lsm303dlhc_mag.c (15812B)
1 /* 2 * LSM303DLHC I2C magnetometer. 3 * 4 * Copyright (C) 2021 Linaro Ltd. 5 * Written by Kevin Townsend <kevin.townsend@linaro.org> 6 * 7 * Based on: https://www.st.com/resource/en/datasheet/lsm303dlhc.pdf 8 * 9 * SPDX-License-Identifier: GPL-2.0-or-later 10 */ 11 12 /* 13 * The I2C address associated with this device is set on the command-line when 14 * initialising the machine, but the following address is standard: 0x1E. 15 * 16 * Get and set functions for 'mag-x', 'mag-y' and 'mag-z' assume that 17 * 1 = 0.001 uT. (NOTE the 1 gauss = 100 uT, so setting a value of 100,000 18 * would be equal to 1 gauss or 100 uT.) 19 * 20 * Get and set functions for 'temperature' assume that 1 = 0.001 C, so 23.6 C 21 * would be equal to 23600. 22 */ 23 24 #include "qemu/osdep.h" 25 #include "hw/i2c/i2c.h" 26 #include "migration/vmstate.h" 27 #include "qapi/error.h" 28 #include "qapi/visitor.h" 29 #include "qemu/module.h" 30 #include "qemu/log.h" 31 #include "qemu/bswap.h" 32 33 enum LSM303DLHCMagReg { 34 LSM303DLHC_MAG_REG_CRA = 0x00, 35 LSM303DLHC_MAG_REG_CRB = 0x01, 36 LSM303DLHC_MAG_REG_MR = 0x02, 37 LSM303DLHC_MAG_REG_OUT_X_H = 0x03, 38 LSM303DLHC_MAG_REG_OUT_X_L = 0x04, 39 LSM303DLHC_MAG_REG_OUT_Z_H = 0x05, 40 LSM303DLHC_MAG_REG_OUT_Z_L = 0x06, 41 LSM303DLHC_MAG_REG_OUT_Y_H = 0x07, 42 LSM303DLHC_MAG_REG_OUT_Y_L = 0x08, 43 LSM303DLHC_MAG_REG_SR = 0x09, 44 LSM303DLHC_MAG_REG_IRA = 0x0A, 45 LSM303DLHC_MAG_REG_IRB = 0x0B, 46 LSM303DLHC_MAG_REG_IRC = 0x0C, 47 LSM303DLHC_MAG_REG_TEMP_OUT_H = 0x31, 48 LSM303DLHC_MAG_REG_TEMP_OUT_L = 0x32 49 }; 50 51 typedef struct LSM303DLHCMagState { 52 I2CSlave parent_obj; 53 uint8_t cra; 54 uint8_t crb; 55 uint8_t mr; 56 int16_t x; 57 int16_t z; 58 int16_t y; 59 int16_t x_lock; 60 int16_t z_lock; 61 int16_t y_lock; 62 uint8_t sr; 63 uint8_t ira; 64 uint8_t irb; 65 uint8_t irc; 66 int16_t temperature; 67 int16_t temperature_lock; 68 uint8_t len; 69 uint8_t buf; 70 uint8_t pointer; 71 } LSM303DLHCMagState; 72 73 #define TYPE_LSM303DLHC_MAG "lsm303dlhc_mag" 74 OBJECT_DECLARE_SIMPLE_TYPE(LSM303DLHCMagState, LSM303DLHC_MAG) 75 76 /* 77 * Conversion factor from Gauss to sensor values for each GN gain setting, 78 * in units "lsb per Gauss" (see data sheet table 3). There is no documented 79 * behaviour if the GN setting in CRB is incorrectly set to 0b000; 80 * we arbitrarily make it the same as 0b001. 81 */ 82 uint32_t xy_gain[] = { 1100, 1100, 855, 670, 450, 400, 330, 230 }; 83 uint32_t z_gain[] = { 980, 980, 760, 600, 400, 355, 295, 205 }; 84 85 static void lsm303dlhc_mag_get_x(Object *obj, Visitor *v, const char *name, 86 void *opaque, Error **errp) 87 { 88 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 89 int gm = extract32(s->crb, 5, 3); 90 91 /* Convert to uT where 1000 = 1 uT. Conversion factor depends on gain. */ 92 int64_t value = muldiv64(s->x, 100000, xy_gain[gm]); 93 visit_type_int(v, name, &value, errp); 94 } 95 96 static void lsm303dlhc_mag_get_y(Object *obj, Visitor *v, const char *name, 97 void *opaque, Error **errp) 98 { 99 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 