1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * SiRFstar GNSS receiver driver 4 * 5 * Copyright (C) 2018 Johan Hovold <johan@kernel.org> 6 */ 7 8 #include <linux/errno.h> 9 #include <linux/gnss.h> 10 #include <linux/gpio/consumer.h> 11 #include <linux/init.h> 12 #include <linux/interrupt.h> 13 #include <linux/kernel.h> 14 #include <linux/module.h> 15 #include <linux/of.h> 16 #include <linux/pm.h> 17 #include <linux/pm_runtime.h> 18 #include <linux/regulator/consumer.h> 19 #include <linux/sched.h> 20 #include <linux/serdev.h> 21 #include <linux/slab.h> 22 #include <linux/wait.h> 23 24 #define SIRF_BOOT_DELAY 500 25 #define SIRF_ON_OFF_PULSE_TIME 100 26 #define SIRF_ACTIVATE_TIMEOUT 200 27 #define SIRF_HIBERNATE_TIMEOUT 200 28 /* 29 * If no data arrives for this time, we assume that the chip is off. 30 * REVISIT: The report cycle is configurable and can be several minutes long, 31 * so this will only work reliably if the report cycle is set to a reasonable 32 * low value. Also power saving settings (like send data only on movement) 33 * might things work even worse. 34 * Workaround might be to parse shutdown or bootup messages. 35 */ 36 #define SIRF_REPORT_CYCLE 2000 37 38 struct sirf_data { 39 struct gnss_device *gdev; 40 struct serdev_device *serdev; 41 speed_t speed; 42 struct regulator *vcc; 43 struct regulator *lna; 44 struct gpio_desc *on_off; 45 struct gpio_desc *wakeup; 46 int irq; 47 bool active; 48 49 struct mutex gdev_mutex; 50 bool open; 51 52 struct mutex serdev_mutex; 53 int serdev_count; 54 55 wait_queue_head_t power_wait; 56 }; 57 58 static int sirf_serdev_open(struct sirf_data *data) 59 { 60 int ret = 0; 61 62 mutex_lock(&data->serdev_mutex); 63 if (++data->serdev_count == 1) { 64 ret = serdev_device_open(data->serdev); 65 if (ret) { 66 data->serdev_count--; 67 goto out_unlock; 68 } 69 70 serdev_device_set_baudrate(data->serdev, data->speed); 71 serdev_device_set_flow_control(data->serdev, false); 72 } 73 74 out_unlock: 75 mutex_unlock(&data->serdev_mutex); 76 77 return ret; 78 } 79 80 static void sirf_serdev_close(struct sirf_data *data) 81 { 82 mutex_lock(&data->serdev_mutex); 83 if (--data->serdev_count == 0) 84 serdev_device_close(data->serdev); 85 mutex_unlock(&data->serdev_mutex); 86 } 87 88 static int sirf_open(struct gnss_device *gdev) 89 { 90 struct sirf_data *data = gnss_get_drvdata(gdev); 91 struct serdev_device *serdev = data->serdev; 92 int ret; 93 94 mutex_lock(&data->gdev_mutex); 95 data->open = true; 96 mutex_unlock(&data->gdev_mutex); 97 98 ret = sirf_serdev_open(data); 99 if (ret) { 100 mutex_lock(&data->gdev_mutex); 101 data->open = false; 102 mutex_unlock(&data->gdev_mutex); 103 return ret; 104 } 105 106 ret = pm_runtime_get_sync(&serdev->dev); 107 if (ret < 0) { 108 dev_err(&gdev->dev, "failed to runtime resume: %d\n", ret); 109 pm_runtime_put_noidle(&serdev->dev); 110 goto err_close; 111 } 112 113 return 0; 114 115 err_close: 116 sirf_serdev_close(data); 117 118 mutex_lock(&data->gdev_mutex); 119 data->open = false; 120 mutex_unlock(&data->gdev_mutex); 121 122 return ret; 123 } 124 125 static void sirf_close(struct gnss_device *gdev) 126 { 127 struct sirf_data *data = gnss_get_drvdata(gdev); 128 struct serdev_device *serdev = data->serdev; 129 130 sirf_serdev_close(data); 131 132 pm_runtime_put(&serdev->dev); 133 134 mutex_lock(&data->gdev_mutex); 135 data->open = false; 136 mutex_unlock(&data->gdev_mutex); 137 } 138 139 static int