gpio-logicvc.c 4.2 KB

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  1. // SPDX-License-Identifier: GPL-2.0+
  2. /*
  3. * Copyright (C) 2019 Bootlin
  4. * Author: Paul Kocialkowski <paul.kocialkowski@bootlin.com>
  5. */
  6. #include <linux/err.h>
  7. #include <linux/gpio/driver.h>
  8. #include <linux/module.h>
  9. #include <linux/of.h>
  10. #include <linux/of_device.h>
  11. #include <linux/of_address.h>
  12. #include <linux/platform_device.h>
  13. #include <linux/regmap.h>
  14. #include <linux/mfd/syscon.h>
  15. #define LOGICVC_CTRL_REG 0x40
  16. #define LOGICVC_CTRL_GPIO_SHIFT 11
  17. #define LOGICVC_CTRL_GPIO_BITS 5
  18. #define LOGICVC_POWER_CTRL_REG 0x78
  19. #define LOGICVC_POWER_CTRL_GPIO_SHIFT 0
  20. #define LOGICVC_POWER_CTRL_GPIO_BITS 4
  21. struct logicvc_gpio {
  22. struct gpio_chip chip;
  23. struct regmap *regmap;
  24. };
  25. static void logicvc_gpio_offset(struct logicvc_gpio *logicvc, unsigned offset,
  26. unsigned int *reg, unsigned int *bit)
  27. {
  28. if (offset >= LOGICVC_CTRL_GPIO_BITS) {
  29. *reg = LOGICVC_POWER_CTRL_REG;
  30. /* To the (virtual) power ctrl offset. */
  31. offset -= LOGICVC_CTRL_GPIO_BITS;
  32. /* To the actual bit offset in reg. */
  33. offset += LOGICVC_POWER_CTRL_GPIO_SHIFT;
  34. } else {
  35. *reg = LOGICVC_CTRL_REG;
  36. /* To the actual bit offset in reg. */
  37. offset += LOGICVC_CTRL_GPIO_SHIFT;
  38. }
  39. *bit = BIT(offset);
  40. }
  41. static int logicvc_gpio_get(struct gpio_chip *chip, unsigned offset)
  42. {
  43. struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
  44. unsigned int reg, bit, value;
  45. int ret;
  46. logicvc_gpio_offset(logicvc, offset, &reg, &bit);
  47. ret = regmap_read(logicvc->regmap, reg, &value);
  48. if (ret)
  49. return ret;
  50. return !!(value & bit);
  51. }
  52. static void logicvc_gpio_set(struct gpio_chip *chip, unsigned offset, int value)
  53. {
  54. struct logicvc_gpio *logicvc = gpiochip_get_data(chip);
  55. unsigned int reg, bit;
  56. logicvc_gpio_offset(logicvc, offset, &reg, &bit);
  57. regmap_update_bits(logicvc->regmap, reg, bit, value ? bit : 0);
  58. }
  59. static int logicvc_gpio_direction_output(struct gpio_chip *chip,
  60. unsigned offset, int value)
  61. {
  62. /* Pins are always configured as output, so just set the value. */
  63. logicvc_gpio_set(chip, offset, value);
  64. return 0;
  65. }
  66. static struct regmap_config logicvc_gpio_regmap_config = {
  67. .reg_bits = 32,
  68. .val_bits = 32,
  69. .reg_stride = 4,
  70. .name = "logicvc-gpio",
  71. };
  72. static int logicvc_gpio_probe(struct platform_device *pdev)
  73. {
  74. struct device *dev = &pdev->dev;
  75. struct device_node *of_node = dev->of_node;
  76. struct logicvc_gpio *logicvc;
  77. int ret;
  78. logicvc = devm_kzalloc(dev, sizeof(*logicvc), GFP_KERNEL);
  79. if (!logicvc)
  80. return -ENOMEM;
  81. /* Try to get regmap from parent first. */
  82. logicvc->regmap = syscon_node_to_regmap(of_node->parent);
  83. /* Grab our own regmap if that fails. */
  84. if (IS_ERR(logicvc->regmap)) {
  85. struct resource res;
  86. void __iomem *base;
  87. ret = of_address_to_resource(of_node, 0, &res);
  88. if (ret) {
  89. dev_err(dev, "Failed to get resource from address\n");
  90. return ret;
  91. }
  92. base = devm_ioremap_resource(dev, &res);
  93. if (IS_ERR(base)) {
  94. dev_err(dev, "Failed to map I/O base\n");
  95. return PTR_ERR(base);
  96. }
  97. logicvc_gpio_regmap_config.max_register = resource_size(&res) -
  98. logicvc_gpio_regmap_config.reg_stride;
  99. logicvc->regmap =
  100. devm_regmap_init_mmio(dev, base,
  101. &logicvc_gpio_regmap_config);
  102. if (IS_ERR(logicvc->regmap)) {
  103. dev_err(dev, "Failed to create regmap for I/O\n");
  104. return PTR_ERR(logicvc->regmap);
  105. }
  106. }
  107. logicvc->chip.parent = dev;
  108. logicvc->chip.owner = THIS_MODULE;
  109. logicvc->chip.label = dev_name(dev);
  110. logicvc->chip.base = -1;
  111. logicvc->chip.ngpio = LOGICVC_CTRL_GPIO_BITS +
  112. LOGICVC_POWER_CTRL_GPIO_BITS;
  113. logicvc->chip.get = logicvc_gpio_get;
  114. logicvc->chip.set = logicvc_gpio_set;
  115. logicvc->chip.direction_output = logicvc_gpio_direction_output;
  116. platform_set_drvdata(pdev, logicvc);
  117. return devm_gpiochip_add_data(dev, &logicvc->chip, logicvc);
  118. }
  119. static const struct of_device_id logicivc_gpio_of_table[] = {
  120. {
  121. .compatible = "xylon,logicvc-3.02.a-gpio",
  122. },
  123. { }
  124. };
  125. MODULE_DEVICE_TABLE(of, logicivc_gpio_of_table);
  126. static struct platform_driver logicvc_gpio_driver = {
  127. .driver = {
  128. .name = "gpio-logicvc",
  129. .of_match_table = logicivc_gpio_of_table,
  130. },
  131. .probe = logicvc_gpio_probe,
  132. };
  133. module_platform_driver(logicvc_gpio_driver);
  134. MODULE_AUTHOR("Paul Kocialkowski <paul.kocialkowski@bootlin.com>");
  135. MODULE_DESCRIPTION("Xylon LogiCVC GPIO driver");
  136. MODULE_LICENSE("GPL");