Patchwork [V4] powerpc/mpc512x: Add gpio driver

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Submitter Anatolij Gustschin
Date June 10, 2010, 4:21 p.m.
Message ID <1276186867-29094-1-git-send-email-agust@denx.de>
Download mbox | patch
Permalink /patch/55237/
State Superseded
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Comments

Anatolij Gustschin - June 10, 2010, 4:21 p.m.
From: Matthias Fuchs <matthias.fuchs@esd.eu>

This patch adds a gpio driver for MPC512X PowerPCs.

It has been tested on our CAN-CBX-CPU5201 module that
uses a MPC5121 CPU. This platform comes with a couple of
LEDs and configuration switches that have been used for testing.

Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
Signed-off-by: Anatolij Gustschin <agust@denx.de>
---
Please consider this patch for inclusion in 2.6.36. Thanks!

v4: - actually v3 was rebased but without shadow
      registers init code as stated in the v3 changelog.
      Correct it now.

v3: - rebase to apply on current mainline tree
    - v2 switched to shadow registers but these are
      not pre-initialized (zero). As a result, setting
      pin direction or ODR register will clear other bits
      in direction and ODR registers. Fix this bug by adding
      shadow registers initialization code.

v2: - move driver to arch/powerpc/platforms/512x directory
    - Kconfig changes are now in arch/powerpc/platform/512x/Kconfig
    - put struct mpc512x_gpio_regs in driver's .c file
    - rename GPIO_MASK into MPC512x_GPIO_MASK
    - use shadow registers instead of r/m/w-operations
    - don't use arch_initcall but call mpc512x_add_gpiochips()
      from mpc512x platform setup code.

 arch/powerpc/platforms/512x/Kconfig          |    9 +
 arch/powerpc/platforms/512x/Makefile         |    1 +
 arch/powerpc/platforms/512x/mpc512x.h        |    3 +
 arch/powerpc/platforms/512x/mpc512x_gpio.c   |  204 ++++++++++++++++++++++++++
 arch/powerpc/platforms/512x/mpc512x_shared.c |    3 +
 5 files changed, 220 insertions(+), 0 deletions(-)
 create mode 100644 arch/powerpc/platforms/512x/mpc512x_gpio.c
Grant Likely - June 10, 2010, 9:48 p.m.
On Thu, Jun 10, 2010 at 10:21 AM, Anatolij Gustschin <agust@denx.de> wrote:
> From: Matthias Fuchs <matthias.fuchs@esd.eu>
>
> This patch adds a gpio driver for MPC512X PowerPCs.
>
> It has been tested on our CAN-CBX-CPU5201 module that
> uses a MPC5121 CPU. This platform comes with a couple of
> LEDs and configuration switches that have been used for testing.
>
> Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
> Signed-off-by: Anatolij Gustschin <agust@denx.de>

Hi Anatolij,

Can you please rework this one on top of my next-devicetree branch.
Change have been made to the of-gpio apis.

g.


