linux/drivers/hwmon/gpio-fan.c
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   1/*
   2 * gpio-fan.c - Hwmon driver for fans connected to GPIO lines.
   3 *
   4 * Copyright (C) 2010 LaCie
   5 *
   6 * Author: Simon Guinot <sguinot@lacie.com>
   7 *
   8 * This program is free software; you can redistribute it and/or modify
   9 * it under the terms of the GNU General Public License as published by
  10 * the Free Software Foundation; either version 2 of the License, or
  11 * (at your option) any later version.
  12 *
  13 * This program is distributed in the hope that it will be useful,
  14 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  16 * GNU General Public License for more details.
  17 *
  18 * You should have received a copy of the GNU General Public License
  19 * along with this program; if not, write to the Free Software
  20 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  21 */
  22
  23#include <linux/module.h>
  24#include <linux/init.h>
  25#include <linux/slab.h>
  26#include <linux/interrupt.h>
  27#include <linux/irq.h>
  28#include <linux/platform_device.h>
  29#include <linux/err.h>
  30#include <linux/mutex.h>
  31#include <linux/hwmon.h>
  32#include <linux/gpio.h>
  33#include <linux/gpio-fan.h>
  34#include <linux/of_platform.h>
  35#include <linux/of_gpio.h>
  36
  37struct gpio_fan_data {
  38        struct platform_device  *pdev;
  39        struct device           *hwmon_dev;
  40        struct mutex            lock; /* lock GPIOs operations. */
  41        int                     num_ctrl;
  42        unsigned                *ctrl;
  43        int                     num_speed;
  44        struct gpio_fan_speed   *speed;
  45        int                     speed_index;
  46#ifdef CONFIG_PM_SLEEP
  47        int                     resume_speed;
  48#endif
  49        bool                    pwm_enable;
  50        struct gpio_fan_alarm   *alarm;
  51        struct work_struct      alarm_work;
  52};
  53
  54/*
  55 * Alarm GPIO.
  56 */
  57
  58static void fan_alarm_notify(struct work_struct *ws)
  59{
  60        struct gpio_fan_data *fan_data =
  61                container_of(ws, struct gpio_fan_data, alarm_work);
  62
  63        sysfs_notify(&fan_data->pdev->dev.kobj, NULL, "fan1_alarm");
  64        kobject_uevent(&fan_data->pdev->dev.kobj, KOBJ_CHANGE);
  65}
  66
  67static irqreturn_t fan_alarm_irq_handler(int irq, void *dev_id)
  68{
  69        struct gpio_fan_data *fan_data = dev_id;
  70
  71        schedule_work(&fan_data->alarm_work);
  72
  73        return IRQ_NONE;
  74}
  75
  76static ssize_t show_fan_alarm(struct device *dev,
  77                              struct device_attribute *attr, char *buf)
  78{
  79        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
  80        struct gpio_fan_alarm *alarm = fan_data->alarm;
  81        int value = gpio_get_value(alarm->gpio);
  82
  83        if (alarm->active_low)
  84                value = !value;
  85
  86        return sprintf(buf, "%d\n", value);
  87}
  88
  89static DEVICE_ATTR(fan1_alarm, S_IRUGO, show_fan_alarm, NULL);
  90
  91static int fan_alarm_init(struct gpio_fan_data *fan_data,
  92                          struct gpio_fan_alarm *alarm)
  93{
  94        int err;
  95        int alarm_irq;
  96        struct platform_device *pdev = fan_data->pdev;
  97
  98        fan_data->alarm = alarm;
  99
 100        err = devm_gpio_request(&pdev->dev, alarm->gpio, "GPIO fan alarm");
 101        if (err)
 102                return err;
 103
 104        err = gpio_direction_input(alarm->gpio);
 105        if (err)
 106                return err;
 107
 108        err = device_create_file(&pdev->dev, &dev_attr_fan1_alarm);
 109        if (err)
 110                return err;
 111
 112        /*
 113         * If the alarm GPIO don't support interrupts, just leave
 114         * without initializing the fail notification support.