100 int gm = extract32(s->crb, 5, 3); 101 102 /* Convert to uT where 1000 = 1 uT. Conversion factor depends on gain. */ 103 int64_t value = muldiv64(s->y, 100000, xy_gain[gm]); 104 visit_type_int(v, name, &value, errp); 105 } 106 107 static void lsm303dlhc_mag_get_z(Object *obj, Visitor *v, const char *name, 108 void *opaque, Error **errp) 109 { 110 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 111 int gm = extract32(s->crb, 5, 3); 112 113 /* Convert to uT where 1000 = 1 uT. Conversion factor depends on gain. */ 114 int64_t value = muldiv64(s->z, 100000, z_gain[gm]); 115 visit_type_int(v, name, &value, errp); 116 } 117 118 static void lsm303dlhc_mag_set_x(Object *obj, Visitor *v, const char *name, 119 void *opaque, Error **errp) 120 { 121 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 122 int64_t value; 123 int64_t reg; 124 int gm = extract32(s->crb, 5, 3); 125 126 if (!visit_type_int(v, name, &value, errp)) { 127 return; 128 } 129 130 reg = muldiv64(value, xy_gain[gm], 100000); 131 132 /* Make sure we are within a 12-bit limit. */ 133 if (reg > 2047 || reg < -2048) { 134 error_setg(errp, "value %" PRId64 " out of register's range", value); 135 return; 136 } 137 138 s->x = (int16_t)reg; 139 } 140 141 static void lsm303dlhc_mag_set_y(Object *obj, Visitor *v, const char *name, 142 void *opaque, Error **errp) 143 { 144 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 145 int64_t value; 146 int64_t reg; 147 int gm = extract32(s->crb, 5, 3); 148 149 if (!visit_type_int(v, name, &value, errp)) { 150 return; 151 } 152 153 reg = muldiv64(value, xy_gain[gm], 100000); 154 155 /* Make sure we are within a 12-bit limit. */ 156 if (reg > 2047 || reg < -2048) { 157 error_setg(errp, "value %" PRId64 " out of register's range", value); 158 return; 159 } 160 161 s->y = (int16_t)reg; 162 } 163 164 static void lsm303dlhc_mag_set_z(Object *obj, Visitor *v, const char *name, 165 void *opaque, Error **errp) 166 { 167 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 168 int64_t value; 169 int64_t reg; 170 int gm = extract32(s->crb, 5, 3); 171 172 if (!visit_type_int(v, name, &value, errp)) { 173 return; 174 } 175 176 reg = muldiv64(value, z_gain[gm], 100000); 177 178 /* Make sure we are within a 12-bit limit. */ 179 if (reg > 2047 || reg < -2048) { 180 error_setg(errp, "value %" PRId64 " out of register's range", value); 181 return; 182 } 183 184 s->z = (int16_t)reg; 185 } 186 187 /* 188 * Get handler for the temperature property. 189 */ 190 static void lsm303dlhc_mag_get_temperature(Object *obj, Visitor *v, 191 const char *name, void *opaque, 192 Error **errp) 193 { 194 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 195 int64_t value; 196 197 /* Convert to 1 lsb = 0.125 C to 1 = 0.001 C for 'temperature' property. */ 198 value = s->temperature * 125; 199 200 visit_type_int(v, name, &value, errp); 201 } 202 203 /* 204 * Set handler for the temperature property. 