1/* 2 * htc-i2cpld.c 3 * Chip driver for an unknown CPLD chip found on omap850 HTC devices like 4 * the HTC Wizard and HTC Herald. 5 * The cpld is located on the i2c bus and acts as an input/output GPIO 6 * extender. 7 * 8 * Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com> 9 * 10 * Based on work done in the linwizard project 11 * Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com> 12 * 13 * This program is free software; you can redistribute it and/or modify 14 * it under the terms of the GNU General Public License as published by 15 * the Free Software Foundation; either version 2 of the License, or 16 * (at your option) any later version. 17 * 18 * This program is distributed in the hope that it will be useful, 19 * but WITHOUT ANY WARRANTY; without even the implied warranty of 20 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 21 * GNU General Public License for more details. 22 * 23 * You should have received a copy of the GNU General Public License 24 * along with this program; if not, write to the Free Software 25 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. 26 */ 27 28#include <linux/kernel.h> 29#include <linux/init.h> 30#include <linux/module.h> 31#include <linux/interrupt.h> 32#include <linux/platform_device.h> 33#include <linux/i2c.h> 34#include <linux/irq.h> 35#include <linux/spinlock.h> 36#include <linux/htcpld.h> 37#include <linux/gpio.h> 38#include <linux/slab.h> 39 40struct htcpld_chip { 41 spinlock_t lock; 42 43 /* chip info */ 44 u8 reset; 45 u8 addr; 46 struct device *dev; 47 struct i2c_client *client; 48 49 /* Output details */ 50 u8 cache_out; 51 struct gpio_chip chip_out; 52 53 /* Input details */ 54 u8 cache_in; 55 struct gpio_chip chip_in; 56 57 u16 irqs_enabled; 58 uint irq_start; 59 int nirqs; 60 61 unsigned int flow_type; 62 /* 63 * Work structure to allow for setting values outside of any 64 * possible interrupt context 65 */ 66 struct work_struct set_val_work; 67}; 68 69struct htcpld_data { 70 /* irq info */ 71 u16 irqs_enabled; 72 uint irq_start; 73 int nirqs; 74 uint chained_irq; 75 unsigned int int_reset_gpio_hi; 76 unsigned int int_reset_gpio_lo; 77 78 /* htcpld info */ 79 struct htcpld_chip *chip; 80 unsigned int nchips; 81}; 82 83/* There does not appear to be a way to proactively mask interrupts 84 * on the htcpld chip itself. So, we simply ignore interrupts that 85 * aren't desired. */ 86static void htcpld_mask(struct irq_data *data) 87{ 88 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data); 89 chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start)); 90 pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled); 91} 92static void htcpld_unmask(struct irq_data *data) 93{ 94 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data); 95 chip->irqs_enabled |= 1 << (data->irq - chip->irq_start); 96 pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled); 97} 98 99static int htcpld_set_type(struct irq_data *data, unsigned int flags) 100{ 101 struct htcpld_chip *chip = irq_data_get_irq_chip_data(data); 102 103 if (flags & ~IRQ_TYPE_SENSE_MASK) 104 return -EINVAL; 105 106 /* We only allow edge triggering */ 107 if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH)) 108 return -EINVAL; 109 110 chip->flow_type = flags; 111 return 0; 112} 113 114static struct irq_chip htcpld_muxed_chip = { 115 .name = "htcpld", 116 .irq_mask = htcpld_mask, 117 .irq_unmask = htcpld_unmask, 118 .irq_set_type = htcpld_set_type, 119}; 120 121/* To properly dispatch IRQ events, we need to read from the 122 * chip. This is an I2C action that could possibly sleep 123 * (which is bad in interrupt context) -- so we use a threaded 124 * interrupt handler to get around that. 125 */ 126static irqreturn_t htcpld_handler(int irq, void *dev) 