1 // SPDX-License-Identifier: GPL-2.0-only 2 /* 3 * Analog Devices AD9739a SPI DAC driver 4 * 5 * Copyright 2015-2024 Analog Devices Inc. 6 */ 7 #include <linux/bitfield.h> 8 #include <linux/bits.h> 9 #include <linux/clk.h> 10 #include <linux/delay.h> 11 #include <linux/device.h> 12 #include <linux/err.h> 13 #include <linux/errno.h> 14 #include <linux/gpio/consumer.h> 15 #include <linux/minmax.h> 16 #include <linux/module.h> 17 #include <linux/mod_devicetable.h> 18 #include <linux/property.h> 19 #include <linux/regmap.h> 20 #include <linux/spi/spi.h> 21 #include <linux/units.h> 22 23 #include <linux/iio/backend.h> 24 #include <linux/iio/iio.h> 25 #include <linux/iio/types.h> 26 27 #define AD9739A_REG_MODE 0 28 #define AD9739A_RESET_MASK BIT(5) 29 #define AD9739A_REG_FSC_1 0x06 30 #define AD9739A_REG_FSC_2 0x07 31 #define AD9739A_FSC_MSB GENMASK(1, 0) 32 #define AD9739A_REG_DEC_CNT 0x8 33 #define AD9739A_NORMAL_MODE 0 34 #define AD9739A_MIXED_MODE 2 35 #define AD9739A_DAC_DEC GENMASK(1, 0) 36 #define AD9739A_REG_LVDS_REC_CNT1 0x10 37 #define AD9739A_RCVR_LOOP_EN_MASK GENMASK(1, 0) 38 #define AD9739A_REG_LVDS_REC_CNT4 0x13 39 #define AD9739A_FINE_DEL_SKW_MASK GENMASK(3, 0) 40 #define AD9739A_REG_LVDS_REC_STAT9 0x21 41 #define AD9739A_RCVR_TRACK_AND_LOCK (BIT(3) | BIT(0)) 42 #define AD9739A_REG_CROSS_CNT1 0x22 43 #define AD9739A_REG_CROSS_CNT2 0x23 44 #define AD9739A_REG_PHS_DET 0x24 45 #define AD9739A_REG_MU_DUTY 0x25 46 #define AD9739A_REG_MU_CNT1 0x26 47 #define AD9739A_MU_EN_MASK BIT(0) 48 #define AD9739A_MU_GAIN_MASK BIT(1) 49 #define AD9739A_REG_MU_CNT2 0x27 50 #define AD9739A_REG_MU_CNT3 0x28 51 #define AD9739A_REG_MU_CNT4 0x29 52 #define AD9739A_MU_CNT4_DEFAULT 0xcb 53 #define AD9739A_REG_MU_STAT1 0x2A 54 #define AD9739A_MU_LOCK_MASK BIT(0) 55 #define AD9739A_REG_ANA_CNT_1 0x32 56 #define AD9739A_REG_ID 0x35 57 58 #define AD9739A_ID 0x24 59 #define AD9739A_REG_IS_RESERVED(reg) \ 60 ((reg) == 0x5 || (reg) == 0x9 || (reg) == 0x0E || (reg) == 0x0D || \ 61 (reg) == 0x2B || (reg) == 0x2C || (reg) == 0x34) 62 63 #define AD9739A_FSC_MIN 8580 64 #define AD9739A_FSC_MAX 31700 65 #define AD9739A_FSC_RANGE (AD9739A_FSC_MAX - AD9739A_FSC_MIN + 1) 66 67 #define AD9739A_MIN_DAC_CLK (1600 * MEGA) 68 #define AD9739A_MAX_DAC_CLK (2500 * MEGA) 69 #define AD9739A_DAC_CLK_RANGE (AD9739A_MAX_DAC_CLK - AD9739A_MIN_DAC_CLK + 1) 70 /* as recommended by the datasheet */ 71 #define AD9739A_LOCK_N_TRIES 3 72 73 struct ad9739a_state { 74 struct iio_backend *back; 75 struct regmap *regmap; 76 unsigned long sample_rate; 77 }; 78 79 static int ad9739a_oper_mode_get(struct iio_dev *indio_dev, 80 const struct iio_chan_spec *chan) 81 { 82 struct ad9739a_state *st = iio_priv(indio_dev); 83 u32 