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SubjectRe: [PATCH v3 2/4] gpio: Add GPIO driver for Nintendo Wii
On Fri, Feb 9, 2018 at 2:07 PM, Jonathan Neuschäfer
<j.neuschaefer@gmx.net> wrote:
> The Nintendo Wii's chipset (called "Hollywood") has a GPIO controller
> that supports a configurable number of pins (up to 32), interrupts, and
> some special mechanisms to share the controller between the system's
> security processor (an ARM926) and the PowerPC CPU. Pin multiplexing is
> not supported.
>
> This patch adds a basic driver for this GPIO controller. Interrupt
> support will come in a later patch.
>
> This patch is based on code developed by Albert Herranz and the GameCube
> Linux Team, file arch/powerpc/platforms/embedded6xx/hlwd-gpio.c,
> available at https://github.com/DeltaResero/GC-Wii-Linux-Kernels, but
> has grown quite dissimilar.
>

Fine to me, though one comment below.
In any case,

Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>

> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Cc: Albert Herranz <albert_herranz@yahoo.es>
> Cc: Segher Boessenkool <segher@kernel.crashing.org>
> <---
>
> v3:
> - Do some style cleanups, as suggest by Andy Shevchenko
>
> v2:
> - Change hlwd_gpio_driver.driver.name to "gpio-hlwd" to match the
> filename (was "hlwd_gpio")
> - Remove unnecessary include of linux/of_gpio.h, as suggested by Linus
> Walleij.
> - Add struct device pointer to context struct to make it possible to use
> dev_info(hlwd->dev, "..."), as suggested by Linus Walleij
> - Use the GPIO_GENERIC library to reduce code size, as suggested by
> Linus Walleij
> - Use iowrite32be instead of __raw_writel for big-endian MMIO access, as
> suggested by Linus Walleij
> - Remove commit message paragraph suggesting to diff against the
> original driver, because it's so different now
> ---
> drivers/gpio/Kconfig | 9 ++++
> drivers/gpio/Makefile | 1 +
> drivers/gpio/gpio-hlwd.c | 115 +++++++++++++++++++++++++++++++++++++++++++++++
> 3 files changed, 125 insertions(+)
> create mode 100644 drivers/gpio/gpio-hlwd.c
>
> diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
> index d6a8e851ad13..47606dfe06cc 100644
> --- a/drivers/gpio/Kconfig
> +++ b/drivers/gpio/Kconfig
> @@ -229,6 +229,15 @@ config GPIO_GRGPIO
> Select this to support Aeroflex Gaisler GRGPIO cores from the GRLIB
> VHDL IP core library.
>
> +config GPIO_HLWD
> + tristate "Nintendo Wii (Hollywood) GPIO"

> + depends on OF_GPIO

You may get rid of it if...

> + select GPIO_GENERIC
> + help
> + Select this to support the GPIO controller of the Nintendo Wii.
> +
> + If unsure, say N.
> +
> config GPIO_ICH
> tristate "Intel ICH GPIO"
> depends on PCI && X86
> diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
> index 4bc24febb889..492f62d0eb59 100644
> --- a/drivers/gpio/Makefile
> +++ b/drivers/gpio/Makefile
> @@ -54,6 +54,7 @@ obj-$(CONFIG_GPIO_FTGPIO010) += gpio-ftgpio010.o
> obj-$(CONFIG_GPIO_GE_FPGA) += gpio-ge.o
> obj-$(CONFIG_GPIO_GPIO_MM) += gpio-gpio-mm.o
> obj-$(CONFIG_GPIO_GRGPIO) += gpio-grgpio.o
> +obj-$(CONFIG_GPIO_HLWD) += gpio-hlwd.o
> obj-$(CONFIG_HTC_EGPIO) += gpio-htc-egpio.o
> obj-$(CONFIG_GPIO_ICH) += gpio-ich.o
> obj-$(CONFIG_GPIO_INGENIC) += gpio-ingenic.o
> diff --git a/drivers/gpio/gpio-hlwd.c b/drivers/gpio/gpio-hlwd.c
> new file mode 100644
> index 000000000000..a63136a68ba3
> --- /dev/null
> +++ b/drivers/gpio/gpio-hlwd.c
> @@ -0,0 +1,115 @@
> +// SPDX-License-Identifier: GPL-2.0+
> +// Copyright (C) 2008-2009 The GameCube Linux Team
> +// Copyright (C) 2008,2009 Albert Herranz
> +// Copyright (C) 2017-2018 Jonathan Neuschäfer
> +//
> +// Nintendo Wii (Hollywood) GPIO driver
> +
> +#include <linux/gpio/driver.h>
> +#include <linux/io.h>
> +#include <linux/kernel.h>
> +#include <linux/module.h>

> +#include <linux/of.h>
> +#include <linux/of_platform.h>

...(and using platform device header I suppose)...