205 */ 206 static void lsm303dlhc_mag_set_temperature(Object *obj, Visitor *v, 207 const char *name, void *opaque, 208 Error **errp) 209 { 210 LSM303DLHCMagState *s = LSM303DLHC_MAG(obj); 211 int64_t value; 212 213 if (!visit_type_int(v, name, &value, errp)) { 214 return; 215 } 216 217 /* Input temperature is in 0.001 C units. Convert to 1 lsb = 0.125 C. */ 218 value /= 125; 219 220 if (value > 2047 || value < -2048) { 221 error_setg(errp, "value %" PRId64 " lsb is out of range", value); 222 return; 223 } 224 225 s->temperature = (int16_t)value; 226 } 227 228 /* 229 * Callback handler whenever a 'I2C_START_RECV' (read) event is received. 230 */ 231 static void lsm303dlhc_mag_read(LSM303DLHCMagState *s) 232 { 233 /* 234 * Set the LOCK bit whenever a new read attempt is made. This will be 235 * cleared in I2C_FINISH. Note that DRDY is always set to 1 in this driver. 236 */ 237 s->sr = 0x3; 238 239 /* 240 * Copy the current X/Y/Z and temp. values into the locked registers so 241 * that 'mag-x', 'mag-y', 'mag-z' and 'temperature' can continue to be 242 * updated via QOM, etc., without corrupting the current read event. 243 */ 244 s->x_lock = s->x; 245 s->z_lock = s->z; 246 s->y_lock = s->y; 247 s->temperature_lock = s->temperature; 248 } 249 250 /* 251 * Callback handler whenever a 'I2C_FINISH' event is received. 252 */ 253 static void lsm303dlhc_mag_finish(LSM303DLHCMagState *s) 254 { 255 /* 256 * Clear the LOCK bit when the read attempt terminates. 257 * This bit is initially set in the I2C_START_RECV handler. 258 */ 259 s->sr = 0x1; 260 } 261 262 /* 263 * Callback handler when a device attempts to write to a register. 264 */ 265 static void lsm303dlhc_mag_write(LSM303DLHCMagState *s) 266 { 267 switch (s->pointer) { 268 case LSM303DLHC_MAG_REG_CRA: 269 s->cra = s->buf; 270 break; 271 case LSM303DLHC_MAG_REG_CRB: 272 /* Make sure gain is at least 1, falling back to 1 on an error. */ 273 if (s->buf >> 5 == 0) { 274 s->buf = 1 << 5; 275 } 276 s->crb = s->buf; 277 break; 278 case LSM303DLHC_MAG_REG_MR: 279 s->mr = s->buf; 280 break; 281 case LSM303DLHC_MAG_REG_SR: 282 s->sr = s->buf; 283 break; 284 case LSM303DLHC_MAG_REG_IRA: 285 s->ira = s->buf; 286 break; 287 case LSM303DLHC_MAG_REG_IRB: 288 s->irb = s->buf; 289 break; 290 case LSM303DLHC_MAG_REG_IRC: 291 s->irc = s->buf; 292 break; 293 default: 294 qemu_log_mask(LOG_GUEST_ERROR, "reg is read-only: 0x%02X", s->buf); 295 break; 296 } 297 } 298 299 /* 300 * Low-level master-to-slave transaction handler. 301 */ 302 static int lsm303dlhc_mag_send(I2CSlave *i2c, uint8_t data) 303 { 304 LSM303DLHCMagState *s = LSM303DLHC_MAG(i2c); 305 306 if (s->len == 0) { 307 /* First byte is the reg pointer */ 308 s->pointer = data; 309 s->len++; 310 } else if (s->len == 1) { 311 /* Second byte is the new register value. */ 312 s->buf = data; 313 lsm303dlhc_mag_write(s); 314 } else { 315 g_assert_not_reached(); 316 } 317 318 return 0; 319 } 320 321 /* 322 * Low-level slave-to-master transaction handler (read attempts). 