drivers/gpio/gpio-hlwd.c

   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
  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");