linux/drivers/gpio/gpio-sx150x.c
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   1/* Copyright (c) 2010, Code Aurora Forum. All rights reserved.
   2 *
   3 * This program is free software; you can redistribute it and/or modify
   4 * it under the terms of the GNU General Public License version 2 and
   5 * only version 2 as published by the Free Software Foundation.
   6 *
   7 * This program is distributed in the hope that it will be useful,
   8 * but WITHOUT ANY WARRANTY; without even the implied warranty of
   9 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  10 * GNU General Public License for more details.
  11 *
  12 * You should have received a copy of the GNU General Public License
  13 * along with this program; if not, write to the Free Software
  14 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
  15 * 02110-1301, USA.
  16 */
  17#include <linux/gpio.h>
  18#include <linux/i2c.h>
  19#include <linux/init.h>
  20#include <linux/interrupt.h>
  21#include <linux/irq.h>
  22#include <linux/module.h>
  23#include <linux/mutex.h>
  24#include <linux/slab.h>
  25#include <linux/workqueue.h>
  26#include <linux/i2c/sx150x.h>
  27
  28#define NO_UPDATE_PENDING       -1
  29
  30struct sx150x_device_data {
  31        u8 reg_pullup;
  32        u8 reg_pulldn;
  33        u8 reg_drain;
  34        u8 reg_polarity;
  35        u8 reg_dir;
  36        u8 reg_data;
  37        u8 reg_irq_mask;
  38        u8 reg_irq_src;
  39        u8 reg_sense;
  40        u8 reg_clock;
  41        u8 reg_misc;
  42        u8 reg_reset;
  43        u8 ngpios;
  44};
  45
  46struct sx150x_chip {
  47        struct gpio_chip                 gpio_chip;
  48        struct i2c_client               *client;
  49        const struct sx150x_device_data *dev_cfg;
  50        int                              irq_summary;
  51        int                              irq_base;
  52        int                              irq_update;
  53        u32                              irq_sense;
  54        u32                              irq_masked;
  55        u32                              dev_sense;
  56        u32                              dev_masked;
  57        struct irq_chip                  irq_chip;
  58        struct mutex                     lock;
  59};
  60
  61static const struct sx150x_device_data sx150x_devices[] = {
  62        [0] = { /* sx1508q */
  63                .reg_pullup   = 0x03,
  64                .reg_pulldn   = 0x04,
  65                .reg_drain    = 0x05,
  66                .reg_polarity = 0x06,
  67                .reg_dir      = 0x07,
  68                .reg_data     = 0x08,
  69                .reg_irq_mask = 0x09,
  70                .reg_irq_src  = 0x0c,
  71                .reg_sense    = 0x0b,
  72                .reg_clock    = 0x0f,
  73                .reg_misc     = 0x10,
  74                .reg_reset    = 0x7d,
  75                .ngpios       = 8
  76        },
  77        [1] = { /* sx1509q */
  78                .reg_pullup   = 0x07,
  79                .reg_pulldn   = 0x09,
  80                .reg_drain    = 0x0b,
  81                .reg_polarity = 0x0d,
  82                .reg_dir      = 0x0f,
  83                .reg_data     = 0x11,
  84                .reg_irq_mask = 0x13,
  85                .reg_irq_src  = 0x19,
  86                .reg_sense    = 0x17,
  87                .reg_clock    = 0x1e,
  88                .reg_misc     = 0x1f,
  89                .reg_reset    = 0x7d,
  90                .ngpios       = 16
  91        },
  92};
  93
  94static const struct i2c_device_id sx150x_id[] = {
  95        {"sx1508q", 0},
  96        {"sx1509q", 1},
  97        {}
  98};
  99MODULE_DEVICE_TABLE(i2c, sx150x_id);
 100
 101static s32 sx150x_i2c_write(struct i2c_client *client, u8 reg, u8 val)
 102{
 103        s32 err = i2c_smbus_write_byte_data(client, reg, val);