> ---
> Please consider this patch for inclusion in 2.6.36. Thanks!
>
> v4: - actually v3 was rebased but without shadow
>      registers init code as stated in the v3 changelog.
>      Correct it now.
>
> v3: - rebase to apply on current mainline tree
>    - v2 switched to shadow registers but these are
>      not pre-initialized (zero). As a result, setting
>      pin direction or ODR register will clear other bits
>      in direction and ODR registers. Fix this bug by adding
>      shadow registers initialization code.
>
> v2: - move driver to arch/powerpc/platforms/512x directory
>    - Kconfig changes are now in arch/powerpc/platform/512x/Kconfig
>    - put struct mpc512x_gpio_regs in driver's .c file
>    - rename GPIO_MASK into MPC512x_GPIO_MASK
>    - use shadow registers instead of r/m/w-operations
>    - don't use arch_initcall but call mpc512x_add_gpiochips()
>      from mpc512x platform setup code.
>
>  arch/powerpc/platforms/512x/Kconfig          |    9 +
>  arch/powerpc/platforms/512x/Makefile         |    1 +
>  arch/powerpc/platforms/512x/mpc512x.h        |    3 +
>  arch/powerpc/platforms/512x/mpc512x_gpio.c   |  204 ++++++++++++++++++++++++++
>  arch/powerpc/platforms/512x/mpc512x_shared.c |    3 +
>  5 files changed, 220 insertions(+), 0 deletions(-)
>  create mode 100644 arch/powerpc/platforms/512x/mpc512x_gpio.c
>
> diff --git a/arch/powerpc/platforms/512x/Kconfig b/arch/powerpc/platforms/512x/Kconfig
> index 4dac9b0..bd763ee 100644
> --- a/arch/powerpc/platforms/512x/Kconfig
> +++ b/arch/powerpc/platforms/512x/Kconfig
> @@ -30,3 +30,12 @@ config MPC5121_GENERIC
>
>          Compatible boards include:  Protonic LVT base boards (ZANMCU
>          and VICVT2).
> +
> +config MPC512x_GPIO
> +       bool "MPC512x GPIO support"
> +       depends on PPC_MPC512x
> +       select GENERIC_GPIO
> +       select ARCH_REQUIRE_GPIOLIB
> +       help
> +         Say Y here if you're going to use hardware that connects to the
> +         MPC512x GPIOs.
> diff --git a/arch/powerpc/platforms/512x/Makefile b/arch/powerpc/platforms/512x/Makefile
> index 90be2f5..12518e3 100644
> --- a/arch/powerpc/platforms/512x/Makefile
> +++ b/arch/powerpc/platforms/512x/Makefile
> @@ -4,3 +4,4 @@
>  obj-y                          += clock.o mpc512x_shared.o
>  obj-$(CONFIG_MPC5121_ADS)      += mpc5121_ads.o mpc5121_ads_cpld.o
>  obj-$(CONFIG_MPC5121_GENERIC)  += mpc5121_generic.o
> +obj-$(CONFIG_MPC512x_GPIO)     += mpc512x_gpio.o
> diff --git a/arch/powerpc/platforms/512x/mpc512x.h b/arch/powerpc/platforms/512x/mpc512x.h
> index b2daca0..4a1b094 100644
> --- a/arch/powerpc/platforms/512x/mpc512x.h
> +++ b/arch/powerpc/platforms/512x/mpc512x.h
> @@ -16,4 +16,7 @@ extern void __init mpc512x_init(void);
>  extern int __init mpc5121_clk_init(void);
>  void __init mpc512x_declare_of_platform_devices(void);
>  extern void mpc512x_restart(char *cmd);
> +#ifdef CONFIG_MPC512x_GPIO
> +extern int mpc512x_add_gpiochips(void);
> +#endif
>  #endif                         /* __MPC512X_H__ */
> diff --git a/arch/powerpc/platforms/512x/mpc512x_gpio.c b/arch/powerpc/platforms/512x/mpc512x_gpio.c
> new file mode 100644
> index 0000000..13b2478
> --- /dev/null
> +++ b/arch/powerpc/platforms/512x/mpc512x_gpio.c
> @@ -0,0 +1,204 @@
> +/*
> + * MPC512x gpio driver
> + *
> + * Copyright (c) 2010 Matthias Fuchs <matthias.fuchs@esd.eu>, esd gmbh
> + *
> + * derived from ppc4xx gpio driver
> + *
> + * Copyright (c) 2008 Harris Corporation
> + * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
> + * Copyright (c) MontaVista Software, Inc. 2008.
> + *
> + * Author: Steve Falco <sfalco@harris.com>
> + *
> + * This program is free software; you can redistribute it and/or modify
> + * it under the terms of the GNU General Public License version 2
> + * as published by the Free Software Foundation.
> + *
> + * This program is distributed in the hope that it will be useful,
> + * but WITHOUT ANY WARRANTY; without even the implied warranty of
> + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
> + * GNU General Public License for more details.
> + *
> + * You should have received a copy of the GNU General Public License
> + * along with this program; if not, write to the Free Software
> + * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
> + */
> +
> +#include <linux/kernel.h>
> +#include <linux/init.h>
> +#include <linux/spinlock.h>
> +#include <linux/io.h>
> +#include <linux/of.h>
> +#include <linux/of_gpio.h>
> +#include <linux/gpio.h>
> +#include <linux/types.h>
> +
> +#define MPC512x_GPIO_MASK(gpio) (0x80000000 >> (gpio))
> +
> +struct mpc512x_gpio_regs {
> +       u32 gpdir;
> +       u32 gpodr;
> +       u32 gpdat;
> +       u32 gpier;
> +       u32 gpimr;
> +       u32 gpicr1;
> +       u32 gpicr2;
> +};
> +
> +struct mpc512x_chip {
> +       struct of_mm_gpio_chip mm_gc;
> +       spinlock_t lock;
> +
> +       /* shadow registers */
> +       u32 dat;
> +       u32 odr;
> +       u32 dir;
> +};
> +
> +/*
> + * GPIO LIB API implementation for GPIOs
> + *