323 */ 324 static uint8_t lsm303dlhc_mag_recv(I2CSlave *i2c) 325 { 326 LSM303DLHCMagState *s = LSM303DLHC_MAG(i2c); 327 uint8_t resp; 328 329 switch (s->pointer) { 330 case LSM303DLHC_MAG_REG_CRA: 331 resp = s->cra; 332 break; 333 case LSM303DLHC_MAG_REG_CRB: 334 resp = s->crb; 335 break; 336 case LSM303DLHC_MAG_REG_MR: 337 resp = s->mr; 338 break; 339 case LSM303DLHC_MAG_REG_OUT_X_H: 340 resp = (uint8_t)(s->x_lock >> 8); 341 break; 342 case LSM303DLHC_MAG_REG_OUT_X_L: 343 resp = (uint8_t)(s->x_lock); 344 break; 345 case LSM303DLHC_MAG_REG_OUT_Z_H: 346 resp = (uint8_t)(s->z_lock >> 8); 347 break; 348 case LSM303DLHC_MAG_REG_OUT_Z_L: 349 resp = (uint8_t)(s->z_lock); 350 break; 351 case LSM303DLHC_MAG_REG_OUT_Y_H: 352 resp = (uint8_t)(s->y_lock >> 8); 353 break; 354 case LSM303DLHC_MAG_REG_OUT_Y_L: 355 resp = (uint8_t)(s->y_lock); 356 break; 357 case LSM303DLHC_MAG_REG_SR: 358 resp = s->sr; 359 break; 360 case LSM303DLHC_MAG_REG_IRA: 361 resp = s->ira; 362 break; 363 case LSM303DLHC_MAG_REG_IRB: 364 resp = s->irb; 365 break; 366 case LSM303DLHC_MAG_REG_IRC: 367 resp = s->irc; 368 break; 369 case LSM303DLHC_MAG_REG_TEMP_OUT_H: 370 /* Check if the temperature sensor is enabled or not (CRA & 0x80). */ 371 if (s->cra & 0x80) { 372 resp = (uint8_t)(s->temperature_lock >> 8); 373 } else { 374 resp = 0; 375 } 376 break; 377 case LSM303DLHC_MAG_REG_TEMP_OUT_L: 378 if (s->cra & 0x80) { 379 resp = (uint8_t)(s->temperature_lock & 0xff); 380 } else { 381 resp = 0; 382 } 383 break; 384 default: 385 resp = 0; 386 break; 387 } 388 389 /* 390 * The address pointer on the LSM303DLHC auto-increments whenever a byte 391 * is read, without the master device having to request the next address. 392 * 393 * The auto-increment process has the following logic: 394 * 395 * - if (s->pointer == 8) then s->pointer = 3 396 * - else: if (s->pointer == 12) then s->pointer = 0 397 * - else: s->pointer += 1 398 * 399 * Reading an invalid address return 0. 400 */ 401 if (s->pointer == LSM303DLHC_MAG_REG_OUT_Y_L) { 402 s->pointer = LSM303DLHC_MAG_REG_OUT_X_H; 403 } else if (s->pointer == LSM303DLHC_MAG_REG_IRC) { 404 s->pointer = LSM303DLHC_MAG_REG_CRA; 405 } else { 406 s->pointer++; 407 } 408 409 return resp; 410 } 411 412 /* 413 * Bus state change handler. 414 */ 415 static int lsm303dlhc_mag_event(I2CSlave *i2c, enum i2c_event event) 416 { 417 LSM303DLHCMagState *s = LSM303DLHC_MAG(i2c); 418 419 switch (event) { 420 case I2C_START_SEND: 421 break; 422 case I2C_START_RECV: 423 lsm303dlhc_mag_read(s); 424 break; 425 case I2C_FINISH: 426 lsm303dlhc_mag_finish(s); 427 break; 428 case I2C_NACK: 429 break; 430 default: 431 return -1; 432 } 433 434 s->len = 0; 435 return 0; 436 } 437 438 /* 439 * Device data description using VMSTATE macros. 440 */ 441 static const VMStateDescription vmstate_lsm303dlhc_mag = { 442 .name = "LSM303DLHC_MAG", 443 .version_id = 0, 444 .minimum_version_id = 0, 445 .fields = (VMStateField[]) { 446 447 VMSTATE_I2C_SLAVE(parent_obj, LSM303DLHCMagState), 448 VMSTATE_UINT8(len, LSM303DLHCMagState), 449 VMSTATE_UINT8(buf, LSM303DLHCMagState), 450 VMSTATE_UINT8(pointer, LSM303DLHCMagState), 451 VMSTATE_UINT8(cra, LSM303DLHCMagState), 452 VMSTATE_UINT8(crb, LSM303DLHCMagState), 453 VMSTATE_UINT8(mr, LSM303DLHCMagState), 454 VMSTATE_INT16(x, LSM303DLHCMagState), 455 