aat2870_bl.c 5.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * linux/drivers/video/backlight/aat2870_bl.c
  4. *
  5. * Copyright (c) 2011, NVIDIA Corporation.
  6. * Author: Jin Park <jinyoungp@nvidia.com>
  7. */
  8. #include <linux/module.h>
  9. #include <linux/kernel.h>
  10. #include <linux/init.h>
  11. #include <linux/platform_device.h>
  12. #include <linux/mutex.h>
  13. #include <linux/delay.h>
  14. #include <linux/fb.h>
  15. #include <linux/backlight.h>
  16. #include <linux/mfd/aat2870.h>
  17. struct aat2870_bl_driver_data {
  18. struct platform_device *pdev;
  19. struct backlight_device *bd;
  20. int channels;
  21. int max_current;
  22. int brightness; /* current brightness */
  23. };
  24. static inline int aat2870_brightness(struct aat2870_bl_driver_data *aat2870_bl,
  25. int brightness)
  26. {
  27. struct backlight_device *bd = aat2870_bl->bd;
  28. int val;
  29. val = brightness * (aat2870_bl->max_current - 1);
  30. val /= bd->props.max_brightness;
  31. return val;
  32. }
  33. static inline int aat2870_bl_enable(struct aat2870_bl_driver_data *aat2870_bl)
  34. {
  35. struct aat2870_data *aat2870
  36. = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
  37. return aat2870->write(aat2870, AAT2870_BL_CH_EN,
  38. (u8)aat2870_bl->channels);
  39. }
  40. static inline int aat2870_bl_disable(struct aat2870_bl_driver_data *aat2870_bl)
  41. {
  42. struct aat2870_data *aat2870
  43. = dev_get_drvdata(aat2870_bl->pdev->dev.parent);
  44. return aat2870->write(aat2870, AAT2870_BL_CH_EN, 0x0);
  45. }
  46. static int aat2870_bl_update_status(struct backlight_device *bd)
  47. {
  48. struct aat2870_bl_driver_data *aat2870_bl = bl_get_data(bd);
  49. struct aat2870_data *aat2870 =
  50. dev_get_drvdata(aat2870_bl->pdev->dev.parent);
  51. int brightness = bd->props.brightness;
  52. int ret;
  53. if ((brightness < 0) || (bd->props.max_brightness < brightness)) {
  54. dev_err(&bd->dev, "invalid brightness, %d\n", brightness);
  55. return -EINVAL;
  56. }
  57. dev_dbg(&bd->dev, "brightness=%d, power=%d, state=%d\n",
  58. bd->props.brightness, bd->props.power, bd->props.state);
  59. if ((bd->props.power != FB_BLANK_UNBLANK) ||
  60. (bd->props.state & BL_CORE_FBBLANK) ||
  61. (bd->props.state & BL_CORE_SUSPENDED))
  62. brightness = 0;
  63. ret = aat2870->write(aat2870, AAT2870_BLM,
  64. (u8)aat2870_brightness(aat2870_bl, brightness));
  65. if (ret < 0)
  66. return ret;
  67. if (brightness == 0) {
  68. ret = aat2870_bl_disable(aat2870_bl);
  69. if (ret < 0)
  70. return ret;
  71. } else if (aat2870_bl->brightness == 0) {
  72. ret = aat2870_bl_enable(aat2870_bl);
  73. if (ret < 0)
  74. return ret;
  75. }
  76. aat2870_bl->brightness = brightness;
  77. return 0;
  78. }
  79. static int aat2870_bl_check_fb(struct backlight_device *bd, struct fb_info *fi)
  80. {
  81. return 1;
  82. }
  83. static const struct backlight_ops aat2870_bl_ops = {
  84. .options = BL_CORE_SUSPENDRESUME,
  85. .update_status = aat2870_bl_update_status,
  86. .check_fb = aat2870_bl_check_fb,
