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 <log.h>
  11. #include <malloc.h>
  12. #include <reset-uclass.h>
  13. #include <regmap.h>
  14. #include <linux/bitops.h>
  15. #define REG_COUNT 8
  16. #define BITS_PER_REG 32
  17. #define LEVEL_OFFSET 0x7c
  18. struct meson_reset_priv {
  19. struct regmap *regmap;
  20. };
  21. static int meson_reset_request(struct reset_ctl *reset_ctl)
  22. {
  23. if (reset_ctl->id > (REG_COUNT * BITS_PER_REG))
  24. return -EINVAL;
  25. return 0;
  26. }
  27. static int meson_reset_free(struct reset_ctl *reset_ctl)
  28. {
  29. return 0;
  30. }
  31. static int meson_reset_level(struct reset_ctl *reset_ctl, bool assert)
  32. {
  33. struct meson_reset_priv *priv = dev_get_priv(reset_ctl->dev);
  34. uint bank = reset_ctl->id / BITS_PER_REG;
  35. uint offset = reset_ctl->id % BITS_PER_REG;
  36. uint reg_offset = LEVEL_OFFSET + (bank << 2);
  37. uint val;
  38. regmap_read(priv->regmap, reg_offset, &val);
  39. if (assert)
  40. val &= ~BIT(offset);
  41. else
  42. val |= BIT(offset);
  43. regmap_write(priv->regmap, reg_offset, val);
  44. return 0;
  45. }
  46. static int meson_reset_assert(struct reset_ctl *reset_ctl)
  47. {
  48. return meson_reset_level(reset_ctl, true);
  49. }
  50. static int meson_reset_deassert(struct reset_ctl *reset_ctl)
  51. {
  52. return meson_reset_level(reset_ctl, false);
  53. }
  54. struct reset_ops meson_reset_ops = {
  55. .request = meson_reset_request,
  56. .rfree = meson_reset_free,
  57. .rst_assert = meson_reset_assert,
  58. .rst_deassert = meson_reset_deassert,
  59. };
  60. static const struct udevice_id meson_reset_ids[] = {
  61. { .compatible = "amlogic,meson-gxbb-reset" },
  62. { .compatible = "amlogic,meson-axg-reset" },
  63. { }
  64. };
  65. static int meson_reset_probe(struct udevice *dev)
  66. {
  67. struct meson_reset_priv *priv = dev_get_priv(dev);
  68. return regmap_init_mem(dev_ofnode(dev), &priv->regmap);
  69. }
  70. U_BOOT_DRIVER(meson_reset) = {
  71. .name = "meson_reset",
  72. .id = UCLASS_RESET,
  73. .of_match = meson_reset_ids,
  74. .probe = meson_reset_probe,
  75. .ops = &meson_reset_ops,
  76. .priv_auto = sizeof(struct meson_reset_priv),
  77. };