clk-twl6040.c 3.7 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * TWL6040 clock module driver for OMAP4 McPDM functional clock
  4. *
  5. * Copyright (C) 2012 Texas Instruments Inc.
  6. * Peter Ujfalusi <peter.ujfalusi@ti.com>
  7. */
  8. #include <linux/module.h>
  9. #include <linux/slab.h>
  10. #include <linux/platform_device.h>
  11. #include <linux/mfd/twl6040.h>
  12. #include <linux/clk-provider.h>
  13. struct twl6040_pdmclk {
  14. struct twl6040 *twl6040;
  15. struct device *dev;
  16. struct clk_hw pdmclk_hw;
  17. int enabled;
  18. };
  19. static int twl6040_pdmclk_is_prepared(struct clk_hw *hw)
  20. {
  21. struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  22. pdmclk_hw);
  23. return pdmclk->enabled;
  24. }
  25. static int twl6040_pdmclk_reset_one_clock(struct twl6040_pdmclk *pdmclk,
  26. unsigned int reg)
  27. {
  28. const u8 reset_mask = TWL6040_HPLLRST; /* Same for HPPLL and LPPLL */
  29. int ret;
  30. ret = twl6040_set_bits(pdmclk->twl6040, reg, reset_mask);
  31. if (ret < 0)
  32. return ret;
  33. ret = twl6040_clear_bits(pdmclk->twl6040, reg, reset_mask);
  34. if (ret < 0)
  35. return ret;
  36. return 0;
  37. }
  38. /*
  39. * TWL6040A2 Phoenix Audio IC erratum #6: "PDM Clock Generation Issue At
  40. * Cold Temperature". This affects cold boot and deeper idle states it
  41. * seems. The workaround consists of resetting HPPLL and LPPLL.
  42. */
  43. static int twl6040_pdmclk_quirk_reset_clocks(struct twl6040_pdmclk *pdmclk)
  44. {
  45. int ret;
  46. ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_HPPLLCTL);
  47. if (ret)
  48. return ret;
  49. ret = twl6040_pdmclk_reset_one_clock(pdmclk, TWL6040_REG_LPPLLCTL);
  50. if (ret)
  51. return ret;
  52. return 0;
  53. }
  54. static int twl6040_pdmclk_prepare(struct clk_hw *hw)
  55. {
  56. struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  57. pdmclk_hw);
  58. int ret;
  59. ret = twl6040_power(pdmclk->twl6040, 1);
  60. if (ret)
  61. return ret;
  62. ret = twl6040_pdmclk_quirk_reset_clocks(pdmclk);
  63. if (ret)
  64. goto out_err;
  65. pdmclk->enabled = 1;
  66. return 0;
  67. out_err:
  68. dev_err(pdmclk->dev, "%s: error %i\n", __func__, ret);
  69. twl6040_power(pdmclk->twl6040, 0);
  70. return ret;
  71. }
  72. static void twl6040_pdmclk_unprepare(struct clk_hw *hw)
  73. {
  74. struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  75. pdmclk_hw);
  76. int ret;
  77. ret = twl6040_power(pdmclk->twl6040, 0);
  78. if (!ret)
  79. pdmclk->enabled = 0;
  80. }
  81. static unsigned long twl6040_pdmclk_recalc_rate(struct clk_hw *hw,
  82. unsigned long parent_rate)
  83. {
  84. struct twl6040_pdmclk *pdmclk = container_of(hw, struct twl6040_pdmclk,
  85. pdmclk_hw);
  86. return twl6040_get_sysclk(pdmclk->twl6040);
  87. }
  88. static const struct clk_ops twl6040_pdmclk_ops = {
  89. .is_prepared = twl6040_pdmclk_is_prepared,
  90. .prepare = twl6040_pdmclk_prepare,
  91. .unprepare = twl6040_pdmclk_unprepare,
  92. .recalc_rate = twl6040_pdmclk_recalc_rate,
  93. };
  94. static const struct clk_init_data twl6040_pdmclk_init = {
  95. .name = "pdmclk",
  96. .ops = &twl6040_pdmclk_ops,
  97. .flags = CLK_GET_RATE_NOCACHE,
  98. };
  99. static int twl6040_pdmclk_probe(struct platform_device *pdev)
  100. {
  101. struct twl6040 *twl6040 = dev_get_drvdata(pdev->dev.parent);
  102. struct twl6040_pdmclk *clkdata;
  103. int ret;
  104. clkdata = devm_kzalloc(&pdev->dev, sizeof(*clkdata), GFP_KERNEL);
  105. if (!clkdata)
  106. return -ENOMEM;
  107. clkdata->dev = &pdev->dev;
  108. clkdata->twl6040 = twl6040;
  109. clkdata->pdmclk_hw.init = &twl6040_pdmclk_init;
  110. ret = devm_clk_hw_register(&pdev->dev, &clkdata->pdmclk_hw);
  111. if (ret)
  112. return ret;
  113. platform_set_drvdata(pdev, clkdata);
  114. return devm_of_clk_add_hw_provider(&pdev->dev, of_clk_hw_simple_get,
  115. &clkdata->pdmclk_hw);
  116. }
  117. static struct platform_driver twl6040_pdmclk_driver = {
  118. .driver = {
  119. .name = "twl6040-pdmclk",
  120. },
  121. .probe = twl6040_pdmclk_probe,
  122. };
  123. module_platform_driver(twl6040_pdmclk_driver);
  124. MODULE_DESCRIPTION("TWL6040 clock driver for McPDM functional clock");
  125. MODULE_AUTHOR("Peter Ujfalusi <peter.ujfalusi@ti.com>");
  126. MODULE_ALIAS("platform:twl6040-pdmclk");
  127. MODULE_LICENSE("GPL");