reset-meson.c 3.8 KB

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  1. // SPDX-License-Identifier: GPL-2.0 OR BSD-3-Clause
  2. /*
  3. * Amlogic Meson Reset Controller driver
  4. *
  5. * Copyright (c) 2016 BayLibre, SAS.
  6. * Author: Neil Armstrong <narmstrong@baylibre.com>
  7. */
  8. #include <linux/err.h>
  9. #include <linux/init.h>
  10. #include <linux/io.h>
  11. #include <linux/of.h>
  12. #include <linux/module.h>
  13. #include <linux/platform_device.h>
  14. #include <linux/reset-controller.h>
  15. #include <linux/slab.h>
  16. #include <linux/types.h>
  17. #include <linux/of_device.h>
  18. #define BITS_PER_REG 32
  19. struct meson_reset_param {
  20. int reg_count;
  21. int level_offset;
  22. };
  23. struct meson_reset {
  24. void __iomem *reg_base;
  25. const struct meson_reset_param *param;
  26. struct reset_controller_dev rcdev;
  27. spinlock_t lock;
  28. };
  29. static int meson_reset_reset(struct reset_controller_dev *rcdev,
  30. unsigned long id)
  31. {
  32. struct meson_reset *data =
  33. container_of(rcdev, struct meson_reset, rcdev);
  34. unsigned int bank = id / BITS_PER_REG;
  35. unsigned int offset = id % BITS_PER_REG;
  36. void __iomem *reg_addr = data->reg_base + (bank << 2);
  37. writel(BIT(offset), reg_addr);
  38. return 0;
  39. }
  40. static int meson_reset_level(struct reset_controller_dev *rcdev,
  41. unsigned long id, bool assert)
  42. {
  43. struct meson_reset *data =
  44. container_of(rcdev, struct meson_reset, rcdev);
  45. unsigned int bank = id / BITS_PER_REG;
  46. unsigned int offset = id % BITS_PER_REG;
  47. void __iomem *reg_addr;
  48. unsigned long flags;
  49. u32 reg;
  50. reg_addr = data->reg_base + data->param->level_offset + (bank << 2);
  51. spin_lock_irqsave(&data->lock, flags);
  52. reg = readl(reg_addr);
  53. if (assert)
  54. writel(reg & ~BIT(offset), reg_addr);
  55. else
  56. writel(reg | BIT(offset), reg_addr);
  57. spin_unlock_irqrestore(&data->lock, flags);
  58. return 0;
  59. }
  60. static int meson_reset_assert(struct reset_controller_dev *rcdev,
  61. unsigned long id)
  62. {
  63. return meson_reset_level(rcdev, id, true);
  64. }
  65. static int meson_reset_deassert(struct reset_controller_dev *rcdev,
  66. unsigned long id)
  67. {
  68. return meson_reset_level(rcdev, id, false);
  69. }
  70. static const struct reset_control_ops meson_reset_ops = {
  71. .reset = meson_reset_reset,
  72. .assert = meson_reset_assert,
  73. .deassert = meson_reset_deassert,
  74. };
  75. static const struct meson_reset_param meson8b_param = {
  76. .reg_count = 8,
  77. .level_offset = 0x7c,
  78. };
  79. static const struct meson_reset_param meson_a1_param = {
  80. .reg_count = 3,
  81. .level_offset = 0x40,
  82. };
  83. static const struct of_device_id meson_reset_dt_ids[] = {
  84. { .compatible = "amlogic,meson8b-reset", .data = &meson8b_param},
  85. { .compatible = "amlogic,meson-gxbb-reset", .data = &meson8b_param},
  86. { .compatible = "amlogic,meson-axg-reset", .data = &meson8b_param},
  87. { .compatible = "amlogic,meson-a1-reset", .data = &meson_a1_param},
  88. { /* sentinel */ },
  89. };
  90. MODULE_DEVICE_TABLE(of, meson_reset_dt_ids);
  91. static int meson_reset_probe(struct platform_device *pdev)
  92. {
  93. struct meson_reset *data;
  94. struct resource *res;
  95. data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  96. if (!data)
  97. return -ENOMEM;
  98. res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  99. data->reg_base = devm_ioremap_resource(&pdev->dev, res);
  100. if (IS_ERR(data->reg_base))
  101. return PTR_ERR(data->reg_base);
  102. data->param = of_device_get_match_data(&pdev->dev);
  103. if (!data->param)
  104. return -ENODEV;
  105. platform_set_drvdata(pdev, data);
  106. spin_lock_init(&data->lock);
  107. data->rcdev.owner = THIS_MODULE;
  108. data->rcdev.nr_resets = data->param->reg_count * BITS_PER_REG;
  109. data->rcdev.ops = &meson_reset_ops;
  110. data->rcdev.of_node = pdev->dev.of_node;
  111. return devm_reset_controller_register(&pdev->dev, &data->rcdev);
  112. }
  113. static struct platform_driver meson_reset_driver = {
  114. .probe = meson_reset_probe,
  115. .driver = {
  116. .name = "meson_reset",
  117. .of_match_table = meson_reset_dt_ids,
  118. },
  119. };
  120. module_platform_driver(meson_reset_driver);
  121. MODULE_DESCRIPTION("Amlogic Meson Reset Controller driver");
  122. MODULE_AUTHOR("Neil Armstrong <narmstrong@baylibre.com>");
  123. MODULE_LICENSE("Dual BSD/GPL");