clk-pfd.c 3.1 KB

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  1. // SPDX-License-Identifier: GPL-2.0-or-later
  2. /*
  3. * Copyright 2012 Freescale Semiconductor, Inc.
  4. * Copyright 2012 Linaro Ltd.
  5. */
  6. #include <linux/clk-provider.h>
  7. #include <linux/io.h>
  8. #include <linux/slab.h>
  9. #include <linux/err.h>
  10. #include "clk.h"
  11. /**
  12. * struct clk_pfd - IMX PFD clock
  13. * @hw: clock source
  14. * @reg: PFD register address
  15. * @idx: the index of PFD encoded in the register
  16. *
  17. * PFD clock found on i.MX6 series. Each register for PFD has 4 clk_pfd
  18. * data encoded, and member idx is used to specify the one. And each
  19. * register has SET, CLR and TOG registers at offset 0x4 0x8 and 0xc.
  20. */
  21. struct clk_pfd {
  22. struct clk_hw hw;
  23. void __iomem *reg;
  24. u8 idx;
  25. };
  26. #define to_clk_pfd(_hw) container_of(_hw, struct clk_pfd, hw)
  27. #define SET 0x4
  28. #define CLR 0x8
  29. #define OTG 0xc
  30. static int clk_pfd_enable(struct clk_hw *hw)
  31. {
  32. struct clk_pfd *pfd = to_clk_pfd(hw);
  33. writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + CLR);
  34. return 0;
  35. }
  36. static void clk_pfd_disable(struct clk_hw *hw)
  37. {
  38. struct clk_pfd *pfd = to_clk_pfd(hw);
  39. writel_relaxed(1 << ((pfd->idx + 1) * 8 - 1), pfd->reg + SET);
  40. }
  41. static unsigned long clk_pfd_recalc_rate(struct clk_hw *hw,
  42. unsigned long parent_rate)
  43. {
  44. struct clk_pfd *pfd = to_clk_pfd(hw);
  45. u64 tmp = parent_rate;
  46. u8 frac = (readl_relaxed(pfd->reg) >> (pfd->idx * 8)) & 0x3f;
  47. tmp *= 18;
  48. do_div(tmp, frac);
  49. return tmp;
  50. }
  51. static long clk_pfd_round_rate(struct clk_hw *hw, unsigned long rate,
  52. unsigned long *prate)
  53. {
  54. u64 tmp = *prate;
  55. u8 frac;
  56. tmp = tmp * 18 + rate / 2;
  57. do_div(tmp, rate);
  58. frac = tmp;
  59. if (frac < 12)
  60. frac = 12;
  61. else if (frac > 35)
  62. frac = 35;
  63. tmp = *prate;
  64. tmp *= 18;
  65. do_div(tmp, frac);
  66. return tmp;
  67. }
  68. static int clk_pfd_set_rate(struct clk_hw *hw, unsigned long rate,
  69. unsigned long parent_rate)
  70. {
  71. struct clk_pfd *pfd = to_clk_pfd(hw);
  72. u64 tmp = parent_rate;
  73. u8 frac;
  74. tmp = tmp * 18 + rate / 2;
  75. do_div(tmp, rate);
  76. frac = tmp;
  77. if (frac < 12)
  78. frac = 12;
  79. else if (frac > 35)
  80. frac = 35;
  81. writel_relaxed(0x3f << (pfd->idx * 8), pfd->reg + CLR);
  82. writel_relaxed(frac << (pfd->idx * 8), pfd->reg + SET);
  83. return 0;
  84. }
  85. static int clk_pfd_is_enabled(struct clk_hw *hw)
  86. {
  87. struct clk_pfd *pfd = to_clk_pfd(hw);
  88. if (readl_relaxed(pfd->reg) & (1 << ((pfd->idx + 1) * 8 - 1)))
  89. return 0;
  90. return 1;
  91. }
  92. static const struct clk_ops clk_pfd_ops = {
  93. .enable = clk_pfd_enable,
  94. .disable = clk_pfd_disable,
  95. .recalc_rate = clk_pfd_recalc_rate,
  96. .round_rate = clk_pfd_round_rate,
  97. .set_rate = clk_pfd_set_rate,
  98. .is_enabled = clk_pfd_is_enabled,
  99. };
  100. struct clk_hw *imx_clk_hw_pfd(const char *name, const char *parent_name,
  101. void __iomem *reg, u8 idx)
  102. {
  103. struct clk_pfd *pfd;
  104. struct clk_hw *hw;
  105. struct clk_init_data init;
  106. int ret;
  107. pfd = kzalloc(sizeof(*pfd), GFP_KERNEL);
  108. if (!pfd)
  109. return ERR_PTR(-ENOMEM);
  110. pfd->reg = reg;
  111. pfd->idx = idx;
  112. init.name = name;
  113. init.ops = &clk_pfd_ops;
  114. init.flags = 0;
  115. init.parent_names = &parent_name;
  116. init.num_parents = 1;
  117. pfd->hw.init = &init;
  118. hw = &pfd->hw;
  119. ret = clk_hw_register(NULL, hw);
  120. if (ret) {
  121. kfree(pfd);
  122. return ERR_PTR(ret);
  123. }
  124. return hw;
  125. }