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
 26struct pt_gpio_chip {
 27	struct gpio_chip         gc;
 28	void __iomem             *reg_base;
 29};
 30
 31static 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
 56static 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
 73static 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
125static void 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
132static const struct acpi_device_id pt_gpio_acpi_match[] = {
133	{ "AMDF030", PT_TOTAL_GPIO },
134	{ "AMDIF030", PT_TOTAL_GPIO },
135	{ "AMDIF031", PT_TOTAL_GPIO_EX },
136	{ },
137};
138MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
139
140static struct platform_driver pt_gpio_driver = {
141	.driver = {
142		.name = "pt-gpio",
143		.acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
144	},
145	.probe = pt_gpio_probe,
146	.remove_new = pt_gpio_remove,
147};
148
149module_platform_driver(pt_gpio_driver);
150
151MODULE_LICENSE("GPL");
152MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
153MODULE_DESCRIPTION("AMD Promontory GPIO Driver");