leds-dac124s085.c 2.4 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright 2008
  4. * Guennadi Liakhovetski, DENX Software Engineering, <lg@denx.de>
  5. *
  6. * LED driver for the DAC124S085 SPI DAC
  7. */
  8. #include <linux/leds.h>
  9. #include <linux/module.h>
  10. #include <linux/mutex.h>
  11. #include <linux/slab.h>
  12. #include <linux/spi/spi.h>
  13. struct dac124s085_led {
  14. struct led_classdev ldev;
  15. struct spi_device *spi;
  16. int id;
  17. char name[sizeof("dac124s085-3")];
  18. struct mutex mutex;
  19. };
  20. struct dac124s085 {
  21. struct dac124s085_led leds[4];
  22. };
  23. #define REG_WRITE (0 << 12)
  24. #define REG_WRITE_UPDATE (1 << 12)
  25. #define ALL_WRITE_UPDATE (2 << 12)
  26. #define POWER_DOWN_OUTPUT (3 << 12)
  27. static int dac124s085_set_brightness(struct led_classdev *ldev,
  28. enum led_brightness brightness)
  29. {
  30. struct dac124s085_led *led = container_of(ldev, struct dac124s085_led,
  31. ldev);
  32. u16 word;
  33. int ret;
  34. mutex_lock(&led->mutex);
  35. word = cpu_to_le16(((led->id) << 14) | REG_WRITE_UPDATE |
  36. (brightness & 0xfff));
  37. ret = spi_write(led->spi, (const u8 *)&word, sizeof(word));
  38. mutex_unlock(&led->mutex);
  39. return ret;
  40. }
  41. static int dac124s085_probe(struct spi_device *spi)
  42. {
  43. struct dac124s085 *dac;
  44. struct dac124s085_led *led;
  45. int i, ret;
  46. dac = devm_kzalloc(&spi->dev, sizeof(*dac), GFP_KERNEL);
  47. if (!dac)
  48. return -ENOMEM;
  49. spi->bits_per_word = 16;
  50. for (i = 0; i < ARRAY_SIZE(dac->leds); i++) {
  51. led = dac->leds + i;
  52. led->id = i;
  53. led->spi = spi;
  54. snprintf(led->name, sizeof(led->name), "dac124s085-%d", i);
  55. mutex_init(&led->mutex);
  56. led->ldev.name = led->name;
  57. led->ldev.brightness = LED_OFF;
  58. led->ldev.max_brightness = 0xfff;
  59. led->ldev.brightness_set_blocking = dac124s085_set_brightness;
  60. ret = led_classdev_register(&spi->dev, &led->ldev);
  61. if (ret < 0)
  62. goto eledcr;
  63. }
  64. spi_set_drvdata(spi, dac);
  65. return 0;
  66. eledcr:
  67. while (i--)
  68. led_classdev_unregister(&dac->leds[i].ldev);
  69. return ret;
  70. }
  71. static int dac124s085_remove(struct spi_device *spi)
  72. {
  73. struct dac124s085 *dac = spi_get_drvdata(spi);
  74. int i;
  75. for (i = 0; i < ARRAY_SIZE(dac->leds); i++)
  76. led_classdev_unregister(&dac->leds[i].ldev);
  77. return 0;
  78. }
  79. static struct spi_driver dac124s085_driver = {
  80. .probe = dac124s085_probe,
  81. .remove = dac124s085_remove,
  82. .driver = {
  83. .name = "dac124s085",
  84. },
  85. };
  86. module_spi_driver(dac124s085_driver);
  87. MODULE_AUTHOR("Guennadi Liakhovetski <lg@denx.de>");
  88. MODULE_DESCRIPTION("DAC124S085 LED driver");
  89. MODULE_LICENSE("GPL v2");
  90. MODULE_ALIAS("spi:dac124s085");