i2c-pasemi-platform.c 2.9 KB

123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122
  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * Copyright (C) 2021 The Asahi Linux Contributors
  4. *
  5. * PA Semi PWRficient SMBus host driver for Apple SoCs
  6. */
  7. #include <linux/clk.h>
  8. #include <linux/i2c.h>
  9. #include <linux/io.h>
  10. #include <linux/kernel.h>
  11. #include <linux/module.h>
  12. #include <linux/platform_device.h>
  13. #include <linux/types.h>
  14. #include "i2c-pasemi-core.h"
  15. struct pasemi_platform_i2c_data {
  16. struct pasemi_smbus smbus;
  17. struct clk *clk_ref;
  18. };
  19. static int
  20. pasemi_platform_i2c_calc_clk_div(struct pasemi_platform_i2c_data *data,
  21. u32 frequency)
  22. {
  23. unsigned long clk_rate = clk_get_rate(data->clk_ref);
  24. if (!clk_rate)
  25. return -EINVAL;
  26. data->smbus.clk_div = DIV_ROUND_UP(clk_rate, 16 * frequency);
  27. if (data->smbus.clk_div < 4)
  28. return dev_err_probe(data->smbus.dev, -EINVAL,
  29. "Bus frequency %d is too fast.\n",
  30. frequency);
  31. if (data->smbus.clk_div > 0xff)
  32. return dev_err_probe(data->smbus.dev, -EINVAL,
  33. "Bus frequency %d is too slow.\n",
  34. frequency);
  35. return 0;
  36. }
  37. static int pasemi_platform_i2c_probe(struct platform_device *pdev)
  38. {
  39. struct device *dev = &pdev->dev;
  40. struct pasemi_platform_i2c_data *data;
  41. struct pasemi_smbus *smbus;
  42. u32 frequency;
  43. int error;
  44. data = devm_kzalloc(dev, sizeof(struct pasemi_platform_i2c_data),
  45. GFP_KERNEL);
  46. if (!data)
  47. return -ENOMEM;
  48. smbus = &data->smbus;
  49. smbus->dev = dev;
  50. smbus->ioaddr = devm_platform_ioremap_resource(pdev, 0);
  51. if (IS_ERR(smbus->ioaddr))
  52. return PTR_ERR(smbus->ioaddr);
  53. if (of_property_read_u32(dev->of_node, "clock-frequency", &frequency))
  54. frequency = I2C_MAX_STANDARD_MODE_FREQ;
  55. data->clk_ref = devm_clk_get(dev, NULL);
  56. if (IS_ERR(data->clk_ref))
  57. return PTR_ERR(data->clk_ref);
  58. error = clk_prepare_enable(data->clk_ref);
  59. if (error)
  60. return error;
  61. error = pasemi_platform_i2c_calc_clk_div(data, frequency);
  62. if (error)
  63. goto out_clk_disable;
  64. smbus->adapter.dev.of_node = pdev->dev.of_node;
  65. error = pasemi_i2c_common_probe(smbus);
  66. if (error)
  67. goto out_clk_disable;
  68. platform_set_drvdata(pdev, data);
  69. return 0;
  70. out_clk_disable:
  71. clk_disable_unprepare(data->clk_ref);
  72. return error;
  73. }
  74. static int pasemi_platform_i2c_remove(struct platform_device *pdev)
  75. {
  76. struct pasemi_platform_i2c_data *data = platform_get_drvdata(pdev);
  77. clk_disable_unprepare(data->clk_ref);
  78. return 0;
  79. }
  80. static const struct of_device_id pasemi_platform_i2c_of_match[] = {
  81. { .compatible = "apple,t8103-i2c" },
  82. { .compatible = "apple,i2c" },
  83. {},
  84. };
  85. MODULE_DEVICE_TABLE(of, pasemi_platform_i2c_of_match);
  86. static struct platform_driver pasemi_platform_i2c_driver = {
  87. .driver = {
  88. .name = "i2c-apple",
  89. .of_match_table = pasemi_platform_i2c_of_match,
  90. },
  91. .probe = pasemi_platform_i2c_probe,
  92. .remove = pasemi_platform_i2c_remove,
  93. };
  94. module_platform_driver(pasemi_platform_i2c_driver);
  95. MODULE_LICENSE("GPL");
  96. MODULE_AUTHOR("Sven Peter <sven@svenpeter.dev>");
  97. MODULE_DESCRIPTION("Apple/PASemi SMBus platform driver");