 115         */
 116        alarm_irq = gpio_to_irq(alarm->gpio);
 117        if (alarm_irq < 0)
 118                return 0;
 119
 120        INIT_WORK(&fan_data->alarm_work, fan_alarm_notify);
 121        irq_set_irq_type(alarm_irq, IRQ_TYPE_EDGE_BOTH);
 122        err = devm_request_irq(&pdev->dev, alarm_irq, fan_alarm_irq_handler,
 123                               IRQF_SHARED, "GPIO fan alarm", fan_data);
 124        if (err)
 125                goto err_free_sysfs;
 126
 127        return 0;
 128
 129err_free_sysfs:
 130        device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 131        return err;
 132}
 133
 134static void fan_alarm_free(struct gpio_fan_data *fan_data)
 135{
 136        struct platform_device *pdev = fan_data->pdev;
 137
 138        device_remove_file(&pdev->dev, &dev_attr_fan1_alarm);
 139}
 140
 141/*
 142 * Control GPIOs.
 143 */
 144
 145/* Must be called with fan_data->lock held, except during initialization. */
 146static void __set_fan_ctrl(struct gpio_fan_data *fan_data, int ctrl_val)
 147{
 148        int i;
 149
 150        for (i = 0; i < fan_data->num_ctrl; i++)
 151                gpio_set_value(fan_data->ctrl[i], (ctrl_val >> i) & 1);
 152}
 153
 154static int __get_fan_ctrl(struct gpio_fan_data *fan_data)
 155{
 156        int i;
 157        int ctrl_val = 0;
 158
 159        for (i = 0; i < fan_data->num_ctrl; i++) {
 160                int value;
 161
 162                value = gpio_get_value(fan_data->ctrl[i]);
 163                ctrl_val |= (value << i);
 164        }
 165        return ctrl_val;
 166}
 167
 168/* Must be called with fan_data->lock held, except during initialization. */
 169static void set_fan_speed(struct gpio_fan_data *fan_data, int speed_index)
 170{
 171        if (fan_data->speed_index == speed_index)
 172                return;
 173
 174        __set_fan_ctrl(fan_data, fan_data->speed[speed_index].ctrl_val);
 175        fan_data->speed_index = speed_index;
 176}
 177
 178static int get_fan_speed_index(struct gpio_fan_data *fan_data)
 179{
 180        int ctrl_val = __get_fan_ctrl(fan_data);
 181        int i;
 182
 183        for (i = 0; i < fan_data->num_speed; i++)
 184                if (fan_data->speed[i].ctrl_val == ctrl_val)
 185                        return i;
 186
 187        dev_warn(&fan_data->pdev->dev,
 188                 "missing speed array entry for GPIO value 0x%x\n", ctrl_val);
 189
 190        return -EINVAL;
 191}
 192
 193static int rpm_to_speed_index(struct gpio_fan_data *fan_data, int rpm)
 194{
 195        struct gpio_fan_speed *speed = fan_data->speed;
 196        int i;
 197
 198        for (i = 0; i < fan_data->num_speed; i++)
 199                if (speed[i].rpm >= rpm)
 200                        return i;
 201
 202        return fan_data->num_speed - 1;
 203}
 204
 205static ssize_t show_pwm(struct device *dev,
 206                        struct device_attribute *attr, char *buf)
 207{
 208        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 209        u8 pwm = fan_data->speed_index * 255 / (fan_data->num_speed - 1);
 210
 211        return sprintf(buf, "%d\n", pwm);
 212}
 213
 214static ssize_t set_pwm(struct device *dev, struct device_attribute *attr,
 215                       const char *buf, size_t count)
 216{
 217        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 218        unsigned long pwm;
 219        int speed_index;
 220        int ret = count;
 221
 222        if (kstrtoul(buf, 10, &pwm) || pwm > 255)
 223                return -EINVAL;
 224