 104
 105        if (err < 0)
 106                dev_warn(&client->dev,
 107                        "i2c write fail: can't write %02x to %02x: %d\n",
 108                        val, reg, err);
 109        return err;
 110}
 111
 112static s32 sx150x_i2c_read(struct i2c_client *client, u8 reg, u8 *val)
 113{
 114        s32 err = i2c_smbus_read_byte_data(client, reg);
 115
 116        if (err >= 0)
 117                *val = err;
 118        else
 119                dev_warn(&client->dev,
 120                        "i2c read fail: can't read from %02x: %d\n",
 121                        reg, err);
 122        return err;
 123}
 124
 125static inline bool offset_is_oscio(struct sx150x_chip *chip, unsigned offset)
 126{
 127        return (chip->dev_cfg->ngpios == offset);
 128}
 129
 130/*
 131 * These utility functions solve the common problem of locating and setting
 132 * configuration bits.  Configuration bits are grouped into registers
 133 * whose indexes increase downwards.  For example, with eight-bit registers,
 134 * sixteen gpios would have their config bits grouped in the following order:
 135 * REGISTER N-1 [ f e d c b a 9 8 ]
 136 *          N   [ 7 6 5 4 3 2 1 0 ]
 137 *
 138 * For multi-bit configurations, the pattern gets wider:
 139 * REGISTER N-3 [ f f e e d d c c ]
 140 *          N-2 [ b b a a 9 9 8 8 ]
 141 *          N-1 [ 7 7 6 6 5 5 4 4 ]
 142 *          N   [ 3 3 2 2 1 1 0 0 ]
 143 *
 144 * Given the address of the starting register 'N', the index of the gpio
 145 * whose configuration we seek to change, and the width in bits of that
 146 * configuration, these functions allow us to locate the correct
 147 * register and mask the correct bits.
 148 */
 149static inline void sx150x_find_cfg(u8 offset, u8 width,
 150                                u8 *reg, u8 *mask, u8 *shift)
 151{
 152        *reg   -= offset * width / 8;
 153        *mask   = (1 << width) - 1;
 154        *shift  = (offset * width) % 8;
 155        *mask <<= *shift;
 156}
 157
 158static s32 sx150x_write_cfg(struct sx150x_chip *chip,
 159                        u8 offset, u8 width, u8 reg, u8 val)
 160{
 161        u8  mask;
 162        u8  data;
 163        u8  shift;
 164        s32 err;
 165
 166        sx150x_find_cfg(offset, width, &reg, &mask, &shift);
 167        err = sx150x_i2c_read(chip->client, reg, &data);
 168        if (err < 0)
 169                return err;
 170
 171        data &= ~mask;
 172        data |= (val << shift) & mask;
 173        return sx150x_i2c_write(chip->client, reg, data);
 174}
 175
 176static int sx150x_get_io(struct sx150x_chip *chip, unsigned offset)
 177{
 178        u8  reg = chip->dev_cfg->reg_data;
 179        u8  mask;
 180        u8  data;
 181        u8  shift;
 182        s32 err;
 183
 184        sx150x_find_cfg(offset, 1, &reg, &mask, &shift);
 185        err = sx150x_i2c_read(chip->client, reg, &data);
 186        if (err >= 0)
 187                err = (data & mask) != 0 ? 1 : 0;
 188
 189        return err;
 190}
 191
 192static void sx150x_set_oscio(struct sx150x_chip *chip, int val)
 193{
 194        sx150x_i2c_write(chip->client,
 195                        chip->dev_cfg->reg_clock,
 196                        (val ? 0x1f : 0x10));
 197}
 198
 199static void sx150x_set_io(struct sx150x_chip *chip, unsigned offset, int val)
 200{
 201        sx150x_write_cfg(chip,
 202                        offset,
 203                        1,
 204                        chip->dev_cfg->reg_data,
 205                        (val ? 1 : 0));
 206}
 207
 208static int sx150x_io_input(struct sx150x_chip *chip, unsigned offset)
 209{
 210        return sx150x_write_cfg(chip,
 211                                offset,
 212                                1,
 213                                chip->dev_cfg->reg_dir,
 214                                1);
 215}
 216