127{ 128 struct htcpld_data *htcpld = dev; 129 unsigned int i; 130 unsigned long flags; 131 int irqpin; 132 133 if (!htcpld) { 134 pr_debug("htcpld is null in ISR\n"); 135 return IRQ_HANDLED; 136 } 137 138 /* 139 * For each chip, do a read of the chip and trigger any interrupts 140 * desired. The interrupts will be triggered from LSB to MSB (i.e. 141 * bit 0 first, then bit 1, etc.) 142 * 143 * For chips that have no interrupt range specified, just skip 'em. 144 */ 145 for (i = 0; i < htcpld->nchips; i++) { 146 struct htcpld_chip *chip = &htcpld->chip[i]; 147 struct i2c_client *client; 148 int val; 149 unsigned long uval, old_val; 150 151 if (!chip) { 152 pr_debug("chip %d is null in ISR\n", i); 153 continue; 154 } 155 156 if (chip->nirqs == 0) 157 continue; 158 159 client = chip->client; 160 if (!client) { 161 pr_debug("client %d is null in ISR\n", i); 162 continue; 163 } 164 165 /* Scan the chip */ 166 val = i2c_smbus_read_byte_data(client, chip->cache_out); 167 if (val < 0) { 168 /* Throw a warning and skip this chip */ 169 dev_warn(chip->dev, "Unable to read from chip: %d\n", 170 val); 171 continue; 172 } 173 174 uval = (unsigned long)val; 175 176 spin_lock_irqsave(&chip->lock, flags); 177 178 /* Save away the old value so we can compare it */ 179 old_val = chip->cache_in; 180 181 /* Write the new value */ 182 chip->cache_in = uval; 183 184 spin_unlock_irqrestore(&chip->lock, flags); 185 186 /* 187 * For each bit in the data (starting at bit 0), trigger 188 * associated interrupts. 189 */ 190 for (irqpin = 0; irqpin < chip->nirqs; irqpin++) { 191 unsigned oldb, newb, type = chip->flow_type; 192 193 irq = chip->irq_start + irqpin; 194 195 /* Run the IRQ handler, but only if the bit value 196 * changed, and the proper flags are set */ 197 oldb = (old_val >> irqpin) & 1; 198 newb = (uval >> irqpin) & 1; 199 200 if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) || 201 (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) { 202 pr_debug("fire IRQ %d\n", irqpin); 203 generic_handle_irq(irq); 204 } 205 } 206 } 207 208 /* 209 * In order to continue receiving interrupts, the int_reset_gpio must 210 * be asserted. 211 */ 212 if (htcpld->int_reset_gpio_hi) 213 gpio_set_value(htcpld->int_reset_gpio_hi, 1); 214 if (htcpld->int_reset_gpio_lo) 215 gpio_set_value(htcpld->int_reset_gpio_lo, 0); 216 217 return IRQ_HANDLED; 218} 219 220/* 221 * The GPIO set routines can be called from interrupt context, especially if, 222 * for example they're attached to the led-gpio framework and a trigger is 223 * enabled. As such, we declared work above in the htcpld_chip structure, 224 * and that work is scheduled in the set routine. The kernel can then run 225 * the I2C functions, which will sleep, in process context. 226 */ 227static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val) 228{ 229 struct i2c_client *client; 230 struct htcpld_chip *chip_data = 231 container_of(chip, struct htcpld_chip, chip_out); 232 unsigned long flags; 233 234 client = chip_data->client; 235 if (!client) 236 return; 237 238 spin_lock_irqsave(&chip_data->lock, flags); 239 if (val) 240 chip_data->cache_out |= (1 << offset); 241 else 242 chip_data->cache_out &= ~(1 << offset); 243 spin_unlock_irqrestore(&chip_data->lock, flags); 244 245 schedule_work(&(chip_data->set_val_work)); 246} 247 248static void htcpld_chip_set_ni(struct work_struct *work) 249{ 250 struct htcpld_chip *chip_data; 251 struct i2c_client *client; 252 253 chip_data = container_of(work, struct htcpld_chip, set_val_work); 254 client = chip_data->client; 255 i2c_smbus_read_byte_data(client, chip_data->cache_out); 256} 257 258static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset) 259{ 260 struct htcpld_chip *chip_data; 261 u8 cache; 262 263 