> + * There are a maximum of 32 gpios in each gpio controller.
> + */
> +static inline struct mpc512x_chip *
> +to_mpc512x_gpiochip(struct of_mm_gpio_chip *mm_gc)
> +{
> +       return container_of(mm_gc, struct mpc512x_chip, mm_gc);
> +}
> +
> +static int mpc512x_gpio_get(struct gpio_chip *gc, unsigned int gpio)
> +{
> +       struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
> +       struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
> +
> +       return in_be32(&regs->gpdat) & MPC512x_GPIO_MASK(gpio);
> +}
> +
> +static inline void
> +__mpc512x_gpio_set(struct of_mm_gpio_chip *mm_gc, unsigned int gpio, int val)
> +{
> +       struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
> +       struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
> +
> +
> +       if (val)
> +               chip->dat |= MPC512x_GPIO_MASK(gpio);
> +       else
> +               chip->dat &= ~MPC512x_GPIO_MASK(gpio);
> +
> +       out_be32(&regs->gpdat, chip->dat);
> +}
> +
> +static void
> +mpc512x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
> +{
> +       struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
> +       struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&chip->lock, flags);
> +
> +       __mpc512x_gpio_set(mm_gc, gpio, val);
> +
> +       spin_unlock_irqrestore(&chip->lock, flags);
> +
> +       pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
> +}
> +
> +static int mpc512x_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
> +{
> +       struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
> +       struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
> +       struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&chip->lock, flags);
> +
> +       /* Disable open-drain function */
> +       chip->odr &= ~MPC512x_GPIO_MASK(gpio);
> +       out_be32(&regs->gpodr, chip->odr);
> +
> +       /* Float the pin */
> +       chip->dir &= ~MPC512x_GPIO_MASK(gpio);
> +       out_be32(&regs->gpdir, chip->dir);
> +
> +       spin_unlock_irqrestore(&chip->lock, flags);
> +
> +       return 0;
> +}
> +
> +static int
> +mpc512x_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
> +{
> +       struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
> +       struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
> +       struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
> +       unsigned long flags;
> +
> +       spin_lock_irqsave(&chip->lock, flags);
> +
> +       /* First set initial value */
> +       __mpc512x_gpio_set(mm_gc, gpio, val);
> +
> +       /* Disable open-drain function */
> +       chip->odr &= ~MPC512x_GPIO_MASK(gpio);
> +       out_be32(&regs->gpodr, chip->odr);
> +
> +       /* Drive the pin */
> +       chip->dir |= MPC512x_GPIO_MASK(gpio);
> +       out_be32(&regs->gpdir, chip->dir);
> +
> +       spin_unlock_irqrestore(&chip->lock, flags);
> +
> +       pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
> +
> +       return 0;
> +}
> +
> +void __init mpc512x_add_gpiochips(void)
> +{
> +       struct device_node *np;
> +
> +       for_each_compatible_node(np, NULL, "fsl,mpc5121-gpio") {
> +               int ret;
> +               struct mpc512x_chip *chip;
> +               struct of_mm_gpio_chip *mm_gc;
> +               struct of_gpio_chip *of_gc;
> +               struct gpio_chip *gc;
> +               struct mpc512x_gpio_regs __iomem *regs;
> +
> +               chip = kzalloc(sizeof(*chip), GFP_KERNEL);
> +               if (!chip) {
> +                       ret = -ENOMEM;
> +                       goto err;
> +               }
> +
> +               spin_lock_init(&chip->lock);
> +
> +               mm_gc = &chip->mm_gc;
> +               of_gc = &mm_gc->of_gc;
> +               gc = &of_gc->gc;
> +
> +               gc->ngpio = 32;
> +               gc->direction_input = mpc512x_gpio_dir_in;
> +               gc->direction_output = mpc512x_gpio_dir_out;
> +               gc->get = mpc512x_gpio_get;
> +               gc->set = mpc512x_gpio_set;
> +
> +               ret = of_mm_gpiochip_add(np, mm_gc);
> +               if (ret)
> +                       goto err;
> +
> +               regs = mm_gc->regs;
> +               chip->dat = in_be32(&regs->gpdat);
> +               chip->dir = in_be32(&regs->gpdir);
> +               chip->odr = in_be32(&regs->gpodr);
> +               continue;
> +err:
> +               pr_err("%s: registration failed with status %d\n",
> +                      np->full_name, ret);
> +               kfree(chip);
> +               /* try others anyway */
> +       }
> +}
> diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
> index 707e572..15da1bc 100644
> --- a/arch/powerpc/platforms/512x/mpc512x_shared.c
> +++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
> @@ -178,4 +178,7 @@ void __init mpc512x_init(void)
>        mpc5121_clk_init();
>        mpc512x_restart_init();
>        mpc512x_psc_fifo_init();
> +#ifdef CONFIG_MPC512x_GPIO
> +       mpc512x_add_gpiochips();
> +#endif
>  }
> --
> 1.7.0.4
>
>
Anatolij Gustschin - June 10, 2010, 10:01 p.m.
Hi Grant,

