1 /* 2 * AD7787/AD7788/AD7789/AD7790/AD7791 SPI ADC driver 3 * 4 * Copyright 2012 Analog Devices Inc. 5 * Author: Lars-Peter Clausen <lars@metafoo.de> 6 * 7 * Licensed under the GPL-2. 8 */ 9 10 #include <linux/interrupt.h> 11 #include <linux/device.h> 12 #include <linux/kernel.h> 13 #include <linux/slab.h> 14 #include <linux/sysfs.h> 15 #include <linux/spi/spi.h> 16 #include <linux/regulator/consumer.h> 17 #include <linux/err.h> 18 #include <linux/sched.h> 19 #include <linux/delay.h> 20 #include <linux/module.h> 21 22 #include <linux/iio/iio.h> 23 #include <linux/iio/sysfs.h> 24 #include <linux/iio/buffer.h> 25 #include <linux/iio/trigger.h> 26 #include <linux/iio/trigger_consumer.h> 27 #include <linux/iio/triggered_buffer.h> 28 #include <linux/iio/adc/ad_sigma_delta.h> 29 30 #include <linux/platform_data/ad7791.h> 31 32 #define AD7791_REG_COMM 0x0 /* For writes */ 33 #define AD7791_REG_STATUS 0x0 /* For reads */ 34 #define AD7791_REG_MODE 0x1 35 #define AD7791_REG_FILTER 0x2 36 #define AD7791_REG_DATA 0x3 37 38 #define AD7791_MODE_CONTINUOUS 0x00 39 #define AD7791_MODE_SINGLE 0x02 40 #define AD7791_MODE_POWERDOWN 0x03 41 42 #define AD7791_CH_AIN1P_AIN1N 0x00 43 #define AD7791_CH_AIN2 0x01 44 #define AD7791_CH_AIN1N_AIN1N 0x02 45 #define AD7791_CH_AVDD_MONITOR 0x03 46 47 #define AD7791_FILTER_CLK_DIV_1 (0x0 << 4) 48 #define AD7791_FILTER_CLK_DIV_2 (0x1 << 4) 49 #define AD7791_FILTER_CLK_DIV_4 (0x2 << 4) 50 #define AD7791_FILTER_CLK_DIV_8 (0x3 << 4) 51 #define AD7791_FILTER_CLK_MASK (0x3 << 4) 52 #define AD7791_FILTER_RATE_120 0x0 53 #define AD7791_FILTER_RATE_100 0x1 54 #define AD7791_FILTER_RATE_33_3 0x2 55 #define AD7791_FILTER_RATE_20 0x3 56 #define AD7791_FILTER_RATE_16_6 0x4 57 #define AD7791_FILTER_RATE_16_7 0x5 58 #define AD7791_FILTER_RATE_13_3 0x6 59 #define AD7791_FILTER_RATE_9_5 0x7 60 #define AD7791_FILTER_RATE_MASK 0x7 61 62 #define AD7791_MODE_BUFFER BIT(1) 63 #define AD7791_MODE_UNIPOLAR BIT(2) 64 #define AD7791_MODE_BURNOUT BIT(3) 65 #define AD7791_MODE_SEL_MASK (0x3 << 6) 66 #define AD7791_MODE_SEL(x) ((x) << 6) 67 68 #define DECLARE_AD7787_CHANNELS(name, bits, storagebits) \ 69 const struct iio_chan_spec name[] = { \ 70 AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \ 71 (bits), (storagebits), 0), \ 72 AD_SD_CHANNEL(1, 1, AD7791_CH_AIN2, (bits), (storagebits), 0), \ 73 AD_SD_SHORTED_CHANNEL(2, 0, AD7791_CH_AIN1N_AIN1N, \ 74 (bits), (storagebits), 0), \ 75 AD_SD_SUPPLY_CHANNEL(3, 2, AD7791_CH_AVDD_MONITOR, \ 76 (bits), (storagebits), 0), \ 77 IIO_CHAN_SOFT_TIMESTAMP(4), \ 78 } 79 80 #define DECLARE_AD7791_CHANNELS(name, bits, storagebits) \ 81 const struct iio_chan_spec name[] = { \ 82 AD_SD_DIFF_CHANNEL(0, 0, 0, AD7791_CH_AIN1P_AIN1N, \ 83 (bits), (storagebits), 0), \ 84 AD_SD_SHORTED_CHANNEL(1, 0, AD7791_CH_AIN1N_AIN1N, \ 85 (bits), (storagebits), 0), \ 86 AD_SD_SUPPLY_CHANNEL(2, 1, AD7791_CH_AVDD_MONITOR, \ 87 (bits), (storagebits), 0), \ 88 IIO_CHAN_SOFT_TIMESTAMP(3), \ 89 } 90 91 static DECLARE_AD7787_CHANNELS(ad7787_channels, 24, 32); 92 static DECLARE_AD7791_CHANNELS(ad7790_channels, 16, 16); 93 static DECLARE_AD7791_CHANNELS(ad7791_channels, 24, 32); 94 95 enum { 96 