if (!strncmp(chip->label, "htcpld-out", 10)) { 264 chip_data = container_of(chip, struct htcpld_chip, chip_out); 265 cache = chip_data->cache_out; 266 } else if (!strncmp(chip->label, "htcpld-in", 9)) { 267 chip_data = container_of(chip, struct htcpld_chip, chip_in); 268 cache = chip_data->cache_in; 269 } else 270 return -EINVAL; 271 272 return (cache >> offset) & 1; 273} 274 275static int htcpld_direction_output(struct gpio_chip *chip, 276 unsigned offset, int value) 277{ 278 htcpld_chip_set(chip, offset, value); 279 return 0; 280} 281 282static int htcpld_direction_input(struct gpio_chip *chip, 283 unsigned offset) 284{ 285 /* 286 * No-op: this function can only be called on the input chip. 287 * We do however make sure the offset is within range. 288 */ 289 return (offset < chip->ngpio) ? 0 : -EINVAL; 290} 291 292static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset) 293{ 294 struct htcpld_chip *chip_data; 295 296 chip_data = container_of(chip, struct htcpld_chip, chip_in); 297 298 if (offset < chip_data->nirqs) 299 return chip_data->irq_start + offset; 300 else 301 return -EINVAL; 302} 303 304static void htcpld_chip_reset(struct i2c_client *client) 305{ 306 struct htcpld_chip *chip_data = i2c_get_clientdata(client); 307 if (!chip_data) 308 return; 309 310 i2c_smbus_read_byte_data( 311 client, (chip_data->cache_out = chip_data->reset)); 312} 313 314static int htcpld_setup_chip_irq( 315 struct platform_device *pdev, 316 int chip_index) 317{ 318 struct htcpld_data *htcpld; 319 struct htcpld_chip *chip; 320 unsigned int irq, irq_end; 321 322 /* Get the platform and driver data */ 323 htcpld = platform_get_drvdata(pdev); 324 chip = &htcpld->chip[chip_index]; 325 326 /* Setup irq handlers */ 327 irq_end = chip->irq_start + chip->nirqs; 328 for (irq = chip->irq_start; irq < irq_end; irq++) { 329 irq_set_chip_and_handler(irq, &htcpld_muxed_chip, 330 handle_simple_irq); 331 irq_set_chip_data(irq, chip); 332 irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE); 333 } 334 335 return 0; 336} 337 338static int htcpld_register_chip_i2c( 339 struct platform_device *pdev, 340 int chip_index) 341{ 342 struct htcpld_data *htcpld; 343 struct device *dev = &pdev->dev; 344 struct htcpld_core_platform_data *pdata; 345 struct htcpld_chip *chip; 346 struct htcpld_chip_platform_data *plat_chip_data; 347 struct i2c_adapter *adapter; 348 struct i2c_client *client; 349 struct i2c_board_info info; 350 351 /* Get the platform and driver data */ 352 pdata = dev_get_platdata(dev); 353 htcpld = platform_get_drvdata(pdev); 354 chip = &htcpld->chip[chip_index]; 355 plat_chip_data = &pdata->chip[chip_index]; 356 357 adapter = i2c_get_adapter(pdata->i2c_adapter_id); 358 if (!adapter) { 359 /* Eek, no such I2C adapter! Bail out. */ 360 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n", 361 plat_chip_data->addr, pdata->i2c_adapter_id); 362 return -ENODEV; 363 } 364 365 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) { 366 dev_warn(dev, "i2c adapter %d non-functional\n", 367 pdata->i2c_adapter_id); 368 return -EINVAL; 369 } 370 371 memset(&info, 0, sizeof(struct i2c_board_info)); 372 info.addr = plat_chip_data->addr; 373 strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE); 374 info.platform_data = chip; 375 376 /* Add the I2C device. This calls the probe() function. */ 377 client = i2c_new_device(adapter, &info); 378 if (!client) { 379 /* I2C device registration failed, contineu with the next */ 380 dev_warn(dev, "Unable to add I2C device for 0x%x\n", 381 plat_chip_data->addr); 382 return -ENODEV; 383 } 384 385 i2c_set_clientdata(client, chip); 386 snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr); 387 chip->client = client; 388 389 /* Reset the chip */ 390 htcpld_chip_reset(client); 