> +#include <linux/slab.h>
> +
> +/*
> + * Register names and offsets courtesy of WiiBrew:
> + * https://wiibrew.org/wiki/Hardware/Hollywood_GPIOs
> + *
> + * Note that for most registers, there are two versions:
> + * - HW_GPIOB_* Is always accessible by the Broadway PowerPC core, but does
> + * always give access to all GPIO lines
> + * - HW_GPIO_* Is only accessible by the Broadway PowerPC code if the memory
> + * firewall (AHBPROT) in the Hollywood chipset has been configured to allow
> + * such access.
> + *
> + * The ownership of each GPIO line can be configured in the HW_GPIO_OWNER
> + * register: A one bit configures the line for access via the HW_GPIOB_*
> + * registers, a zero bit indicates access via HW_GPIO_*. This driver uses
> + * HW_GPIOB_*.
> + */
> +#define HW_GPIOB_OUT 0x00
> +#define HW_GPIOB_DIR 0x04
> +#define HW_GPIOB_IN 0x08
> +#define HW_GPIOB_INTLVL 0x0c
> +#define HW_GPIOB_INTFLAG 0x10
> +#define HW_GPIOB_INTMASK 0x14
> +#define HW_GPIOB_INMIR 0x18
> +#define HW_GPIO_ENABLE 0x1c
> +#define HW_GPIO_OUT 0x20
> +#define HW_GPIO_DIR 0x24
> +#define HW_GPIO_IN 0x28
> +#define HW_GPIO_INTLVL 0x2c
> +#define HW_GPIO_INTFLAG 0x30
> +#define HW_GPIO_INTMASK 0x34
> +#define HW_GPIO_INMIR 0x38
> +#define HW_GPIO_OWNER 0x3c
> +
> +struct hlwd_gpio {
> + struct gpio_chip gpioc;
> + void __iomem *regs;
> +};
> +
> +static int hlwd_gpio_probe(struct platform_device *pdev)
> +{
> + struct hlwd_gpio *hlwd;
> + struct resource *regs_resource;
> + u32 ngpios;
> + int res;
> +
> + hlwd = devm_kzalloc(&pdev->dev, sizeof(*hlwd), GFP_KERNEL);
> + if (!hlwd)
> + return -ENOMEM;
> +
> + regs_resource = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> + hlwd->regs = devm_ioremap_resource(&pdev->dev, regs_resource);
> + if (IS_ERR(hlwd->regs))
> + return PTR_ERR(hlwd->regs);
> +
> + /*
> + * Claim all GPIOs using the OWNER register. This will not work on
> + * systems where the AHBPROT memory firewall hasn't been configured to
> + * permit PPC access to HW_GPIO_*.
> + *
> + * Note that this has to happen before bgpio_init reads the
> + * HW_GPIOB_OUT and HW_GPIOB_DIR, because otherwise it reads the wrong
> + * values.
> + */
> + iowrite32be(0xffffffff, hlwd->regs + HW_GPIO_OWNER);
> +
> + res = bgpio_init(&hlwd->gpioc, &pdev->dev, 4,
> + hlwd->regs + HW_GPIOB_IN, hlwd->regs + HW_GPIOB_OUT,
> + NULL, hlwd->regs + HW_GPIOB_DIR, NULL,
> + BGPIOF_BIG_ENDIAN_BYTE_ORDER);
> + if (res < 0) {
> + dev_warn(&pdev->dev, "bgpio_init failed: %d\n", res);
> + return res;
> + }
> +

> + res = of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios);

...if you switch to unified device property API.

> + if (res)
> + ngpios = 32;
> + hlwd->gpioc.ngpio = ngpios;
> +
> + return devm_gpiochip_add_data(&pdev->dev, &hlwd->gpioc, hlwd);
> +}
> +
> +static const struct of_device_id hlwd_gpio_match[] = {
> + { .compatible = "nintendo,hollywood-gpio", },
> + {},
> +};
> +MODULE_DEVICE_TABLE(of, hlwd_gpio_match);
> +
> +static struct platform_driver hlwd_gpio_driver = {
> + .driver = {
> + .name = "gpio-hlwd",
> + .of_match_table = hlwd_gpio_match,
> + },
> + .probe = hlwd_gpio_probe,
> +};
> +module_platform_driver(hlwd_gpio_driver);
> +
> +MODULE_AUTHOR("Jonathan Neuschäfer <j.neuschaefer@gmx.net>");
> +MODULE_DESCRIPTION("Nintendo Wii GPIO driver");
> +MODULE_LICENSE("GPL");
> --
> 2.15.1
>



--
With Best Regards,
Andy Shevchenko

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