 217static int sx150x_io_output(struct sx150x_chip *chip, unsigned offset, int val)
 218{
 219        int err;
 220
 221        err = sx150x_write_cfg(chip,
 222                        offset,
 223                        1,
 224                        chip->dev_cfg->reg_data,
 225                        (val ? 1 : 0));
 226        if (err >= 0)
 227                err = sx150x_write_cfg(chip,
 228                                offset,
 229                                1,
 230                                chip->dev_cfg->reg_dir,
 231                                0);
 232        return err;
 233}
 234
 235static int sx150x_gpio_get(struct gpio_chip *gc, unsigned offset)
 236{
 237        struct sx150x_chip *chip;
 238        int status = -EINVAL;
 239
 240        chip = container_of(gc, struct sx150x_chip, gpio_chip);
 241
 242        if (!offset_is_oscio(chip, offset)) {
 243                mutex_lock(&chip->lock);
 244                status = sx150x_get_io(chip, offset);
 245                mutex_unlock(&chip->lock);
 246        }
 247
 248        return status;
 249}
 250
 251static void sx150x_gpio_set(struct gpio_chip *gc, unsigned offset, int val)
 252{
 253        struct sx150x_chip *chip;
 254
 255        chip = container_of(gc, struct sx150x_chip, gpio_chip);
 256
 257        mutex_lock(&chip->lock);
 258        if (offset_is_oscio(chip, offset))
 259                sx150x_set_oscio(chip, val);
 260        else
 261                sx150x_set_io(chip, offset, val);
 262        mutex_unlock(&chip->lock);
 263}
 264
 265static int sx150x_gpio_direction_input(struct gpio_chip *gc, unsigned offset)
 266{
 267        struct sx150x_chip *chip;
 268        int status = -EINVAL;
 269
 270        chip = container_of(gc, struct sx150x_chip, gpio_chip);
 271
 272        if (!offset_is_oscio(chip, offset)) {
 273                mutex_lock(&chip->lock);
 274                status = sx150x_io_input(chip, offset);
 275                mutex_unlock(&chip->lock);
 276        }
 277        return status;
 278}
 279
 280static int sx150x_gpio_direction_output(struct gpio_chip *gc,
 281                                        unsigned offset,
 282                                        int val)
 283{
 284        struct sx150x_chip *chip;
 285        int status = 0;
 286
 287        chip = container_of(gc, struct sx150x_chip, gpio_chip);
 288
 289        if (!offset_is_oscio(chip, offset)) {
 290                mutex_lock(&chip->lock);
 291                status = sx150x_io_output(chip, offset, val);
 292                mutex_unlock(&chip->lock);
 293        }
 294        return status;
 295}
 296
 297static int sx150x_gpio_to_irq(struct gpio_chip *gc, unsigned offset)
 298{
 299        struct sx150x_chip *chip;
 300
 301        chip = container_of(gc, struct sx150x_chip, gpio_chip);
 302
 303        if (offset >= chip->dev_cfg->ngpios)
 304                return -EINVAL;
 305
 306        if (chip->irq_base < 0)
 307                return -EINVAL;
 308
 309        return chip->irq_base + offset;
 310}
 311
 312static void sx150x_irq_mask(struct irq_data *d)
 313{
 314        struct sx150x_chip *chip = irq_data_get_irq_chip_data(d);
 315        unsigned n;
 316
 317        n = d->irq - chip->irq_base;
 318        chip->irq_masked |= (1 << n);
 319        chip->irq_update = n;
 320}
 321
 322static void sx150x_irq_unmask(struct irq_data *d)
 323{
 324        struct sx150x_chip *chip = irq_data_get_irq_chip_data(d);
 325        unsigned n;
 326
 327        n = d->irq - chip->irq_base;
 328        chip->irq_masked &= ~(1 << n);
 329        chip->irq_update = n;
 330}
 331
 332static int sx150x_irq_set_type(struct irq_data *d, unsigned int flow_type)
 333{
 334        struct sx150x_chip *chip = irq_data_get_irq_chip_data(d);
 335        unsigned n, val = 0;
 336
 337        if (flow_type & (IRQ_TYPE_LEVEL_HIGH | IRQ_TYPE_LEVEL_LOW))
 338                return -EINVAL;
