clk-usb.c 3.3 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (C) 2018 Microhip / Atmel Corporation
  4. * Wenyou.Yang <wenyou.yang@microchip.com>
  5. */
  6. #include <common.h>
  7. #include <clk-uclass.h>
  8. #include <log.h>
  9. #include <dm/device.h>
  10. #include <linux/err.h>
  11. #include <linux/io.h>
  12. #include <mach/at91_pmc.h>
  13. #include "pmc.h"
  14. DECLARE_GLOBAL_DATA_PTR;
  15. #define AT91_USB_CLK_SOURCE_MAX 2
  16. #define AT91_USB_CLK_MAX_DIV 15
  17. struct at91_usb_clk_priv {
  18. u32 num_clksource;
  19. };
  20. static ulong at91_usb_clk_get_rate(struct clk *clk)
  21. {
  22. struct pmc_platdata *plat = dev_get_platdata(clk->dev);
  23. struct at91_pmc *pmc = plat->reg_base;
  24. struct clk source;
  25. u32 tmp, usbdiv;
  26. u8 source_index;
  27. int ret;
  28. tmp = readl(&pmc->pcr);
  29. source_index = (tmp >> AT91_PMC_USB_USBS_OFFSET) &
  30. AT91_PMC_USB_USBS_MASK;
  31. usbdiv = (tmp >> AT91_PMC_USB_DIV_OFFSET) & AT91_PMC_USB_DIV_MASK;
  32. ret = clk_get_by_index(clk->dev, source_index, &source);
  33. if (ret)
  34. return 0;
  35. return clk_get_rate(&source) / (usbdiv + 1);
  36. }
  37. static ulong at91_usb_clk_set_rate(struct clk *clk, ulong rate)
  38. {
  39. struct pmc_platdata *plat = dev_get_platdata(clk->dev);
  40. struct at91_pmc *pmc = plat->reg_base;
  41. struct at91_usb_clk_priv *priv = dev_get_priv(clk->dev);
  42. struct clk source, best_source;
  43. ulong tmp_rate, best_rate = rate, source_rate;
  44. int tmp_diff, best_diff = -1;
  45. u32 div, best_div = 0;
  46. u8 best_source_index = 0;
  47. u8 i;
  48. u32 tmp;
  49. int ret;
  50. for (i = 0; i < priv->num_clksource; i++) {
  51. ret = clk_get_by_index(clk->dev, i, &source);
  52. if (ret)
  53. return ret;
  54. source_rate = clk_get_rate(&source);
  55. if (IS_ERR_VALUE(source_rate))
  56. return source_rate;
  57. for (div = 1; div < AT91_USB_CLK_MAX_DIV + 2; div++) {
  58. tmp_rate = DIV_ROUND_CLOSEST(source_rate, div);
  59. tmp_diff = abs(rate - tmp_rate);
  60. if (best_diff < 0 || best_diff > tmp_diff) {
  61. best_rate = tmp_rate;
  62. best_diff = tmp_diff;
  63. best_div = div - 1;
  64. best_source = source;
  65. best_source_index = i;
  66. }
  67. if (!best_diff || tmp_rate < rate)
  68. break;
  69. }
  70. if (!best_diff)
  71. break;
  72. }
  73. debug("AT91 USB: best sourc: %s, best_rate = %ld, best_div = %d\n",
  74. best_source.dev->name, best_rate, best_div);
  75. ret = clk_enable(&best_source);
  76. if (ret)
  77. return ret;
  78. tmp = AT91_PMC_USB_USBS_(best_source_index) |
  79. AT91_PMC_USB_DIV_(best_div);
  80. writel(tmp, &pmc->usb);
  81. return 0;
  82. }
  83. static struct clk_ops at91_usb_clk_ops = {
  84. .get_rate = at91_usb_clk_get_rate,
  85. .set_rate = at91_usb_clk_set_rate,
  86. };
  87. static int at91_usb_clk_ofdata_to_platdata(struct udevice *dev)
  88. {
  89. struct at91_usb_clk_priv *priv = dev_get_priv(dev);
  90. u32 cells[AT91_USB_CLK_SOURCE_MAX];
  91. u32 num_clksource;
  92. num_clksource = fdtdec_get_int_array_count(gd->fdt_blob,
  93. dev_of_offset(dev),
  94. "clocks", cells,
  95. AT91_USB_CLK_SOURCE_MAX);
  96. if (!num_clksource)
  97. return -1;
  98. priv->num_clksource = num_clksource;
  99. return 0;
  100. }
  101. static int at91_usb_clk_probe(struct udevice *dev)
  102. {
  103. return at91_pmc_core_probe(dev);
  104. }
  105. static const struct udevice_id at91_usb_clk_match[] = {
  106. { .compatible = "atmel,at91sam9x5-clk-usb" },
  107. {}
  108. };
  109. U_BOOT_DRIVER(at91_usb_clk) = {
  110. .name = "at91-usb-clk",
  111. .id = UCLASS_CLK,
  112. .of_match = at91_usb_clk_match,
  113. .probe = at91_usb_clk_probe,
  114. .ofdata_to_platdata = at91_usb_clk_ofdata_to_platdata,
  115. .priv_auto_alloc_size = sizeof(struct at91_usb_clk_priv),
  116. .platdata_auto_alloc_size = sizeof(struct pmc_platdata),
  117. .ops = &at91_usb_clk_ops,
  118. };