1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * HMC425A and similar Gain Amplifiers 4 * 5 * Copyright 2020, 2024 Analog Devices Inc. 6 */ 7 8 #include <linux/bits.h> 9 #include <linux/bitops.h> 10 #include <linux/device.h> 11 #include <linux/err.h> 12 #include <linux/gpio/consumer.h> 13 #include <linux/iio/iio.h> 14 #include <linux/iio/sysfs.h> 15 #include <linux/kernel.h> 16 #include <linux/math.h> 17 #include <linux/mod_devicetable.h> 18 #include <linux/module.h> 19 #include <linux/platform_device.h> 20 #include <linux/property.h> 21 #include <linux/slab.h> 22 #include <linux/regulator/consumer.h> 23 #include <linux/sysfs.h> 24 25 /* 26 * The LTC6373 amplifier supports configuring gain using GPIO's with the following 27 * values (OUTPUT_V / INPUT_V): 0(shutdown), 0.25, 0.5, 1, 2, 4, 8, 16 28 * 29 * Except for the shutdown value, all can be converted to dB using 20 * log10(x) 30 * From here, it is observed that all values are multiples of the '2' gain setting, 31 * with the correspondent of 6.020dB. 32 */ 33 #define LTC6373_CONVERSION_CONSTANT 6020 34 #define LTC6373_MIN_GAIN_CODE 0x6 35 #define LTC6373_CONVERSION_MASK GENMASK(2, 0) 36 #define LTC6373_SHUTDOWN GENMASK(2, 0) 37 38 enum hmc425a_type { 39 ID_HMC425A, 40 ID_HMC540S, 41 ID_ADRF5740, 42 ID_LTC6373, 43 }; 44 45 struct hmc425a_chip_info { 46 const char *name; 47 const struct iio_chan_spec *channels; 48 unsigned int num_channels; 49 unsigned int num_gpios; 50 int gain_min; 51 int gain_max; 52 int default_gain; 53 int powerdown_val; 54 bool has_powerdown; 55 56 int (*gain_dB_to_code)(int gain, int *code); 57 int (*code_to_gain_dB)(int code, int *val, int *val2); 58 }; 59 60 struct hmc425a_state { 61 struct mutex lock; /* protect sensor state */ 62 const struct hmc425a_chip_info *chip_info; 63 struct gpio_descs *gpios; 64 u32 gain; 65 bool powerdown; 66 }; 67 68 static int gain_dB_to_code(struct hmc425a_state *st, int val, int val2, int *code) 69 { 70 const struct hmc425a_chip_info *inf = st->chip_info; 71 int gain; 72 73 if (val < 0) 74 gain = (val * 1000) - (val2 / 1000); 75 else 76 gain = (val * 1000) + (val2 / 1000); 77 78 if (gain > inf->gain_max || gain < inf->gain_min) 79 return -EINVAL; 80 if (st->powerdown) 81 return -EPERM; 82 83 return st->chip_info->gain_dB_to_code(gain, code); 84 } 85 86 static int hmc425a_gain_dB_to_code(int gain, int *code) 87 { 88 *code = ~((abs(gain) / 500) & 0x3F); 89 return 0; 90 } 91 92 static int hmc540s_gain_dB_to_code(int gain, int *code) 93 { 94 *code = ~((abs(gain) / 1000) & 0xF); 95 return 0; 96 } 97 98 static int adrf5740_gain_dB_to_code(int gain, int *code) 99 { 100 int temp = (abs(gain) / 2000) & 0xF; 101 102 /* Bit [0-3]: 2dB 4dB 8dB 8dB */ 103 *code = temp & BIT(3) ? temp | BIT(2) : temp; 104 return 0; 105 } 106 107 static int ltc6373_gain_dB_to_code(int gain, int *code) 108 { 109 *code = ~(DIV_ROUND_CLOSEST(gain, LTC6373_CONVERSION_CONSTANT) + 