linux/drivers/mfd/htc-i2cpld.c
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   1// SPDX-License-Identifier: GPL-2.0-or-later
   2/*
   3 *  htc-i2cpld.c
   4 *  Chip driver for an unknown CPLD chip found on omap850 HTC devices like
   5 *  the HTC Wizard and HTC Herald.
   6 *  The cpld is located on the i2c bus and acts as an input/output GPIO
   7 *  extender.
   8 *
   9 *  Copyright (C) 2009 Cory Maccarrone <darkstar6262@gmail.com>
  10 *
  11 *  Based on work done in the linwizard project
  12 *  Copyright (C) 2008-2009 Angelo Arrifano <miknix@gmail.com>
  13 */
  14
  15#include <linux/kernel.h>
  16#include <linux/init.h>
  17#include <linux/interrupt.h>
  18#include <linux/platform_device.h>
  19#include <linux/i2c.h>
  20#include <linux/irq.h>
  21#include <linux/spinlock.h>
  22#include <linux/htcpld.h>
  23#include <linux/gpio.h>
  24#include <linux/slab.h>
  25
  26struct htcpld_chip {
  27        spinlock_t              lock;
  28
  29        /* chip info */
  30        u8                      reset;
  31        u8                      addr;
  32        struct device           *dev;
  33        struct i2c_client       *client;
  34
  35        /* Output details */
  36        u8                      cache_out;
  37        struct gpio_chip        chip_out;
  38
  39        /* Input details */
  40        u8                      cache_in;
  41        struct gpio_chip        chip_in;
  42
  43        u16                     irqs_enabled;
  44        uint                    irq_start;
  45        int                     nirqs;
  46
  47        unsigned int            flow_type;
  48        /*
  49         * Work structure to allow for setting values outside of any
  50         * possible interrupt context
  51         */
  52        struct work_struct set_val_work;
  53};
  54
  55struct htcpld_data {
  56        /* irq info */
  57        u16                irqs_enabled;
  58        uint               irq_start;
  59        int                nirqs;
  60        uint               chained_irq;
  61        unsigned int       int_reset_gpio_hi;
  62        unsigned int       int_reset_gpio_lo;
  63
  64        /* htcpld info */
  65        struct htcpld_chip *chip;
  66        unsigned int       nchips;
  67};
  68
  69/* There does not appear to be a way to proactively mask interrupts
  70 * on the htcpld chip itself.  So, we simply ignore interrupts that
  71 * aren't desired. */
  72static void htcpld_mask(struct irq_data *data)
  73{
  74        struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  75        chip->irqs_enabled &= ~(1 << (data->irq - chip->irq_start));
  76        pr_debug("HTCPLD mask %d %04x\n", data->irq, chip->irqs_enabled);
  77}
  78static void htcpld_unmask(struct irq_data *data)
  79{
  80        struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  81        chip->irqs_enabled |= 1 << (data->irq - chip->irq_start);
  82        pr_debug("HTCPLD unmask %d %04x\n", data->irq, chip->irqs_enabled);
  83}
  84
  85static int htcpld_set_type(struct irq_data *data, unsigned int flags)
  86{
  87        struct htcpld_chip *chip = irq_data_get_irq_chip_data(data);
  88
  89        if (flags & ~IRQ_TYPE_SENSE_MASK)
  90                return -EINVAL;
  91
  92        /* We only allow edge triggering */
  93        if (flags & (IRQ_TYPE_LEVEL_LOW|IRQ_TYPE_LEVEL_HIGH))
  94                return -EINVAL;
  95
  96        chip->flow_type = flags;
  97        return 0;
  98}
  99
 100static struct irq_chip htcpld_muxed_chip = {
 101        .name         = "htcpld",
 102        .irq_mask     = htcpld_mask,
 103        .irq_unmask   = htcpld_unmask,
 104        .irq_set_type = htcpld_set_type,
 105};
 106
 107/* To properly dispatch IRQ events, we need to read from the
 108 * chip.  This is an I2C action that could possibly sleep
 109 * (which is bad in interrupt context) -- so we use a threaded
 110 * interrupt handler to get around that.