 225        mutex_lock(&fan_data->lock);
 226
 227        if (!fan_data->pwm_enable) {
 228                ret = -EPERM;
 229                goto exit_unlock;
 230        }
 231
 232        speed_index = DIV_ROUND_UP(pwm * (fan_data->num_speed - 1), 255);
 233        set_fan_speed(fan_data, speed_index);
 234
 235exit_unlock:
 236        mutex_unlock(&fan_data->lock);
 237
 238        return ret;
 239}
 240
 241static ssize_t show_pwm_enable(struct device *dev,
 242                               struct device_attribute *attr, char *buf)
 243{
 244        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 245
 246        return sprintf(buf, "%d\n", fan_data->pwm_enable);
 247}
 248
 249static ssize_t set_pwm_enable(struct device *dev, struct device_attribute *attr,
 250                              const char *buf, size_t count)
 251{
 252        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 253        unsigned long val;
 254
 255        if (kstrtoul(buf, 10, &val) || val > 1)
 256                return -EINVAL;
 257
 258        if (fan_data->pwm_enable == val)
 259                return count;
 260
 261        mutex_lock(&fan_data->lock);
 262
 263        fan_data->pwm_enable = val;
 264
 265        /* Disable manual control mode: set fan at full speed. */
 266        if (val == 0)
 267                set_fan_speed(fan_data, fan_data->num_speed - 1);
 268
 269        mutex_unlock(&fan_data->lock);
 270
 271        return count;
 272}
 273
 274static ssize_t show_pwm_mode(struct device *dev,
 275                             struct device_attribute *attr, char *buf)
 276{
 277        return sprintf(buf, "0\n");
 278}
 279
 280static ssize_t show_rpm_min(struct device *dev,
 281                            struct device_attribute *attr, char *buf)
 282{
 283        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 284
 285        return sprintf(buf, "%d\n", fan_data->speed[0].rpm);
 286}
 287
 288static ssize_t show_rpm_max(struct device *dev,
 289                            struct device_attribute *attr, char *buf)
 290{
 291        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 292
 293        return sprintf(buf, "%d\n",
 294                       fan_data->speed[fan_data->num_speed - 1].rpm);
 295}
 296
 297static ssize_t show_rpm(struct device *dev,
 298                        struct device_attribute *attr, char *buf)
 299{
 300        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 301
 302        return sprintf(buf, "%d\n", fan_data->speed[fan_data->speed_index].rpm);
 303}
 304
 305static ssize_t set_rpm(struct device *dev, struct device_attribute *attr,
 306                       const char *buf, size_t count)
 307{
 308        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 309        unsigned long rpm;
 310        int ret = count;
 311
 312        if (kstrtoul(buf, 10, &rpm))
 313                return -EINVAL;
 314
 315        mutex_lock(&fan_data->lock);
 316
 317        if (!fan_data->pwm_enable) {
 318                ret = -EPERM;
 319                goto exit_unlock;
 320        }
 321
 322        set_fan_speed(fan_data, rpm_to_speed_index(fan_data, rpm));
 323
 324exit_unlock:
 325        mutex_unlock(&fan_data->lock);
 326
 327        return ret;
 328}
 329
 330static DEVICE_ATTR(pwm1, S_IRUGO | S_IWUSR, show_pwm, set_pwm);
 331static DEVICE_ATTR(pwm1_enable, S_IRUGO | S_IWUSR,
 332                   show_pwm_enable, set_pwm_enable);
 333static DEVICE_ATTR(pwm1_mode, S_IRUGO, show_pwm_mode, NULL);
 334static DEVICE_ATTR(fan1_min, S_IRUGO, show_rpm_min, NULL);
