gpio-amdpt.c 3.9 KB

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  1. // SPDX-License-Identifier: GPL-2.0-only
  2. /*
  3. * AMD Promontory GPIO driver
  4. *
  5. * Copyright (C) 2015 ASMedia Technology Inc.
  6. * Author: YD Tseng <yd_tseng@asmedia.com.tw>
  7. */
  8. #include <linux/kernel.h>
  9. #include <linux/module.h>
  10. #include <linux/gpio/driver.h>
  11. #include <linux/spinlock.h>
  12. #include <linux/acpi.h>
  13. #include <linux/platform_device.h>
  14. #define PT_TOTAL_GPIO 8
  15. /* PCI-E MMIO register offsets */
  16. #define PT_DIRECTION_REG 0x00
  17. #define PT_INPUTDATA_REG 0x04
  18. #define PT_OUTPUTDATA_REG 0x08
  19. #define PT_CLOCKRATE_REG 0x0C
  20. #define PT_SYNC_REG 0x28
  21. struct pt_gpio_chip {
  22. struct gpio_chip gc;
  23. void __iomem *reg_base;
  24. };
  25. static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
  26. {
  27. struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  28. unsigned long flags;
  29. u32 using_pins;
  30. dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
  31. spin_lock_irqsave(&gc->bgpio_lock, flags);
  32. using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  33. if (using_pins & BIT(offset)) {
  34. dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
  35. offset);
  36. spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  37. return -EINVAL;
  38. }
  39. writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
  40. spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  41. return 0;
  42. }
  43. static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
  44. {
  45. struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
  46. unsigned long flags;
  47. u32 using_pins;
  48. spin_lock_irqsave(&gc->bgpio_lock, flags);
  49. using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
  50. using_pins &= ~BIT(offset);
  51. writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
  52. spin_unlock_irqrestore(&gc->bgpio_lock, flags);
  53. dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
  54. }
  55. static int pt_gpio_probe(struct platform_device *pdev)
  56. {
  57. struct device *dev = &pdev->dev;
  58. struct acpi_device *acpi_dev;
  59. acpi_handle handle = ACPI_HANDLE(dev);
  60. struct pt_gpio_chip *pt_gpio;
  61. int ret = 0;
  62. if (acpi_bus_get_device(handle, &acpi_dev)) {
  63. dev_err(dev, "PT GPIO device node not found\n");
  64. return -ENODEV;
  65. }
  66. pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
  67. if (!pt_gpio)
  68. return -ENOMEM;
  69. pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
  70. if (IS_ERR(pt_gpio->reg_base)) {
  71. dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
  72. return PTR_ERR(pt_gpio->reg_base);
  73. }
  74. ret = bgpio_init(&pt_gpio->gc, dev, 4,
  75. pt_gpio->reg_base + PT_INPUTDATA_REG,
  76. pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
  77. pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
  78. BGPIOF_READ_OUTPUT_REG_SET);
  79. if (ret) {
  80. dev_err(dev, "bgpio_init failed\n");
  81. return ret;
  82. }
  83. pt_gpio->gc.owner = THIS_MODULE;
  84. pt_gpio->gc.request = pt_gpio_request;
  85. pt_gpio->gc.free = pt_gpio_free;
  86. pt_gpio->gc.ngpio = PT_TOTAL_GPIO;
  87. #if defined(CONFIG_OF_GPIO)
  88. pt_gpio->gc.of_node = dev->of_node;
  89. #endif
  90. ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
  91. if (ret) {
  92. dev_err(dev, "Failed to register GPIO lib\n");
  93. return ret;
  94. }
  95. platform_set_drvdata(pdev, pt_gpio);
  96. /* initialize register setting */
  97. writel(0, pt_gpio->reg_base + PT_SYNC_REG);
  98. writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
  99. dev_dbg(dev, "PT GPIO driver loaded\n");
  100. return ret;
  101. }
  102. static int pt_gpio_remove(struct platform_device *pdev)
  103. {
  104. struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
  105. gpiochip_remove(&pt_gpio->gc);
  106. return 0;
  107. }
  108. static const struct acpi_device_id pt_gpio_acpi_match[] = {
  109. { "AMDF030", 0 },
  110. { "AMDIF030", 0 },
  111. { },
  112. };
  113. MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
  114. static struct platform_driver pt_gpio_driver = {
  115. .driver = {
  116. .name = "pt-gpio",
  117. .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
  118. },
  119. .probe = pt_gpio_probe,
  120. .remove = pt_gpio_remove,
  121. };
  122. module_platform_driver(pt_gpio_driver);
  123. MODULE_LICENSE("GPL");
  124. MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
  125. MODULE_DESCRIPTION("AMD Promontory GPIO Driver");