关于震动转一篇

驱动代码 创建timed_output类 kernel/drivers/staging/android/Timed_output.c 在sys/class目录创建timed_output子目录和文件enable  timed_output_class = class_create(THIS_MODULE, "timed_output");创建timed_output子目录  ret = device_create_file(tdev->dev, &dev_attr_enable);在sys/class/timed_output子目录创建文件enable   static int create_timed_output_class(void) {  if (!timed_output_class) {   timed_output_class = class_create(THIS_MODULE, "timed_output");   if (IS_ERR(timed_output_class))    return PTR_ERR(timed_output_class);   atomic_set(&device_count, 0);  }  return 0; } int timed_output_dev_register(struct timed_output_dev *tdev) {  int ret;  if (!tdev || !tdev->name || !tdev->enable || !tdev->get_time)   return -EINVAL;  ret = create_timed_output_class();  if (ret < 0)   return ret;  tdev->index = atomic_inc_return(&device_count);  tdev->dev = device_create(timed_output_class, NULL,   MKDEV(0, tdev->index), NULL, tdev->name);  if (IS_ERR(tdev->dev))   return PTR_ERR(tdev->dev);  ret = device_create_file(tdev->dev, &dev_attr_enable);  if (ret < 0)   goto err_create_file;  dev_set_drvdata(tdev->dev, tdev);  tdev->state = 0;  return 0; err_create_file:  device_destroy(timed_output_class, MKDEV(0, tdev->index));  printk(KERN_ERR "timed_output: Failed to register driver %s/n",    tdev->name);  return ret; } EXPORT_SYMBOL_GPL(timed_output_dev_register); 驱动注册马达的驱动，注册一个定时器用于控制震动时间（回调函数vibrator_timer_func），注册两个队列，一共给马达打开用，一共为马达震动关闭用。   static void pmic_vibrator_on(struct work_struct *work) {  set_pmic_vibrator(1); } static void pmic_vibrator_off(struct work_struct *work) {  set_pmic_vibrator(0); } static void timed_vibrator_on(struct timed_output_dev *sdev) {  schedule_work(&work_vibrator_on); } static void timed_vibrator_off(struct timed_output_dev *sdev) {  schedule_work(&work_vibrator_off); } static void vibrator_enable(struct timed_output_dev *dev, int value) {  hrtimer_cancel(&vibe_timer);  if (value == 0)   timed_vibrator_off(dev);  else {   value = (value > 15000 ? 15000 : value);   timed_vibrator_on(dev);   hrtimer_start(&vibe_timer,          ktime_set(value / 1000, (value % 1000) * 1000000),          HRTIMER_MODE_REL);  } } static int vibrator_get_time(struct timed_output_dev *dev) {  if (hrtimer_active(&vibe_timer)) {   ktime_t r = hrtimer_get_remaining(&vibe_timer);   return r.tv.sec * 1000 + r.tv.nsec / 1000000;  } else   return 0; } static enum hrtimer_restart vibrator_timer_func(struct hrtimer *timer) {  timed_vibrator_off(NULL);  return HRTIMER_NORESTART; } static struct timed_output_dev pmic_vibrator = {  .name = "vibrator",  .get_time = vibrator_get_time,  .enable = vibrator_enable, }; void __init pxa_init_pmic_vibrator(void) {  INIT_WORK(&work_vibrator_on, pmic_vibrator_on);  INIT_WORK(&work_vibrator_off, pmic_vibrator_off);  hrtimer_init(&vibe_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);  vibe_timer.function = vibrator_timer_func;  timed_output_dev_register(&pmic_vibrator); } 当上层要设置马达震动时，往文件/sys/class/timed_output/vibrator/enable写入振动的时间长度，通过 static ssize_t enable_store(   struct device *dev, struct device_attribute *attr,   const char *buf, size_t size) {  struct timed_output_dev *tdev = dev_get_drvdata(dev);  int value;  sscanf(buf, "%d", &value);  tdev->enable(tdev, value);  return size; } 调用驱动的enable函数也就是vibrator_enable（ .enable = vibrator_enable,）   vibrator_enable          |          |          v timed_vibrator_on(dev);          |          |          v  schedule_work(&work_vibrator_on);          |          |          v pmic_vibrator_on          |          |          v set_pmic_vibrator(1);   //给马达供电震动          |          |          v   hrtimer_start(&vibe_timer,          ktime_set(value / 1000, (value % 1000) * 1000000),          HRTIMER_MODE_REL); 最终是设置马达的硬件控制驱动管给马达供电，并且启动定时器，定时时间是上层给的参数。 