1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * AD5721, AD5721R, AD5761, AD5761R, Voltage Output Digital to Analog Converter 4 * 5 * Copyright 2016 Qtechnology A/S 6 * 2016 Ricardo Ribalda <ribalda@kernel.org> 7 */ 8 #include <linux/kernel.h> 9 #include <linux/module.h> 10 #include <linux/spi/spi.h> 11 #include <linux/bitops.h> 12 #include <linux/iio/iio.h> 13 #include <linux/iio/sysfs.h> 14 #include <linux/regulator/consumer.h> 15 #include <linux/platform_data/ad5761.h> 16 17 #define AD5761_ADDR(addr) ((addr & 0xf) << 16) 18 #define AD5761_ADDR_NOOP 0x0 19 #define AD5761_ADDR_DAC_WRITE 0x3 20 #define AD5761_ADDR_CTRL_WRITE_REG 0x4 21 #define AD5761_ADDR_SW_DATA_RESET 0x7 22 #define AD5761_ADDR_DAC_READ 0xb 23 #define AD5761_ADDR_CTRL_READ_REG 0xc 24 #define AD5761_ADDR_SW_FULL_RESET 0xf 25 26 #define AD5761_CTRL_USE_INTVREF BIT(5) 27 #define AD5761_CTRL_ETS BIT(6) 28 29 /** 30 * struct ad5761_chip_info - chip specific information 31 * @int_vref: Value of the internal reference voltage in mV - 0 if external 32 * reference voltage is used 33 * @channel: channel specification 34 */ 35 36 struct ad5761_chip_info { 37 unsigned long int_vref; 38 const struct iio_chan_spec channel; 39 }; 40 41 struct ad5761_range_params { 42 int m; 43 int c; 44 }; 45 46 enum ad5761_supported_device_ids { 47 ID_AD5721, 48 ID_AD5721R, 49 ID_AD5761, 50 ID_AD5761R, 51 }; 52 53 /** 54 * struct ad5761_state - driver instance specific data 55 * @spi: spi_device 56 * @vref_reg: reference voltage regulator 57 * @use_intref: true when the internal voltage reference is used 58 * @vref: actual voltage reference in mVolts 59 * @range: output range mode used 60 * @lock: lock to protect the data buffer during SPI ops 61 * @data: cache aligned spi buffer 62 */ 63 struct ad5761_state { 64 struct spi_device *spi; 65 struct regulator *vref_reg; 66 struct mutex lock; 67 68 bool use_intref; 69 int vref; 70 enum ad5761_voltage_range range; 71 72 /* 73 * DMA (thus cache coherency maintenance) requires the 74 * transfer buffers to live in their own cache lines. 75 */ 76 union { 77 __be32 d32; 78 u8 d8[4]; 79 } data[3] ____cacheline_aligned; 80 }; 81 82 static const struct ad5761_range_params ad5761_range_params[] = { 83 [AD5761_VOLTAGE_RANGE_M10V_10V] = { 84 .m = 80, 85 .c = 40, 86 }, 87 [AD5761_VOLTAGE_RANGE_0V_10V] = { 88 .m = 40, 89 .c = 0, 90 }, 91 [AD5761_VOLTAGE_RANGE_M5V_5V] = { 92 .m = 40, 93 .c = 20, 94 }, 95 [AD5761_VOLTAGE_RANGE_0V_5V] = { 96 .m = 20, 97 .c = 0, 98 }, 99 [AD5761_VOLTAGE_RANGE_M2V5_7V5] = { 100 .m = 40, 101 .c = 10, 102 }, 103 [AD5761_VOLTAGE_RANGE_M3V_3V] = { 104 .m = 24, 105 .c = 12, 106 }, 107 [AD5761_VOLTAGE_RANGE_0V_16V] = { 108 .m = 64, 109 .c = 0, 110 }, 111 [AD5761_VOLTAGE_RANGE_0V_20V] = { 112 .m = 80, 113 .c = 0, 114 }, 115 }; 116 117 static int _ad5761_spi_write(struct ad5761_state *st, u8 addr, u16 val) 118 { 119 st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr) | val); 120 121 return spi_write(st->spi, &st->data[0].d8[1], 3); 122 } 123 124 static int ad5761_spi_write(struct iio_dev *indio_dev, u8 addr, u16 val) 125 { 126 struct ad5761_state *st = iio_priv(indio_dev); 127 int ret; 128 129 mutex_lock(&st->lock); 130 ret = _ad5761_spi_write(st, addr, val); 131 mutex_unlock(&st->lock); 132 133 return ret; 134 } 135 136 static int _ad5761_spi_read(struct ad5761_state *st, u8 addr, u16 *val) 137 { 138 int ret; 139 struct spi_transfer xfers[] = { 140 { 141 .tx_buf = &st->data[0].d8[1], 142 .bits_per_word = 8, 143 .len = 3, 144 .cs_change = true, 145 }, { 146 .tx_buf = &st->data[1].d8[1], 147 .rx_buf = &st->data[2].d8[1], 148 .bits_per_word = 8, 149 .len = 3, 150 }, 151 }; 152 153 st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr)); 154 st->data[1].d32 = cpu_to_be32(AD5761_ADDR(AD5761_ADDR_NOOP)); 155 156 ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers)); 157 158 *val = be32_to_cpu(st->data[2].d32); 159 160 return ret; 161 } 162 163 static int ad5761_spi_read(struct iio_dev *indio_dev, u8 addr, u16 *val) 164 { 165 struct ad5761_state *st = iio_priv(indio_dev); 166 int ret; 167 168 mutex_lock(&st->lock); 169 ret = _ad5761_spi_read(st, addr, val); 170 mutex_unlock(&st->lock); 171 172 return ret; 173 } 174 175 static int ad5761_spi_set_range(struct ad5761_state *st, 176 enum ad5761_voltage_range range) 177 { 178 u16 aux; 179 int ret; 180 181 aux = (range & 0x7) | AD5761_CTRL_ETS; 182 183 if (st->use_intref) 184 aux |= AD5761_CTRL_USE_INTVREF; 185 186 ret = _ad5761_spi_write(st, AD5761_ADDR_SW_FULL_RESET, 0); 187 if (ret) 188 return ret; 189 190 ret = _ad5761_spi_write(st, AD5761_ADDR_CTRL_WRITE_REG, aux); 191 if (ret) 192 return ret; 193 194 st->range = range; 195 196 return 0; 197 } 198 199 static int ad5761_read_raw(struct iio_dev *indio_dev, 200 struct iio_chan_spec const *chan, 201 int *val, 202 int *val2, 203 long mask) 204 { 205 struct ad5761_state *st; 206 int ret; 207 u16 aux; 208 209 switch (mask) { 210 case IIO_CHAN_INFO_RAW: 211 ret = ad5761_spi_read(indio_dev, AD5761_ADDR_DAC_READ, &aux); 212 if (ret) 213 return ret; 214 *val = aux >> chan->scan_type.shift; 215 return IIO_VAL_INT; 216 case IIO_CHAN_INFO_SCALE: 217 st = iio_priv(indio_dev); 218 *val = st->vref * ad5761_range_params[st->range].m; 219 *val /= 10; 220 *val2 = chan->scan_type.realbits; 221 return IIO_VAL_FRACTIONAL_LOG2; 222 case IIO_CHAN_INFO_OFFSET: 223 st = iio_priv(indio_dev); 224 *val = -(1 << chan->scan_type.realbits); 225 *val *= ad5761_range_params[st->range].c; 226 *val /= ad5761_range_params[st->range].m; 227 return IIO_VAL_INT; 228 default: 229 return -EINVAL; 230 } 231 } 232 233 static int ad5761_write_raw(struct iio_dev *indio_dev, 234 struct iio_chan_spec const *chan, 235 int val, 236 int val2, 237 long mask) 238 { 239 u16 aux; 240 241 if (mask != IIO_CHAN_INFO_RAW) 242 return -EINVAL; 243 244 if (val2 || (val << chan->scan_type.shift) > 0xffff || val < 0) 245 return -EINVAL; 246 247 aux = val << chan->scan_type.shift; 248 249 return ad5761_spi_write(indio_dev, AD5761_ADDR_DAC_WRITE, aux); 250 } 251 252 static const struct iio_info ad5761_info = { 253 .read_raw = &ad5761_read_raw, 254 .write_raw = &ad5761_write_raw, 255 }; 256 257 #define AD5761_CHAN(_bits) { \ 258 .type = IIO_VOLTAGE, \ 259 .output = 1, \ 260 .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ 261 .