reset-k210.c 3.0 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * Copyright (c) 2020 Western Digital Corporation or its affiliates.
  4. */
  5. #include <linux/of.h>
  6. #include <linux/of_device.h>
  7. #include <linux/platform_device.h>
  8. #include <linux/reset-controller.h>
  9. #include <linux/delay.h>
  10. #include <linux/mfd/syscon.h>
  11. #include <linux/regmap.h>
  12. #include <soc/canaan/k210-sysctl.h>
  13. #include <dt-bindings/reset/k210-rst.h>
  14. #define K210_RST_MASK 0x27FFFFFF
  15. struct k210_rst {
  16. struct regmap *map;
  17. struct reset_controller_dev rcdev;
  18. };
  19. static inline struct k210_rst *
  20. to_k210_rst(struct reset_controller_dev *rcdev)
  21. {
  22. return container_of(rcdev, struct k210_rst, rcdev);
  23. }
  24. static inline int k210_rst_assert(struct reset_controller_dev *rcdev,
  25. unsigned long id)
  26. {
  27. struct k210_rst *ksr = to_k210_rst(rcdev);
  28. return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 1);
  29. }
  30. static inline int k210_rst_deassert(struct reset_controller_dev *rcdev,
  31. unsigned long id)
  32. {
  33. struct k210_rst *ksr = to_k210_rst(rcdev);
  34. return regmap_update_bits(ksr->map, K210_SYSCTL_PERI_RESET, BIT(id), 0);
  35. }
  36. static int k210_rst_reset(struct reset_controller_dev *rcdev,
  37. unsigned long id)
  38. {
  39. int ret;
  40. ret = k210_rst_assert(rcdev, id);
  41. if (ret == 0) {
  42. udelay(10);
  43. ret = k210_rst_deassert(rcdev, id);
  44. }
  45. return ret;
  46. }
  47. static int k210_rst_status(struct reset_controller_dev *rcdev,
  48. unsigned long id)
  49. {
  50. struct k210_rst *ksr = to_k210_rst(rcdev);
  51. u32 reg, bit = BIT(id);
  52. int ret;
  53. ret = regmap_read(ksr->map, K210_SYSCTL_PERI_RESET, &reg);
  54. if (ret)
  55. return ret;
  56. return reg & bit;
  57. }
  58. static int k210_rst_xlate(struct reset_controller_dev *rcdev,
  59. const struct of_phandle_args *reset_spec)
  60. {
  61. unsigned long id = reset_spec->args[0];
  62. if (!(BIT(id) & K210_RST_MASK))
  63. return -EINVAL;
  64. return id;
  65. }
  66. static const struct reset_control_ops k210_rst_ops = {
  67. .assert = k210_rst_assert,
  68. .deassert = k210_rst_deassert,
  69. .reset = k210_rst_reset,
  70. .status = k210_rst_status,
  71. };
  72. static int k210_rst_probe(struct platform_device *pdev)
  73. {
  74. struct device *dev = &pdev->dev;
  75. struct device_node *parent_np = of_get_parent(dev->of_node);
  76. struct k210_rst *ksr;
  77. dev_info(dev, "K210 reset controller\n");
  78. ksr = devm_kzalloc(dev, sizeof(*ksr), GFP_KERNEL);
  79. if (!ksr)
  80. return -ENOMEM;
  81. ksr->map = syscon_node_to_regmap(parent_np);
  82. of_node_put(parent_np);
  83. if (IS_ERR(ksr->map))
  84. return PTR_ERR(ksr->map);
  85. ksr->rcdev.owner = THIS_MODULE;
  86. ksr->rcdev.dev = dev;
  87. ksr->rcdev.of_node = dev->of_node;
  88. ksr->rcdev.ops = &k210_rst_ops;
  89. ksr->rcdev.nr_resets = fls(K210_RST_MASK);
  90. ksr->rcdev.of_reset_n_cells = 1;
  91. ksr->rcdev.of_xlate = k210_rst_xlate;
  92. return devm_reset_controller_register(dev, &ksr->rcdev);
  93. }
  94. static const struct of_device_id k210_rst_dt_ids[] = {
  95. { .compatible = "canaan,k210-rst" },
  96. { /* sentinel */ },
  97. };
  98. static struct platform_driver k210_rst_driver = {
  99. .probe = k210_rst_probe,
  100. .driver = {
  101. .name = "k210-rst",
  102. .of_match_table = k210_rst_dt_ids,
  103. },
  104. };
  105. builtin_platform_driver(k210_rst_driver);