sirf_write_raw(struct gnss_device *gdev, const unsigned char *buf, 140 size_t count) 141 { 142 struct sirf_data *data = gnss_get_drvdata(gdev); 143 struct serdev_device *serdev = data->serdev; 144 int ret; 145 146 /* write is only buffered synchronously */ 147 ret = serdev_device_write(serdev, buf, count, MAX_SCHEDULE_TIMEOUT); 148 if (ret < 0 || ret < count) 149 return ret; 150 151 /* FIXME: determine if interrupted? */ 152 serdev_device_wait_until_sent(serdev, 0); 153 154 return count; 155 } 156 157 static const struct gnss_operations sirf_gnss_ops = { 158 .open = sirf_open, 159 .close = sirf_close, 160 .write_raw = sirf_write_raw, 161 }; 162 163 static int sirf_receive_buf(struct serdev_device *serdev, 164 const unsigned char *buf, size_t count) 165 { 166 struct sirf_data *data = serdev_device_get_drvdata(serdev); 167 struct gnss_device *gdev = data->gdev; 168 int ret = 0; 169 170 if (!data->wakeup && !data->active) { 171 data->active = true; 172 wake_up_interruptible(&data->power_wait); 173 } 174 175 mutex_lock(&data->gdev_mutex); 176 if (data->open) 177 ret = gnss_insert_raw(gdev, buf, count); 178 mutex_unlock(&data->gdev_mutex); 179 180 return ret; 181 } 182 183 static const struct serdev_device_ops sirf_serdev_ops = { 184 .receive_buf = sirf_receive_buf, 185 .write_wakeup = serdev_device_write_wakeup, 186 }; 187 188 static irqreturn_t sirf_wakeup_handler(int irq, void *dev_id) 189 { 190 struct sirf_data *data = dev_id; 191 struct device *dev = &data->serdev->dev; 192 int ret; 193 194 ret = gpiod_get_value_cansleep(data->wakeup); 195 dev_dbg(dev, "%s - wakeup = %d\n", __func__, ret); 196 if (ret < 0) 197 goto out; 198 199 data->active = ret; 200 wake_up_interruptible(&data->power_wait); 201 out: 202 return IRQ_HANDLED; 203 } 204 205 static int sirf_wait_for_power_state_nowakeup(struct sirf_data *data, 206 bool active, 207 unsigned long timeout) 208 { 209 int ret; 210 211 /* Wait for state change (including any shutdown messages). */ 212 msleep(timeout); 213 214 /* Wait for data reception or timeout. */ 215 data->active = false; 216 ret = wait_event_interruptible_timeout(data->power_wait, 217 data->active, msecs_to_jiffies(SIRF_REPORT_CYCLE)); 218 if (ret < 0) 219 return ret; 220 221 if (ret > 0 && !active) 222 return -ETIMEDOUT; 223 224 if (ret == 0 && active) 225 return -ETIMEDOUT; 226 227 return 0; 228 } 229 230 static int sirf_wait_for_power_state(struct sirf_data *data, bool active, 231 unsigned long timeout) 232 { 233 int ret; 234 235 if (!data->wakeup) 236 return sirf_wait_for_power_state_nowakeup(data, active, timeout); 237 238 ret = wait_event_interruptible_timeout(data->power_wait, 239 data->active == active, msecs_to_jiffies(timeout)); 240 if (ret < 0) 241 return ret; 242 243 if (ret == 0) { 244 dev_warn(&data->serdev->dev, "timeout waiting for active state = %d\n", 245 active); 246 return -ETIMEDOUT; 247 } 248 249 return 0; 250 } 251 252 static void sirf_pulse_on_off(struct sirf_data *data) 253 { 254 gpiod_set_value_cansleep(data->on_off, 1); 255 msleep(SIRF_ON_OFF_PULSE_TIME); 256 gpiod_set_value_cansleep(data->on_off, 0); 257 } 258 259 static int sirf_set_active(struct sirf_data *data, bool active) 260 { 261 unsigned long timeout; 262 int retries = 3; 263 int ret; 264 265 if (active) 266 timeout = SIRF_ACTIVATE_TIMEOUT; 267 else 268 timeout = SIRF_HIBERNATE_TIMEOUT; 269 270 if (!data->wakeup) { 271 ret = sirf_serdev_open(data); 272 if (ret) 273 return ret; 274 } 275 276 do { 277 sirf_pulse_on_off(data); 278 ret = sirf_wait_for_power_state(data, active, timeout); 279 } while (ret == -ETIMEDOUT && retries--); 280 281 if (!data->wakeup) 282 sirf_serdev_close(data); 283 284 if (ret) 285 return ret; 286 287 return 0; 288 } 289 290 static int sirf_runtime_suspend(struct device *dev) 291 { 292 struct sirf_data *data = dev_get_drvdata(dev); 293 int ret2; 294 int ret; 295 296 if (data->on_off) 297 ret = sirf_set_active(data, false); 298 else 299 ret = regulator_disable(data->vcc); 300 301 if (ret) 302 return ret; 303 304 ret = regulator_disable(data->lna); 305 if (ret) 306 goto err_reenable; 307 308 return 0; 309 310 err_reenable: 311 if (data->on_off) 312 ret2 = sirf_set_active(data, true); 313 else 314 ret2 = regulator_enable(data->vcc); 315 316 if (ret2) 317 dev_err(dev, 318 "failed to reenable power on failed suspend: %d\n", 319 ret2); 320 321 return ret; 322 } 323 324 static int sirf_runtime_resume(struct device *dev) 325 { 326 struct sirf_data *data = dev_get_drvdata(dev); 327 int ret; 328 329 ret = regulator_enable(data->lna); 330 if (ret) 331 return ret; 332 333 if (data->on_off) 334 ret = sirf_set_active(data, true); 335 else 336 ret = regulator_enable(data->vcc); 337 338 if (ret) 339 goto err_disable_lna; 340 341 return 0; 342 343 err_disable_lna: 344 regulator_disable(data->lna); 345 346 return ret; 347 } 348 349 static int __maybe_unused sirf_suspend(struct device *dev) 350 { 351 struct sirf_data *data = dev_get_drvdata(dev); 352 int ret = 0; 353 354 if (!pm_runtime_suspended(dev)) 355 ret = sirf_runtime_suspend(dev); 356 357 if (data->wakeup) 358 disable_irq(data->irq); 359 360 return ret; 361 } 362 363 static int __maybe_unused sirf_resume(struct device *dev) 364 { 365 struct sirf_data *data = dev_get_drvdata(dev); 366 int ret = 0; 367 368 if (data->wakeup) 369 enable_irq(data->irq); 370 371 if (!pm_runtime_suspended(dev)) 372 ret = sirf_runtime_resume(dev); 373 374 return ret; 375 } 376 377 static const struct dev_pm_ops sirf_pm_ops = { 378 SET_SYSTEM_SLEEP_PM_OPS(sirf_suspend, sirf_resume) 379 SET_RUNTIME_PM_OPS(sirf_runtime_suspend, sirf_runtime_resume, NULL) 380 }; 381 382 static int sirf_parse_dt(struct serdev_device *serdev) 383 { 384 struct sirf_data *data = serdev_device_get_drvdata(serdev); 385 struct device_node *node = serdev->dev.of_node; 386 u32 speed = 9600; 387 388 of_property_read_u32(node, "current-speed", &speed); 389 390 data->speed = speed; 391 392 return 0; 393 } 394 395 static int sirf_probe(struct serdev_device *serdev) 396 { 397 struct device *dev = &serdev->dev; 398 struct gnss_device *gdev; 399 struct sirf_data *data; 400 int ret; 401 402 data = devm_kzalloc(dev, sizeof(*data), GFP_KERNEL); 403 if (!data) 404 return -ENOMEM; 405 406 gdev = gnss_allocate_device(dev); 407 if (!gdev) 408 return -ENOMEM; 409 410 gdev->type = GNSS_TYPE_SIRF; 411 gdev->ops = &sirf_gnss_ops; 412 gnss_set_drvdata(gdev, data); 413 414 data->serdev = serdev; 415 data->gdev = gdev; 416 417 mutex_init(&data->gdev_mutex); 418 mutex_init(&data->serdev_mutex); 419 init_waitqueue_head(&data->power_wait); 420 421 serdev_device_set_drvdata(serdev, data); 422 serdev_device_set_client_ops(serdev, &sirf_serdev_ops); 423 424 ret = sirf_parse_dt(serdev); 425 if (ret) 426 goto err_put_device; 427 428 data->vcc = devm_regulator_get(dev, "vcc"); 429 if (IS_ERR(data->vcc)) { 430 ret = PTR_ERR(data->vcc); 431 goto err_put_device; 432 } 433 434 