 335static DEVICE_ATTR(fan1_max, S_IRUGO, show_rpm_max, NULL);
 336static DEVICE_ATTR(fan1_input, S_IRUGO, show_rpm, NULL);
 337static DEVICE_ATTR(fan1_target, S_IRUGO | S_IWUSR, show_rpm, set_rpm);
 338
 339static struct attribute *gpio_fan_ctrl_attributes[] = {
 340        &dev_attr_pwm1.attr,
 341        &dev_attr_pwm1_enable.attr,
 342        &dev_attr_pwm1_mode.attr,
 343        &dev_attr_fan1_input.attr,
 344        &dev_attr_fan1_target.attr,
 345        &dev_attr_fan1_min.attr,
 346        &dev_attr_fan1_max.attr,
 347        NULL
 348};
 349
 350static const struct attribute_group gpio_fan_ctrl_group = {
 351        .attrs = gpio_fan_ctrl_attributes,
 352};
 353
 354static int fan_ctrl_init(struct gpio_fan_data *fan_data,
 355                         struct gpio_fan_platform_data *pdata)
 356{
 357        struct platform_device *pdev = fan_data->pdev;
 358        int num_ctrl = pdata->num_ctrl;
 359        unsigned *ctrl = pdata->ctrl;
 360        int i, err;
 361
 362        for (i = 0; i < num_ctrl; i++) {
 363                err = devm_gpio_request(&pdev->dev, ctrl[i],
 364                                        "GPIO fan control");
 365                if (err)
 366                        return err;
 367
 368                err = gpio_direction_output(ctrl[i], gpio_get_value(ctrl[i]));
 369                if (err)
 370                        return err;
 371        }
 372
 373        fan_data->num_ctrl = num_ctrl;
 374        fan_data->ctrl = ctrl;
 375        fan_data->num_speed = pdata->num_speed;
 376        fan_data->speed = pdata->speed;
 377        fan_data->pwm_enable = true; /* Enable manual fan speed control. */
 378        fan_data->speed_index = get_fan_speed_index(fan_data);
 379        if (fan_data->speed_index < 0)
 380                return -ENODEV;
 381
 382        err = sysfs_create_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 383        return err;
 384}
 385
 386static void fan_ctrl_free(struct gpio_fan_data *fan_data)
 387{
 388        struct platform_device *pdev = fan_data->pdev;
 389
 390        sysfs_remove_group(&pdev->dev.kobj, &gpio_fan_ctrl_group);
 391}
 392
 393/*
 394 * Platform driver.
 395 */
 396
 397static ssize_t show_name(struct device *dev,
 398                         struct device_attribute *attr, char *buf)
 399{
 400        return sprintf(buf, "gpio-fan\n");
 401}
 402
 403static DEVICE_ATTR(name, S_IRUGO, show_name, NULL);
 404
 405
 406#ifdef CONFIG_OF_GPIO
 407/*
 408 * Translate OpenFirmware node properties into platform_data
 409 */
 410static int gpio_fan_get_of_pdata(struct device *dev,
 411                            struct gpio_fan_platform_data *pdata)
 412{
 413        struct device_node *node;
 414        struct gpio_fan_speed *speed;
 415        unsigned *ctrl;
 416        unsigned i;
 417        u32 u;
 418        struct property *prop;
 419        const __be32 *p;
 420
 421        node = dev->of_node;
 422
 423        /* Fill GPIO pin array */
 424        pdata->num_ctrl = of_gpio_count(node);
 425        if (!pdata->num_ctrl) {
 426                dev_err(dev, "gpios DT property empty / missing");
 427                return -ENODEV;
 428        }
 429        ctrl = devm_kzalloc(dev, pdata->num_ctrl * sizeof(unsigned),
 430                                GFP_KERNEL);
 431        if (!ctrl)
 432                return -ENOMEM;
 433        for (i = 0; i < pdata->num_ctrl; i++) {
 434                int val;
 435
 436                val = of_get_gpio(node, i);
 437                if (val < 0)
 438                        return val;