On Thu, 10 Jun 2010 15:48:42 -0600
Grant Likely <grant.likely@secretlab.ca> wrote:

> On Thu, Jun 10, 2010 at 10:21 AM, Anatolij Gustschin <agust@denx.de> wrote:
> > From: Matthias Fuchs <matthias.fuchs@esd.eu>
> >
> > This patch adds a gpio driver for MPC512X PowerPCs.
> >
> > It has been tested on our CAN-CBX-CPU5201 module that
> > uses a MPC5121 CPU. This platform comes with a couple of
> > LEDs and configuration switches that have been used for testing.
> >
> > Signed-off-by: Matthias Fuchs <matthias.fuchs@esd.eu>
> > Signed-off-by: Anatolij Gustschin <agust@denx.de>
> 
> Hi Anatolij,
> 
> Can you please rework this one on top of my next-devicetree branch.
> Change have been made to the of-gpio apis.

Ok, I'll look at it.

Anatolij

Patch

diff --git a/arch/powerpc/platforms/512x/Kconfig b/arch/powerpc/platforms/512x/Kconfig
index 4dac9b0..bd763ee 100644
--- a/arch/powerpc/platforms/512x/Kconfig
+++ b/arch/powerpc/platforms/512x/Kconfig
@@ -30,3 +30,12 @@  config MPC5121_GENERIC
 