  87. };
  88. static int aat2870_bl_probe(struct platform_device *pdev)
  89. {
  90. struct aat2870_bl_platform_data *pdata = dev_get_platdata(&pdev->dev);
  91. struct aat2870_bl_driver_data *aat2870_bl;
  92. struct backlight_device *bd;
  93. struct backlight_properties props;
  94. int ret = 0;
  95. if (!pdata) {
  96. dev_err(&pdev->dev, "No platform data\n");
  97. ret = -ENXIO;
  98. goto out;
  99. }
  100. if (pdev->id != AAT2870_ID_BL) {
  101. dev_err(&pdev->dev, "Invalid device ID, %d\n", pdev->id);
  102. ret = -EINVAL;
  103. goto out;
  104. }
  105. aat2870_bl = devm_kzalloc(&pdev->dev,
  106. sizeof(struct aat2870_bl_driver_data),
  107. GFP_KERNEL);
  108. if (!aat2870_bl) {
  109. ret = -ENOMEM;
  110. goto out;
  111. }
  112. memset(&props, 0, sizeof(struct backlight_properties));
  113. props.type = BACKLIGHT_RAW;
  114. bd = devm_backlight_device_register(&pdev->dev, "aat2870-backlight",
  115. &pdev->dev, aat2870_bl, &aat2870_bl_ops,
  116. &props);
  117. if (IS_ERR(bd)) {
  118. dev_err(&pdev->dev,
  119. "Failed allocate memory for backlight device\n");
  120. ret = PTR_ERR(bd);
  121. goto out;
  122. }
  123. aat2870_bl->pdev = pdev;
  124. platform_set_drvdata(pdev, aat2870_bl);
  125. aat2870_bl->bd = bd;
  126. if (pdata->channels > 0)
  127. aat2870_bl->channels = pdata->channels;
  128. else
  129. aat2870_bl->channels = AAT2870_BL_CH_ALL;
  130. if (pdata->max_current > 0)
  131. aat2870_bl->max_current = pdata->max_current;
  132. else
  133. aat2870_bl->max_current = AAT2870_CURRENT_27_9;
  134. if (pdata->max_brightness > 0)
  135. bd->props.max_brightness = pdata->max_brightness;
  136. else
  137. bd->props.max_brightness = 255;
  138. aat2870_bl->brightness = 0;
  139. bd->props.power = FB_BLANK_UNBLANK;
  140. bd->props.brightness = bd->props.max_brightness;
  141. ret = aat2870_bl_update_status(bd);
  142. if (ret < 0) {
  143. dev_err(&pdev->dev, "Failed to initialize\n");
  144. return ret;
  145. }
  146. return 0;
  147. out:
  148. return ret;
  149. }
  150. static int aat2870_bl_remove(struct platform_device *pdev)
  151. {
  152. struct aat2870_bl_driver_data *aat2870_bl = platform_get_drvdata(pdev);
  153. struct backlight_device *bd = aat2870_bl->bd;
  154. bd->props.power = FB_BLANK_POWERDOWN;
  155. bd->props.brightness = 0;
  156. backlight_update_status(bd);
  157. return 0;
  158. }
  159. static struct platform_driver aat2870_bl_driver = {
  160. .driver = {
  161. .name = "aat2870-backlight",
  162. },
  163. .probe = aat2870_bl_probe,
  164. .remove = aat2870_bl_remove,
  165. };
  166. static int __init aat2870_bl_init(void)
  167. {
  168. return platform_driver_register(&aat2870_bl_driver);
  169. }
  170. subsys_initcall(aat2870_bl_init);
  171. static void __exit aat2870_bl_exit(void)
  172. {
  173. platform_driver_unregister(&aat2870_bl_driver);
  174. }
  175. module_exit(aat2870_bl_exit);
  176. MODULE_DESCRIPTION("AnalogicTech AAT2870 Backlight");
  177. MODULE_LICENSE("GPL");
  178. MODULE_AUTHOR("Jin Park <jinyoungp@nvidia.com>");