 111 */
 112static irqreturn_t htcpld_handler(int irq, void *dev)
 113{
 114        struct htcpld_data *htcpld = dev;
 115        unsigned int i;
 116        unsigned long flags;
 117        int irqpin;
 118
 119        if (!htcpld) {
 120                pr_debug("htcpld is null in ISR\n");
 121                return IRQ_HANDLED;
 122        }
 123
 124        /*
 125         * For each chip, do a read of the chip and trigger any interrupts
 126         * desired.  The interrupts will be triggered from LSB to MSB (i.e.
 127         * bit 0 first, then bit 1, etc.)
 128         *
 129         * For chips that have no interrupt range specified, just skip 'em.
 130         */
 131        for (i = 0; i < htcpld->nchips; i++) {
 132                struct htcpld_chip *chip = &htcpld->chip[i];
 133                struct i2c_client *client;
 134                int val;
 135                unsigned long uval, old_val;
 136
 137                if (!chip) {
 138                        pr_debug("chip %d is null in ISR\n", i);
 139                        continue;
 140                }
 141
 142                if (chip->nirqs == 0)
 143                        continue;
 144
 145                client = chip->client;
 146                if (!client) {
 147                        pr_debug("client %d is null in ISR\n", i);
 148                        continue;
 149                }
 150
 151                /* Scan the chip */
 152                val = i2c_smbus_read_byte_data(client, chip->cache_out);
 153                if (val < 0) {
 154                        /* Throw a warning and skip this chip */
 155                        dev_warn(chip->dev, "Unable to read from chip: %d\n",
 156                                 val);
 157                        continue;
 158                }
 159
 160                uval = (unsigned long)val;
 161
 162                spin_lock_irqsave(&chip->lock, flags);
 163
 164                /* Save away the old value so we can compare it */
 165                old_val = chip->cache_in;
 166
 167                /* Write the new value */
 168                chip->cache_in = uval;
 169
 170                spin_unlock_irqrestore(&chip->lock, flags);
 171
 172                /*
 173                 * For each bit in the data (starting at bit 0), trigger
 174                 * associated interrupts.
 175                 */
 176                for (irqpin = 0; irqpin < chip->nirqs; irqpin++) {
 177                        unsigned oldb, newb, type = chip->flow_type;
 178
 179                        irq = chip->irq_start + irqpin;
 180
 181                        /* Run the IRQ handler, but only if the bit value
 182                         * changed, and the proper flags are set */
 183                        oldb = (old_val >> irqpin) & 1;
 184                        newb = (uval >> irqpin) & 1;
 185
 186                        if ((!oldb && newb && (type & IRQ_TYPE_EDGE_RISING)) ||
 187                            (oldb && !newb && (type & IRQ_TYPE_EDGE_FALLING))) {
 188                                pr_debug("fire IRQ %d\n", irqpin);
 189                                generic_handle_irq(irq);
 190                        }
 191                }
 192        }
 193
 194        /*
 195         * In order to continue receiving interrupts, the int_reset_gpio must
 196         * be asserted.
 197         */
 198        if (htcpld->int_reset_gpio_hi)
 199                gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 200        if (htcpld->int_reset_gpio_lo)
 201                gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 202
 203        return IRQ_HANDLED;
 204}
 205
 206/*
 207 * The GPIO set routines can be called from interrupt context, especially if,
 208 * for example they're attached to the led-gpio framework and a trigger is
 209 * enabled.  As such, we declared work above in the htcpld_chip structure,
 210 * and that work is scheduled in the set routine.  The kernel can then run
 211 * the I2C functions, which will sleep, in process context.