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \ 262 BIT(IIO_CHAN_INFO_OFFSET), \ 263 .scan_type = { \ 264 .sign = 'u', \ 265 .realbits = (_bits), \ 266 .storagebits = 16, \ 267 .shift = 16 - (_bits), \ 268 }, \ 269 } 270 271 static const struct ad5761_chip_info ad5761_chip_infos[] = { 272 [ID_AD5721] = { 273 .int_vref = 0, 274 .channel = AD5761_CHAN(12), 275 }, 276 [ID_AD5721R] = { 277 .int_vref = 2500, 278 .channel = AD5761_CHAN(12), 279 }, 280 [ID_AD5761] = { 281 .int_vref = 0, 282 .channel = AD5761_CHAN(16), 283 }, 284 [ID_AD5761R] = { 285 .int_vref = 2500, 286 .channel = AD5761_CHAN(16), 287 }, 288 }; 289 290 static int ad5761_get_vref(struct ad5761_state *st, 291 const struct ad5761_chip_info *chip_info) 292 { 293 int ret; 294 295 st->vref_reg = devm_regulator_get_optional(&st->spi->dev, "vref"); 296 if (PTR_ERR(st->vref_reg) == -ENODEV) { 297 /* Use Internal regulator */ 298 if (!chip_info->int_vref) { 299 dev_err(&st->spi->dev, 300 "Voltage reference not found\n"); 301 return -EIO; 302 } 303 304 st->use_intref = true; 305 st->vref = chip_info->int_vref; 306 return 0; 307 } 308 309 if (IS_ERR(st->vref_reg)) { 310 dev_err(&st->spi->dev, 311 "Error getting voltage reference regulator\n"); 312 return PTR_ERR(st->vref_reg); 313 } 314 315 ret = regulator_enable(st->vref_reg); 316 if (ret) { 317 dev_err(&st->spi->dev, 318 "Failed to enable voltage reference\n"); 319 return ret; 320 } 321 322 ret = regulator_get_voltage(st->vref_reg); 323 if (ret < 0) { 324 dev_err(&st->spi->dev, 325 "Failed to get voltage reference value\n"); 326 goto disable_regulator_vref; 327 } 328 329 if (ret < 2000000 || ret > 3000000) { 330 dev_warn(&st->spi->dev, 331 "Invalid external voltage ref. value %d uV\n", ret); 332 ret = -EIO; 333 goto disable_regulator_vref; 334 } 335 336 st->vref = ret / 1000; 337 st->use_intref = false; 338 339 return 0; 340 341 disable_regulator_vref: 342 regulator_disable(st->vref_reg); 343 st->vref_reg = NULL; 344 return ret; 345 } 346 347 static int ad5761_probe(struct spi_device *spi) 348 { 349 struct iio_dev *iio_dev; 350 struct ad5761_state *st; 351 int ret; 352 const struct ad5761_chip_info *chip_info = 353 &ad5761_chip_infos[spi_get_device_id(spi)->driver_data]; 354 enum ad5761_voltage_range voltage_range = AD5761_VOLTAGE_RANGE_0V_5V; 355 struct ad5761_platform_data *pdata = dev_get_platdata(&spi->dev); 356 357 iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st)); 358 if (!iio_dev) 359 return -ENOMEM; 360 361 st = iio_priv(iio_dev); 362 363 st->spi = spi; 364 spi_set_drvdata(spi, iio_dev); 365 366 ret = ad5761_get_vref(st, chip_info); 367 if (ret) 368 return ret; 369 370 if (pdata) 371 voltage_range = pdata->voltage_range; 372 373 mutex_init(&st->lock); 374 375 ret = ad5761_spi_set_range(st, voltage_range); 376 if (ret) 377 goto disable_regulator_err; 378 379 iio_dev->info = &ad5761_info; 380 iio_dev->modes = INDIO_DIRECT_MODE; 381 iio_dev->channels = &chip_info->channel; 382 iio_dev->num_channels = 1; 383 iio_dev->name = spi_get_device_id(st->spi)->name; 384 ret = iio_device_register(iio_dev); 385 if (ret) 386 goto disable_regulator_err; 387 388 return 0; 389 390 disable_regulator_err: 391 if (!IS_ERR_OR_NULL(st->vref_reg)) 392 regulator_disable(st->vref_reg); 393 394 return ret; 395 } 396 397 static void ad5761_remove(struct spi_device *spi) 398 { 399 struct iio_dev *iio_dev = spi_get_drvdata(spi); 400 struct ad5761_state *st = iio_priv(iio_dev); 401 402 iio_device_unregister(iio_dev); 403 404 if (!IS_ERR_OR_NULL(st->vref_reg)) 405 regulator_disable(st->vref_reg); 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 <ribalda@kernel.org>"); 428 MODULE_DESCRIPTION("Analog Devices AD5721, AD5721R, AD5761, AD5761R driver"); 429 MODULE_LICENSE("GPL v2"); 430