3) 110 & LTC6373_CONVERSION_MASK; 111 return 0; 112 } 113 114 static int code_to_gain_dB(struct hmc425a_state *st, int *val, int *val2) 115 { 116 if (st->powerdown) 117 return -EPERM; 118 return st->chip_info->code_to_gain_dB(st->gain, val, val2); 119 } 120 121 static int hmc425a_code_to_gain_dB(int code, int *val, int *val2) 122 { 123 *val = (~code * -500) / 1000; 124 *val2 = ((~code * -500) % 1000) * 1000; 125 return 0; 126 } 127 128 static int hmc540s_code_to_gain_dB(int code, int *val, int *val2) 129 { 130 *val = (~code * -1000) / 1000; 131 *val2 = ((~code * -1000) % 1000) * 1000; 132 return 0; 133 } 134 135 static int adrf5740_code_to_gain_dB(int code, int *val, int *val2) 136 { 137 /* 138 * Bit [0-3]: 2dB 4dB 8dB 8dB 139 * When BIT(3) is set, unset BIT(2) and use 3 as double the place value 140 */ 141 code = code & BIT(3) ? code & ~BIT(2) : code; 142 *val = (code * -2000) / 1000; 143 *val2 = ((code * -2000) % 1000) * 1000; 144 return 0; 145 } 146 147 static int ltc6373_code_to_gain_dB(int code, int *val, int *val2) 148 { 149 int gain = ((~code & LTC6373_CONVERSION_MASK) - 3) * 150 LTC6373_CONVERSION_CONSTANT; 151 152 *val = gain / 1000; 153 *val2 = (gain % 1000) * 1000; 154 return 0; 155 } 156 157 static int hmc425a_write(struct iio_dev *indio_dev, u32 value) 158 { 159 struct hmc425a_state *st = iio_priv(indio_dev); 160 DECLARE_BITMAP(values, BITS_PER_TYPE(value)); 161 162 values[0] = value; 163 164 gpiod_set_array_value_cansleep(st->gpios->ndescs, st->gpios->desc, 165 NULL, values); 166 return 0; 167 } 168 169 static int hmc425a_read_raw(struct iio_dev *indio_dev, 170 struct iio_chan_spec const *chan, int *val, 171 int *val2, long m) 172 { 173 struct hmc425a_state *st = iio_priv(indio_dev); 174 int ret; 175 176 mutex_lock(&st->lock); 177 switch (m) { 178 case IIO_CHAN_INFO_HARDWAREGAIN: 179 ret = code_to_gain_dB(st, val, val2); 180 if (ret) 181 break; 182 ret = IIO_VAL_INT_PLUS_MICRO_DB; 183 break; 184 default: 185 ret = -EINVAL; 186 } 187 mutex_unlock(&st->lock); 188 189 return ret; 190 }; 191 192 static int hmc425a_write_raw(struct iio_dev *indio_dev, 193 struct iio_chan_spec const *chan, int val, 194 int val2, long mask) 195 { 196 struct hmc425a_state *st = iio_priv(indio_dev); 197 int code = 0, ret; 198 199 mutex_lock(&st->lock); 200 switch (mask) { 201 case IIO_CHAN_INFO_HARDWAREGAIN: 202 ret = gain_dB_to_code(st, val, val2, &code); 203 if (ret) 204 break; 205 st->gain = code; 206 207 ret = hmc425a_write(indio_dev, st->gain); 208 break; 209 default: 210 ret = -EINVAL; 211 } 212 mutex_unlock(&st->lock); 213 214 return ret; 215 } 216 217 static int hmc425a_write_raw_get_fmt(struct iio_dev *indio_dev, 218 struct iio_chan_spec const *chan, 219 long mask) 220 { 221 switch (mask) { 222 case IIO_CHAN_INFO_HARDWAREGAIN: 223 return IIO_VAL_INT_PLUS_MICRO_DB; 224 default: 225 return -EINVAL; 226 } 227 } 228 229 static