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
  9#include <linux/kernel.h>
 10#include <linux/module.h>
 11#include <linux/gpio/driver.h>
 12#include <linux/spinlock.h>
 13#include <linux/acpi.h>
 14#include <linux/platform_device.h>
 15
 16#define PT_TOTAL_GPIO 8
 17
 18/* PCI-E MMIO register offsets */
 19#define PT_DIRECTION_REG   0x00
 20#define PT_INPUTDATA_REG   0x04
 21#define PT_OUTPUTDATA_REG  0x08
 22#define PT_CLOCKRATE_REG   0x0C
 23#define PT_SYNC_REG        0x28
 24
 25struct pt_gpio_chip {
 26	struct gpio_chip         gc;
 27	void __iomem             *reg_base;
 28};
 29
 30static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
 31{
 32	struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
 33	unsigned long flags;
 34	u32 using_pins;
 35
 36	dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
 37
 38	spin_lock_irqsave(&gc->bgpio_lock, flags);
 39
 40	using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
 41	if (using_pins & BIT(offset)) {
 42		dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
 43			 offset);
 44		spin_unlock_irqrestore(&gc->bgpio_lock, flags);
 45		return -EINVAL;
 46	}
 47
 48	writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
 49
 50	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
 51
 52	return 0;
 53}
 54
 55static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
 56{
 57	struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
 58	unsigned long flags;
 59	u32 using_pins;
 60
 61	spin_lock_irqsave(&gc->bgpio_lock, flags);
 62
 63	using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
 64	using_pins &= ~BIT(offset);
 65	writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
 66
 67	spin_unlock_irqrestore(&gc->bgpio_lock, flags);
 68
 69	dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
 70}
 71
 72static int pt_gpio_probe(struct platform_device *pdev)
 73{
 74	struct device *dev = &pdev->dev;
 75	struct acpi_device *acpi_dev;
 76	acpi_handle handle = ACPI_HANDLE(dev);
 77	struct pt_gpio_chip *pt_gpio;
 78	int ret = 0;
 79
 80	if (acpi_bus_get_device(handle, &acpi_dev)) {
 81		dev_err(dev, "PT GPIO device node not found\n");
 82		return -ENODEV;
 83	}
 84
 85	pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
 86	if (!pt_gpio)
 87		return -ENOMEM;
 88
 89	pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
 90	if (IS_ERR(pt_gpio->reg_base)) {
 91		dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
 92		return PTR_ERR(pt_gpio->reg_base);
 93	}
 94
 95	ret = bgpio_init(&pt_gpio->gc, dev, 4,
 96			 pt_gpio->reg_base + PT_INPUTDATA_REG,
 97			 pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
 98			 pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
 99			 BGPIOF_READ_OUTPUT_REG_SET);
100	if (ret) {
101		dev_err(dev, "bgpio_init failed\n");
102		return ret;
103	}
104
105	pt_gpio->gc.owner            = THIS_MODULE;
106	pt_gpio->gc.request          = pt_gpio_request;
107	pt_gpio->gc.free             = pt_gpio_free;
108	pt_gpio->gc.ngpio            = PT_TOTAL_GPIO;
109#if defined(CONFIG_OF_GPIO)
110	pt_gpio->gc.of_node          = dev->of_node;
111#endif
112	ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
113	if (ret) {
114		dev_err(dev, "Failed to register GPIO lib\n");
115		return ret;
116	}
117
118	platform_set_drvdata(pdev, pt_gpio);
119
120	/* initialize register setting */
121	writel(0, pt_gpio->reg_base + PT_SYNC_REG);
122	writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
123
124	dev_dbg(dev, "PT GPIO driver loaded\n");
125	return ret;
126}
127
128static int pt_gpio_remove(struct platform_device *pdev)
129{
130	struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
131
132	gpiochip_remove(&pt_gpio->gc);
133
134	return 0;
135}
136
137static const struct acpi_device_id pt_gpio_acpi_match[] = {
138	{ "AMDF030", 0 },
139	{ "AMDIF030", 0 },
140	{ },
141};
142MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
143
144static struct platform_driver pt_gpio_driver = {
145	.driver = {
146		.name = "pt-gpio",
147		.acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
148	},
149	.probe = pt_gpio_probe,
150	.remove = pt_gpio_remove,
151};
152
153module_platform_driver(pt_gpio_driver);
154
155MODULE_LICENSE("GPL");
156MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
157MODULE_DESCRIPTION("AMD Promontory GPIO Driver");