391 chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out); 392 393 return 0; 394} 395 396static void htcpld_unregister_chip_i2c( 397 struct platform_device *pdev, 398 int chip_index) 399{ 400 struct htcpld_data *htcpld; 401 struct htcpld_chip *chip; 402 403 /* Get the platform and driver data */ 404 htcpld = platform_get_drvdata(pdev); 405 chip = &htcpld->chip[chip_index]; 406 407 if (chip->client) 408 i2c_unregister_device(chip->client); 409} 410 411static int htcpld_register_chip_gpio( 412 struct platform_device *pdev, 413 int chip_index) 414{ 415 struct htcpld_data *htcpld; 416 struct device *dev = &pdev->dev; 417 struct htcpld_core_platform_data *pdata; 418 struct htcpld_chip *chip; 419 struct htcpld_chip_platform_data *plat_chip_data; 420 struct gpio_chip *gpio_chip; 421 int ret = 0; 422 423 /* Get the platform and driver data */ 424 pdata = dev_get_platdata(dev); 425 htcpld = platform_get_drvdata(pdev); 426 chip = &htcpld->chip[chip_index]; 427 plat_chip_data = &pdata->chip[chip_index]; 428 429 /* Setup the GPIO chips */ 430 gpio_chip = &(chip->chip_out); 431 gpio_chip->label = "htcpld-out"; 432 gpio_chip->dev = dev; 433 gpio_chip->owner = THIS_MODULE; 434 gpio_chip->get = htcpld_chip_get; 435 gpio_chip->set = htcpld_chip_set; 436 gpio_chip->direction_input = NULL; 437 gpio_chip->direction_output = htcpld_direction_output; 438 gpio_chip->base = plat_chip_data->gpio_out_base; 439 gpio_chip->ngpio = plat_chip_data->num_gpios; 440 441 gpio_chip = &(chip->chip_in); 442 gpio_chip->label = "htcpld-in"; 443 gpio_chip->dev = dev; 444 gpio_chip->owner = THIS_MODULE; 445 gpio_chip->get = htcpld_chip_get; 446 gpio_chip->set = NULL; 447 gpio_chip->direction_input = htcpld_direction_input; 448 gpio_chip->direction_output = NULL; 449 gpio_chip->to_irq = htcpld_chip_to_irq; 450 gpio_chip->base = plat_chip_data->gpio_in_base; 451 gpio_chip->ngpio = plat_chip_data->num_gpios; 452 453 /* Add the GPIO chips */ 454 ret = gpiochip_add(&(chip->chip_out)); 455 if (ret) { 456 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n", 457 plat_chip_data->addr, ret); 458 return ret; 459 } 460 461 ret = gpiochip_add(&(chip->chip_in)); 462 if (ret) { 463 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n", 464 plat_chip_data->addr, ret); 465 gpiochip_remove(&(chip->chip_out)); 466 return ret; 467 } 468 469 return 0; 470} 471 472static int htcpld_setup_chips(struct platform_device *pdev) 473{ 474 struct htcpld_data *htcpld; 475 struct device *dev = &pdev->dev; 476 struct htcpld_core_platform_data *pdata; 477 int i; 478 479 /* Get the platform and driver data */ 480 pdata = dev_get_platdata(dev); 481 htcpld = platform_get_drvdata(pdev); 482 483 /* Setup each chip's output GPIOs */ 484 htcpld->nchips = pdata->num_chip; 485 htcpld->chip = devm_kzalloc(dev, sizeof(struct htcpld_chip) * htcpld->nchips, 486 GFP_KERNEL); 487 if (!htcpld->chip) { 488 dev_warn(dev, "Unable to allocate memory for chips\n"); 489 return -ENOMEM; 490 } 491 492 /* Add the chips as best we can */ 493 for (i = 0; i < htcpld->nchips; i++) { 494 int ret; 495 496 /* Setup the HTCPLD chips */ 497 htcpld->chip[i].reset = pdata->chip[i].reset; 498 htcpld->chip[i].cache_out = pdata->chip[i].reset; 499 htcpld->chip[i].cache_in = 0; 500 htcpld->chip[i].dev = dev; 501 htcpld->chip[i].irq_start = pdata->chip[i].irq_base; 502 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs; 503 504 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni); 505 spin_lock_init(&(htcpld->chip[i].lock)); 506 507 /* Setup the interrupts for the chip */ 508 if (htcpld->chained_irq) { 509 ret = htcpld_setup_chip_irq(pdev, i); 510 if (ret) 511 continue; 512 } 513 514 /* Register the chip with I2C */ 515 ret = htcpld_register_chip_i2c(pdev, i); 516 if (ret) 