mode; 84 int ret; 85 86 ret = regmap_read(st->regmap, AD9739A_REG_DEC_CNT, &mode); 87 if (ret) 88 return ret; 89 90 mode = FIELD_GET(AD9739A_DAC_DEC, mode); 91 /* sanity check we get valid values from the HW */ 92 if (mode != AD9739A_NORMAL_MODE && mode != AD9739A_MIXED_MODE) 93 return -EIO; 94 if (!mode) 95 return AD9739A_NORMAL_MODE; 96 97 /* 98 * We get 2 from the device but for IIO modes, that means 1. Hence the 99 * minus 1. 100 */ 101 return AD9739A_MIXED_MODE - 1; 102 } 103 104 static int ad9739a_oper_mode_set(struct iio_dev *indio_dev, 105 const struct iio_chan_spec *chan, u32 mode) 106 { 107 struct ad9739a_state *st = iio_priv(indio_dev); 108 109 /* 110 * On the IIO interface we have 0 and 1 for mode. But for mixed_mode, we 111 * need to write 2 in the device. That's what the below check is about. 112 */ 113 if (mode == AD9739A_MIXED_MODE - 1) 114 mode = AD9739A_MIXED_MODE; 115 116 return regmap_update_bits(st->regmap, AD9739A_REG_DEC_CNT, 117 AD9739A_DAC_DEC, mode); 118 } 119 120 static int ad9739a_read_raw(struct iio_dev *indio_dev, 121 struct iio_chan_spec const *chan, 122 int *val, int *val2, long mask) 123 { 124 struct ad9739a_state *st = iio_priv(indio_dev); 125 126 switch (mask) { 127 case IIO_CHAN_INFO_SAMP_FREQ: 128 *val = st->sample_rate; 129 *val2 = 0; 130 return IIO_VAL_INT_64; 131 default: 132 return -EINVAL; 133 } 134 } 135 136 static int ad9739a_buffer_preenable(struct iio_dev *indio_dev) 137 { 138 struct ad9739a_state *st = iio_priv(indio_dev); 139 140 return iio_backend_data_source_set(st->back, 0, IIO_BACKEND_EXTERNAL); 141 } 142 143 static int ad9739a_buffer_postdisable(struct iio_dev *indio_dev) 144 { 145 struct ad9739a_state *st = iio_priv(indio_dev); 146 147 return iio_backend_data_source_set(st->back, 0, 148 IIO_BACKEND_INTERNAL_CONTINUOS_WAVE); 149 } 150 151 static bool ad9739a_reg_accessible(struct device *dev, unsigned int reg) 152 { 153 if (AD9739A_REG_IS_RESERVED(reg)) 154 return false; 155 if (reg > AD9739A_REG_MU_STAT1 && reg < AD9739A_REG_ANA_CNT_1) 156 return false; 157 158 return true; 159 } 160 161 static int ad9739a_reset(struct device *dev, const struct ad9739a_state *st) 162 { 163 struct gpio_desc *gpio; 164 int ret; 165 166 gpio = devm_gpiod_get_optional(dev, "reset", GPIOD_OUT_HIGH); 167 if (IS_ERR(gpio)) 168 return PTR_ERR(gpio); 169 if (gpio) { 170 /* minimum pulse width of 40ns */ 171 ndelay(40); 172 gpiod_set_value_cansleep(gpio, 0); 173 return 0; 174 } 175 176 /* bring all registers to their default state */ 177 ret = regmap_set_bits(st->regmap, AD9739A_REG_MODE, AD9739A_RESET_MASK); 178 if (ret) 179 return ret; 180 181 ndelay(40); 182 183 return regmap_clear_bits(st->regmap, AD9739A_REG_MODE, 184 AD9739A_RESET_MASK); 185 } 186 187 /* 188 * Recommended values (as per datasheet) for the dac clk common mode voltage 189 * and Mu controller. Look at table 29. 