 	  Compatible boards include:  Protonic LVT base boards (ZANMCU
 	  and VICVT2).
+
+config MPC512x_GPIO
+	bool "MPC512x GPIO support"
+	depends on PPC_MPC512x
+	select GENERIC_GPIO
+	select ARCH_REQUIRE_GPIOLIB
+	help
+	  Say Y here if you're going to use hardware that connects to the
+	  MPC512x GPIOs.
diff --git a/arch/powerpc/platforms/512x/Makefile b/arch/powerpc/platforms/512x/Makefile
index 90be2f5..12518e3 100644
--- a/arch/powerpc/platforms/512x/Makefile
+++ b/arch/powerpc/platforms/512x/Makefile
@@ -4,3 +4,4 @@ 
 obj-y				+= clock.o mpc512x_shared.o
 obj-$(CONFIG_MPC5121_ADS)	+= mpc5121_ads.o mpc5121_ads_cpld.o
 obj-$(CONFIG_MPC5121_GENERIC)	+= mpc5121_generic.o
+obj-$(CONFIG_MPC512x_GPIO)	+= mpc512x_gpio.o
diff --git a/arch/powerpc/platforms/512x/mpc512x.h b/arch/powerpc/platforms/512x/mpc512x.h
index b2daca0..4a1b094 100644
--- a/arch/powerpc/platforms/512x/mpc512x.h
+++ b/arch/powerpc/platforms/512x/mpc512x.h
@@ -16,4 +16,7 @@  extern void __init mpc512x_init(void);
 extern int __init mpc5121_clk_init(void);
 void __init mpc512x_declare_of_platform_devices(void);
 extern void mpc512x_restart(char *cmd);
+#ifdef CONFIG_MPC512x_GPIO
+extern int mpc512x_add_gpiochips(void);
+#endif
 #endif				/* __MPC512X_H__ */
diff --git a/arch/powerpc/platforms/512x/mpc512x_gpio.c b/arch/powerpc/platforms/512x/mpc512x_gpio.c
new file mode 100644
index 0000000..13b2478
--- /dev/null
+++ b/arch/powerpc/platforms/512x/mpc512x_gpio.c
@@ -0,0 +1,204 @@ 
+/*
+ * MPC512x gpio driver
+ *
+ * Copyright (c) 2010 Matthias Fuchs <matthias.fuchs@esd.eu>, esd gmbh
+ *
+ * derived from ppc4xx gpio driver
+ *
+ * Copyright (c) 2008 Harris Corporation
+ * Copyright (c) 2008 Sascha Hauer <s.hauer@pengutronix.de>, Pengutronix
+ * Copyright (c) MontaVista Software, Inc. 2008.
+ *
+ * Author: Steve Falco <sfalco@harris.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2
+ * as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ */
+
+#include <linux/kernel.h>
+#include <linux/init.h>
+#include <linux/spinlock.h>
+#include <linux/io.h>
+#include <linux/of.h>
+#include <linux/of_gpio.h>
+#include <linux/gpio.h>
+#include <linux/types.h>
+
+#define MPC512x_GPIO_MASK(gpio) (0x80000000 >> (gpio))
+
+struct mpc512x_gpio_regs {
+	u32 gpdir;
+	u32 gpodr;
+	u32 gpdat;
+	u32 gpier;
+	u32 gpimr;
+	u32 gpicr1;
+	u32 gpicr2;
+};
+
+struct mpc512x_chip {
+	struct of_mm_gpio_chip mm_gc;
+	spinlock_t lock;
+
+	/* shadow registers */
+	u32 dat;
+	u32 odr;
+	u32 dir;
+};
+
+/*
+ * GPIO LIB API implementation for GPIOs
+ *
+ * There are a maximum of 32 gpios in each gpio controller.
+ */
+static inline struct mpc512x_chip *
+to_mpc512x_gpiochip(struct of_mm_gpio_chip *mm_gc)
+{
+	return container_of(mm_gc, struct mpc512x_chip, mm_gc);
+}
+
+static int mpc512x_gpio_get(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
+
+	return in_be32(&regs->gpdat) & MPC512x_GPIO_MASK(gpio);
+}
+
+static inline void
+__mpc512x_gpio_set(struct of_mm_gpio_chip *mm_gc, unsigned int gpio, int val)
+{
+	struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