 212 */
 213static void htcpld_chip_set(struct gpio_chip *chip, unsigned offset, int val)
 214{
 215        struct i2c_client *client;
 216        struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 217        unsigned long flags;
 218
 219        client = chip_data->client;
 220        if (!client)
 221                return;
 222
 223        spin_lock_irqsave(&chip_data->lock, flags);
 224        if (val)
 225                chip_data->cache_out |= (1 << offset);
 226        else
 227                chip_data->cache_out &= ~(1 << offset);
 228        spin_unlock_irqrestore(&chip_data->lock, flags);
 229
 230        schedule_work(&(chip_data->set_val_work));
 231}
 232
 233static void htcpld_chip_set_ni(struct work_struct *work)
 234{
 235        struct htcpld_chip *chip_data;
 236        struct i2c_client *client;
 237
 238        chip_data = container_of(work, struct htcpld_chip, set_val_work);
 239        client = chip_data->client;
 240        i2c_smbus_read_byte_data(client, chip_data->cache_out);
 241}
 242
 243static int htcpld_chip_get(struct gpio_chip *chip, unsigned offset)
 244{
 245        struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 246        u8 cache;
 247
 248        if (!strncmp(chip->label, "htcpld-out", 10)) {
 249                cache = chip_data->cache_out;
 250        } else if (!strncmp(chip->label, "htcpld-in", 9)) {
 251                cache = chip_data->cache_in;
 252        } else
 253                return -EINVAL;
 254
 255        return (cache >> offset) & 1;
 256}
 257
 258static int htcpld_direction_output(struct gpio_chip *chip,
 259                                        unsigned offset, int value)
 260{
 261        htcpld_chip_set(chip, offset, value);
 262        return 0;
 263}
 264
 265static int htcpld_direction_input(struct gpio_chip *chip,
 266                                        unsigned offset)
 267{
 268        /*
 269         * No-op: this function can only be called on the input chip.
 270         * We do however make sure the offset is within range.
 271         */
 272        return (offset < chip->ngpio) ? 0 : -EINVAL;
 273}
 274
 275static int htcpld_chip_to_irq(struct gpio_chip *chip, unsigned offset)
 276{
 277        struct htcpld_chip *chip_data = gpiochip_get_data(chip);
 278
 279        if (offset < chip_data->nirqs)
 280                return chip_data->irq_start + offset;
 281        else
 282                return -EINVAL;
 283}
 284
 285static void htcpld_chip_reset(struct i2c_client *client)
 286{
 287        struct htcpld_chip *chip_data = i2c_get_clientdata(client);
 288        if (!chip_data)
 289                return;
 290
 291        i2c_smbus_read_byte_data(
 292                client, (chip_data->cache_out = chip_data->reset));
 293}
 294
 295static int htcpld_setup_chip_irq(
 296                struct platform_device *pdev,
 297                int chip_index)
 298{
 299        struct htcpld_data *htcpld;
 300        struct htcpld_chip *chip;
 301        unsigned int irq, irq_end;
 302
 303        /* Get the platform and driver data */
 304        htcpld = platform_get_drvdata(pdev);
 305        chip = &htcpld->chip[chip_index];
 306
 307        /* Setup irq handlers */
 308        irq_end = chip->irq_start + chip->nirqs;
 309        for (irq = chip->irq_start; irq < irq_end; irq++) {
 310                irq_set_chip_and_handler(irq, &htcpld_muxed_chip,
 311                                         handle_simple_irq);
 312                irq_set_chip_data(irq, chip);
 313                irq_clear_status_flags(irq, IRQ_NOREQUEST | IRQ_NOPROBE);
 314        }
 315
 316        return 0;
 317}
 318
 319static int htcpld_register_chip_i2c(
 320                struct platform_device *pdev,
 321                int chip_index)
 322{
 323        struct htcpld_data *htcpld;
 324        struct device *dev = &pdev->dev;
 325        struct htcpld_core_platform_data *pdata;
 326        struct htcpld_chip *chip;
 327        struct htcpld_chip_platform_data *plat_chip_data;
