ret < 0) 97 return ret; 98 } 99 100 return 0; 101 } 102 103 /** 104 * cm32181_read_als_it() - Get sensor integration time (ms) 105 * @cm32181: pointer of struct cm32181 106 * @val2: pointer of int to load the als_it value. 107 * 108 * Report the current integartion time by millisecond. 109 * 110 * Return: IIO_VAL_INT_PLUS_MICRO for success, otherwise -EINVAL. 111 */ 112 static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val2) 113 { 114 u16 als_it; 115 int i; 116 117 als_it = cm32181->conf_regs[CM32181_REG_ADDR_CMD]; 118 als_it &= CM32181_CMD_ALS_IT_MASK; 119 als_it >>= CM32181_CMD_ALS_IT_SHIFT; 120 for (i = 0; i < ARRAY_SIZE(als_it_bits); i++) { 121 if (als_it == als_it_bits[i]) { 122 *val2 = als_it_value[i]; 123 return IIO_VAL_INT_PLUS_MICRO; 124 } 125 } 126 127 return -EINVAL; 128 } 129 130 /** 131 * cm32181_write_als_it() - Write sensor integration time 132 * @cm32181: pointer of struct cm32181. 133 * @val: integration time by millisecond. 134 * 135 * Convert integration time (ms) to sensor value. 136 * 137 * Return: i2c_smbus_write_word_data command return value. 138 */ 139 static int cm32181_write_als_it(struct cm32181_chip *cm32181, int val) 140 { 141 struct i2c_client *client = cm32181->client; 142 u16 als_it; 143 int ret, i, n; 144 145 n = ARRAY_SIZE(als_it_value); 146 for (i = 0; i < n; i++) 147 if (val <= als_it_value[i]) 148 break; 149 if (i >= n) 150 i = n - 1; 151 152 als_it = als_it_bits[i]; 153 als_it <<= CM32181_CMD_ALS_IT_SHIFT; 154 155 mutex_lock(&cm32181->lock); 156 cm32181->conf_regs[CM32181_REG_ADDR_CMD] &= 157 ~CM32181_CMD_ALS_IT_MASK; 158 cm32181->conf_regs[CM32181_REG_ADDR_CMD] |= 159 als_it; 160 ret = i2c_smbus_write_word_data(client, CM32181_REG_ADDR_CMD, 161 cm32181->conf_regs[CM32181_REG_ADDR_CMD]); 162 mutex_unlock(&cm32181->lock); 163 164 return ret; 165 } 166 167 /** 168 * cm32181_get_lux() - report current lux value 169 * @cm32181: pointer of struct cm32181. 170 * 171 * Convert sensor raw data to lux. It depends on integration 172 * time and calibscale variable. 173 * 174 * Return: Positive value is lux, otherwise is error code. 175 */ 176 static int cm32181_get_lux(struct cm32181_chip *cm32181) 177 { 178 struct i2c_client *client = cm32181->client; 179 int ret; 180 int als_it; 181 unsigned long lux; 182 183 ret = cm32181_read_als_it(cm32181, &als_it); 184 if (ret < 0) 185 return -EINVAL; 186 187 lux = CM32181_MLUX_PER_BIT; 188 lux *= CM32181_MLUX_PER_BIT_BASE_IT; 189 lux /= als_it; 190 191 ret = i2c_smbus_read_word_data(client, CM32181_REG_ADDR_ALS); 192 if (ret < 0) 193 return ret; 194 195 lux *= ret; 196 lux *= cm32181->calibscale; 197 lux /= CM32181_CALIBSCALE_RESOLUTION; 198 lux /= MLUX_PER_LUX; 199 200 if (lux > 0xFFFF) 201 lux = 0xFFFF; 202 203 return lux; 204 } 205 206 static int cm32181_read_raw(struct iio_dev *indio_dev, 207 struct iio_chan_spec const *chan, 208 int *val, int *val2, long mask) 209 { 210 struct cm32181_chip *cm32181 = iio_priv(indio_dev); 211 int ret; 212 213 switch (mask) { 214 case IIO_CHAN_INFO_PROCESSED: 215 ret = cm32181_get_lux(cm32181); 216 if (ret < 0) 217 return ret; 218 *val = ret; 219 return IIO_VAL_INT; 220 case IIO_CHAN_INFO_CALIBSCALE: 221 *val = cm32181->calibscale; 222 return IIO_VAL_INT; 223 case IIO_CHAN_INFO_INT_TIME: 224 *val = 0; 225 ret = cm32181_read_als_it(cm32181, val2); 226 return ret; 227 } 228 229 return -EINVAL; 230 } 231 232 static int cm32181_write_raw(struct iio_dev *indio_dev, 233 struct iio_chan_spec const *chan, 234 int val, int val2, long mask) 235 { 236 struct cm32181_chip *cm32181 = iio_priv(indio_dev); 237 int ret; 238 239 switch (mask) { 240 case IIO_CHAN_INFO_CALIBSCALE: 241 cm32181->calibscale = val; 242 return val; 243 case IIO_CHAN_INFO_INT_TIME: 244 ret = cm32181_write_als_it(cm32181, val2); 245 return ret; 246 } 247 248 return -EINVAL; 249 } 250 251 /** 252 * cm32181_get_it_available() - Get available ALS IT value 253 * @dev: pointer of struct device. 