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 #define PT_TOTAL_GPIO_EX 24
18
19 /* PCI-E MMIO register offsets */
20 #define PT_DIRECTION_REG 0x00
21 #define PT_INPUTDATA_REG 0x04
22 #define PT_OUTPUTDATA_REG 0x08
23 #define PT_CLOCKRATE_REG 0x0C
24 #define PT_SYNC_REG 0x28
25
26 struct pt_gpio_chip {
27 struct gpio_chip gc;
28 void __iomem *reg_base;
29 };
30
pt_gpio_request(struct gpio_chip * gc,unsigned offset)31 static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
32 {
33 struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
34 unsigned long flags;
35 u32 using_pins;
36
37 dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
38
39 raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
40
41 using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
42 if (using_pins & BIT(offset)) {
43 dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
44 offset);
45 raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
46 return -EINVAL;
47 }
48
49 writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
50
51 raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
52
53 return 0;
54 }
55
pt_gpio_free(struct gpio_chip * gc,unsigned offset)56 static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
57 {
58 struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
59 unsigned long flags;
60 u32 using_pins;
61
62 raw_spin_lock_irqsave(&gc->bgpio_lock, flags);
63
64 using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
65 using_pins &= ~BIT(offset);
66 writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
67
68 raw_spin_unlock_irqrestore(&gc->bgpio_lock, flags);
69
70 dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
71 }
72
pt_gpio_probe(struct platform_device * pdev)73 static int pt_gpio_probe(struct platform_device *pdev)
74 {
75 struct device *dev = &pdev->dev;
76 struct pt_gpio_chip *pt_gpio;
77 int ret = 0;
78
79 if (!ACPI_COMPANION(dev)) {
80 dev_err(dev, "PT GPIO device node not found\n");
81 return -ENODEV;
82 }
83
84 pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
85 if (!pt_gpio)
86 return -ENOMEM;
87
88 pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
89 if (IS_ERR(pt_gpio->reg_base)) {
90 dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
91 return PTR_ERR(pt_gpio->reg_base);
92 }
93
94 ret = bgpio_init(&pt_gpio->gc, dev, 4,
95 pt_gpio->reg_base + PT_INPUTDATA_REG,
96 pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
97 pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
98 BGPIOF_READ_OUTPUT_REG_SET);
99 if (ret) {
100 dev_err(dev, "bgpio_init failed\n");
101 return ret;
102 }
103
104 pt_gpio->gc.owner = THIS_MODULE;
105 pt_gpio->gc.request = pt_gpio_request;
106 pt_gpio->gc.free = pt_gpio_free;
107 pt_gpio->gc.ngpio = (uintptr_t)device_get_match_data(dev);
108
109 ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
110 if (ret) {
111 dev_err(dev, "Failed to register GPIO lib\n");
112 return ret;
113 }
114
115 platform_set_drvdata(pdev, pt_gpio);
116
117 /* initialize register setting */
118 writel(0, pt_gpio->reg_base + PT_SYNC_REG);
119 writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
120
121 dev_dbg(dev, "PT GPIO driver loaded\n");
122 return ret;
123 }
124
pt_gpio_remove(struct platform_device * pdev)125 static int pt_gpio_remove(struct platform_device *pdev)
126 {
127 struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
128
129 gpiochip_remove(&pt_gpio->gc);
130
131 return 0;
132 }
133
134 static const struct acpi_device_id pt_gpio_acpi_match[] = {
135 { "AMDF030", PT_TOTAL_GPIO },
136 { "AMDIF030", PT_TOTAL_GPIO },
137 { "AMDIF031", PT_TOTAL_GPIO_EX },
138 { },
139 };
140 MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
141
142 static struct platform_driver pt_gpio_driver = {
143 .driver = {
144 .name = "pt-gpio",
145 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
146 },
147 .probe = pt_gpio_probe,
148 .remove = pt_gpio_remove,
149 };
150
151 module_platform_driver(pt_gpio_driver);
152
153 MODULE_LICENSE("GPL");
154 MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
155 MODULE_DESCRIPTION("AMD Promontory GPIO Driver");
156