 328        struct i2c_adapter *adapter;
 329        struct i2c_client *client;
 330        struct i2c_board_info info;
 331
 332        /* Get the platform and driver data */
 333        pdata = dev_get_platdata(dev);
 334        htcpld = platform_get_drvdata(pdev);
 335        chip = &htcpld->chip[chip_index];
 336        plat_chip_data = &pdata->chip[chip_index];
 337
 338        adapter = i2c_get_adapter(pdata->i2c_adapter_id);
 339        if (!adapter) {
 340                /* Eek, no such I2C adapter!  Bail out. */
 341                dev_warn(dev, "Chip at i2c address 0x%x: Invalid i2c adapter %d\n",
 342                         plat_chip_data->addr, pdata->i2c_adapter_id);
 343                return -ENODEV;
 344        }
 345
 346        if (!i2c_check_functionality(adapter, I2C_FUNC_SMBUS_READ_BYTE_DATA)) {
 347                dev_warn(dev, "i2c adapter %d non-functional\n",
 348                         pdata->i2c_adapter_id);
 349                i2c_put_adapter(adapter);
 350                return -EINVAL;
 351        }
 352
 353        memset(&info, 0, sizeof(struct i2c_board_info));
 354        info.addr = plat_chip_data->addr;
 355        strlcpy(info.type, "htcpld-chip", I2C_NAME_SIZE);
 356        info.platform_data = chip;
 357
 358        /* Add the I2C device.  This calls the probe() function. */
 359        client = i2c_new_client_device(adapter, &info);
 360        if (IS_ERR(client)) {
 361                /* I2C device registration failed, contineu with the next */
 362                dev_warn(dev, "Unable to add I2C device for 0x%x\n",
 363                         plat_chip_data->addr);
 364                i2c_put_adapter(adapter);
 365                return PTR_ERR(client);
 366        }
 367
 368        i2c_set_clientdata(client, chip);
 369        snprintf(client->name, I2C_NAME_SIZE, "Chip_0x%x", client->addr);
 370        chip->client = client;
 371
 372        /* Reset the chip */
 373        htcpld_chip_reset(client);
 374        chip->cache_in = i2c_smbus_read_byte_data(client, chip->cache_out);
 375
 376        return 0;
 377}
 378
 379static void htcpld_unregister_chip_i2c(
 380                struct platform_device *pdev,
 381                int chip_index)
 382{
 383        struct htcpld_data *htcpld;
 384        struct htcpld_chip *chip;
 385
 386        /* Get the platform and driver data */
 387        htcpld = platform_get_drvdata(pdev);
 388        chip = &htcpld->chip[chip_index];
 389
 390        i2c_unregister_device(chip->client);
 391}
 392
 393static int htcpld_register_chip_gpio(
 394                struct platform_device *pdev,
 395                int chip_index)
 396{
 397        struct htcpld_data *htcpld;
 398        struct device *dev = &pdev->dev;
 399        struct htcpld_core_platform_data *pdata;
 400        struct htcpld_chip *chip;
 401        struct htcpld_chip_platform_data *plat_chip_data;
 402        struct gpio_chip *gpio_chip;
 403        int ret = 0;
 404
 405        /* Get the platform and driver data */
 406        pdata = dev_get_platdata(dev);
 407        htcpld = platform_get_drvdata(pdev);
 408        chip = &htcpld->chip[chip_index];
 409        plat_chip_data = &pdata->chip[chip_index];
 410
 411        /* Setup the GPIO chips */
 412        gpio_chip = &(chip->chip_out);
 413        gpio_chip->label           = "htcpld-out";
 414        gpio_chip->parent             = dev;
 415        gpio_chip->owner           = THIS_MODULE;
 416        gpio_chip->get             = htcpld_chip_get;
 417        gpio_chip->set             = htcpld_chip_set;
 418        gpio_chip->direction_input = NULL;
 419        gpio_chip->direction_output = htcpld_direction_output;
 420        gpio_chip->base            = plat_chip_data->gpio_out_base;
 421        gpio_chip->ngpio           = plat_chip_data->num_gpios;
 422
 423        gpio_chip = &(chip->chip_in);
 424        gpio_chip->label           = "htcpld-in";
 425        gpio_chip->parent             = dev;