data->lna = devm_regulator_get(dev, "lna"); 435 if (IS_ERR(data->lna)) { 436 ret = PTR_ERR(data->lna); 437 goto err_put_device; 438 } 439 440 data->on_off = devm_gpiod_get_optional(dev, "sirf,onoff", 441 GPIOD_OUT_LOW); 442 if (IS_ERR(data->on_off)) 443 goto err_put_device; 444 445 if (data->on_off) { 446 data->wakeup = devm_gpiod_get_optional(dev, "sirf,wakeup", 447 GPIOD_IN); 448 if (IS_ERR(data->wakeup)) 449 goto err_put_device; 450 451 ret = regulator_enable(data->vcc); 452 if (ret) 453 goto err_put_device; 454 455 /* Wait for chip to boot into hibernate mode. */ 456 msleep(SIRF_BOOT_DELAY); 457 } 458 459 if (data->wakeup) { 460 ret = gpiod_get_value_cansleep(data->wakeup); 461 if (ret < 0) 462 goto err_disable_vcc; 463 data->active = ret; 464 465 ret = gpiod_to_irq(data->wakeup); 466 if (ret < 0) 467 goto err_disable_vcc; 468 data->irq = ret; 469 470 ret = request_threaded_irq(data->irq, NULL, sirf_wakeup_handler, 471 IRQF_TRIGGER_RISING | IRQF_TRIGGER_FALLING | IRQF_ONESHOT, 472 "wakeup", data); 473 if (ret) 474 goto err_disable_vcc; 475 } 476 477 if (data->on_off) { 478 if (!data->wakeup) { 479 data->active = false; 480 481 ret = sirf_serdev_open(data); 482 if (ret) 483 goto err_disable_vcc; 484 485 msleep(SIRF_REPORT_CYCLE); 486 sirf_serdev_close(data); 487 } 488 489 /* Force hibernate mode if already active. */ 490 if (data->active) { 491 ret = sirf_set_active(data, false); 492 if (ret) { 493 dev_err(dev, "failed to set hibernate mode: %d\n", 494 ret); 495 goto err_free_irq; 496 } 497 } 498 } 499 500 if (IS_ENABLED(CONFIG_PM)) { 501 pm_runtime_set_suspended(dev); /* clear runtime_error flag */ 502 pm_runtime_enable(dev); 503 } else { 504 ret = sirf_runtime_resume(dev); 505 if (ret < 0) 506 goto err_free_irq; 507 } 508 509 ret = gnss_register_device(gdev); 510 if (ret) 511 goto err_disable_rpm; 512 513 return 0; 514 515 err_disable_rpm: 516 if (IS_ENABLED(CONFIG_PM)) 517 pm_runtime_disable(dev); 518 else 519 sirf_runtime_suspend(dev); 520 err_free_irq: 521 if (data->wakeup) 522 free_irq(data->irq, data); 523 err_disable_vcc: 524 if (data->on_off) 525 regulator_disable(data->vcc); 526 err_put_device: 527 gnss_put_device(data->gdev); 528 529 return ret; 530 } 531 532 static void sirf_remove(struct serdev_device *serdev) 533 { 534 struct sirf_data *data = serdev_device_get_drvdata(serdev); 535 536 gnss_deregister_device(data->gdev); 537 538 if (IS_ENABLED(CONFIG_PM)) 539 pm_runtime_disable(&serdev->dev); 540 else 541 sirf_runtime_suspend(&serdev->dev); 542 543 if (data->wakeup) 544 free_irq(data->irq, data); 545 546 if (data->on_off) 547 regulator_disable(data->vcc); 548 549 gnss_put_device(data->gdev); 550 }; 551 552 #ifdef CONFIG_OF 553 static const struct of_device_id sirf_of_match[] = { 554 { .compatible = "fastrax,uc430" }, 555 { .compatible = "linx,r4" }, 556 { .compatible = "wi2wi,w2sg0004" }, 557 { .compatible = "wi2wi,w2sg0008i" }, 558 { .compatible = "wi2wi,w2sg0084i" }, 559 {}, 560 }; 561 MODULE_DEVICE_TABLE(of, sirf_of_match); 562 #endif 563 564 static struct serdev_device_driver sirf_driver = { 565 .driver = { 566 .name = "gnss-sirf", 567 .of_match_table = of_match_ptr(sirf_of_match), 568 .pm = &sirf_pm_ops, 569 }, 570 .probe = sirf_probe, 571 .remove = sirf_remove, 572 }; 573 module_serdev_device_driver(sirf_driver); 574 575 MODULE_AUTHOR("Johan Hovold <johan@kernel.org>"); 576 MODULE_DESCRIPTION("SiRFstar GNSS receiver driver"); 577 MODULE_LICENSE("GPL v2"); 578