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");
158