 339
 340        n = d->irq - chip->irq_base;
 341
 342        if (flow_type & IRQ_TYPE_EDGE_RISING)
 343                val |= 0x1;
 344        if (flow_type & IRQ_TYPE_EDGE_FALLING)
 345                val |= 0x2;
 346
 347        chip->irq_sense &= ~(3UL << (n * 2));
 348        chip->irq_sense |= val << (n * 2);
 349        chip->irq_update = n;
 350        return 0;
 351}
 352
 353static irqreturn_t sx150x_irq_thread_fn(int irq, void *dev_id)
 354{
 355        struct sx150x_chip *chip = (struct sx150x_chip *)dev_id;
 356        unsigned nhandled = 0;
 357        unsigned sub_irq;
 358        unsigned n;
 359        s32 err;
 360        u8 val;
 361        int i;
 362
 363        for (i = (chip->dev_cfg->ngpios / 8) - 1; i >= 0; --i) {
 364                err = sx150x_i2c_read(chip->client,
 365                                      chip->dev_cfg->reg_irq_src - i,
 366                                      &val);
 367                if (err < 0)
 368                        continue;
 369
 370                sx150x_i2c_write(chip->client,
 371                                chip->dev_cfg->reg_irq_src - i,
 372                                val);
 373                for (n = 0; n < 8; ++n) {
 374                        if (val & (1 << n)) {
 375                                sub_irq = chip->irq_base + (i * 8) + n;
 376                                handle_nested_irq(sub_irq);
 377                                ++nhandled;
 378                        }
 379                }
 380        }
 381
 382        return (nhandled > 0 ? IRQ_HANDLED : IRQ_NONE);
 383}
 384
 385static void sx150x_irq_bus_lock(struct irq_data *d)
 386{
 387        struct sx150x_chip *chip = irq_data_get_irq_chip_data(d);
 388
 389        mutex_lock(&chip->lock);
 390}
 391
 392static void sx150x_irq_bus_sync_unlock(struct irq_data *d)
 393{
 394        struct sx150x_chip *chip = irq_data_get_irq_chip_data(d);
 395        unsigned n;
 396
 397        if (chip->irq_update == NO_UPDATE_PENDING)
 398                goto out;
 399
 400        n = chip->irq_update;
 401        chip->irq_update = NO_UPDATE_PENDING;
 402
 403        /* Avoid updates if nothing changed */
 404        if (chip->dev_sense == chip->irq_sense &&
 405            chip->dev_sense == chip->irq_masked)
 406                goto out;
 407
 408        chip->dev_sense = chip->irq_sense;
 409        chip->dev_masked = chip->irq_masked;
 410
 411        if (chip->irq_masked & (1 << n)) {
 412                sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 1);
 413                sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense, 0);
 414        } else {
 415                sx150x_write_cfg(chip, n, 1, chip->dev_cfg->reg_irq_mask, 0);
 416                sx150x_write_cfg(chip, n, 2, chip->dev_cfg->reg_sense,
 417                                 chip->irq_sense >> (n * 2));
 418        }
 419out:
 420        mutex_unlock(&chip->lock);
 421}
 422
 423static void sx150x_init_chip(struct sx150x_chip *chip,
 424                        struct i2c_client *client,
 425                        kernel_ulong_t driver_data,
 426                        struct sx150x_platform_data *pdata)
 427{
 428        mutex_init(&chip->lock);
 429
 430        chip->client                     = client;
 431        chip->dev_cfg                    = &sx150x_devices[driver_data];
 432        chip->gpio_chip.label            = client->name;
 433        chip->gpio_chip.direction_input  = sx150x_gpio_direction_input;
 434        chip->gpio_chip.direction_output = sx150x_gpio_direction_output;
 435        chip->gpio_chip.get              = sx150x_gpio_get;
 436        chip->gpio_chip.set              = sx150x_gpio_set;
 437        chip->gpio_chip.to_irq           = sx150x_gpio_to_irq;
 438        chip->gpio_chip.base             = pdata->gpio_base;
 439        chip->gpio_chip.can_sleep        = 1;
