[v3,2/4] gpio: Add GPIO driver for Nintendo Wii

Message ID 20180209120732.17863-3-j.neuschaefer@gmx.net
State New
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Series
  • Nintendo Wii GPIO driver
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Commit Message

Jonathan Neuschäfer Feb. 9, 2018, 12:07 p.m.
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.

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

Comments

Segher Boessenkool Feb. 9, 2018, 3:11 p.m. | #1
On Fri, Feb 09, 2018 at 01:07:29PM +0100, Jonathan Neuschäfer 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.
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Cc: Albert Herranz <albert_herranz@yahoo.es>
> Cc: Segher Boessenkool <segher@kernel.crashing.org>

Reviewed-by: Segher Boessenkool <segher@kernel.crashing.org>

Looks just fine to me :-)


Segher
Andy Shevchenko Feb. 9, 2018, 3:30 p.m. | #2
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
>
Jonathan Neuschäfer Feb. 9, 2018, 3:48 p.m. | #3
On Fri, Feb 09, 2018 at 01:07:29PM +0100, Jonathan Neuschäfer 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.
> 
> Signed-off-by: Jonathan Neuschäfer <j.neuschaefer@gmx.net>
> Cc: Albert Herranz <albert_herranz@yahoo.es>
> Cc: Segher Boessenkool <segher@kernel.crashing.org>
> <---

Ooops, I just noticed that I broke the separator here. This should be a
normal --- line, obviously.


Jonathan Neuschäfer
Jonathan Neuschäfer Feb. 9, 2018, 4:58 p.m. | #4
On Fri, Feb 09, 2018 at 05:30:55PM +0200, Andy Shevchenko wrote:
> 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>

Thank you.


[...]
> > 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...

[ Even if this driver isn't switched to the unified device property API,
  I think "depends on OF" would be enough here, because it doesn't use
  the code that's guarded by CONFIG_OF_GPIO (gpiolib-of.c), but this
  applies to other drivers (e.g. gpio-aspeed, gpio-bcm-kona) as well, so
  this would ideally be a bigger cleanup patch. ]


> > +       res = of_property_read_u32(pdev->dev.of_node, "ngpios", &ngpios);
> 
> ...if you switch to unified device property API.

I don't think this change is worth making, unless/until the of_property
API is deprecated. I'm rather sure this GPIO controller won't appear in
an ACPI-based system.


Thanks,
Jonathan Neuschäfer

Patch

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
+	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>
+#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 (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");