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 int ret = 0; 322 323 /* Get the platform and driver data */ 324 htcpld = platform_get_drvdata(pdev); 325 chip = &htcpld->chip[chip_index]; 326 327 /* Setup irq handlers */ 328 irq_end = chip->irq_start + chip->nirqs; 329 for (irq = chip->irq_start; irq < irq_end; irq++) { 330 irq_set_chip_and_handler(irq, &htcpld_muxed_chip, 331 handle_simple_irq); 332 irq_set_chip_data(irq, chip); 333#ifdef CONFIG_ARM 334 set_irq_flags(irq, IRQF_VALID | IRQF_PROBE); 335#else 336 irq_set_probe(irq); 337#endif 338 } 339 340 return ret; 341} 342 343static int htcpld_register_chip_i2c( 344 struct platform_device *pdev, 345 int chip_index) 346{ 347 struct htcpld_data *htcpld; 348 struct device *dev = &pdev->dev; 349 struct htcpld_core_platform_data *pdata; 350 struct htcpld_chip *chip; 351 struct htcpld_chip_platform_data *plat_chip_data; 352 struct i2c_adapter *adapter; 353 struct i2c_client *client; 354 struct i2c_board_info info; 355 356 /* Get the platform and driver data */ 357 pdata = dev_get_platdata(dev); 358 htcpld = platform_get_drvdata(pdev); 359 chip = &htcpld->chip[chip_index]; 360 plat_chip_data = &pdata->chip[chip_index]; 361 362 adapter = i2c_get_adapter(pdata->i2c_adapter_id); 363 if (!adapter) { 364 /* Eek, no such I2C adapter! Bail out. */ 365 dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n", 366 plat_chip_data->addr, pdata->i2c_adapter_id); 367 return -ENODEV; 368 } 369 370 if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) { 371 dev_warn(dev, "i2c adapter %d non-functional\n", 372 pdata->i2c_adapter_id); 373 return -EINVAL; 374 } 375 376 memset(&info, 0, sizeof(struct i2c_board_info)); 377 info.addr = plat_chip_data->addr; 378 strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE); 379 info.platform_data = chip; 380 381 /* Add the I2C device. This calls the probe() function. */ 382 client = i2c_new_device(adapter, &info); 383 if (!client) { 384 /* I2C device registration failed, contineu with the next */ 385 dev_warn(dev, "Unable to add I2C device for 0x%x\n", 386 plat_chip_data->addr); 387 return -ENODEV; 388 } 389 390 i2c_set_clientdata(client, chip); 391 snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr); 392 chip->client = client; 393 394 /* Reset the chip */ 395 htcpld_chip_reset(client); 396 chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out); 397 398 return 0; 399} 400 401static void htcpld_unregister_chip_i2c( 402 struct platform_device *pdev, 403 int chip_index) 404{ 405 struct htcpld_data *htcpld; 406 struct htcpld_chip *chip; 407 408 /* Get the platform and driver data */ 409 htcpld = platform_get_drvdata(pdev); 410 chip = &htcpld->chip[chip_index]; 411 412 if (chip->client) 413 i2c_unregister_device(chip->client); 414} 415 416static int htcpld_register_chip_gpio( 417 struct platform_device *pdev, 418 int chip_index) 419{ 420 struct htcpld_data *htcpld; 421 struct device *dev = &pdev->dev; 422 struct htcpld_core_platform_data *pdata; 423 struct htcpld_chip *chip; 424 struct htcpld_chip_platform_data *plat_chip_data; 425 struct gpio_chip *gpio_chip; 426 int ret = 0; 427 428 /* Get the platform and driver data */ 429 pdata = dev_get_platdata(dev); 430 htcpld = platform_get_drvdata(pdev); 431 chip = &htcpld->chip[chip_index]; 432 plat_chip_data = &pdata->chip[chip_index]; 433 434 /* Setup the GPIO chips */ 435 gpio_chip = &(chip->chip_out); 436 gpio_chip->label = "htcpld-out"; 437 gpio_chip->dev = dev; 438 gpio_chip->owner = THIS_MODULE; 439 gpio_chip->get = htcpld_chip_get; 440 gpio_chip->set = htcpld_chip_set; 441 gpio_chip->direction_input = NULL; 442 gpio_chip->direction_output = htcpld_direction_output; 443 gpio_chip->base = plat_chip_data->gpio_out_base; 444 gpio_chip->ngpio = plat_chip_data->num_gpios; 445 446 gpio_chip = &(chip->chip_in); 447 gpio_chip->label = "htcpld-in"; 448 gpio_chip->dev = dev; 449 gpio_chip->owner = THIS_MODULE; 450 gpio_chip->get = htcpld_chip_get; 451 gpio_chip->set = NULL; 452 gpio_chip->direction_input = htcpld_direction_input; 453 gpio_chip->direction_output = NULL; 454 gpio_chip->to_irq = htcpld_chip_to_irq; 455 gpio_chip->base = plat_chip_data->gpio_in_base; 456 gpio_chip->ngpio = plat_chip_data->num_gpios; 457 458 /* Add the GPIO chips */ 459 ret = gpiochip_add(&(chip->chip_out)); 460 if (ret) { 461 dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n", 462 plat_chip_data->addr, ret); 463 return ret; 464 } 465 466 ret = gpiochip_add(&(chip->chip_in)); 467 if (ret) { 468 dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n", 469 plat_chip_data->addr, ret); 470 gpiochip_remove(&(chip->chip_out)); 471 return ret; 472 } 473 474 return 0; 475} 476 477static int htcpld_setup_chips(struct platform_device *pdev) 478{ 479 struct htcpld_data *htcpld; 480 struct device *dev = &pdev->dev; 481 struct htcpld_core_platform_data *pdata; 482 int i; 483 484 /* Get the platform and driver