517 continue; 518 519 520 /* Register the chips with the GPIO subsystem */ 521 ret = htcpld_register_chip_gpio(pdev, i); 522 if (ret) { 523 /* Unregister the chip from i2c and continue */ 524 htcpld_unregister_chip_i2c(pdev, i); 525 continue; 526 } 527 528 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr); 529 } 530 531 return 0; 532} 533 534static int htcpld_core_probe(struct platform_device *pdev) 535{ 536 struct htcpld_data *htcpld; 537 struct device *dev = &pdev->dev; 538 struct htcpld_core_platform_data *pdata; 539 struct resource *res; 540 int ret = 0; 541 542 if (!dev) 543 return -ENODEV; 544 545 pdata = dev_get_platdata(dev); 546 if (!pdata) { 547 dev_warn(dev, "Platform data not found for htcpld core!\n"); 548 return -ENXIO; 549 } 550 551 htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL); 552 if (!htcpld) 553 return -ENOMEM; 554 555 /* Find chained irq */ 556 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 557 if (res) { 558 int flags; 559 htcpld->chained_irq = res->start; 560 561 /* Setup the chained interrupt handler */ 562 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING | 563 IRQF_ONESHOT; 564 ret = request_threaded_irq(htcpld->chained_irq, 565 NULL, htcpld_handler, 566 flags, pdev->name, htcpld); 567 if (ret) { 568 dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret); 569 return ret; 570 } else 571 device_init_wakeup(dev, 0); 572 } 573 574 /* Set the driver data */ 575 platform_set_drvdata(pdev, htcpld); 576 577 /* Setup the htcpld chips */ 578 ret = htcpld_setup_chips(pdev); 579 if (ret) 580 return ret; 581 582 /* Request the GPIO(s) for the int reset and set them up */ 583 if (pdata->int_reset_gpio_hi) { 584 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core"); 585 if (ret) { 586 /* 587 * If it failed, that sucks, but we can probably 588 * continue on without it. 589 */ 590 dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n"); 591 htcpld->int_reset_gpio_hi = 0; 592 } else { 593 htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi; 594 gpio_set_value(htcpld->int_reset_gpio_hi, 1); 595 } 596 } 597 598 if (pdata->int_reset_gpio_lo) { 599 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core"); 600 if (ret) { 601 /* 602 * If it failed, that sucks, but we can probably 603 * continue on without it. 604 */ 605 dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n"); 606 htcpld->int_reset_gpio_lo = 0; 607 } else { 608 htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo; 609 gpio_set_value(htcpld->int_reset_gpio_lo, 0); 610 } 611 } 612 613 dev_info(dev, "Initialized successfully\n"); 614 return 0; 615} 616 617/* The I2C Driver -- used internally */ 618static const struct i2c_device_id htcpld_chip_id[] = { 619 { "htcpld-chip", 0 }, 620 { } 621}; 622MODULE_DEVICE_TABLE(i2c, htcpld_chip_id); 623 624 625static struct i2c_driver htcpld_chip_driver = { 626 .driver = { 627 .name = "htcpld-chip", 628 }, 629 .id_table = htcpld_chip_id, 630}; 631 632/* The Core Driver */ 633static struct platform_driver htcpld_core_driver = { 634 .driver = { 635 .name = "i2c-htcpld", 636 }, 637}; 638 639static int __init htcpld_core_init(void) 640{ 641 int ret; 642 643 /* Register the I2C Chip driver */ 644 ret = i2c_add_driver(&htcpld_chip_driver); 645 if (ret) 646 return ret; 647 648 /* Probe for our chips */ 649 return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe); 650} 651 652static void __exit htcpld_core_exit(void) 653{ 654 i2c_del_driver(&htcpld_chip_driver); 655 platform_driver_unregister(&htcpld_core_driver); 656} 657 658module_init(htcpld_core_init); 659module_exit(htcpld_core_exit); 660 661MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>"); 662MODULE_DESCRIPTION("I2C HTC PLD Driver"); 663MODULE_LICENSE("GPL"); 664 665