254 * @attr: pointer of struct device_attribute. 255 * @buf: pointer of return string buffer. 256 * 257 * Display the available integration time values by millisecond. 258 * 259 * Return: string length. 260 */ 261 static ssize_t cm32181_get_it_available(struct device *dev, 262 struct device_attribute *attr, char *buf) 263 { 264 int i, n, len; 265 266 n = ARRAY_SIZE(als_it_value); 267 for (i = 0, len = 0; i < n; i++) 268 len += sprintf(buf + len, "0.%06u ", als_it_value[i]); 269 return len + sprintf(buf + len, "\n"); 270 } 271 272 static const struct iio_chan_spec cm32181_channels[] = { 273 { 274 .type = IIO_LIGHT, 275 .info_mask_separate = 276 BIT(IIO_CHAN_INFO_PROCESSED) | 277 BIT(IIO_CHAN_INFO_CALIBSCALE) | 278 BIT(IIO_CHAN_INFO_INT_TIME), 279 } 280 }; 281 282 static IIO_DEVICE_ATTR(in_illuminance_integration_time_available, 283 S_IRUGO, cm32181_get_it_available, NULL, 0); 284 285 static struct attribute *cm32181_attributes[] = { 286 &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr, 287 NULL, 288 }; 289 290 static const struct attribute_group cm32181_attribute_group = { 291 .attrs = cm32181_attributes 292 }; 293 294 static const struct iio_info cm32181_info = { 295 .read_raw = &cm32181_read_raw, 296 .write_raw = &cm32181_write_raw, 297 .attrs = &cm32181_attribute_group, 298 }; 299 300 static int cm32181_probe(struct i2c_client *client, 301 const struct i2c_device_id *id) 302 { 303 struct cm32181_chip *cm32181; 304 struct iio_dev *indio_dev; 305 int ret; 306 307 indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*cm32181)); 308 if (!indio_dev) { 309 dev_err(&client->dev, "devm_iio_device_alloc failed\n"); 310 return -ENOMEM; 311 } 312 313 cm32181 = iio_priv(indio_dev); 314 i2c_set_clientdata(client, indio_dev); 315 cm32181->client = client; 316 317 mutex_init(&cm32181->lock); 318 indio_dev->dev.parent = &client->dev; 319 indio_dev->channels = cm32181_channels; 320 indio_dev->num_channels = ARRAY_SIZE(cm32181_channels); 321 indio_dev->info = &cm32181_info; 322 indio_dev->name = id->name; 323 indio_dev->modes = INDIO_DIRECT_MODE; 324 325 ret = cm32181_reg_init(cm32181); 326 if (ret) { 327 dev_err(&client->dev, 328 "%s: register init failed\n", 329 __func__); 330 return ret; 331 } 332 333 ret = devm_iio_device_register(&client->dev, indio_dev); 334 if (ret) { 335 dev_err(&client->dev, 336 "%s: regist device failed\n", 337 __func__); 338 return ret; 339 } 340 341 return 0; 342 } 343 344 static const struct i2c_device_id cm32181_id[] = { 345 { "cm32181", 0 }, 346 { } 347 }; 348 349 MODULE_DEVICE_TABLE(i2c, cm32181_id); 350 351 static const struct of_device_id cm32181_of_match[] = { 352 { .compatible = "capella,cm32181" }, 353 { } 354 }; 355 MODULE_DEVICE_TABLE(of, cm32181_of_match); 356 357 static struct i2c_driver cm32181_driver = { 358 .driver = { 359 .name = "cm32181", 360 .of_match_table = of_match_ptr(cm32181_of_match), 361 }, 362 .id_table = cm32181_id, 363 .probe = cm32181_probe, 364 }; 365 366 module_i2c_driver(cm32181_driver); 367 368 MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>"); 369 MODULE_DESCRIPTION("CM32181 ambient light sensor driver"); 370 MODULE_LICENSE("GPL"); 371