data */ 485 pdata = dev_get_platdata(dev); 486 htcpld = platform_get_drvdata(pdev); 487 488 /* Setup each chip's output GPIOs */ 489 htcpld->nchips = pdata->num_chip; 490 htcpld->chip = devm_kzalloc(dev, sizeof(struct htcpld_chip) * htcpld->nchips, 491 GFP_KERNEL); 492 if (!htcpld->chip) { 493 dev_warn(dev, "Unable to allocate memory for chips\n"); 494 return -ENOMEM; 495 } 496 497 /* Add the chips as best we can */ 498 for (i = 0; i < htcpld->nchips; i++) { 499 int ret; 500 501 /* Setup the HTCPLD chips */ 502 htcpld->chip[i].reset = pdata->chip[i].reset; 503 htcpld->chip[i].cache_out = pdata->chip[i].reset; 504 htcpld->chip[i].cache_in = 0; 505 htcpld->chip[i].dev = dev; 506 htcpld->chip[i].irq_start = pdata->chip[i].irq_base; 507 htcpld->chip[i].nirqs = pdata->chip[i].num_irqs; 508 509 INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni); 510 spin_lock_init(&(htcpld->chip[i].lock)); 511 512 /* Setup the interrupts for the chip */ 513 if (htcpld->chained_irq) { 514 ret = htcpld_setup_chip_irq(pdev, i); 515 if (ret) 516 continue; 517 } 518 519 /* Register the chip with I2C */ 520 ret = htcpld_register_chip_i2c(pdev, i); 521 if (ret) 522 continue; 523 524 525 /* Register the chips with the GPIO subsystem */ 526 ret = htcpld_register_chip_gpio(pdev, i); 527 if (ret) { 528 /* Unregister the chip from i2c and continue */ 529 htcpld_unregister_chip_i2c(pdev, i); 530 continue; 531 } 532 533 dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr); 534 } 535 536 return 0; 537} 538 539static int htcpld_core_probe(struct platform_device *pdev) 540{ 541 struct htcpld_data *htcpld; 542 struct device *dev = &pdev->dev; 543 struct htcpld_core_platform_data *pdata; 544 struct resource *res; 545 int ret = 0; 546 547 if (!dev) 548 return -ENODEV; 549 550 pdata = dev_get_platdata(dev); 551 if (!pdata) { 552 dev_warn(dev, "Platform data not found for htcpld core!\n"); 553 return -ENXIO; 554 } 555 556 htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL); 557 if (!htcpld) 558 return -ENOMEM; 559 560 /* Find chained irq */ 561 res = platform_get_resource(pdev, IORESOURCE_IRQ, 0); 562 if (res) { 563 int flags; 564 htcpld->chained_irq = res->start; 565 566 /* Setup the chained interrupt handler */ 567 flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING; 568 ret = request_threaded_irq(htcpld->chained_irq, 569 NULL, htcpld_handler, 570 flags, pdev->name, htcpld); 571 if (ret) { 572 dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret); 573 return ret; 574 } else 575 device_init_wakeup(dev, 0); 576 } 577 578 /* Set the driver data */ 579 platform_set_drvdata(pdev, htcpld); 580 581 /* Setup the htcpld chips */ 582 ret = htcpld_setup_chips(pdev); 583 if (ret) 584 return ret; 585 586 /* Request the GPIO(s) for the int reset and set them up */ 587 if (pdata->int_reset_gpio_hi) { 588 ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core"); 589 if (ret) { 590 /* 591 * If it failed, that sucks, but we can probably 592 * continue on without it. 593 */ 594 dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n"); 595 htcpld->int_reset_gpio_hi = 0; 596 } else { 597 htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi; 598 gpio_set_value(htcpld->int_reset_gpio_hi, 1); 599 } 600 } 601 602 if (pdata->int_reset_gpio_lo) { 603 ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core"); 604 if (ret) { 605 /* 606 * If it failed, that sucks, but we can probably 607 * continue on without it. 608 */ 609 dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n"); 610 htcpld->int_reset_gpio_lo = 0; 611 } else { 612 htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo; 613 gpio_set_value(htcpld->int_reset_gpio_lo, 0); 614 } 615 } 616 617 dev_info(dev, "Initialized successfully\n"); 618 return 0; 619} 620 621/* The I2C Driver -- used internally */ 622static const struct i2c_device_id htcpld_chip_id[] = { 623 { "htcpld-chip", 0 }, 624 { } 625}; 626MODULE_DEVICE_TABLE(i2c, htcpld_chip_id); 627 628 629static struct i2c_driver htcpld_chip_driver = { 630 .driver = { 631 .name = "htcpld-chip", 632 }, 633 .id_table = htcpld_chip_id, 634}; 635 636/* The Core Driver */ 637static struct platform_driver htcpld_core_driver = { 638 .driver = { 639 .name = "i2c-htcpld", 640 }, 641}; 642 643static int __init htcpld_core_init(void) 644{ 645 int ret; 646 647 /* Register the I2C Chip driver */ 648 ret = i2c_add_driver(&htcpld_chip_driver); 649 if (ret) 650 return ret; 651 652 /* Probe for our chips */ 653 return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe); 654} 655 656static void __exit htcpld_core_exit(void) 657{ 658 i2c_del_driver(&htcpld_chip_driver); 659 platform_driver_unregister(&htcpld_core_driver); 660} 661 662module_init(htcpld_core_init); 663module_exit(htcpld_core_exit); 664 665MODULE_AUTHOR("Cory Maccarrone <darkstar6262@gmail.com>"); 666MODULE_DESCRIPTION("I2C HTC PLD Driver"); 667MODULE_LICENSE("GPL"); 668 669