 426        gpio_chip->owner           = THIS_MODULE;
 427        gpio_chip->get             = htcpld_chip_get;
 428        gpio_chip->set             = NULL;
 429        gpio_chip->direction_input = htcpld_direction_input;
 430        gpio_chip->direction_output = NULL;
 431        gpio_chip->to_irq          = htcpld_chip_to_irq;
 432        gpio_chip->base            = plat_chip_data->gpio_in_base;
 433        gpio_chip->ngpio           = plat_chip_data->num_gpios;
 434
 435        /* Add the GPIO chips */
 436        ret = gpiochip_add_data(&(chip->chip_out), chip);
 437        if (ret) {
 438                dev_warn(dev, "Unable to register output GPIOs for 0x%x: %d\n",
 439                         plat_chip_data->addr, ret);
 440                return ret;
 441        }
 442
 443        ret = gpiochip_add_data(&(chip->chip_in), chip);
 444        if (ret) {
 445                dev_warn(dev, "Unable to register input GPIOs for 0x%x: %d\n",
 446                         plat_chip_data->addr, ret);
 447                gpiochip_remove(&(chip->chip_out));
 448                return ret;
 449        }
 450
 451        return 0;
 452}
 453
 454static int htcpld_setup_chips(struct platform_device *pdev)
 455{
 456        struct htcpld_data *htcpld;
 457        struct device *dev = &pdev->dev;
 458        struct htcpld_core_platform_data *pdata;
 459        int i;
 460
 461        /* Get the platform and driver data */
 462        pdata = dev_get_platdata(dev);
 463        htcpld = platform_get_drvdata(pdev);
 464
 465        /* Setup each chip's output GPIOs */
 466        htcpld->nchips = pdata->num_chip;
 467        htcpld->chip = devm_kcalloc(dev,
 468                                    htcpld->nchips,
 469                                    sizeof(struct htcpld_chip),
 470                                    GFP_KERNEL);
 471        if (!htcpld->chip)
 472                return -ENOMEM;
 473
 474        /* Add the chips as best we can */
 475        for (i = 0; i < htcpld->nchips; i++) {
 476                int ret;
 477
 478                /* Setup the HTCPLD chips */
 479                htcpld->chip[i].reset = pdata->chip[i].reset;
 480                htcpld->chip[i].cache_out = pdata->chip[i].reset;
 481                htcpld->chip[i].cache_in = 0;
 482                htcpld->chip[i].dev = dev;
 483                htcpld->chip[i].irq_start = pdata->chip[i].irq_base;
 484                htcpld->chip[i].nirqs = pdata->chip[i].num_irqs;
 485
 486                INIT_WORK(&(htcpld->chip[i].set_val_work), &htcpld_chip_set_ni);
 487                spin_lock_init(&(htcpld->chip[i].lock));
 488
 489                /* Setup the interrupts for the chip */
 490                if (htcpld->chained_irq) {
 491                        ret = htcpld_setup_chip_irq(pdev, i);
 492                        if (ret)
 493                                continue;
 494                }
 495
 496                /* Register the chip with I2C */
 497                ret = htcpld_register_chip_i2c(pdev, i);
 498                if (ret)
 499                        continue;
 500
 501
 502                /* Register the chips with the GPIO subsystem */
 503                ret = htcpld_register_chip_gpio(pdev, i);
 504                if (ret) {
 505                        /* Unregister the chip from i2c and continue */
 506                        htcpld_unregister_chip_i2c(pdev, i);
 507                        continue;
 508                }
 509
 510                dev_info(dev, "Registered chip at 0x%x\n", pdata->chip[i].addr);
 511        }
 512
 513        return 0;
 514}
 515
 516static int htcpld_core_probe(struct platform_device *pdev)
 517{
 518        struct htcpld_data *htcpld;
 519        struct device *dev = &pdev->dev;
 520        struct htcpld_core_platform_data *pdata;
 521        struct resource *res;
 522        int ret = 0;
 523
 524        if (!dev)
 525                return -ENODEV;
 526
 527        pdata = dev_get_platdata(dev);
