tjh.dev
Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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/gpio/generic.h>
13#include <linux/spinlock.h>
14#include <linux/acpi.h>
15#include <linux/platform_device.h>
16
17#define PT_TOTAL_GPIO 8
18#define PT_TOTAL_GPIO_EX 24
19
20/* PCI-E MMIO register offsets */
21#define PT_DIRECTION_REG 0x00
22#define PT_INPUTDATA_REG 0x04
23#define PT_OUTPUTDATA_REG 0x08
24#define PT_CLOCKRATE_REG 0x0C
25#define PT_SYNC_REG 0x28
26
27struct pt_gpio_chip {
28 struct gpio_generic_chip chip;
29 void __iomem *reg_base;
30};
31
32static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
33{
34 struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc);
35 struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
36 u32 using_pins;
37
38 dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
39
40 guard(gpio_generic_lock_irqsave)(gen_gc);
41
42 using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
43 if (using_pins & BIT(offset)) {
44 dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
45 offset);
46 return -EINVAL;
47 }
48
49 writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
50
51 return 0;
52}
53
54static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
55{
56 struct gpio_generic_chip *gen_gc = to_gpio_generic_chip(gc);
57 struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
58 u32 using_pins;
59
60 guard(gpio_generic_lock_irqsave)(gen_gc);
61
62 using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
63 using_pins &= ~BIT(offset);
64 writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
65
66 dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
67}
68
69static int pt_gpio_probe(struct platform_device *pdev)
70{
71 struct gpio_generic_chip_config config;
72 struct device *dev = &pdev->dev;
73 struct pt_gpio_chip *pt_gpio;
74 int ret = 0;
75
76 if (!ACPI_COMPANION(dev)) {
77 dev_err(dev, "PT GPIO device node not found\n");
78 return -ENODEV;
79 }
80
81 pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
82 if (!pt_gpio)
83 return -ENOMEM;
84
85 pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
86 if (IS_ERR(pt_gpio->reg_base)) {
87 dev_err(dev, "Failed to map MMIO resource for PT GPIO.\n");
88 return PTR_ERR(pt_gpio->reg_base);
89 }
90
91 config = (struct gpio_generic_chip_config) {
92 .dev = dev,
93 .sz = 4,
94 .dat = pt_gpio->reg_base + PT_INPUTDATA_REG,
95 .set = pt_gpio->reg_base + PT_OUTPUTDATA_REG,
96 .dirout = pt_gpio->reg_base + PT_DIRECTION_REG,
97 .flags = GPIO_GENERIC_READ_OUTPUT_REG_SET,
98 };
99
100 ret = gpio_generic_chip_init(&pt_gpio->chip, &config);
101 if (ret) {
102 dev_err(dev, "failed to initialize the generic GPIO chip\n");
103 return ret;
104 }
105
106 pt_gpio->chip.gc.owner = THIS_MODULE;
107 pt_gpio->chip.gc.request = pt_gpio_request;
108 pt_gpio->chip.gc.free = pt_gpio_free;
109 pt_gpio->chip.gc.ngpio = (uintptr_t)device_get_match_data(dev);
110
111 ret = devm_gpiochip_add_data(dev, &pt_gpio->chip.gc, pt_gpio);
112 if (ret) {
113 dev_err(dev, "Failed to register GPIO lib\n");
114 return ret;
115 }
116
117 platform_set_drvdata(pdev, pt_gpio);
118
119 /* initialize register setting */
120 writel(0, pt_gpio->reg_base + PT_SYNC_REG);
121 writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
122
123 dev_dbg(dev, "PT GPIO driver loaded\n");
124 return ret;
125}
126
127static const struct acpi_device_id pt_gpio_acpi_match[] = {
128 { "AMDF030", PT_TOTAL_GPIO },
129 { "AMDIF030", PT_TOTAL_GPIO },
130 { "AMDIF031", PT_TOTAL_GPIO_EX },
131 { },
132};
133MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
134
135static struct platform_driver pt_gpio_driver = {
136 .driver = {
137 .name = "pt-gpio",
138 .acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
139 },
140 .probe = pt_gpio_probe,
141};
142
143module_platform_driver(pt_gpio_driver);
144
145MODULE_LICENSE("GPL");
146MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
147MODULE_DESCRIPTION("AMD Promontory GPIO Driver");