leds-regulator.c 4.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * leds-regulator.c - LED class driver for regulator driven LEDs.
  4. *
  5. * Copyright (C) 2009 Antonio Ospite <ospite@studenti.unina.it>
  6. *
  7. * Inspired by leds-wm8350 driver.
  8. */
  9. #include <linux/module.h>
  10. #include <linux/err.h>
  11. #include <linux/slab.h>
  12. #include <linux/leds.h>
  13. #include <linux/leds-regulator.h>
  14. #include <linux/platform_device.h>
  15. #include <linux/regulator/consumer.h>
  16. #define to_regulator_led(led_cdev) \
  17. container_of(led_cdev, struct regulator_led, cdev)
  18. struct regulator_led {
  19. struct led_classdev cdev;
  20. int enabled;
  21. struct mutex mutex;
  22. struct regulator *vcc;
  23. };
  24. static inline int led_regulator_get_max_brightness(struct regulator *supply)
  25. {
  26. int ret;
  27. int voltage = regulator_list_voltage(supply, 0);
  28. if (voltage <= 0)
  29. return 1;
  30. /* even if regulator can't change voltages,
  31. * we still assume it can change status
  32. * and the LED can be turned on and off.
  33. */
  34. ret = regulator_set_voltage(supply, voltage, voltage);
  35. if (ret < 0)
  36. return 1;
  37. return regulator_count_voltages(supply);
  38. }
  39. static int led_regulator_get_voltage(struct regulator *supply,
  40. enum led_brightness brightness)
  41. {
  42. if (brightness == 0)
  43. return -EINVAL;
  44. return regulator_list_voltage(supply, brightness - 1);
  45. }
  46. static void regulator_led_enable(struct regulator_led *led)
  47. {
  48. int ret;
  49. if (led->enabled)
  50. return;
  51. ret = regulator_enable(led->vcc);
  52. if (ret != 0) {
  53. dev_err(led->cdev.dev, "Failed to enable vcc: %d\n", ret);
  54. return;
  55. }
  56. led->enabled = 1;
  57. }
  58. static void regulator_led_disable(struct regulator_led *led)
  59. {
  60. int ret;
  61. if (!led->enabled)
  62. return;
  63. ret = regulator_disable(led->vcc);
  64. if (ret != 0) {
  65. dev_err(led->cdev.dev, "Failed to disable vcc: %d\n", ret);
  66. return;
  67. }
  68. led->enabled = 0;
  69. }
  70. static int regulator_led_brightness_set(struct led_classdev *led_cdev,
  71. enum led_brightness value)
  72. {
  73. struct regulator_led *led = to_regulator_led(led_cdev);
  74. int voltage;
  75. int ret = 0;
  76. mutex_lock(&led->mutex);
  77. if (value == LED_OFF) {
  78. regulator_led_disable(led);
  79. goto out;
  80. }
  81. if (led->cdev.max_brightness > 1) {
  82. voltage = led_regulator_get_voltage(led->vcc, value);
  83. dev_dbg(led->cdev.dev, "brightness: %d voltage: %d\n",
  84. value, voltage);
  85. ret = regulator_set_voltage(led->vcc, voltage, voltage);
  86. if (ret != 0)
  87. dev_err(led->cdev.dev, "Failed to set voltage %d: %d\n",
  88. voltage, ret);
  89. }
  90. regulator_led_enable(led);
  91. out:
  92. mutex_unlock(&led->mutex);
  93. return ret;
  94. }
  95. static int regulator_led_probe(struct platform_device *pdev)
  96. {
  97. struct led_regulator_platform_data *pdata =
  98. dev_get_platdata(&pdev->dev);
  99. struct regulator_led *led;
  100. struct regulator *vcc;
  101. int ret = 0;
  102. if (pdata == NULL) {
  103. dev_err(&pdev->dev, "no platform data\n");
  104. return -ENODEV;
  105. }
  106. vcc = devm_regulator_get_exclusive(&pdev->dev, "vled");
  107. if (IS_ERR(vcc)) {
  108. dev_err(&pdev->dev, "Cannot get vcc for %s\n", pdata->name);
  109. return PTR_ERR(vcc);
  110. }
  111. led = devm_kzalloc(&pdev->dev, sizeof(*led), GFP_KERNEL);
  112. if (led == NULL)
  113. return -ENOMEM;
  114. led->cdev.max_brightness = led_regulator_get_max_brightness(vcc);
  115. if (pdata->brightness > led->cdev.max_brightness) {
  116. dev_err(&pdev->dev, "Invalid default brightness %d\n",
  117. pdata->brightness);
  118. return -EINVAL;
  119. }
  120. led->cdev.brightness_set_blocking = regulator_led_brightness_set;
  121. led->cdev.name = pdata->name;
  122. led->cdev.flags |= LED_CORE_SUSPENDRESUME;
  123. led->vcc = vcc;
  124. /* to handle correctly an already enabled regulator */
  125. if (regulator_is_enabled(led->vcc))
  126. led->enabled = 1;
  127. mutex_init(&led->mutex);
  128. platform_set_drvdata(pdev, led);
  129. ret = led_classdev_register(&pdev->dev, &led->cdev);
  130. if (ret < 0)
  131. return ret;
  132. /* to expose the default value to userspace */
  133. led->cdev.brightness = pdata->brightness;
  134. /* Set the default led status */
  135. regulator_led_brightness_set(&led->cdev, led->cdev.brightness);
  136. return 0;
  137. }
  138. static int regulator_led_remove(struct platform_device *pdev)
  139. {
  140. struct regulator_led *led = platform_get_drvdata(pdev);
  141. led_classdev_unregister(&led->cdev);
  142. regulator_led_disable(led);
  143. return 0;
  144. }
  145. static struct platform_driver regulator_led_driver = {
  146. .driver = {
  147. .name = "leds-regulator",
  148. },
  149. .probe = regulator_led_probe,
  150. .remove = regulator_led_remove,
  151. };
  152. module_platform_driver(regulator_led_driver);
  153. MODULE_AUTHOR("Antonio Ospite <ospite@studenti.unina.it>");
  154. MODULE_DESCRIPTION("Regulator driven LED driver");
  155. MODULE_LICENSE("GPL");
  156. MODULE_ALIAS("platform:leds-regulator");