 439                ctrl[i] = val;
 440        }
 441        pdata->ctrl = ctrl;
 442
 443        /* Get number of RPM/ctrl_val pairs in speed map */
 444        prop = of_find_property(node, "gpio-fan,speed-map", &i);
 445        if (!prop) {
 446                dev_err(dev, "gpio-fan,speed-map DT property missing");
 447                return -ENODEV;
 448        }
 449        i = i / sizeof(u32);
 450        if (i == 0 || i & 1) {
 451                dev_err(dev, "gpio-fan,speed-map contains zero/odd number of entries");
 452                return -ENODEV;
 453        }
 454        pdata->num_speed = i / 2;
 455
 456        /*
 457         * Populate speed map
 458         * Speed map is in the form <RPM ctrl_val RPM ctrl_val ...>
 459         * this needs splitting into pairs to create gpio_fan_speed structs
 460         */
 461        speed = devm_kzalloc(dev,
 462                        pdata->num_speed * sizeof(struct gpio_fan_speed),
 463                        GFP_KERNEL);
 464        if (!speed)
 465                return -ENOMEM;
 466        p = NULL;
 467        for (i = 0; i < pdata->num_speed; i++) {
 468                p = of_prop_next_u32(prop, p, &u);
 469                if (!p)
 470                        return -ENODEV;
 471                speed[i].rpm = u;
 472                p = of_prop_next_u32(prop, p, &u);
 473                if (!p)
 474                        return -ENODEV;
 475                speed[i].ctrl_val = u;
 476        }
 477        pdata->speed = speed;
 478
 479        /* Alarm GPIO if one exists */
 480        if (of_gpio_named_count(node, "alarm-gpios")) {
 481                struct gpio_fan_alarm *alarm;
 482                int val;
 483                enum of_gpio_flags flags;
 484
 485                alarm = devm_kzalloc(dev, sizeof(struct gpio_fan_alarm),
 486                                        GFP_KERNEL);
 487                if (!alarm)
 488                        return -ENOMEM;
 489
 490                val = of_get_named_gpio_flags(node, "alarm-gpios", 0, &flags);
 491                if (val < 0)
 492                        return val;
 493                alarm->gpio = val;
 494                alarm->active_low = flags & OF_GPIO_ACTIVE_LOW;
 495
 496                pdata->alarm = alarm;
 497        }
 498
 499        return 0;
 500}
 501
 502static struct of_device_id of_gpio_fan_match[] __devinitdata = {
 503        { .compatible = "gpio-fan", },
 504        {},
 505};
 506#endif /* CONFIG_OF_GPIO */
 507
 508static int __devinit gpio_fan_probe(struct platform_device *pdev)
 509{
 510        int err;
 511        struct gpio_fan_data *fan_data;
 512        struct gpio_fan_platform_data *pdata = pdev->dev.platform_data;
 513
 514#ifdef CONFIG_OF_GPIO
 515        if (!pdata) {
 516                pdata = devm_kzalloc(&pdev->dev,
 517                                        sizeof(struct gpio_fan_platform_data),
 518                                        GFP_KERNEL);
 519                if (!pdata)
 520                        return -ENOMEM;
 521
 522                err = gpio_fan_get_of_pdata(&pdev->dev, pdata);
 523                if (err)
 524                        return err;
 525        }
 526#else /* CONFIG_OF_GPIO */
 527        if (!pdata)
 528                return -EINVAL;
 529#endif /* CONFIG_OF_GPIO */
 530
 531        fan_data = devm_kzalloc(&pdev->dev, sizeof(struct gpio_fan_data),
 532                                GFP_KERNEL);
 533        if (!fan_data)
 534                return -ENOMEM;
 535
 536        fan_data->pdev = pdev;
