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
25 struct pt_gpio_chip {
26 struct gpio_chip gc;
27 void __iomem *reg_base;
28 };
29
pt_gpio_request(struct gpio_chip * gc,unsigned offset)30 static 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
pt_gpio_free(struct gpio_chip * gc,unsigned offset)55 static 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
pt_gpio_probe(struct platform_device * pdev)72 static 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
pt_gpio_remove(struct platform_device * pdev)128 static 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
137 static const struct acpi_device_id pt_gpio_acpi_match[] = {
138 { "AMDF030", 0 },
139 { "AMDIF030", 0 },
140 { },
141 };
142 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
143
144 static 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
153 module_platform_driver(pt_gpio_driver);
154
155 MODULE_LICENSE("GPL");
156 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
157 MODULE_DESCRIPTION("AMD Promontory GPIO Driver");
158