AD7787, 97 AD7788, 98 AD7789, 99 AD7790, 100 AD7791, 101 }; 102 103 enum ad7791_chip_info_flags { 104 AD7791_FLAG_HAS_FILTER = (1 << 0), 105 AD7791_FLAG_HAS_BUFFER = (1 << 1), 106 AD7791_FLAG_HAS_UNIPOLAR = (1 << 2), 107 AD7791_FLAG_HAS_BURNOUT = (1 << 3), 108 }; 109 110 struct ad7791_chip_info { 111 const struct iio_chan_spec *channels; 112 unsigned int num_channels; 113 enum ad7791_chip_info_flags flags; 114 }; 115 116 static const struct ad7791_chip_info ad7791_chip_infos[] = { 117 [AD7787] = { 118 .channels = ad7787_channels, 119 .num_channels = ARRAY_SIZE(ad7787_channels), 120 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER | 121 AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT, 122 }, 123 [AD7788] = { 124 .channels = ad7790_channels, 125 .num_channels = ARRAY_SIZE(ad7790_channels), 126 .flags = AD7791_FLAG_HAS_UNIPOLAR, 127 }, 128 [AD7789] = { 129 .channels = ad7791_channels, 130 .num_channels = ARRAY_SIZE(ad7791_channels), 131 .flags = AD7791_FLAG_HAS_UNIPOLAR, 132 }, 133 [AD7790] = { 134 .channels = ad7790_channels, 135 .num_channels = ARRAY_SIZE(ad7790_channels), 136 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER | 137 AD7791_FLAG_HAS_BURNOUT, 138 }, 139 [AD7791] = { 140 .channels = ad7791_channels, 141 .num_channels = ARRAY_SIZE(ad7791_channels), 142 .flags = AD7791_FLAG_HAS_FILTER | AD7791_FLAG_HAS_BUFFER | 143 AD7791_FLAG_HAS_UNIPOLAR | AD7791_FLAG_HAS_BURNOUT, 144 }, 145 }; 146 147 struct ad7791_state { 148 struct ad_sigma_delta sd; 149 uint8_t mode; 150 uint8_t filter; 151 152 struct regulator *reg; 153 const struct ad7791_chip_info *info; 154 }; 155 156 static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd) 157 { 158 return container_of(sd, struct ad7791_state, sd); 159 } 160 161 static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel) 162 { 163 ad_sd_set_comm(sd, channel); 164 165 return 0; 166 } 167 168 static int ad7791_set_mode(struct ad_sigma_delta *sd, 169 enum ad_sigma_delta_mode mode) 170 { 171 struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd); 172 173 switch (mode) { 174 case AD_SD_MODE_CONTINUOUS: 175 mode = AD7791_MODE_CONTINUOUS; 176 break; 177 case AD_SD_MODE_SINGLE: 178 mode = AD7791_MODE_SINGLE; 179 break; 180 case AD_SD_MODE_IDLE: 181 case AD_SD_MODE_POWERDOWN: 182 mode = AD7791_MODE_POWERDOWN; 183 break; 184 } 185 186 st->mode &= ~AD7791_MODE_SEL_MASK; 187 st->mode |= AD7791_MODE_SEL(mode); 188 189 return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode); 190 } 191 192 static const struct ad_sigma_delta_info ad7791_sigma_delta_info = { 193 .set_channel = ad7791_set_channel, 194 .set_mode = ad7791_set_mode, 195 .has_registers = true, 196 .addr_shift = 4, 197 .read_mask = BIT(3), 198 }; 199 200 static int ad7791_read_raw(struct iio_dev *indio_dev, 201 const struct iio_chan_spec *chan, int *val, int *val2, long info) 202 { 203 struct ad7791_state *st = iio_priv(indio_dev); 204 bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR); 205 206 switch (info) { 207 case IIO_CHAN_INFO_RAW: 208 return ad_sigma_delta_single_conversion(indio_dev, chan, val); 209 case IIO_CHAN_INFO_OFFSET: 210 /** 211 * Unipolar: 0 to VREF 212 * Bipolar -VREF to VREF 213 **/ 214 if (unipolar) 215 *val = 0; 216 else 217 *val = -(1 << (chan->scan_type.realbits - 1)); 218 return IIO_VAL_INT; 219 case IIO_CHAN_INFO_SCALE: 220 /* The monitor channel uses an internal reference. */ 221 if (chan->address == AD7791_CH_AVDD_MONITOR) { 222 /* 223 * The signal is attenuated by a factor of 5 and 224 * compared against a 1.17V internal reference. 