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