 440        chip->gpio_chip.ngpio            = chip->dev_cfg->ngpios;
 441        if (pdata->oscio_is_gpo)
 442                ++chip->gpio_chip.ngpio;
 443
 444        chip->irq_chip.name                = client->name;
 445        chip->irq_chip.irq_mask            = sx150x_irq_mask;
 446        chip->irq_chip.irq_unmask          = sx150x_irq_unmask;
 447        chip->irq_chip.irq_set_type        = sx150x_irq_set_type;
 448        chip->irq_chip.irq_bus_lock        = sx150x_irq_bus_lock;
 449        chip->irq_chip.irq_bus_sync_unlock = sx150x_irq_bus_sync_unlock;
 450        chip->irq_summary                  = -1;
 451        chip->irq_base                     = -1;
 452        chip->irq_masked                   = ~0;
 453        chip->irq_sense                    = 0;
 454        chip->dev_masked                   = ~0;
 455        chip->dev_sense                    = 0;
 456        chip->irq_update                   = NO_UPDATE_PENDING;
 457}
 458
 459static int sx150x_init_io(struct sx150x_chip *chip, u8 base, u16 cfg)
 460{
 461        int err = 0;
 462        unsigned n;
 463
 464        for (n = 0; err >= 0 && n < (chip->dev_cfg->ngpios / 8); ++n)
 465                err = sx150x_i2c_write(chip->client, base - n, cfg >> (n * 8));
 466        return err;
 467}
 468
 469static int sx150x_reset(struct sx150x_chip *chip)
 470{
 471        int err;
 472
 473        err = i2c_smbus_write_byte_data(chip->client,
 474                                        chip->dev_cfg->reg_reset,
 475                                        0x12);
 476        if (err < 0)
 477                return err;
 478
 479        err = i2c_smbus_write_byte_data(chip->client,
 480                                        chip->dev_cfg->reg_reset,
 481                                        0x34);
 482        return err;
 483}
 484
 485static int sx150x_init_hw(struct sx150x_chip *chip,
 486                        struct sx150x_platform_data *pdata)
 487{
 488        int err = 0;
 489
 490        if (pdata->reset_during_probe) {
 491                err = sx150x_reset(chip);
 492                if (err < 0)
 493                        return err;
 494        }
 495
 496        err = sx150x_i2c_write(chip->client,
 497                        chip->dev_cfg->reg_misc,
 498                        0x01);
 499        if (err < 0)
 500                return err;
 501
 502        err = sx150x_init_io(chip, chip->dev_cfg->reg_pullup,
 503                        pdata->io_pullup_ena);
 504        if (err < 0)
 505                return err;
 506
 507        err = sx150x_init_io(chip, chip->dev_cfg->reg_pulldn,
 508                        pdata->io_pulldn_ena);
 509        if (err < 0)
 510                return err;
 511
 512        err = sx150x_init_io(chip, chip->dev_cfg->reg_drain,
 513                        pdata->io_open_drain_ena);
 514        if (err < 0)
 515                return err;
 516
 517        err = sx150x_init_io(chip, chip->dev_cfg->reg_polarity,
 518                        pdata->io_polarity);
 519        if (err < 0)
 520                return err;
 521
 522        if (pdata->oscio_is_gpo)
 523                sx150x_set_oscio(chip, 0);
 524
 525        return err;
 526}
 527
 528static int sx150x_install_irq_chip(struct sx150x_chip *chip,
 529                                int irq_summary,
 530                                int irq_base)
 531{
 532        int err;
 533        unsigned n;
 534        unsigned irq;
 535
 536        chip->irq_summary = irq_summary;
 537        chip->irq_base    = irq_base;
 538
 539        for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
 540                irq = irq_base + n;
 541                irq_set_chip_data(irq, chip);
 542                irq_set_chip_and_handler(irq, &chip->irq_chip, handle_edge_irq);
 543                irq_set_nested_thread(irq, 1);
 544#ifdef CONFIG_ARM
 545                set_irq_flags(irq, IRQF_VALID);