const struct iio_info hmc425a_info = { 230 .read_raw = &hmc425a_read_raw, 231 .write_raw = &hmc425a_write_raw, 232 .write_raw_get_fmt = &hmc425a_write_raw_get_fmt, 233 }; 234 235 static ssize_t ltc6373_read_powerdown(struct iio_dev *indio_dev, 236 uintptr_t private, 237 const struct iio_chan_spec *chan, 238 char *buf) 239 { 240 struct hmc425a_state *st = iio_priv(indio_dev); 241 242 return sysfs_emit(buf, "%d\n", st->powerdown); 243 } 244 245 static ssize_t ltc6373_write_powerdown(struct iio_dev *indio_dev, 246 uintptr_t private, 247 const struct iio_chan_spec *chan, 248 const char *buf, 249 size_t len) 250 { 251 struct hmc425a_state *st = iio_priv(indio_dev); 252 bool powerdown; 253 int code, ret; 254 255 ret = kstrtobool(buf, &powerdown); 256 if (ret) 257 return ret; 258 259 mutex_lock(&st->lock); 260 st->powerdown = powerdown; 261 code = (powerdown) ? LTC6373_SHUTDOWN : st->gain; 262 hmc425a_write(indio_dev, code); 263 mutex_unlock(&st->lock); 264 return len; 265 } 266 267 static const struct iio_chan_spec_ext_info ltc6373_ext_info[] = { 268 { 269 .name = "powerdown", 270 .read = ltc6373_read_powerdown, 271 .write = ltc6373_write_powerdown, 272 .shared = IIO_SEPARATE, 273 }, 274 {} 275 }; 276 277 #define HMC425A_CHAN(_channel) \ 278 { \ 279 .type = IIO_VOLTAGE, \ 280 .output = 1, \ 281 .indexed = 1, \ 282 .channel = _channel, \ 283 .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ 284 } 285 286 #define LTC6373_CHAN(_channel) \ 287 { \ 288 .type = IIO_VOLTAGE, \ 289 .output = 1, \ 290 .indexed = 1, \ 291 .channel = _channel, \ 292 .info_mask_separate = BIT(IIO_CHAN_INFO_HARDWAREGAIN), \ 293 .ext_info = ltc6373_ext_info, \ 294 } 295 296 static const struct iio_chan_spec hmc425a_channels[] = { 297 HMC425A_CHAN(0), 298 }; 299 300 static const struct iio_chan_spec ltc6373_channels[] = { 301 LTC6373_CHAN(0), 302 }; 303 304 static const struct hmc425a_chip_info hmc425a_chip_info_tbl[] = { 305 [ID_HMC425A] = { 306 .name = "hmc425a", 307 .channels = hmc425a_channels, 308 .num_channels = ARRAY_SIZE(hmc425a_channels), 309 .num_gpios = 6, 310 .gain_min = -31500, 311 .gain_max = 0, 312 .default_gain = -0x40, /* set default gain -31.5db*/ 313 .gain_dB_to_code = hmc425a_gain_dB_to_code, 314 .code_to_gain_dB = hmc425a_code_to_gain_dB, 315 }, 316 [ID_HMC540S] = { 317 .name = "hmc540s", 318 .channels = hmc425a_channels, 319 .num_channels = ARRAY_SIZE(hmc425a_channels), 320 .num_gpios = 4, 321 .gain_min = -15000, 322 .gain_max = 0, 323 .default_gain = -0x10, /* set default gain -15.0db*/ 324 .gain_dB_to_code = hmc540s_gain_dB_to_code, 325 .code_to_gain_dB = hmc540s_code_to_gain_dB, 326 }, 327 [ID_ADRF5740] = { 328 .name = "adrf5740", 329 .channels = hmc425a_channels, 330 .num_channels = ARRAY_SIZE(hmc425a_channels), 331 .num_gpios = 4, 332 .gain_min = -22000, 333 .gain_max = 0, 334 .default_gain = 0xF, /* set default gain -22.0db*/ 335 .gain_dB_to_code = adrf5740_gain_dB_to_code, 336 .code_to_gain_dB = adrf5740_code_to_gain_dB, 337 }, 338 [ID_LTC6373] = { 339 .name = "ltc6373", 340 .channels = ltc6373_channels, 341 .num_channels = ARRAY_SIZE(ltc6373_channels), 342 .num_gpios = 3, 343 .gain_min = -12041, /* gain setting x0.25*/ 344 .gain_max = 24082, /* gain setting x16 */ 345 .default_gain = LTC6373_MIN_GAIN_CODE, 346 .powerdown_val = LTC6373_SHUTDOWN, 347 .has_powerdown = true, 348 .gain_dB_to_code = ltc6373_gain_dB_to_code, 349 .code_to_gain_dB = ltc6373_code_to_gain_dB, 350 }, 351 }; 352 353 static int hmc425a_probe(struct platform_device *pdev) 354 { 355 struct iio_dev *indio_dev; 356 struct hmc425a_state *st; 357 int ret; 358 359 indio_dev = devm_iio_device_alloc(&pdev->dev, sizeof(*st)); 360 if (!indio_dev) 361 return -ENOMEM; 362 363 st = iio_priv(indio_dev); 364 365 st->chip_info = device_get_match_data(&pdev->dev); 366 indio_dev->num_channels = st->chip_info->num_channels; 367 indio_dev->channels = st->chip_info->channels; 368 indio_dev->name = st->chip_info->name; 369 st->gain = st->chip_info->default_gain; 370 371 st->gpios = devm_gpiod_get_array(&pdev->dev, "ctrl", GPIOD_OUT_LOW); 372 if (IS_ERR(st->gpios)) 373 return dev_err_probe(&pdev->dev, PTR_ERR(st->gpios), 374 "failed to get gpios\n"); 375 376 if (st->gpios->ndescs != st->chip_info->num_gpios) { 377 dev_err(&pdev->dev, "%d GPIOs needed to operate\n", 378 st->chip_info->num_gpios); 379 return -ENODEV; 380 } 381 382 ret = devm_regulator_get_enable(&pdev->dev, "vcc-supply"); 383 if (ret) 384 return ret; 385 386 mutex_init(&st->lock); 387 388 indio_dev->info = &hmc425a_info; 389 indio_dev->modes = INDIO_DIRECT_MODE; 390 391 if (st->chip_info->has_powerdown) { 392 st->powerdown = true; 393 hmc425a_write(indio_dev, st->chip_info->powerdown_val); 394 } else { 395 /* Set default gain */ 396 hmc425a_write(indio_dev, st->gain); 397 } 398 399 return devm_iio_device_register(&pdev->dev, indio_dev); 400 } 401 402 /* Match table for of_platform binding */ 403 static const struct of_device_id hmc425a_of_match[] = { 404 { .compatible = "adi,hmc425a", 405 .data = &hmc425a_chip_info_tbl[ID_HMC425A]}, 406 { .compatible = "adi,hmc540s", 407 .data = &hmc425a_chip_info_tbl[ID_HMC540S]}, 408 { .compatible = "adi,adrf5740", 409 .data = &hmc425a_chip_info_tbl[ID_ADRF5740]}, 410 { .compatible = "adi,ltc6373", 411 .data = &hmc425a_chip_info_tbl[ID_LTC6373]}, 412 {} 413 }; 414 MODULE_DEVICE_TABLE(of, hmc425a_of_match); 415 416 static struct platform_driver hmc425a_driver = { 417 .driver = { 418 .name = KBUILD_MODNAME, 419 .of_match_table = hmc425a_of_match, 420 }, 421 .probe = hmc425a_probe, 422 }; 423 module_platform_driver(hmc425a_driver); 424 425 MODULE_AUTHOR("Michael Hennerich <michael.hennerich@analog.com>"); 426 MODULE_DESCRIPTION("Analog Devices HMC425A and similar GPIO control Gain Amplifiers"); 427 MODULE_LICENSE("GPL v2"); 428