gpio-amdpt.c

  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");