 528        if (!pdata) {
 529                dev_warn(dev, "Platform data not found for htcpld core!\n");
 530                return -ENXIO;
 531        }
 532
 533        htcpld = devm_kzalloc(dev, sizeof(struct htcpld_data), GFP_KERNEL);
 534        if (!htcpld)
 535                return -ENOMEM;
 536
 537        /* Find chained irq */
 538        res = platform_get_resource(pdev, IORESOURCE_IRQ, 0);
 539        if (res) {
 540                int flags;
 541                htcpld->chained_irq = res->start;
 542
 543                /* Setup the chained interrupt handler */
 544                flags = IRQF_TRIGGER_FALLING | IRQF_TRIGGER_RISING |
 545                        IRQF_ONESHOT;
 546                ret = request_threaded_irq(htcpld->chained_irq,
 547                                           NULL, htcpld_handler,
 548                                           flags, pdev->name, htcpld);
 549                if (ret) {
 550                        dev_warn(dev, "Unable to setup chained irq handler: %d\n", ret);
 551                        return ret;
 552                } else
 553                        device_init_wakeup(dev, 0);
 554        }
 555
 556        /* Set the driver data */
 557        platform_set_drvdata(pdev, htcpld);
 558
 559        /* Setup the htcpld chips */
 560        ret = htcpld_setup_chips(pdev);
 561        if (ret)
 562                return ret;
 563
 564        /* Request the GPIO(s) for the int reset and set them up */
 565        if (pdata->int_reset_gpio_hi) {
 566                ret = gpio_request(pdata->int_reset_gpio_hi, "htcpld-core");
 567                if (ret) {
 568                        /*
 569                         * If it failed, that sucks, but we can probably
 570                         * continue on without it.
 571                         */
 572                        dev_warn(dev, "Unable to request int_reset_gpio_hi -- interrupts may not work\n");
 573                        htcpld->int_reset_gpio_hi = 0;
 574                } else {
 575                        htcpld->int_reset_gpio_hi = pdata->int_reset_gpio_hi;
 576                        gpio_set_value(htcpld->int_reset_gpio_hi, 1);
 577                }
 578        }
 579
 580        if (pdata->int_reset_gpio_lo) {
 581                ret = gpio_request(pdata->int_reset_gpio_lo, "htcpld-core");
 582                if (ret) {
 583                        /*
 584                         * If it failed, that sucks, but we can probably
 585                         * continue on without it.
 586                         */
 587                        dev_warn(dev, "Unable to request int_reset_gpio_lo -- interrupts may not work\n");
 588                        htcpld->int_reset_gpio_lo = 0;
 589                } else {
 590                        htcpld->int_reset_gpio_lo = pdata->int_reset_gpio_lo;
 591                        gpio_set_value(htcpld->int_reset_gpio_lo, 0);
 592                }
 593        }
 594
 595        dev_info(dev, "Initialized successfully\n");
 596        return 0;
 597}
 598
 599/* The I2C Driver -- used internally */
 600static const struct i2c_device_id htcpld_chip_id[] = {
 601        { "htcpld-chip", 0 },
 602        { }
 603};
 604
 605static struct i2c_driver htcpld_chip_driver = {
 606        .driver = {
 607                .name   = "htcpld-chip",
 608        },
 609        .id_table = htcpld_chip_id,
 610};
 611
 612/* The Core Driver */
 613static struct platform_driver htcpld_core_driver = {
 614        .driver = {
 615                .name = "i2c-htcpld",
 616        },
 617};
 618
 619static int __init htcpld_core_init(void)
 620{
 621        int ret;
 622
 623        /* Register the I2C Chip driver */
 624        ret = i2c_add_driver(&htcpld_chip_driver);
 625        if (ret)
 626                return ret;
 627
 628        /* Probe for our chips */
 629        return platform_driver_probe(&htcpld_core_driver, htcpld_core_probe);
 630}
 631device_initcall(htcpld_core_init);
 632