1 /* 2 * AD5721, AD5721R, AD5761, AD5761R, Voltage Output Digital to Analog Converter 3 * 4 * Copyright 2016 Qtechnology A/S 5 * 2016 Ricardo Ribalda <ricardo.ribalda@gmail.com> 6 * 7 * Licensed under the GPL-2. 8 */ 9 #include <linux/kernel.h> 10 #include <linux/module.h> 11 #include <linux/spi/spi.h> 12 #include <linux/bitops.h> 13 #include <linux/iio/iio.h> 14 #include <linux/iio/sysfs.h> 15 #include <linux/regulator/consumer.h> 16 #include <linux/platform_data/ad5761.h> 17 18 #define AD5761_ADDR(addr) ((addr & 0xf) << 16) 19 #define AD5761_ADDR_NOOP 0x0 20 #define AD5761_ADDR_DAC_WRITE 0x3 21 #define AD5761_ADDR_CTRL_WRITE_REG 0x4 22 #define AD5761_ADDR_SW_DATA_RESET 0x7 23 #define AD5761_ADDR_DAC_READ 0xb 24 #define AD5761_ADDR_CTRL_READ_REG 0xc 25 #define AD5761_ADDR_SW_FULL_RESET 0xf 26 27 #define AD5761_CTRL_USE_INTVREF BIT(5) 28 #define AD5761_CTRL_ETS BIT(6) 29 30 /** 31 * struct ad5761_chip_info - chip specific information 32 * @int_vref: Value of the internal reference voltage in mV - 0 if external 33 * reference voltage is used 34 * @channel: channel specification 35 */ 36 37 struct ad5761_chip_info { 38 unsigned long int_vref; 39 const struct iio_chan_spec channel; 40 }; 41 42 struct ad5761_range_params { 43 int m; 44 int c; 45 }; 46 47 enum ad5761_supported_device_ids { 48 ID_AD5721, 49 ID_AD5721R, 50 ID_AD5761, 51 ID_AD5761R, 52 }; 53 54 /** 55 * struct ad5761_state - driver instance specific data 56 * @spi: spi_device 57 * @vref_reg: reference voltage regulator 58 * @use_intref: true when the internal voltage reference is used 59 * @vref: actual voltage reference in mVolts 60 * @range: output range mode used 61 * @data: cache aligned spi buffer 62 */ 63 struct ad5761_state { 64 struct spi_device *spi; 65 struct regulator *vref_reg; 66 67 bool use_intref; 68 int vref; 69 enum ad5761_voltage_range range; 70 71 /* 72 * DMA (thus cache coherency maintenance) requires the 73 * transfer buffers to live in their own cache lines. 74 */ 75 union { 76 __be32 d32; 77 u8 d8[4]; 78 } data[3] ____cacheline_aligned; 79 }; 80 81 static const struct ad5761_range_params ad5761_range_params[] = { 82 [AD5761_VOLTAGE_RANGE_M10V_10V] = { 83 .m = 80, 84 .c = 40, 85 }, 86 [AD5761_VOLTAGE_RANGE_0V_10V] = { 87 .m = 40, 88 .c = 0, 89 }, 90 [AD5761_VOLTAGE_RANGE_M5V_5V] = { 91 .m = 40, 92 .c = 20, 93 }, 94 [AD5761_VOLTAGE_RANGE_0V_5V] = { 95 .m = 20, 96 .c = 0, 97 }, 98 [AD5761_VOLTAGE_RANGE_M2V5_7V5] = { 99 .m = 40, 100 .c = 10, 101 }, 102 [AD5761_VOLTAGE_RANGE_M3V_3V] = { 103 .m = 24, 104 .c = 12, 105 }, 106 [AD5761_VOLTAGE_RANGE_0V_16V] = { 107 .m = 64, 108 .c = 0, 109 }, 110 [AD5761_VOLTAGE_RANGE_0V_20V] = { 111 .m = 80, 112 .c = 0, 113 }, 114 }; 115 116 static int _ad5761_spi_write(struct ad5761_state *st, u8 addr, u16 val) 117 { 118 st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr) | val); 119 120 return spi_write(st->spi, &st->data[0].d8[1], 3); 121 } 122 123 static int ad5761_spi_write(struct iio_dev *indio_dev, u8 addr, u16 val) 124 { 125 struct ad5761_state *st = iio_priv(indio_dev); 126 int ret; 127 128 mutex_lock(&indio_dev->mlock); 129 ret = _ad5761_spi_write(st, addr, val); 130 mutex_unlock(&indio_dev->mlock); 131 132 return ret; 133 } 134 135 static int _ad5761_spi_read(struct ad5761_state *st, u8 addr, u16 *val) 136 { 137 int ret; 138 struct spi_transfer xfers[] = { 139 { 140 .tx_buf = &st->data[0].d8[1], 141 .bits_per_word = 8, 142 .len = 3, 143 .cs_change = true, 144 }, { 145 .tx_buf = &st->data[1].d8[1], 