 537        platform_set_drvdata(pdev, fan_data);
 538        mutex_init(&fan_data->lock);
 539
 540        /* Configure alarm GPIO if available. */
 541        if (pdata->alarm) {
 542                err = fan_alarm_init(fan_data, pdata->alarm);
 543                if (err)
 544                        return err;
 545        }
 546
 547        /* Configure control GPIOs if available. */
 548        if (pdata->ctrl && pdata->num_ctrl > 0) {
 549                if (!pdata->speed || pdata->num_speed <= 1) {
 550                        err = -EINVAL;
 551                        goto err_free_alarm;
 552                }
 553                err = fan_ctrl_init(fan_data, pdata);
 554                if (err)
 555                        goto err_free_alarm;
 556        }
 557
 558        err = device_create_file(&pdev->dev, &dev_attr_name);
 559        if (err)
 560                goto err_free_ctrl;
 561
 562        /* Make this driver part of hwmon class. */
 563        fan_data->hwmon_dev = hwmon_device_register(&pdev->dev);
 564        if (IS_ERR(fan_data->hwmon_dev)) {
 565                err = PTR_ERR(fan_data->hwmon_dev);
 566                goto err_remove_name;
 567        }
 568
 569        dev_info(&pdev->dev, "GPIO fan initialized\n");
 570
 571        return 0;
 572
 573err_remove_name:
 574        device_remove_file(&pdev->dev, &dev_attr_name);
 575err_free_ctrl:
 576        if (fan_data->ctrl)
 577                fan_ctrl_free(fan_data);
 578err_free_alarm:
 579        if (fan_data->alarm)
 580                fan_alarm_free(fan_data);
 581        return err;
 582}
 583
 584static int __devexit gpio_fan_remove(struct platform_device *pdev)
 585{
 586        struct gpio_fan_data *fan_data = platform_get_drvdata(pdev);
 587
 588        hwmon_device_unregister(fan_data->hwmon_dev);
 589        device_remove_file(&pdev->dev, &dev_attr_name);
 590        if (fan_data->alarm)
 591                fan_alarm_free(fan_data);
 592        if (fan_data->ctrl)
 593                fan_ctrl_free(fan_data);
 594
 595        return 0;
 596}
 597
 598#ifdef CONFIG_PM_SLEEP
 599static int gpio_fan_suspend(struct device *dev)
 600{
 601        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 602
 603        if (fan_data->ctrl) {
 604                fan_data->resume_speed = fan_data->speed_index;
 605                set_fan_speed(fan_data, 0);
 606        }
 607
 608        return 0;
 609}
 610
 611static int gpio_fan_resume(struct device *dev)
 612{
 613        struct gpio_fan_data *fan_data = dev_get_drvdata(dev);
 614
 615        if (fan_data->ctrl)
 616                set_fan_speed(fan_data, fan_data->resume_speed);
 617
 618        return 0;
 619}
 620
 621static SIMPLE_DEV_PM_OPS(gpio_fan_pm, gpio_fan_suspend, gpio_fan_resume);
 622#define GPIO_FAN_PM     &gpio_fan_pm
 623#else
 624#define GPIO_FAN_PM     NULL
 625#endif
 626
 627static struct platform_driver gpio_fan_driver = {
 628        .probe          = gpio_fan_probe,
 629        .remove         = __devexit_p(gpio_fan_remove),
 630        .driver = {
 631                .name   = "gpio-fan",
 632                .pm     = GPIO_FAN_PM,
 633#ifdef CONFIG_OF_GPIO
 634                .of_match_table = of_match_ptr(of_gpio_fan_match),
 635#endif
 636        },
 637};
 638
 639module_platform_driver(gpio_fan_driver);
 640
 641MODULE_AUTHOR("Simon Guinot <sguinot@lacie.com>");
 642MODULE_DESCRIPTION("GPIO FAN driver");
 643MODULE_LICENSE("GPL");
 644MODULE_ALIAS("platform:gpio-fan");
 645
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