hid-picolcd_backlight.c 3.3 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /***************************************************************************
  3. * Copyright (C) 2010-2012 by Bruno Prémont <bonbons@linux-vserver.org> *
  4. * *
  5. * Based on Logitech G13 driver (v0.4) *
  6. * Copyright (C) 2009 by Rick L. Vinyard, Jr. <rvinyard@cs.nmsu.edu> *
  7. * *
  8. ***************************************************************************/
  9. #include <linux/hid.h>
  10. #include <linux/fb.h>
  11. #include <linux/backlight.h>
  12. #include "hid-picolcd.h"
  13. static int picolcd_get_brightness(struct backlight_device *bdev)
  14. {
  15. struct picolcd_data *data = bl_get_data(bdev);
  16. return data->lcd_brightness;
  17. }
  18. static int picolcd_set_brightness(struct backlight_device *bdev)
  19. {
  20. struct picolcd_data *data = bl_get_data(bdev);
  21. struct hid_report *report = picolcd_out_report(REPORT_BRIGHTNESS, data->hdev);
  22. unsigned long flags;
  23. if (!report || report->maxfield != 1 || report->field[0]->report_count != 1)
  24. return -ENODEV;
  25. data->lcd_brightness = bdev->props.brightness & 0x0ff;
  26. data->lcd_power = bdev->props.power;
  27. spin_lock_irqsave(&data->lock, flags);
  28. hid_set_field(report->field[0], 0, data->lcd_power == FB_BLANK_UNBLANK ? data->lcd_brightness : 0);
  29. if (!(data->status & PICOLCD_FAILED))
  30. hid_hw_request(data->hdev, report, HID_REQ_SET_REPORT);
  31. spin_unlock_irqrestore(&data->lock, flags);
  32. return 0;
  33. }
  34. static int picolcd_check_bl_fb(struct backlight_device *bdev, struct fb_info *fb)
  35. {
  36. return fb && fb == picolcd_fbinfo((struct picolcd_data *)bl_get_data(bdev));
  37. }
  38. static const struct backlight_ops picolcd_blops = {
  39. .update_status = picolcd_set_brightness,
  40. .get_brightness = picolcd_get_brightness,
  41. .check_fb = picolcd_check_bl_fb,
  42. };
  43. int picolcd_init_backlight(struct picolcd_data *data, struct hid_report *report)
  44. {
  45. struct device *dev = &data->hdev->dev;
  46. struct backlight_device *bdev;
  47. struct backlight_properties props;
  48. if (!report)
  49. return -ENODEV;
  50. if (report->maxfield != 1 || report->field[0]->report_count != 1 ||
  51. report->field[0]->report_size != 8) {
  52. dev_err(dev, "unsupported BRIGHTNESS report");
  53. return -EINVAL;
  54. }
  55. memset(&props, 0, sizeof(props));
  56. props.type = BACKLIGHT_RAW;
  57. props.max_brightness = 0xff;
  58. bdev = backlight_device_register(dev_name(dev), dev, data,
  59. &picolcd_blops, &props);
  60. if (IS_ERR(bdev)) {
  61. dev_err(dev, "failed to register backlight\n");
  62. return PTR_ERR(bdev);
  63. }
  64. bdev->props.brightness = 0xff;
  65. data->lcd_brightness = 0xff;
  66. data->backlight = bdev;
  67. picolcd_set_brightness(bdev);
  68. return 0;
  69. }
  70. void picolcd_exit_backlight(struct picolcd_data *data)
  71. {
  72. struct backlight_device *bdev = data->backlight;
  73. data->backlight = NULL;
  74. backlight_device_unregister(bdev);
  75. }
  76. int picolcd_resume_backlight(struct picolcd_data *data)
  77. {
  78. if (!data->backlight)
  79. return 0;
  80. return picolcd_set_brightness(data->backlight);
  81. }
  82. #ifdef CONFIG_PM
  83. void picolcd_suspend_backlight(struct picolcd_data *data)
  84. {
  85. int bl_power = data->lcd_power;
  86. if (!data->backlight)
  87. return;
  88. data->backlight->props.power = FB_BLANK_POWERDOWN;
  89. picolcd_set_brightness(data->backlight);
  90. data->lcd_power = data->backlight->props.power = bl_power;
  91. }
  92. #endif /* CONFIG_PM */