146 .rx_buf = &st->data[2].d8[1], 147 .bits_per_word = 8, 148 .len = 3, 149 }, 150 }; 151 152 st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr)); 153 st->data[1].d32 = cpu_to_be32(AD5761_ADDR(AD5761_ADDR_NOOP)); 154 155 ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); 156 157 *val = be32_to_cpu(st->data[2].d32); 158 159 return ret; 160 } 161 162 static int ad5761_spi_read(struct iio_dev *indio_dev, u8 addr, u16 *val) 163 { 164 struct ad5761_state *st = iio_priv(indio_dev); 165 int ret; 166 167 mutex_lock(&indio_dev->mlock); 168 ret = _ad5761_spi_read(st, addr, val); 169 mutex_unlock(&indio_dev->mlock); 170 171 return ret; 172 } 173 174 static int ad5761_spi_set_range(struct ad5761_state *st, 175 enum ad5761_voltage_range range) 176 { 177 u16 aux; 178 int ret; 179 180 aux = (range & 0x7) | AD5761_CTRL_ETS; 181 182 if (st->use_intref) 183 aux |= AD5761_CTRL_USE_INTVREF; 184 185 ret = _ad5761_spi_write(st, AD5761_ADDR_SW_FULL_RESET, 0); 186 if (ret) 187 return ret; 188 189 ret = _ad5761_spi_write(st, AD5761_ADDR_CTRL_WRITE_REG, aux); 190 if (ret) 191 return ret; 192 193 st->range = range; 194 195 return 0; 196 } 197 198 static int ad5761_read_raw(struct iio_dev *indio_dev, 199 struct iio_chan_spec const *chan, 200 int *val, 201 int *val2, 202 long mask) 203 { 204 struct ad5761_state *st; 205 int ret; 206 u16 aux; 207 208 switch (mask) { 209 case IIO_CHAN_INFO_RAW: 210 ret = ad5761_spi_read(indio_dev, AD5761_ADDR_DAC_READ, &aux); 211 if (ret) 212 return ret; 213 *val = aux >> chan->scan_type.shift; 214 return IIO_VAL_INT; 215 case IIO_CHAN_INFO_SCALE: 216 st = iio_priv(indio_dev); 217 *val = st->vref * ad5761_range_params[st->range].m; 218 *val /= 10; 219 *val2 = chan->scan_type.realbits; 220 return IIO_VAL_FRACTIONAL_LOG2; 221 case IIO_CHAN_INFO_OFFSET: 222 st = iio_priv(indio_dev); 223 *val = -(1 << chan->scan_type.realbits); 224 *val *= ad5761_range_params[st->range].c; 225 *val /= ad5761_range_params[st->range].m; 226 return IIO_VAL_INT; 227 default: 228 return -EINVAL; 229 } 230 } 231 232 static int ad5761_write_raw(struct iio_dev *indio_dev, 233 struct iio_chan_spec const *chan, 234 int val, 235 int val2, 236 long mask) 237 { 238 u16 aux; 239 240 if (mask != IIO_CHAN_INFO_RAW) 241 return -EINVAL; 242 243 if (val2 || (val << chan->scan_type.shift) > 0xffff || val < 0) 244 return -EINVAL; 245 246 aux = val << chan->scan_type.shift; 247 248 return ad5761_spi_write(indio_dev, AD5761_ADDR_DAC_WRITE, aux); 249 } 250 251 static const struct iio_info ad5761_info = { 252 .read_raw = &ad5761_read_raw, 253 .write_raw = &ad5761_write_raw, 254 }; 255 256 #define AD5761_CHAN(_bits) { \ 257 .type = IIO_VOLTAGE, \ 258 .output = 1, \ 259 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 260 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 261 BIT(IIO_CHAN_INFO_OFFSET), \ 262 .scan_type = { \ 263 .sign = 'u', \ 264 .realbits = (_bits), \ 265 .storagebits = 16, \ 266 .shift = 16 - (_bits), \ 267 }, \ 268 } 269 270 static const struct ad5761_chip_info ad5761_chip_infos[] = { 271 [ID_AD5721] = { 272 .int_vref = 0, 273 .channel = AD5761_CHAN(12), 274 }, 275 [ID_AD5721R] = { 276 .int_vref = 2500, 277 .channel = AD5761_CHAN(12), 278 }, 279 [ID_AD5761] = { 280 .int_vref = 0, 281 .channel = AD5761_CHAN(16), 282 }, 283 [ID_AD5761R] = { 284 .int_vref = 2500, 285 .channel = AD5761_CHAN(16), 286 }, 287 }; 288 289 static int ad5761_get_vref(struct ad5761_state *st, 290 const struct ad5761_chip_info *chip_info) 291 { 