225 */ 226 *val = 1170 * 5; 227 } else { 228 int voltage_uv; 229 230 voltage_uv = regulator_get_voltage(st->reg); 231 if (voltage_uv < 0) 232 return voltage_uv; 233 234 *val = voltage_uv / 1000; 235 } 236 if (unipolar) 237 *val2 = chan->scan_type.realbits; 238 else 239 *val2 = chan->scan_type.realbits - 1; 240 241 return IIO_VAL_FRACTIONAL_LOG2; 242 } 243 244 return -EINVAL; 245 } 246 247 static const char * const ad7791_sample_freq_avail[] = { 248 [AD7791_FILTER_RATE_120] = "120", 249 [AD7791_FILTER_RATE_100] = "100", 250 [AD7791_FILTER_RATE_33_3] = "33.3", 251 [AD7791_FILTER_RATE_20] = "20", 252 [AD7791_FILTER_RATE_16_6] = "16.6", 253 [AD7791_FILTER_RATE_16_7] = "16.7", 254 [AD7791_FILTER_RATE_13_3] = "13.3", 255 [AD7791_FILTER_RATE_9_5] = "9.5", 256 }; 257 258 static ssize_t ad7791_read_frequency(struct device *dev, 259 struct device_attribute *attr, char *buf) 260 { 261 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 262 struct ad7791_state *st = iio_priv(indio_dev); 263 unsigned int rate = st->filter & AD7791_FILTER_RATE_MASK; 264 265 return sprintf(buf, "%s\n", ad7791_sample_freq_avail[rate]); 266 } 267 268 static ssize_t ad7791_write_frequency(struct device *dev, 269 struct device_attribute *attr, const char *buf, size_t len) 270 { 271 struct iio_dev *indio_dev = dev_to_iio_dev(dev); 272 struct ad7791_state *st = iio_priv(indio_dev); 273 int i, ret; 274 275 i = sysfs_match_string(ad7791_sample_freq_avail, buf); 276 if (i < 0) 277 return i; 278 279 ret = iio_device_claim_direct_mode(indio_dev); 280 if (ret) 281 return ret; 282 st->filter &= ~AD7791_FILTER_RATE_MASK; 283 st->filter |= i; 284 ad_sd_write_reg(&st->sd, AD7791_REG_FILTER, sizeof(st->filter), 285 st->filter); 286 iio_device_release_direct_mode(indio_dev); 287 288 return len; 289 } 290 291 static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO, 292 ad7791_read_frequency, 293 ad7791_write_frequency); 294 295 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5"); 296 297 static struct attribute *ad7791_attributes[] = { 298 &iio_dev_attr_sampling_frequency.dev_attr.attr, 299 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 300 NULL 301 }; 302 303 static const struct attribute_group ad7791_attribute_group = { 304 .attrs = ad7791_attributes, 305 }; 306 307 static const struct iio_info ad7791_info = { 308 .read_raw = &ad7791_read_raw, 309 .attrs = &ad7791_attribute_group, 310 .validate_trigger = ad_sd_validate_trigger, 311 }; 312 313 static const struct iio_info ad7791_no_filter_info = { 314 .read_raw = &ad7791_read_raw, 315 .validate_trigger = ad_sd_validate_trigger, 316 }; 317 318 static int ad7791_setup(struct ad7791_state *st, 319 struct ad7791_platform_data *pdata) 320 { 321 /* Set to poweron-reset default values */ 322 st->mode = AD7791_MODE_BUFFER; 323 st->filter = AD7791_FILTER_RATE_16_6; 324 325 if (!pdata) 326 return 0; 327 328 if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered) 329 st->mode &= ~AD7791_MODE_BUFFER; 330 331 if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) && 332 pdata->burnout_current) 333 st->mode |= AD7791_MODE_BURNOUT; 334 335 if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar) 336 st->mode |= AD7791_MODE_UNIPOLAR; 337 338 return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode), 339 st->mode); 340 } 341 342 static int ad7791_probe(struct spi_device *spi) 343 { 344 struct ad7791_platform_data *pdata = spi->dev.platform_data; 345 struct iio_dev *indio_dev; 346 struct ad7791_state *st; 347 int ret; 348 349 if (!spi->irq) { 350 dev_err(&spi->dev, "Missing IRQ.\n"); 351 return -ENXIO; 352 } 353 354 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 355 if (!indio_dev) 356 return -ENOMEM; 357 358 st = iio_priv(indio_dev); 359 360 st->reg = devm_regulator_get(&spi->dev, "refin"); 361 if (IS_ERR(st->reg)) 362 return PTR_ERR(st->reg); 363 364 ret = regulator_enable(st->reg); 365 if (ret) 366 return ret; 367 368 st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data]; 369 ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info); 370 371 spi_set_drvdata(spi, indio_dev); 372 373 indio_dev->dev.parent = &spi->dev; 374 indio_dev->dev.of_node = spi->dev.of_node; 375 indio_dev->name = spi_get_device_id(spi)->name; 376 indio_dev->modes = INDIO_DIRECT_MODE; 377 indio_dev->channels = st->info->channels; 378 indio_dev->num_channels = st->info->num_channels; 379 if (st->info->flags & AD7791_FLAG_HAS_FILTER) 380 indio_dev->info = &ad7791_info; 381 else 382 indio_dev->info = &ad7791_no_filter_info; 383 384 ret = ad_sd_setup_buffer_and_trigger(indio_dev); 385 if (ret) 386 goto error_disable_reg; 387 388 ret = ad7791_setup(st, pdata); 389 if (ret) 390 goto error_remove_trigger; 391 392 ret = iio_device_register(indio_dev); 393 if (ret) 394 goto error_remove_trigger; 395 396 return 0; 397 398 error_remove_trigger: 399 ad_sd_cleanup_buffer_and_trigger(indio_dev); 400 error_disable_reg: 401 regulator_disable(st->reg); 402 403 return ret; 404 } 405 406 static int ad7791_remove(struct spi_device *spi) 407 { 408 struct iio_dev *indio_dev = spi_get_drvdata(spi); 409 struct ad7791_state *st = iio_priv(indio_dev); 410 411 iio_device_unregister(indio_dev); 412 ad_sd_cleanup_buffer_and_trigger(indio_dev); 413 414 regulator_disable(st->reg); 415 416 return 0; 417 } 418 419 static const struct spi_device_id ad7791_spi_ids[] = { 420 { "ad7787", AD7787 }, 421 { "ad7788", AD7788 }, 422 { "ad7789", AD7789 }, 423 { "ad7790", AD7790 }, 424 { "ad7791", AD7791 }, 425 {} 426 }; 427 MODULE_DEVICE_TABLE(spi, ad7791_spi_ids); 428 429 static struct spi_driver ad7791_driver = { 430 .driver = { 431 .name = "ad7791", 432 }, 433 .probe = ad7791_probe, 434 .remove = ad7791_remove, 435 .id_table = ad7791_spi_ids, 436 }; 437 module_spi_driver(ad7791_driver); 438 439 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 440 MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver"); 441 MODULE_LICENSE("GPL v2"); 442