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 
49 struct hlwd_gpio {
50 	struct gpio_chip gpioc;
51 	void __iomem *regs;
52 };
53 
hlwd_gpio_probe(struct platform_device * pdev)54 static 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 
98 static const struct of_device_id hlwd_gpio_match[] = {
99 	{ .compatible = "nintendo,hollywood-gpio", },
100 	{},
101 };
102 MODULE_DEVICE_TABLE(of, hlwd_gpio_match);
103 
104 static 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 };
111 module_platform_driver(hlwd_gpio_driver);
112 
113 MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
114 MODULE_DESCRIPTION("Nintendo Wii GPIO driver");
115 MODULE_LICENSE("GPL");
116