 546#else
 547                irq_set_noprobe(irq);
 548#endif
 549        }
 550
 551        err = request_threaded_irq(irq_summary,
 552                                NULL,
 553                                sx150x_irq_thread_fn,
 554                                IRQF_SHARED | IRQF_TRIGGER_FALLING,
 555                                chip->irq_chip.name,
 556                                chip);
 557        if (err < 0) {
 558                chip->irq_summary = -1;
 559                chip->irq_base    = -1;
 560        }
 561
 562        return err;
 563}
 564
 565static void sx150x_remove_irq_chip(struct sx150x_chip *chip)
 566{
 567        unsigned n;
 568        unsigned irq;
 569
 570        free_irq(chip->irq_summary, chip);
 571
 572        for (n = 0; n < chip->dev_cfg->ngpios; ++n) {
 573                irq = chip->irq_base + n;
 574                irq_set_chip_and_handler(irq, NULL, NULL);
 575        }
 576}
 577
 578static int sx150x_probe(struct i2c_client *client,
 579                                const struct i2c_device_id *id)
 580{
 581        static const u32 i2c_funcs = I2C_FUNC_SMBUS_BYTE_DATA |
 582                                     I2C_FUNC_SMBUS_WRITE_WORD_DATA;
 583        struct sx150x_platform_data *pdata;
 584        struct sx150x_chip *chip;
 585        int rc;
 586
 587        pdata = client->dev.platform_data;
 588        if (!pdata)
 589                return -EINVAL;
 590
 591        if (!i2c_check_functionality(client->adapter, i2c_funcs))
 592                return -ENOSYS;
 593
 594        chip = kzalloc(sizeof(struct sx150x_chip), GFP_KERNEL);
 595        if (!chip)
 596                return -ENOMEM;
 597
 598        sx150x_init_chip(chip, client, id->driver_data, pdata);
 599        rc = sx150x_init_hw(chip, pdata);
 600        if (rc < 0)
 601                goto probe_fail_pre_gpiochip_add;
 602
 603        rc = gpiochip_add(&chip->gpio_chip);
 604        if (rc < 0)
 605                goto probe_fail_pre_gpiochip_add;
 606
 607        if (pdata->irq_summary >= 0) {
 608                rc = sx150x_install_irq_chip(chip,
 609                                        pdata->irq_summary,
 610                                        pdata->irq_base);
 611                if (rc < 0)
 612                        goto probe_fail_post_gpiochip_add;
 613        }
 614
 615        i2c_set_clientdata(client, chip);
 616
 617        return 0;
 618probe_fail_post_gpiochip_add:
 619        WARN_ON(gpiochip_remove(&chip->gpio_chip) < 0);
 620probe_fail_pre_gpiochip_add:
 621        kfree(chip);
 622        return rc;
 623}
 624
 625static int sx150x_remove(struct i2c_client *client)
 626{
 627        struct sx150x_chip *chip;
 628        int rc;
 629
 630        chip = i2c_get_clientdata(client);
 631        rc = gpiochip_remove(&chip->gpio_chip);
 632        if (rc < 0)
 633                return rc;
 634
 635        if (chip->irq_summary >= 0)
 636                sx150x_remove_irq_chip(chip);
 637
 638        kfree(chip);
 639
 640        return 0;
 641}
 642
 643static struct i2c_driver sx150x_driver = {
 644        .driver = {
 645                .name = "sx150x",
 646                .owner = THIS_MODULE
 647        },
 648        .probe    = sx150x_probe,
 649        .remove   = sx150x_remove,
 650        .id_table = sx150x_id,
 651};
 652
 653static int __init sx150x_init(void)
 654{
 655        return i2c_add_driver(&sx150x_driver);
 656}
 657subsys_initcall(sx150x_init);
 658
 659static void __exit sx150x_exit(void)
 660{
 661        return i2c_del_driver(&sx150x_driver);
 662}
 663module_exit(sx150x_exit);
 664
 665MODULE_AUTHOR("Gregory Bean <gbean@codeaurora.org>");
 666MODULE_DESCRIPTION("Driver for Semtech SX150X I2C GPIO Expanders");
 667MODULE_LICENSE("GPL v2");
 668MODULE_ALIAS("i2c:sx150x");
 669
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