irq-ts4800.c 3.9 KB

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  1. /*
  2. * Multiplexed-IRQs driver for TS-4800's FPGA
  3. *
  4. * Copyright (c) 2015 - Savoir-faire Linux
  5. *
  6. * This file is licensed under the terms of the GNU General Public
  7. * License version 2. This program is licensed "as is" without any
  8. * warranty of any kind, whether express or implied.
  9. */
  10. #include <linux/interrupt.h>
  11. #include <linux/io.h>
  12. #include <linux/irq.h>
  13. #include <linux/irqchip.h>
  14. #include <linux/irqchip/chained_irq.h>
  15. #include <linux/irqdomain.h>
  16. #include <linux/module.h>
  17. #include <linux/of.h>
  18. #include <linux/of_address.h>
  19. #include <linux/of_irq.h>
  20. #include <linux/platform_device.h>
  21. #define IRQ_MASK 0x4
  22. #define IRQ_STATUS 0x8
  23. struct ts4800_irq_data {
  24. void __iomem *base;
  25. struct irq_domain *domain;
  26. struct irq_chip irq_chip;
  27. };
  28. static void ts4800_irq_mask(struct irq_data *d)
  29. {
  30. struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
  31. u16 reg = readw(data->base + IRQ_MASK);
  32. u16 mask = 1 << d->hwirq;
  33. writew(reg | mask, data->base + IRQ_MASK);
  34. }
  35. static void ts4800_irq_unmask(struct irq_data *d)
  36. {
  37. struct ts4800_irq_data *data = irq_data_get_irq_chip_data(d);
  38. u16 reg = readw(data->base + IRQ_MASK);
  39. u16 mask = 1 << d->hwirq;
  40. writew(reg & ~mask, data->base + IRQ_MASK);
  41. }
  42. static int ts4800_irqdomain_map(struct irq_domain *d, unsigned int irq,
  43. irq_hw_number_t hwirq)
  44. {
  45. struct ts4800_irq_data *data = d->host_data;
  46. irq_set_chip_and_handler(irq, &data->irq_chip, handle_simple_irq);
  47. irq_set_chip_data(irq, data);
  48. irq_set_noprobe(irq);
  49. return 0;
  50. }
  51. static const struct irq_domain_ops ts4800_ic_ops = {
  52. .map = ts4800_irqdomain_map,
  53. .xlate = irq_domain_xlate_onecell,
  54. };
  55. static void ts4800_ic_chained_handle_irq(struct irq_desc *desc)
  56. {
  57. struct ts4800_irq_data *data = irq_desc_get_handler_data(desc);
  58. struct irq_chip *chip = irq_desc_get_chip(desc);
  59. u16 status = readw(data->base + IRQ_STATUS);
  60. chained_irq_enter(chip, desc);
  61. if (unlikely(status == 0)) {
  62. handle_bad_irq(desc);
  63. goto out;
  64. }
  65. do {
  66. unsigned int bit = __ffs(status);
  67. int irq = irq_find_mapping(data->domain, bit);
  68. status &= ~(1 << bit);
  69. generic_handle_irq(irq);
  70. } while (status);
  71. out:
  72. chained_irq_exit(chip, desc);
  73. }
  74. static int ts4800_ic_probe(struct platform_device *pdev)
  75. {
  76. struct device_node *node = pdev->dev.of_node;
  77. struct ts4800_irq_data *data;
  78. struct irq_chip *irq_chip;
  79. struct resource *res;
  80. int parent_irq;
  81. data = devm_kzalloc(&pdev->dev, sizeof(*data), GFP_KERNEL);
  82. if (!data)
  83. return -ENOMEM;
  84. res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
  85. data->base = devm_ioremap_resource(&pdev->dev, res);
  86. if (IS_ERR(data->base))
  87. return PTR_ERR(data->base);
  88. writew(0xFFFF, data->base + IRQ_MASK);
  89. parent_irq = irq_of_parse_and_map(node, 0);
  90. if (!parent_irq) {
  91. dev_err(&pdev->dev, "failed to get parent IRQ\n");
  92. return -EINVAL;
  93. }
  94. irq_chip = &data->irq_chip;
  95. irq_chip->name = dev_name(&pdev->dev);
  96. irq_chip->irq_mask = ts4800_irq_mask;
  97. irq_chip->irq_unmask = ts4800_irq_unmask;
  98. data->domain = irq_domain_add_linear(node, 8, &ts4800_ic_ops, data);
  99. if (!data->domain) {
  100. dev_err(&pdev->dev, "cannot add IRQ domain\n");
  101. return -ENOMEM;
  102. }
  103. irq_set_chained_handler_and_data(parent_irq,
  104. ts4800_ic_chained_handle_irq, data);
  105. platform_set_drvdata(pdev, data);
  106. return 0;
  107. }
  108. static int ts4800_ic_remove(struct platform_device *pdev)
  109. {
  110. struct ts4800_irq_data *data = platform_get_drvdata(pdev);
  111. irq_domain_remove(data->domain);
  112. return 0;
  113. }
  114. static const struct of_device_id ts4800_ic_of_match[] = {
  115. { .compatible = "technologic,ts4800-irqc", },
  116. {},
  117. };
  118. MODULE_DEVICE_TABLE(of, ts4800_ic_of_match);
  119. static struct platform_driver ts4800_ic_driver = {
  120. .probe = ts4800_ic_probe,
  121. .remove = ts4800_ic_remove,
  122. .driver = {
  123. .name = "ts4800-irqc",
  124. .of_match_table = ts4800_ic_of_match,
  125. },
  126. };
  127. module_platform_driver(ts4800_ic_driver);
  128. MODULE_AUTHOR("Damien Riegel <damien.riegel@savoirfairelinux.com>");
  129. MODULE_LICENSE("GPL v2");
  130. MODULE_ALIAS("platform:ts4800_irqc");