reset-meson.c 2.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0
  2. /*
  3. * Amlogic Meson Reset Controller driver
  4. *
  5. * Copyright (c) 2018 BayLibre, SAS.
  6. * Author: Neil Armstrong <narmstrong@baylibre.com>
  7. */
  8. #include <common.h>
  9. #include <dm.h>
  10. #include <reset-uclass.h>
  11. #include <regmap.h>
  12. #define REG_COUNT 8
  13. #define BITS_PER_REG 32
  14. #define LEVEL_OFFSET 0x7c
  15. struct meson_reset_priv {
  16. struct regmap *regmap;
  17. };
  18. static int meson_reset_request(struct reset_ctl *reset_ctl)
  19. {
  20. if (reset_ctl->id > (REG_COUNT * BITS_PER_REG))
  21. return -EINVAL;
  22. return 0;
  23. }
  24. static int meson_reset_free(struct reset_ctl *reset_ctl)
  25. {
  26. return 0;
  27. }
  28. static int meson_reset_level(struct reset_ctl *reset_ctl, bool assert)
  29. {
  30. struct meson_reset_priv *priv = dev_get_priv(reset_ctl->dev);
  31. uint bank = reset_ctl->id / BITS_PER_REG;
  32. uint offset = reset_ctl->id % BITS_PER_REG;
  33. uint reg_offset = LEVEL_OFFSET + (bank << 2);
  34. uint val;
  35. regmap_read(priv->regmap, reg_offset, &val);
  36. if (assert)
  37. val &= ~BIT(offset);
  38. else
  39. val |= BIT(offset);
  40. regmap_write(priv->regmap, reg_offset, val);
  41. return 0;
  42. }
  43. static int meson_reset_assert(struct reset_ctl *reset_ctl)
  44. {
  45. return meson_reset_level(reset_ctl, true);
  46. }
  47. static int meson_reset_deassert(struct reset_ctl *reset_ctl)
  48. {
  49. return meson_reset_level(reset_ctl, false);
  50. }
  51. struct reset_ops meson_reset_ops = {
  52. .request = meson_reset_request,
  53. .free = meson_reset_free,
  54. .rst_assert = meson_reset_assert,
  55. .rst_deassert = meson_reset_deassert,
  56. };
  57. static const struct udevice_id meson_reset_ids[] = {
  58. { .compatible = "amlogic,meson-gxbb-reset" },
  59. { .compatible = "amlogic,meson-axg-reset" },
  60. { }
  61. };
  62. static int meson_reset_probe(struct udevice *dev)
  63. {
  64. struct meson_reset_priv *priv = dev_get_priv(dev);
  65. return regmap_init_mem(dev_ofnode(dev), &priv->regmap);
  66. }
  67. U_BOOT_DRIVER(meson_reset) = {
  68. .name = "meson_reset",
  69. .id = UCLASS_RESET,
  70. .of_match = meson_reset_ids,
  71. .probe = meson_reset_probe,
  72. .ops = &meson_reset_ops,
  73. .priv_auto_alloc_size = sizeof(struct meson_reset_priv),
  74. };