定时时间到了就调用定时器的回调函数vibrator_timer_func vibrator_timer_func          |          |          v timed_vibrator_off(NULL);          |          |          v  schedule_work(&work_vibrator_off);          |          |          v pmic_vibrator_off          |          |          v set_pmic_vibrator(0);     //断开马达的供电，马达停止震动 最终是设置马达的硬件控制驱动管断开马达供电，停止马达震动   led类驱动 4.1，驱动创建leds类，系统启动时执行leds_init在目录/sys/class/创建子目录leds  kernel/drivers/leds/Led-class.c   static int __init leds_init(void) {  leds_class = class_create(THIS_MODULE, "leds");  if (IS_ERR(leds_class))   return PTR_ERR(leds_class);  leds_class->suspend = led_suspend;  leds_class->resume = led_resume;  return 0; }   4.2，led_classdev_register，调用这个函数就在目录/sys/class/leds创建子目录led_cdev->name和属性文件brightness 对brightness文件写就执行led_brightness_store，对brightness文件读就执行led_brightness_show，为下面的lcd，led注册做好准备  kernel/drivers/leds/Led-class.c static ssize_t led_brightness_show(struct device *dev,   struct device_attribute *attr, char *buf) {  struct led_classdev *led_cdev = dev_get_drvdata(dev);  /* no lock needed for this */  led_update_brightness(led_cdev);  return sprintf(buf, "%u/n", led_cdev->brightness); } static ssize_t led_brightness_store(struct device *dev,   struct device_attribute *attr, const char *buf, size_t size) {  struct led_classdev *led_cdev = dev_get_drvdata(dev);  ssize_t ret = -EINVAL;  char *after;  unsigned long state = simple_strtoul(buf, &after, 10);  size_t count = after - buf;  if (*after && isspace(*after))   count++;  if (count == size) {   ret = count;   if (state == LED_OFF)    led_trigger_remove(led_cdev);   led_set_brightness(led_cdev, state);  }  return ret; } static DEVICE_ATTR(brightness, 0644, led_brightness_show, led_brightness_store); /**  * led_classdev_register - register a new object of led_classdev class.  * @parent: The device to register.  * @led_cdev: the led_classdev structure for this device.  */ int led_classdev_register(struct device *parent, struct led_classdev *led_cdev) {  int rc;  led_cdev->dev = device_create(leds_class, parent, 0, led_cdev,           "%s", led_cdev->name);  if (IS_ERR(led_cdev->dev))   return PTR_ERR(led_cdev->dev);  /* register the attributes */  rc = device_create_file(led_cdev->dev, &dev_attr_brightness);  if (rc)   goto err_out; #ifdef CONFIG_LEDS_TRIGGERS  init_rwsem(&led_cdev->trigger_lock); #endif  /* add to the list of leds */  down_write(&leds_list_lock);  list_add_tail(&led_cdev->node, &leds_list);  up_write(&leds_list_lock);  led_update_brightness(led_cdev); #ifdef CONFIG_LEDS_TRIGGERS  rc = device_create_file(led_cdev->dev, &dev_attr_trigger);  if (rc)   goto err_out_led_list;  led_trigger_set_default(led_cdev); #endif  printk(KERN_INFO "Registered led device: %s/n",    led_cdev->name);  return 0; #ifdef CONFIG_LEDS_TRIGGERS err_out_led_list:  device_remove_file(led_cdev->dev, &dev_attr_brightness);  list_del(&led_cdev->node); #endif err_out:  device_unregister(led_cdev->dev);  return rc; } EXPORT_SYMBOL_GPL(led_classdev_register);   4.3，lcd驱动调用led_classdev_register，在目录/sys/class/leds创建子目录lcd-backlight和属性文件brightness  kernel/drivers/video/msm/Msm_fb.c static int lcd_backlight_registered; static void msm_fb_set_bl_brightness(struct led_classdev *led_cdev,      enum led_brightness value) {  struct msm_fb_data_type *mfd = dev_get_drvdata(led_cdev->dev->parent);  int bl_lvl;  if (value > MAX_BACKLIGHT_BRIGHTNESS)   value = MAX_BACKLIGHT_BRIGHTNESS;  /* This maps android backlight level 0 to 255 into     driver backlight level 0 to bl_max with rounding */  bl_lvl = (2 * value * mfd->panel_info.bl_max + MAX_BACKLIGHT_BRIGHTNESS)   /(2 * MAX_BACKLIGHT_BRIGHTNESS);  if (!bl_lvl && value)   bl_lvl = 1;  msm_fb_set_backlight(mfd, bl_lvl, 1); } static struct led_classdev backlight_led = {  .name  = "lcd-backlight",  .brightness = MAX_BACKLIGHT_BRIGHTNESS,  .brightness_set = msm_fb_set_bl_brightness, };      if (!lcd_backlight_registered) {   if (led_classdev_register(&pdev->dev, &backlight_led))    printk(KERN_ERR "led_classdev_register failed/n");   else    lcd_backlight_registered = 1;  } 就在目录/sys/class/leds创建子目录 lcd-backlight和属性文件brightness 当按键或者来的或者改变lcd亮度时，上层对属性文件/sys/class/leds/lcd-backlight/brightness写入背光的亮度数值就 调用led_brightness_store 调用simple_strtoul(buf, &after, 10);将输入的字符串转换为10进制的数字 执行led_set_brightness 执行led_cdev->brightness_set(led_cdev, value 调用msm_fb_set_bl_brightness ，因为  .brightness_set = msm_fb_set_bl_brightness,  /* This maps android backlight level 0 to 255 into    driver backlight level 0 to bl_max with rounding */  bl_lvl = (2 * value * mfd->panel_info.bl_max + MAX_BACKLIGHT_BRIGHTNESS)  /(2 * MAX_BACKLIGHT_BRIGHTNESS); 将输入的0--255转换为IC的0--bl_max 调用 msm_fb_set_backlight(mfd, bl_lvl, 1); 最终改变LCD的背光驱动电路的设置，调节LCD的背光的亮度     4.4 键盘背光灯 上层对属性文件/sys/class/leds/keyboard-backlight/brightness写入背光的亮度数值   (kernel/drivers/leds/Leds-msm-pmic.c #define MAX_KEYPAD_BL_LEVEL 16 static void msm_keypad_bl_led_set(struct led_classdev *led_cdev,  enum led_brightness value) {  int ret;  ret = pmic_set_led_intensity(LED_KEYPAD, value / MAX_KEYPAD_BL_LEVEL);  if (ret)   dev_err(led_cdev->dev, "can't set keypad backlight/n"); } static struct led_classdev msm_kp_bl_led = {  .name   = "keyboard-backlight",  .brightness_set  = msm_keypad_bl_led_set,  .brightness  = LED_OFF, }; static int msm_pmic_led_probe(struct platform_device *pdev) {  int rc;  rc = led_classdev_register(&pdev->dev, &msm_kp_bl_led);  if (rc) {   dev_err(&pdev->dev, "unable to register led class driver/n");   return rc;  }  msm_keypad_bl_led_set(&msm_kp_bl_led, LED_OFF);  return rc; } static int __devexit msm_pmic_led_remove(struct platform_device *pdev) {  led_classdev_unregister(&msm_kp_bl_led);  return 0; } #ifdef CONFIG_PM static int msm_pmic_led_suspend(struct platform_device *dev,   pm_message_t state) {  led_classdev_suspend(&msm_kp_bl_led);  return 0; } static int msm_pmic_led_resume(struct platform_device *dev) {  led_classdev_resume(&msm_kp_bl_led);  return 0; } #else #define msm_pmic_led_suspend NULL #define msm_pmic_led_resume NULL #endif static struct platform_driver msm_pmic_led_driver = {  .probe  = msm_pmic_led_probe,  .remove  = __devexit_p(msm_pmic_led_remove),  .suspend = msm_pmic_led_suspend,  .resume  = msm_pmic_led_resume,  .driver  = {   .name = "pmic-leds",   .owner = THIS_MODULE,  }, }; static int __init msm_pmic_led_init(void) {  return platform_driver_register(&msm_pmic_led_driver); } module_init(msm_pmic_led_init); static void __exit msm_pmic_led_exit(void) {  platform_driver_unregister(&msm_pmic_led_driver); } module_exit(msm_pmic_led_exit); MODULE_DESCRIPTION("MSM PMIC LEDs driver"); MODULE_LICENSE("GPL v2"); MODULE_ALIAS("platform:p   系统行动执行msm_pmic_led_init(void) 调用 platform_driver_register(&msm_pmic_led_driver); 调用msm_pmic_led_probe 调用 led_classdev_register(&pdev->dev, &msm_kp_bl_led); 就在目录/sys/class/leds创建子目录 keyboard-backlight和属性文件brightness 当按键时，上层对属性文件/sys/class/leds/keyboard-backlight/brightness写入背光的亮度数值就 调用led_brightness_store 调用simple_strtoul(buf, &after, 10);将输入的字符串转换为10进制的数字 执行led_set_brightness 执行led_cdev->brightness_set(led_cdev, value 调用msm_keypad_bl_led_set ，因为 .brightness_set  = msm_keypad_bl_led_set, 调用 ret = pmic_set_led_intensity(LED_KEYPAD, value / MAX_KEYPAD_BL_LEVEL); 最终改变LED驱动电路的设置，调节LED的亮度