+	struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
+
+
+	if (val)
+		chip->dat |= MPC512x_GPIO_MASK(gpio);
+	else
+		chip->dat &= ~MPC512x_GPIO_MASK(gpio);
+
+	out_be32(&regs->gpdat, chip->dat);
+}
+
+static void
+mpc512x_gpio_set(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	__mpc512x_gpio_set(mm_gc, gpio, val);
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
+}
+
+static int mpc512x_gpio_dir_in(struct gpio_chip *gc, unsigned int gpio)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
+	struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	/* Disable open-drain function */
+	chip->odr &= ~MPC512x_GPIO_MASK(gpio);
+	out_be32(&regs->gpodr, chip->odr);
+
+	/* Float the pin */
+	chip->dir &= ~MPC512x_GPIO_MASK(gpio);
+	out_be32(&regs->gpdir, chip->dir);
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	return 0;
+}
+
+static int
+mpc512x_gpio_dir_out(struct gpio_chip *gc, unsigned int gpio, int val)
+{
+	struct of_mm_gpio_chip *mm_gc = to_of_mm_gpio_chip(gc);
+	struct mpc512x_chip *chip = to_mpc512x_gpiochip(mm_gc);
+	struct mpc512x_gpio_regs __iomem *regs = mm_gc->regs;
+	unsigned long flags;
+
+	spin_lock_irqsave(&chip->lock, flags);
+
+	/* First set initial value */
+	__mpc512x_gpio_set(mm_gc, gpio, val);
+
+	/* Disable open-drain function */
+	chip->odr &= ~MPC512x_GPIO_MASK(gpio);
+	out_be32(&regs->gpodr, chip->odr);
+
+	/* Drive the pin */
+	chip->dir |= MPC512x_GPIO_MASK(gpio);
+	out_be32(&regs->gpdir, chip->dir);
+
+	spin_unlock_irqrestore(&chip->lock, flags);
+
+	pr_debug("%s: gpio: %d val: %d\n", __func__, gpio, val);
+
+	return 0;
+}
+
+void __init mpc512x_add_gpiochips(void)
+{
+	struct device_node *np;
+
+	for_each_compatible_node(np, NULL, "fsl,mpc5121-gpio") {
+		int ret;
+		struct mpc512x_chip *chip;
+		struct of_mm_gpio_chip *mm_gc;
+		struct of_gpio_chip *of_gc;
+		struct gpio_chip *gc;
+		struct mpc512x_gpio_regs __iomem *regs;
+
+		chip = kzalloc(sizeof(*chip), GFP_KERNEL);
+		if (!chip) {
+			ret = -ENOMEM;
+			goto err;
+		}
+
+		spin_lock_init(&chip->lock);
+
+		mm_gc = &chip->mm_gc;
+		of_gc = &mm_gc->of_gc;
+		gc = &of_gc->gc;
+
+		gc->ngpio = 32;
+		gc->direction_input = mpc512x_gpio_dir_in;
+		gc->direction_output = mpc512x_gpio_dir_out;
+		gc->get = mpc512x_gpio_get;
+		gc->set = mpc512x_gpio_set;
+
+		ret = of_mm_gpiochip_add(np, mm_gc);
+		if (ret)
+			goto err;
+
+		regs = mm_gc->regs;
+		chip->dat = in_be32(&regs->gpdat);
+		chip->dir = in_be32(&regs->gpdir);
+		chip->odr = in_be32(&regs->gpodr);
+		continue;
+err:
+		pr_err("%s: registration failed with status %d\n",
+		       np->full_name, ret);
+		kfree(chip);
+		/* try others anyway */
+	}
+}
diff --git a/arch/powerpc/platforms/512x/mpc512x_shared.c b/arch/powerpc/platforms/512x/mpc512x_shared.c
index 707e572..15da1bc 100644
--- a/arch/powerpc/platforms/512x/mpc512x_shared.c
+++ b/arch/powerpc/platforms/512x/mpc512x_shared.c
@@ -178,4 +178,7 @@  void __init mpc512x_init(void)
 	mpc5121_clk_init();
 	mpc512x_restart_init();
 	mpc512x_psc_fifo_init();
+#ifdef CONFIG_MPC512x_GPIO
+	mpc512x_add_gpiochips();
+#endif
 }