Kevin Tsai | 971672c | 2013-12-24 01:53:00 +0000 | [diff] [blame^] | 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 | * @val: pointer of int to load the als_it value. |
| 107 | * |
| 108 | * Report the current integartion time by millisecond. |
| 109 | * |
| 110 | * Return: IIO_VAL_INT for success, otherwise -EINVAL. |
| 111 | */ |
| 112 | static int cm32181_read_als_it(struct cm32181_chip *cm32181, int *val) |
| 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 | *val = als_it_value[i]; |
| 123 | return IIO_VAL_INT; |
| 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 claibscale 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 | ret = cm32181_read_als_it(cm32181, val); |
| 225 | return ret; |
| 226 | } |
| 227 | |
| 228 | return -EINVAL; |
| 229 | } |
| 230 | |
| 231 | static int cm32181_write_raw(struct iio_dev *indio_dev, |
| 232 | struct iio_chan_spec const *chan, |
| 233 | int val, int val2, long mask) |
| 234 | { |
| 235 | struct cm32181_chip *cm32181 = iio_priv(indio_dev); |
| 236 | int ret; |
| 237 | |
| 238 | switch (mask) { |
| 239 | case IIO_CHAN_INFO_CALIBSCALE: |
| 240 | cm32181->calibscale = val; |
| 241 | return val; |
| 242 | case IIO_CHAN_INFO_INT_TIME: |
| 243 | ret = cm32181_write_als_it(cm32181, val); |
| 244 | return ret; |
| 245 | } |
| 246 | |
| 247 | return -EINVAL; |
| 248 | } |
| 249 | |
| 250 | /** |
| 251 | * cm32181_get_it_available() - Get available ALS IT value |
| 252 | * @dev: pointer of struct device. |
| 253 | * @attr: pointer of struct device_attribute. |
| 254 | * @buf: pointer of return string buffer. |
| 255 | * |
| 256 | * Display the available integration time values by millisecond. |
| 257 | * |
| 258 | * Return: string length. |
| 259 | */ |
| 260 | static ssize_t cm32181_get_it_available(struct device *dev, |
| 261 | struct device_attribute *attr, char *buf) |
| 262 | { |
| 263 | int i, n, len; |
| 264 | |
| 265 | n = ARRAY_SIZE(als_it_value); |
| 266 | for (i = 0, len = 0; i < n; i++) |
| 267 | len += sprintf(buf + len, "%d ", als_it_value[i]); |
| 268 | return len + sprintf(buf + len, "\n"); |
| 269 | } |
| 270 | |
| 271 | static const struct iio_chan_spec cm32181_channels[] = { |
| 272 | { |
| 273 | .type = IIO_LIGHT, |
| 274 | .info_mask_separate = |
| 275 | BIT(IIO_CHAN_INFO_PROCESSED) | |
| 276 | BIT(IIO_CHAN_INFO_CALIBSCALE) | |
| 277 | BIT(IIO_CHAN_INFO_INT_TIME), |
| 278 | } |
| 279 | }; |
| 280 | |
| 281 | static IIO_DEVICE_ATTR(in_illuminance_integration_time_available, |
| 282 | S_IRUGO, cm32181_get_it_available, NULL, 0); |
| 283 | |
| 284 | static struct attribute *cm32181_attributes[] = { |
| 285 | &iio_dev_attr_in_illuminance_integration_time_available.dev_attr.attr, |
| 286 | NULL, |
| 287 | }; |
| 288 | |
| 289 | static const struct attribute_group cm32181_attribute_group = { |
| 290 | .attrs = cm32181_attributes |
| 291 | }; |
| 292 | |
| 293 | static const struct iio_info cm32181_info = { |
| 294 | .driver_module = THIS_MODULE, |
| 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 = iio_device_register(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 int cm32181_remove(struct i2c_client *client) |
| 345 | { |
| 346 | struct iio_dev *indio_dev = i2c_get_clientdata(client); |
| 347 | |
| 348 | iio_device_unregister(indio_dev); |
| 349 | return 0; |
| 350 | } |
| 351 | |
| 352 | static const struct i2c_device_id cm32181_id[] = { |
| 353 | { "cm32181", 0 }, |
| 354 | { } |
| 355 | }; |
| 356 | |
| 357 | MODULE_DEVICE_TABLE(i2c, cm32181_id); |
| 358 | |
| 359 | static const struct of_device_id cm32181_of_match[] = { |
| 360 | { .compatible = "capella,cm32181" }, |
| 361 | { } |
| 362 | }; |
| 363 | |
| 364 | static struct i2c_driver cm32181_driver = { |
| 365 | .driver = { |
| 366 | .name = "cm32181", |
| 367 | .of_match_table = of_match_ptr(cm32181_of_match), |
| 368 | .owner = THIS_MODULE, |
| 369 | }, |
| 370 | .id_table = cm32181_id, |
| 371 | .probe = cm32181_probe, |
| 372 | .remove = cm32181_remove, |
| 373 | }; |
| 374 | |
| 375 | module_i2c_driver(cm32181_driver); |
| 376 | |
| 377 | MODULE_AUTHOR("Kevin Tsai <ktsai@capellamicro.com>"); |
| 378 | MODULE_DESCRIPTION("CM32181 ambient light sensor driver"); |
| 379 | MODULE_LICENSE("GPL"); |