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/*
* AMD Promontory GPIO driver
*
* Copyright (C) 2015 ASMedia Technology Inc.
* Author: YD Tseng <yd_tseng@asmedia.com.tw>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/gpio/driver.h>
#include <linux/spinlock.h>
#include <linux/acpi.h>
#include <linux/platform_device.h>
#define PT_TOTAL_GPIO 8
/* PCI-E MMIO register offsets */
#define PT_DIRECTION_REG 0x00
#define PT_INPUTDATA_REG 0x04
#define PT_OUTPUTDATA_REG 0x08
#define PT_CLOCKRATE_REG 0x0C
#define PT_SYNC_REG 0x28
struct pt_gpio_chip {
struct gpio_chip gc;
void __iomem *reg_base;
};
static int pt_gpio_request(struct gpio_chip *gc, unsigned offset)
{
struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
unsigned long flags;
u32 using_pins;
dev_dbg(gc->parent, "pt_gpio_request offset=%x\n", offset);
spin_lock_irqsave(&gc->bgpio_lock, flags);
using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
if (using_pins & BIT(offset)) {
dev_warn(gc->parent, "PT GPIO pin %x reconfigured\n",
offset);
spin_unlock_irqrestore(&gc->bgpio_lock, flags);
return -EINVAL;
}
writel(using_pins | BIT(offset), pt_gpio->reg_base + PT_SYNC_REG);
spin_unlock_irqrestore(&gc->bgpio_lock, flags);
return 0;
}
static void pt_gpio_free(struct gpio_chip *gc, unsigned offset)
{
struct pt_gpio_chip *pt_gpio = gpiochip_get_data(gc);
unsigned long flags;
u32 using_pins;
spin_lock_irqsave(&gc->bgpio_lock, flags);
using_pins = readl(pt_gpio->reg_base + PT_SYNC_REG);
using_pins &= ~BIT(offset);
writel(using_pins, pt_gpio->reg_base + PT_SYNC_REG);
spin_unlock_irqrestore(&gc->bgpio_lock, flags);
dev_dbg(gc->parent, "pt_gpio_free offset=%x\n", offset);
}
static int pt_gpio_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
struct acpi_device *acpi_dev;
acpi_handle handle = ACPI_HANDLE(dev);
struct pt_gpio_chip *pt_gpio;
int ret = 0;
if (acpi_bus_get_device(handle, &acpi_dev)) {
dev_err(dev, "PT GPIO device node not found\n");
return -ENODEV;
}
pt_gpio = devm_kzalloc(dev, sizeof(struct pt_gpio_chip), GFP_KERNEL);
if (!pt_gpio)
return -ENOMEM;
pt_gpio->reg_base = devm_platform_ioremap_resource(pdev, 0);
if (IS_ERR(pt_gpio->reg_base)) {
dev_err(&pdev->dev, "Failed to map MMIO resource for PT GPIO.\n");
return PTR_ERR(pt_gpio->reg_base);
}
ret = bgpio_init(&pt_gpio->gc, dev, 4,
pt_gpio->reg_base + PT_INPUTDATA_REG,
pt_gpio->reg_base + PT_OUTPUTDATA_REG, NULL,
pt_gpio->reg_base + PT_DIRECTION_REG, NULL,
BGPIOF_READ_OUTPUT_REG_SET);
if (ret) {
dev_err(&pdev->dev, "bgpio_init failed\n");
return ret;
}
pt_gpio->gc.owner = THIS_MODULE;
pt_gpio->gc.request = pt_gpio_request;
pt_gpio->gc.free = pt_gpio_free;
pt_gpio->gc.ngpio = PT_TOTAL_GPIO;
#if defined(CONFIG_OF_GPIO)
pt_gpio->gc.of_node = pdev->dev.of_node;
#endif
ret = gpiochip_add_data(&pt_gpio->gc, pt_gpio);
if (ret) {
dev_err(&pdev->dev, "Failed to register GPIO lib\n");
return ret;
}
platform_set_drvdata(pdev, pt_gpio);
/* initialize register setting */
writel(0, pt_gpio->reg_base + PT_SYNC_REG);
writel(0, pt_gpio->reg_base + PT_CLOCKRATE_REG);
dev_dbg(&pdev->dev, "PT GPIO driver loaded\n");
return ret;
}
static int pt_gpio_remove(struct platform_device *pdev)
{
struct pt_gpio_chip *pt_gpio = platform_get_drvdata(pdev);
gpiochip_remove(&pt_gpio->gc);
return 0;
}
static const struct acpi_device_id pt_gpio_acpi_match[] = {
{ "AMDF030", 0 },
{ "AMDIF030", 0 },
{ },
};
MODULE_DEVICE_TABLE(acpi, pt_gpio_acpi_match);
static struct platform_driver pt_gpio_driver = {
.driver = {
.name = "pt-gpio",
.acpi_match_table = ACPI_PTR(pt_gpio_acpi_match),
},
.probe = pt_gpio_probe,
.remove = pt_gpio_remove,
};
module_platform_driver(pt_gpio_driver);
MODULE_LICENSE("GPL");
MODULE_AUTHOR("YD Tseng <yd_tseng@asmedia.com.tw>");
MODULE_DESCRIPTION("AMD Promontory GPIO Driver");
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