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 const int ad7791_sample_freq_avail[8][2] = { 157 [AD7791_FILTER_RATE_120] = { 120, 0 }, 158 [AD7791_FILTER_RATE_100] = { 100, 0 }, 159 [AD7791_FILTER_RATE_33_3] = { 33, 300000 }, 160 [AD7791_FILTER_RATE_20] = { 20, 0 }, 161 [AD7791_FILTER_RATE_16_6] = { 16, 600000 }, 162 [AD7791_FILTER_RATE_16_7] = { 16, 700000 }, 163 [AD7791_FILTER_RATE_13_3] = { 13, 300000 }, 164 [AD7791_FILTER_RATE_9_5] = { 9, 500000 }, 165 }; 166 167 static struct ad7791_state *ad_sigma_delta_to_ad7791(struct ad_sigma_delta *sd) 168 { 169 return container_of(sd, struct ad7791_state, sd); 170 } 171 172 static int ad7791_set_channel(struct ad_sigma_delta *sd, unsigned int channel) 173 { 174 ad_sd_set_comm(sd, channel); 175 176 return 0; 177 } 178 179 static int ad7791_set_mode(struct ad_sigma_delta *sd, 180 enum ad_sigma_delta_mode mode) 181 { 182 struct ad7791_state *st = ad_sigma_delta_to_ad7791(sd); 183 184 switch (mode) { 185 case AD_SD_MODE_CONTINUOUS: 186 mode = AD7791_MODE_CONTINUOUS; 187 break; 188 case AD_SD_MODE_SINGLE: 189 mode = AD7791_MODE_SINGLE; 190 break; 191 case AD_SD_MODE_IDLE: 192 case AD_SD_MODE_POWERDOWN: 193 mode = AD7791_MODE_POWERDOWN; 194 break; 195 } 196 197 st->mode &= ~AD7791_MODE_SEL_MASK; 198 st->mode |= AD7791_MODE_SEL(mode); 199 200 return ad_sd_write_reg(sd, AD7791_REG_MODE, sizeof(st->mode), st->mode); 201 } 202 203 static const struct ad_sigma_delta_info ad7791_sigma_delta_info = { 204 .set_channel = ad7791_set_channel, 205 .set_mode = ad7791_set_mode, 206 .has_registers = true, 207 .addr_shift = 4, 208 .read_mask = BIT(3), 209 }; 210 211 static int ad7791_read_raw(struct iio_dev *indio_dev, 212 const struct iio_chan_spec *chan, int *val, int *val2, long info) 213 { 214 struct ad7791_state *st = iio_priv(indio_dev); 215 bool unipolar = !!(st->mode & AD7791_MODE_UNIPOLAR); 216 unsigned int rate; 217 218 switch (info) { 219 case IIO_CHAN_INFO_RAW: 220 return ad_sigma_delta_single_conversion(indio_dev, chan, val); 221 case IIO_CHAN_INFO_OFFSET: 222 /** 223 * Unipolar: 0 to VREF 224 * Bipolar -VREF to VREF 225 **/ 226 if (unipolar) 227 *val = 0; 228 else 229 *val = -(1 << (chan->scan_type.realbits - 1)); 230 return IIO_VAL_INT; 231 case IIO_CHAN_INFO_SCALE: 232 /* The monitor channel uses an internal reference. */ 233 if (chan->address == AD7791_CH_AVDD_MONITOR) { 234 /* 235 * The signal is attenuated by a factor of 5 and 236 * compared against a 1.17V internal reference. 237 */ 238 *val = 1170 * 5; 239 } else { 240 int voltage_uv; 241 242 voltage_uv = regulator_get_voltage(st->reg); 243 if (voltage_uv < 0) 244 return voltage_uv; 245 246 *val = voltage_uv / 1000; 247 } 248 if (unipolar) 249 *val2 = chan->scan_type.realbits; 250 else 251 *val2 = chan->scan_type.realbits - 1; 252 253 return IIO_VAL_FRACTIONAL_LOG2; 254 case IIO_CHAN_INFO_SAMP_FREQ: 255 rate = st->filter & AD7791_FILTER_RATE_MASK; 256 *val = ad7791_sample_freq_avail[rate][0]; 257 *val2 = ad7791_sample_freq_avail[rate][1]; 258 return IIO_VAL_INT_PLUS_MICRO; 259 } 260 261 return -EINVAL; 262 } 263 264 static int ad7791_write_raw(struct iio_dev *indio_dev, 265 struct iio_chan_spec const *chan, int val, int val2, long mask) 266 { 267 struct ad7791_state *st = iio_priv(indio_dev); 268 int ret, i; 269 270 ret = iio_device_claim_direct_mode(indio_dev); 271 if (ret) 272 return ret; 273 274 switch (mask) { 275 case IIO_CHAN_INFO_SAMP_FREQ: 276 for (i = 0; i < ARRAY_SIZE(ad7791_sample_freq_avail); i++) { 277 if (ad7791_sample_freq_avail[i][0] == val && 278 ad7791_sample_freq_avail[i][1] == val2) 279 break; 280 } 281 282 if (i == ARRAY_SIZE(ad7791_sample_freq_avail)) { 283 ret = -EINVAL; 284 break; 285 } 286 287 st->filter &= ~AD7791_FILTER_RATE_MASK; 288 st->filter |= i; 289 ad_sd_write_reg(&st->sd, AD7791_REG_FILTER, 290 sizeof(st->filter), 291 st->filter); 292 break; 293 default: 294 ret = -EINVAL; 295 } 296 297 iio_device_release_direct_mode(indio_dev); 298 return ret; 299 } 300 301 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("120 100 33.3 20 