292 int ret; 293 294 st->vref_reg = devm_regulator_get_optional(&st->spi->dev, "vref"); 295 if (PTR_ERR(st->vref_reg) == -ENODEV) { 296 /* Use Internal regulator */ 297 if (!chip_info->int_vref) { 298 dev_err(&st->spi->dev, 299 "Voltage reference not found\n"); 300 return -EIO; 301 } 302 303 st->use_intref = true; 304 st->vref = chip_info->int_vref; 305 return 0; 306 } 307 308 if (IS_ERR(st->vref_reg)) { 309 dev_err(&st->spi->dev, 310 "Error getting voltage reference regulator\n"); 311 return PTR_ERR(st->vref_reg); 312 } 313 314 ret = regulator_enable(st->vref_reg); 315 if (ret) { 316 dev_err(&st->spi->dev, 317 "Failed to enable voltage reference\n"); 318 return ret; 319 } 320 321 ret = regulator_get_voltage(st->vref_reg); 322 if (ret < 0) { 323 dev_err(&st->spi->dev, 324 "Failed to get voltage reference value\n"); 325 goto disable_regulator_vref; 326 } 327 328 if (ret < 2000000 || ret > 3000000) { 329 dev_warn(&st->spi->dev, 330 "Invalid external voltage ref. value %d uV\n", ret); 331 ret = -EIO; 332 goto disable_regulator_vref; 333 } 334 335 st->vref = ret / 1000; 336 st->use_intref = false; 337 338 return 0; 339 340 disable_regulator_vref: 341 regulator_disable(st->vref_reg); 342 st->vref_reg = NULL; 343 return ret; 344 } 345 346 static int ad5761_probe(struct spi_device *spi) 347 { 348 struct iio_dev *iio_dev; 349 struct ad5761_state *st; 350 int ret; 351 const struct ad5761_chip_info *chip_info = 352 &ad5761_chip_infos[spi_get_device_id(spi)->driver_data]; 353 enum ad5761_voltage_range voltage_range = AD5761_VOLTAGE_RANGE_0V_5V; 354 struct ad5761_platform_data *pdata = dev_get_platdata(&spi->dev); 355 356 iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 357 if (!iio_dev) 358 return -ENOMEM; 359 360 st = iio_priv(iio_dev); 361 362 st->spi = spi; 363 spi_set_drvdata(spi, iio_dev); 364 365 ret = ad5761_get_vref(st, chip_info); 366 if (ret) 367 return ret; 368 369 if (pdata) 370 voltage_range = pdata->voltage_range; 371 372 ret = ad5761_spi_set_range(st, voltage_range); 373 if (ret) 374 goto disable_regulator_err; 375 376 iio_dev->dev.parent = &spi->dev; 377 iio_dev->info = &ad5761_info; 378 iio_dev->modes = INDIO_DIRECT_MODE; 379 iio_dev->channels = &chip_info->channel; 380 iio_dev->num_channels = 1; 381 iio_dev->name = spi_get_device_id(st->spi)->name; 382 ret = iio_device_register(iio_dev); 383 if (ret) 384 goto disable_regulator_err; 385 386 return 0; 387 388 disable_regulator_err: 389 if (!IS_ERR_OR_NULL(st->vref_reg)) 390 regulator_disable(st->vref_reg); 391 392 return ret; 393 } 394 395 static int ad5761_remove(struct spi_device *spi) 396 { 397 struct iio_dev *iio_dev = spi_get_drvdata(spi); 398 struct ad5761_state *st = iio_priv(iio_dev); 399 400 iio_device_unregister(iio_dev); 401 402 if (!IS_ERR_OR_NULL(st->vref_reg)) 403 regulator_disable(st->vref_reg); 404 405 return 0; 406 } 407 408 static const struct spi_device_id ad5761_id[] = { 409 {"ad5721", ID_AD5721}, 410 {"ad5721r", ID_AD5721R}, 411 {"ad5761", ID_AD5761}, 412 {"ad5761r", ID_AD5761R}, 413 {} 414 }; 415 MODULE_DEVICE_TABLE(spi, ad5761_id); 416 417 static struct spi_driver ad5761_driver = { 418 .driver = { 419 .name = "ad5761", 420 }, 421 .probe = ad5761_probe, 422 .remove = ad5761_remove, 423 .id_table = ad5761_id, 424 }; 425 module_spi_driver(ad5761_driver); 426 427 MODULE_AUTHOR("Ricardo Ribalda <ricardo.ribalda@gmail.com>"); 428 MODULE_DESCRIPTION("Analog Devices AD5721, AD5721R, AD5761, AD5761R driver"); 429 MODULE_LICENSE("GPL v2"); 430