VMSTATE_INT16(z, LSM303DLHCMagState), 456 VMSTATE_INT16(y, LSM303DLHCMagState), 457 VMSTATE_INT16(x_lock, LSM303DLHCMagState), 458 VMSTATE_INT16(z_lock, LSM303DLHCMagState), 459 VMSTATE_INT16(y_lock, LSM303DLHCMagState), 460 VMSTATE_UINT8(sr, LSM303DLHCMagState), 461 VMSTATE_UINT8(ira, LSM303DLHCMagState), 462 VMSTATE_UINT8(irb, LSM303DLHCMagState), 463 VMSTATE_UINT8(irc, LSM303DLHCMagState), 464 VMSTATE_INT16(temperature, LSM303DLHCMagState), 465 VMSTATE_INT16(temperature_lock, LSM303DLHCMagState), 466 VMSTATE_END_OF_LIST() 467 } 468 }; 469 470 /* 471 * Put the device into post-reset default state. 472 */ 473 static void lsm303dlhc_mag_default_cfg(LSM303DLHCMagState *s) 474 { 475 /* Set the device into is default reset state. */ 476 s->len = 0; 477 s->pointer = 0; /* Current register. */ 478 s->buf = 0; /* Shared buffer. */ 479 s->cra = 0x10; /* Temp Enabled = 0, Data Rate = 15.0 Hz. */ 480 s->crb = 0x20; /* Gain = +/- 1.3 Gauss. */ 481 s->mr = 0x3; /* Operating Mode = Sleep. */ 482 s->x = 0; 483 s->z = 0; 484 s->y = 0; 485 s->x_lock = 0; 486 s->z_lock = 0; 487 s->y_lock = 0; 488 s->sr = 0x1; /* DRDY = 1. */ 489 s->ira = 0x48; 490 s->irb = 0x34; 491 s->irc = 0x33; 492 s->temperature = 0; /* Default to 0 degrees C (0/8 lsb = 0 C). */ 493 s->temperature_lock = 0; 494 } 495 496 /* 497 * Callback handler when DeviceState 'reset' is set to true. 498 */ 499 static void lsm303dlhc_mag_reset(DeviceState *dev) 500 { 501 I2CSlave *i2c = I2C_SLAVE(dev); 502 LSM303DLHCMagState *s = LSM303DLHC_MAG(i2c); 503 504 /* Set the device into its default reset state. */ 505 lsm303dlhc_mag_default_cfg(s); 506 } 507 508 /* 509 * Initialisation of any public properties. 510 */ 511 static void lsm303dlhc_mag_initfn(Object *obj) 512 { 513 object_property_add(obj, "mag-x", "int", 514 lsm303dlhc_mag_get_x, 515 lsm303dlhc_mag_set_x, NULL, NULL); 516 517 object_property_add(obj, "mag-y", "int", 518 lsm303dlhc_mag_get_y, 519 lsm303dlhc_mag_set_y, NULL, NULL); 520 521 object_property_add(obj, "mag-z", "int", 522 lsm303dlhc_mag_get_z, 523 lsm303dlhc_mag_set_z, NULL, NULL); 524 525 object_property_add(obj, "temperature", "int", 526 lsm303dlhc_mag_get_temperature, 527 lsm303dlhc_mag_set_temperature, NULL, NULL); 528 } 529 530 /* 531 * Set the virtual method pointers (bus state change, tx/rx, etc.). 532 */ 533 static void lsm303dlhc_mag_class_init(ObjectClass *klass, void *data) 534 { 535 DeviceClass *dc = DEVICE_CLASS(klass); 536 I2CSlaveClass *k = I2C_SLAVE_CLASS(klass); 537 538 dc->reset = lsm303dlhc_mag_reset; 539 dc->vmsd = &vmstate_lsm303dlhc_mag; 540 k->event = lsm303dlhc_mag_event; 541 k->recv = lsm303dlhc_mag_recv; 542 k->send = lsm303dlhc_mag_send; 543 } 544 545 static const TypeInfo lsm303dlhc_mag_info = { 546 .name = TYPE_LSM303DLHC_MAG, 547 .parent = TYPE_I2C_SLAVE, 548 .instance_size = sizeof(LSM303DLHCMagState), 549 .instance_init = lsm303dlhc_mag_initfn, 550 .class_init = lsm303dlhc_mag_class_init, 551 }; 552 553 static void lsm303dlhc_mag_register_types(void) 554 { 555 type_register_static(&lsm303dlhc_mag_info); 556 } 557 558 type_init(lsm303dlhc_mag_register_types)