16.7 16.6 13.3 9.5"); 302 303 static struct attribute *ad7791_attributes[] = { 304 &iio_const_attr_sampling_frequency_available.dev_attr.attr, 305 NULL 306 }; 307 308 static const struct attribute_group ad7791_attribute_group = { 309 .attrs = ad7791_attributes, 310 }; 311 312 static const struct iio_info ad7791_info = { 313 .read_raw = &ad7791_read_raw, 314 .write_raw = &ad7791_write_raw, 315 .attrs = &ad7791_attribute_group, 316 .validate_trigger = ad_sd_validate_trigger, 317 }; 318 319 static const struct iio_info ad7791_no_filter_info = { 320 .read_raw = &ad7791_read_raw, 321 .write_raw = &ad7791_write_raw, 322 .validate_trigger = ad_sd_validate_trigger, 323 }; 324 325 static int ad7791_setup(struct ad7791_state *st, 326 struct ad7791_platform_data *pdata) 327 { 328 /* Set to poweron-reset default values */ 329 st->mode = AD7791_MODE_BUFFER; 330 st->filter = AD7791_FILTER_RATE_16_6; 331 332 if (!pdata) 333 return 0; 334 335 if ((st->info->flags & AD7791_FLAG_HAS_BUFFER) && !pdata->buffered) 336 st->mode &= ~AD7791_MODE_BUFFER; 337 338 if ((st->info->flags & AD7791_FLAG_HAS_BURNOUT) && 339 pdata->burnout_current) 340 st->mode |= AD7791_MODE_BURNOUT; 341 342 if ((st->info->flags & AD7791_FLAG_HAS_UNIPOLAR) && pdata->unipolar) 343 st->mode |= AD7791_MODE_UNIPOLAR; 344 345 return ad_sd_write_reg(&st->sd, AD7791_REG_MODE, sizeof(st->mode), 346 st->mode); 347 } 348 349 static int ad7791_probe(struct spi_device *spi) 350 { 351 struct ad7791_platform_data *pdata = spi->dev.platform_data; 352 struct iio_dev *indio_dev; 353 struct ad7791_state *st; 354 int ret; 355 356 if (!spi->irq) { 357 dev_err(&spi->dev, "Missing IRQ.\n"); 358 return -ENXIO; 359 } 360 361 indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 362 if (!indio_dev) 363 return -ENOMEM; 364 365 st = iio_priv(indio_dev); 366 367 st->reg = devm_regulator_get(&spi->dev, "refin"); 368 if (IS_ERR(st->reg)) 369 return PTR_ERR(st->reg); 370 371 ret = regulator_enable(st->reg); 372 if (ret) 373 return ret; 374 375 st->info = &ad7791_chip_infos[spi_get_device_id(spi)->driver_data]; 376 ad_sd_init(&st->sd, indio_dev, spi, &ad7791_sigma_delta_info); 377 378 spi_set_drvdata(spi, indio_dev); 379 380 indio_dev->dev.parent = &spi->dev; 381 indio_dev->dev.of_node = spi->dev.of_node; 382 indio_dev->name = spi_get_device_id(spi)->name; 383 indio_dev->modes = INDIO_DIRECT_MODE; 384 indio_dev->channels = st->info->channels; 385 indio_dev->num_channels = st->info->num_channels; 386 if (st->info->flags & AD7791_FLAG_HAS_FILTER) 387 indio_dev->info = &ad7791_info; 388 else 389 indio_dev->info = &ad7791_no_filter_info; 390 391 ret = ad_sd_setup_buffer_and_trigger(indio_dev); 392 if (ret) 393 goto error_disable_reg; 394 395 ret = ad7791_setup(st, pdata); 396 if (ret) 397 goto error_remove_trigger; 398 399 ret = iio_device_register(indio_dev); 400 if (ret) 401 goto error_remove_trigger; 402 403 return 0; 404 405 error_remove_trigger: 406 ad_sd_cleanup_buffer_and_trigger(indio_dev); 407 error_disable_reg: 408 regulator_disable(st->reg); 409 410 return ret; 411 } 412 413 static int ad7791_remove(struct spi_device *spi) 414 { 415 struct iio_dev *indio_dev = spi_get_drvdata(spi); 416 struct ad7791_state *st = iio_priv(indio_dev); 417 418 iio_device_unregister(indio_dev); 419 ad_sd_cleanup_buffer_and_trigger(indio_dev); 420 421 regulator_disable(st->reg); 422 423 return 0; 424 } 425 426 static const struct spi_device_id ad7791_spi_ids[] = { 427 { "ad7787", AD7787 }, 428 { "ad7788", AD7788 }, 429 { "ad7789", AD7789 }, 430 { "ad7790", AD7790 }, 431 { "ad7791", AD7791 }, 432 {} 433 }; 434 MODULE_DEVICE_TABLE(spi, ad7791_spi_ids); 435 436 static struct spi_driver ad7791_driver = { 437 .driver = { 438 .name = "ad7791", 439 }, 440 .probe = ad7791_probe, 441 .remove = ad7791_remove, 442 .id_table = ad7791_spi_ids, 443 }; 444 module_spi_driver(ad7791_driver); 445 446 MODULE_AUTHOR("Lars-Peter Clausen <lars@metafoo.de>"); 447 MODULE_DESCRIPTION("Analog Device AD7787/AD7788/AD7789/AD7790/AD7791 ADC driver"); 448 MODULE_LICENSE("GPL v2"); 449