1// SPDX-License-Identifier: GPL-2.0+
  2// Copyright (C) 2008-2009 The GameCube Linux Team
  3// Copyright (C) 2008,2009 Albert Herranz
  4// Copyright (C) 2017-2018 Jonathan Neuschäfer
  5//
  6// Nintendo Wii (Hollywood) GPIO driver
  7
  8#include <linux/gpio/driver.h>
  9#include <linux/io.h>
 10#include <linux/kernel.h>
 11#include <linux/module.h>
 12#include <linux/of.h>
 13#include <linux/of_platform.h>
 14#include <linux/slab.h>
 15
 16/*
 17 * Register names and offsets courtesy of WiiBrew:
 18 * https://wiibrew.org/wiki/Hardware/Hollywood_GPIOs
 19 *
 20 * Note that for most registers, there are two versions:
 21 * - HW_GPIOB_* Is always accessible by the Broadway PowerPC core, but does
 22 *   always give access to all GPIO lines
 23 * - HW_GPIO_* Is only accessible by the Broadway PowerPC code if the memory
 24 *   firewall (AHBPROT) in the Hollywood chipset has been configured to allow
 25 *   such access.
 26 *
 27 * The ownership of each GPIO line can be configured in the HW_GPIO_OWNER
 28 * register: A one bit configures the line for access via the HW_GPIOB_*
 29 * registers, a zero bit indicates access via HW_GPIO_*. This driver uses
 30 * HW_GPIOB_*.
 31 */
 32#define HW_GPIOB_OUT		0x00
 33#define HW_GPIOB_DIR		0x04
 34#define HW_GPIOB_IN		0x08
 35#define HW_GPIOB_INTLVL		0x0c
 36#define HW_GPIOB_INTFLAG	0x10
 37#define HW_GPIOB_INTMASK	0x14
 38#define HW_GPIOB_INMIR		0x18
 39#define HW_GPIO_ENABLE		0x1c
 40#define HW_GPIO_OUT		0x20
 41#define HW_GPIO_DIR		0x24
 42#define HW_GPIO_IN		0x28
 43#define HW_GPIO_INTLVL		0x2c
 44#define HW_GPIO_INTFLAG		0x30
 45#define HW_GPIO_INTMASK		0x34
 46#define HW_GPIO_INMIR		0x38
 47#define HW_GPIO_OWNER		0x3c
 48
 49struct hlwd_gpio {
 50	struct gpio_chip gpioc;
 51	void __iomem *regs;
 52};
 53
 54static int hlwd_gpio_probe(struct platform_device *pdev)
 55{
 56	struct hlwd_gpio *hlwd;
 57	struct resource *regs_resource;
 58	u32 ngpios;
 59	int res;
 60
 61	hlwd = devm_kzalloc(&pdev->dev, sizeof(*hlwd), GFP_KERNEL);
 62	if (!hlwd)
 63		return -ENOMEM;
 64
 65	regs_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
 66	hlwd->regs = devm_ioremap_resource(&pdev->dev, regs_resource);
 67	if (IS_ERR(hlwd->regs))
 68		return PTR_ERR(hlwd->regs);
 69
 70	/*
 71	 * Claim all GPIOs using the OWNER register. This will not work on
 72	 * systems where the AHBPROT memory firewall hasn't been configured to
 73	 * permit PPC access to HW_GPIO_*.
 74	 *
 75	 * Note that this has to happen before bgpio_init reads the
 76	 * HW_GPIOB_OUT and HW_GPIOB_DIR, because otherwise it reads the wrong
 77	 * values.
 78	 */
 79	iowrite32be(0xffffffff, hlwd->regs + HW_GPIO_OWNER);
 80
 81	res = bgpio_init(&hlwd->gpioc, &pdev->dev, 4,
 82			hlwd->regs + HW_GPIOB_IN, hlwd->regs + HW_GPIOB_OUT,
 83			NULL, hlwd->regs + HW_GPIOB_DIR, NULL,
 84			BGPIOF_BIG_ENDIAN_BYTE_ORDER);
 85	if (res < 0) {
 86		dev_warn(&pdev->dev, "bgpio_init failed: %d\n", res);
 87		return res;
 88	}
 89
 90	res = of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios);
 91	if (res)
 92		ngpios = 32;
 93	hlwd->gpioc.ngpio = ngpios;
 94
 95	return devm_gpiochip_add_data(&pdev->dev, &hlwd->gpioc, hlwd);
 96}
 97
 98static const struct of_device_id hlwd_gpio_match[] = {
 99	{ .compatible = "nintendo,hollywood-gpio", },
100	{},
101};
102MODULE_DEVICE_TABLE(of, hlwd_gpio_match);
103
104static struct platform_driver hlwd_gpio_driver = {
105	.driver	= {
106		.name		= "gpio-hlwd",
107		.of_match_table	= hlwd_gpio_match,
108	},
109	.probe	= hlwd_gpio_probe,
110};
111module_platform_driver(hlwd_gpio_driver);
112
113MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
114MODULE_DESCRIPTION("Nintendo Wii GPIO driver");
115MODULE_LICENSE("GPL");