190 */ 191 static const struct reg_sequence ad9739a_clk_mu_ctrl[] = { 192 /* DAC clk common mode voltage */ 193 { AD9739A_REG_CROSS_CNT1, 0x0f }, 194 { AD9739A_REG_CROSS_CNT2, 0x0f }, 195 /* Mu controller configuration */ 196 { AD9739A_REG_PHS_DET, 0x30 }, 197 { AD9739A_REG_MU_DUTY, 0x80 }, 198 { AD9739A_REG_MU_CNT2, 0x44 }, 199 { AD9739A_REG_MU_CNT3, 0x6c }, 200 }; 201 202 static int ad9739a_init(struct device *dev, const struct ad9739a_state *st) 203 { 204 unsigned int i = 0, lock, fsc; 205 u32 fsc_raw; 206 int ret; 207 208 ret = regmap_multi_reg_write(st->regmap, ad9739a_clk_mu_ctrl, 209 ARRAY_SIZE(ad9739a_clk_mu_ctrl)); 210 if (ret) 211 return ret; 212 213 /* 214 * Try to get the Mu lock. Repeat the below steps AD9739A_LOCK_N_TRIES 215 * (as specified by the datasheet) until we get the lock. 216 */ 217 do { 218 ret = regmap_write(st->regmap, AD9739A_REG_MU_CNT4, 219 AD9739A_MU_CNT4_DEFAULT); 220 if (ret) 221 return ret; 222 223 /* Enable the Mu controller search and track mode. */ 224 ret = regmap_write(st->regmap, AD9739A_REG_MU_CNT1, 225 AD9739A_MU_EN_MASK | AD9739A_MU_GAIN_MASK); 226 if (ret) 227 return ret; 228 229 /* Ensure the DLL loop is locked */ 230 ret = regmap_read_poll_timeout(st->regmap, AD9739A_REG_MU_STAT1, 231 lock, lock & AD9739A_MU_LOCK_MASK, 232 0, 1000); 233 if (ret && ret != -ETIMEDOUT) 234 return ret; 235 } while (ret && ++i < AD9739A_LOCK_N_TRIES); 236 237 if (i == AD9739A_LOCK_N_TRIES) 238 return dev_err_probe(dev, ret, "Mu lock timeout\n"); 239 240 /* Receiver tracking and lock. Same deal as the Mu controller */ 241 i = 0; 242 do { 243 ret = regmap_update_bits(st->regmap, AD9739A_REG_LVDS_REC_CNT4, 244 AD9739A_FINE_DEL_SKW_MASK, 245 FIELD_PREP(AD9739A_FINE_DEL_SKW_MASK, 2)); 246 if (ret) 247 return ret; 248 249 /* Disable the receiver and the loop. */ 250 ret = regmap_write(st->regmap, AD9739A_REG_LVDS_REC_CNT1, 0); 251 if (ret) 252 return ret; 253 254 /* 255 * Re-enable the loop so it falls out of lock and begins the 256 * search/track routine again. 257 */ 258 ret = regmap_set_bits(st->regmap, AD9739A_REG_LVDS_REC_CNT1, 259 AD9739A_RCVR_LOOP_EN_MASK); 260 if (ret) 261 return ret; 262 263 /* Ensure the DLL loop is locked */ 264 ret = regmap_read_poll_timeout(st->regmap, 265 AD9739A_REG_LVDS_REC_STAT9, lock, 266 lock == AD9739A_RCVR_TRACK_AND_LOCK, 267 0, 1000); 268 if (ret && ret != -ETIMEDOUT) 269 return ret; 270 } while (ret && ++i < AD9739A_LOCK_N_TRIES); 271 272 if (i == AD9739A_LOCK_N_TRIES) 273 return dev_err_probe(dev, ret, "Receiver lock timeout\n"); 274 275 ret = device_property_read_u32(dev, "adi,full-scale-microamp", &fsc); 276 if (ret && ret == -EINVAL) 277 return 0; 278 if (ret) 279 return ret; 280 if (!in_range(fsc, AD9739A_FSC_MIN, AD9739A_FSC_RANGE)) 281 return dev_err_probe(dev, -EINVAL, 282 "Invalid full scale current(%u) [%u %u]\n", 283 fsc, AD9739A_FSC_MIN, AD9739A_FSC_MAX); 284 /* 285 * IOUTFS is given by 286 * Ioutfs = 0.0226 * FSC + 8.58 287 * and is given in mA. Hence we'll have to multiply by 10 * MILLI in 288 * order to get rid of the fractional. 289 */ 290 fsc_raw = DIV_ROUND_CLOSEST(fsc * 10 - 85800, 226); 291 292 ret = regmap_write(st->regmap, AD9739A_REG_FSC_1, fsc_raw & 0xff); 293 if (ret) 294 return ret; 295 296 return regmap_update_bits(st->regmap, AD9739A_REG_FSC_2, 297 AD9739A_FSC_MSB, fsc_raw >> 8); 298 } 299 300 static const char * const ad9739a_modes_avail[] = { "normal", "mixed-mode" }; 301 302 static const struct iio_enum ad9739a_modes = { 303 .items = ad9739a_modes_avail, 304 .num_items = ARRAY_SIZE(ad9739a_modes_avail), 305 .get = ad9739a_oper_mode_get, 306 .set = ad9739a_oper_mode_set, 307 }; 308 309 static const struct iio_chan_spec_ext_info ad9739a_ext_info[] = { 310 IIO_ENUM_AVAILABLE("operating_mode", IIO_SEPARATE, &ad9739a_modes), 311 IIO_ENUM("operating_mode", IIO_SEPARATE, &ad9739a_modes), 312 { } 313 }; 314 315 /* 316 * The reason for having two different channels is because we have, in reality, 317 * two sources of data: 318 * ALTVOLTAGE: It's a Continuous Wave that's internally generated by the 319 * backend device. 320 * VOLTAGE: It's the typical data we can have in a DAC device and the source 321 * of it has nothing to do with the backend. The backend will only 322 * forward it into our data interface to be sent out. 323 */ 324 static struct iio_chan_spec ad9739a_channels[] = { 325 { 326 .type = IIO_ALTVOLTAGE, 327 .indexed = 1, 328 .output = 1, 329 .scan_index = -1, 330 }, 331 { 332 .type = IIO_VOLTAGE, 333 .indexed = 1, 334 .info_mask_shared_by_all = BIT(IIO_CHAN_INFO_SAMP_FREQ), 335 .output = 1, 336 .ext_info = ad9739a_ext_info, 337 .scan_type = { 338 .sign = 's', 339 .storagebits = 16, 340 .realbits = 16, 341 }, 342 } 343 }; 344 345 static const struct iio_info ad9739a_info = { 346 .read_raw = ad9739a_read_raw, 347 }; 348 349 static const struct iio_buffer_setup_ops ad9739a_buffer_setup_ops = { 350 .preenable = &ad9739a_buffer_preenable, 351 .postdisable = &ad9739a_buffer_postdisable, 352 }; 353 354 static const struct regmap_config ad9739a_regmap_config = { 355 .reg_bits = 8, 356 .val_bits = 8, 357 .readable_reg = ad9739a_reg_accessible, 358 .writeable_reg = ad9739a_reg_accessible, 359 .max_register = AD9739A_REG_ID, 360 }; 361 362 static int ad9739a_probe(struct spi_device *spi) 363 { 364 struct device *dev = &spi->dev; 365 struct iio_dev *indio_dev; 366 struct ad9739a_state *st; 367 unsigned int id; 368 struct clk *clk; 369 int ret; 370 371 indio_dev = devm_iio_device_alloc(dev, sizeof(*st)); 372 if (!indio_dev) 373 return -ENOMEM; 374 375 st = iio_priv(indio_dev); 376 377 clk = devm_clk_get_enabled(dev, NULL); 378 if (IS_ERR(clk)) 379 return dev_err_probe(dev, PTR_ERR(clk), "Could not get clkin\n"); 380 381 st->sample_rate = clk_get_rate(clk); 382 if (!in_range(st->sample_rate, AD9739A_MIN_DAC_CLK, 383 AD9739A_DAC_CLK_RANGE)) 384 return dev_err_probe(dev, -EINVAL, 385 "Invalid dac clk range(%lu) [%lu %lu]\n", 386 st->sample_rate, AD9739A_MIN_DAC_CLK, 387 AD9739A_MAX_DAC_CLK); 388 389 st->regmap = devm_regmap_init_spi(spi, &ad9739a_regmap_config); 390 if (IS_ERR(st->regmap)) 391 return PTR_ERR(st->regmap); 392 393 ret = regmap_read(st->regmap, AD9739A_REG_ID, &id); 394 if (ret) 395 return ret; 396 397 if (id != AD9739A_ID) 398 dev_warn(dev, "Unrecognized CHIP_ID 0x%X", id); 399 400 ret = ad9739a_reset(dev, st); 401 if (ret) 402 return ret; 403 404 ret = ad9739a_init(dev, st); 405 if (ret) 406 return ret; 407 408 st->back = devm_iio_backend_get(dev, NULL); 409 if (IS_ERR(st->back)) 410 return PTR_ERR(st->back); 411 412 ret = devm_iio_backend_request_buffer(dev, st->back, indio_dev); 413 if (ret) 414 return ret; 415 416 ret = iio_backend_extend_chan_spec(indio_dev, st->back, 417 &ad9739a_channels[0]); 418 if (ret) 419 return ret; 420 421 ret = iio_backend_set_sampling_freq(st->back, 0, st->sample_rate); 422 if (ret) 423 return ret; 424 425 ret = devm_iio_backend_enable(dev, st->back); 426 if (ret) 427 return ret; 428 429 indio_dev->name = "ad9739a"; 430 indio_dev->info = &ad9739a_info; 431 indio_dev->channels = ad9739a_channels; 432 indio_dev->num_channels = ARRAY_SIZE(ad9739a_channels); 433 indio_dev->setup_ops = &ad9739a_buffer_setup_ops; 434 435 return devm_iio_device_register(&spi->dev, indio_dev); 436 } 437 438 static const struct of_device_id ad9739a_of_match[] = { 439 { .compatible = "adi,ad9739a" }, 440 {} 441 }; 442 MODULE_DEVICE_TABLE(of, ad9739a_of_match); 443 444 static const struct spi_device_id ad9739a_id[] = { 445 {"ad9739a"}, 446 {} 447 }; 448 MODULE_DEVICE_TABLE(spi, ad9739a_id); 449 450 static struct spi_driver ad9739a_driver = { 451 .driver = { 452 .name = "ad9739a", 453 .of_match_table = ad9739a_of_match, 454 }, 455 .probe = ad9739a_probe, 456 .id_table = ad9739a_id, 457 }; 458 module_spi_driver(ad9739a_driver); 459 460 MODULE_AUTHOR("Dragos Bogdan <dragos.bogdan@analog.com>"); 461 MODULE_AUTHOR("Nuno Sa <nuno.sa@analog.com>"); 462 MODULE_DESCRIPTION("Analog Devices AD9739 DAC"); 463 MODULE_LICENSE("GPL"); 464 MODULE_IMPORT_NS(IIO_BACKEND); 465