[PATCH 1/2] gpio: Adjust of_xlate API to support multiple GPIO chips

[PATCH 1/2] gpio: Adjust of_xlate API to support multiple GPIO chips

[Roland Stigge]

From: Grant Likely <grant.likely@secretlab.ca>

This patch changes the of_xlate API to make it possible for multiple
gpio_chips to refer to the same device tree node.  This is useful for
banked GPIO controllers that use multiple gpio_chips for a single
device.  With this change the core code will try calling of_xlate on
each gpio_chip that references the device_node and will return the
gpio number for the first one to return 'true'.

Cc: Roland Stigge <stigge@antcom.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
Tested-by: Roland Stigge <stigge@antcom.de>

---
 arch/arm/mach-imx/mach-mx35_3ds.c |    3 +-
 drivers/gpio/gpiolib-of.c         |   80 ++++++++++++++++++-------------------
 drivers/gpio/gpiolib.c            |    2 +-
 include/asm-generic/gpio.h        |    2 +-
 include/linux/of_gpio.h           |    1 -
 5 files changed, 41 insertions(+), 47 deletions(-)

diff --git a/arch/arm/mach-imx/mach-mx35_3ds.c b/arch/arm/mach-imx/mach-mx35_3ds.c
index 6ae51c6..6a7cf91 100644
--- a/arch/arm/mach-imx/mach-mx35_3ds.c
+++ b/arch/arm/mach-imx/mach-mx35_3ds.c
@@ -96,8 +96,7 @@ static struct i2c_board_info __initdata i2c_devices_3ds[] = {
 
 static int lcd_power_gpio = -ENXIO;
 
-static int mc9s08dz60_gpiochip_match(struct gpio_chip *chip,
-						     const void *data)
+static int mc9s08dz60_gpiochip_match(struct gpio_chip *chip, void *data)
 {
 	return !strcmp(chip->label, data);
 }
diff --git a/drivers/gpio/gpiolib-of.c b/drivers/gpio/gpiolib-of.c
index bf984b6..d18068a 100644
--- a/drivers/gpio/gpiolib-of.c
+++ b/drivers/gpio/gpiolib-of.c
@@ -15,11 +15,39 @@
 #include <linux/errno.h>
 #include <linux/module.h>
 #include <linux/io.h>
+#include <linux/gpio.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/of_gpio.h>
 #include <linux/slab.h>
 
+/* Private data structure for of_gpiochip_is_match */
+struct gg_data {
+	enum of_gpio_flags *flags;
+	struct of_phandle_args gpiospec;
+
+	int out_gpio;
+};
+
+/* Private function for resolving node pointer to gpio_chip */
+static int of_gpiochip_find_and_xlate(struct gpio_chip *gc, void *data)
+{
+	struct gg_data *gg_data = data;
+	int ret;
+
+	if ((gc->of_node != gg_data->gpiospec.np) ||
+	    (gc->of_gpio_n_cells != gg_data->gpiospec.args_count) ||
+	    (!gc->of_xlate))
+		return false;
+
+	ret = gc->of_xlate(gc, &gg_data->gpiospec, gg_data->flags);
+	if (ret < 0)
+		return false;
+
+	gg_data->out_gpio = ret + gc->base;
+	return true;
+}
+
 /**
  * of_get_named_gpio_flags() - Get a GPIO number and flags to use with GPIO API
  * @np:		device node to get GPIO from
@@ -34,46 +62,25 @@
 int of_get_named_gpio_flags(struct device_node *np, const char *propname,
                            int index, enum of_gpio_flags *flags)
 {
+	struct gg_data gg_data = { .flags = flags, .out_gpio = -ENODEV };
 	int ret;
-	struct gpio_chip *gc;
-	struct of_phandle_args gpiospec;
+
+	/* .of_xlate might decide to not fill in the flags, so clear it. */
+	if (flags)
+		*flags = 0;
 
 	ret = of_parse_phandle_with_args(np, propname, "#gpio-cells", index,
-					 &gpiospec);
+					 &gg_data.gpiospec);
 	if (ret) {
 		pr_debug("%s: can't parse gpios property\n", __func__);
-		goto err0;
-	}
-
-	gc = of_node_to_gpiochip(gpiospec.np);
-	if (!gc) {
-		pr_debug("%s: gpio controller %s isn't registered\n",
-			 np->full_name, gpiospec.np->full_name);
-		ret = -ENODEV;
-		goto err1;
-	}
-
-	if (gpiospec.args_count != gc->of_gpio_n_cells) {
-		pr_debug("%s: wrong #gpio-cells for %s\n",
-			 np->full_name, gpiospec.np->full_name);
-		ret = -EINVAL;
-		goto err1;
+		return -EINVAL;
 	}
 
-	/* .xlate might decide to not fill in the flags, so clear it. */
-	if (flags)
-		*flags = 0;
-
-	ret = gc->of_xlate(gc, &gpiospec, flags);
-	if (ret < 0)
-		goto err1;
+	gpiochip_find(&gg_data, of_gpiochip_find_and_xlate);
 
-	ret += gc->base;
-err1:
-	of_node_put(gpiospec.np);
-err0:
+	of_node_put(gg_data.gpiospec.np);
 	pr_debug("%s exited with status %d\n", __func__, ret);
-	return ret;
+	return gg_data.out_gpio;
 }
 EXPORT_SYMBOL(of_get_named_gpio_flags);
 
@@ -227,14 +234,3 @@ void of_gpiochip_remove(struct gpio_chip *chip)
 	if (chip->of_node)
 		of_node_put(chip->of_node);
 }
-
-/* Private function for resolving node pointer to gpio_chip */
-static int of_gpiochip_is_match(struct gpio_chip *chip, const void *data)
-{
-	return chip->of_node == data;
-}
-
-struct gpio_chip *of_node_to_gpiochip(struct device_node *np)
-{
-	return gpiochip_find(np, of_gpiochip_is_match);
-}
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index 566d012..38353c0 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -1156,7 +1156,7 @@ EXPORT_SYMBOL_GPL(gpiochip_remove);
  */
 struct gpio_chip *gpiochip_find(const void *data,
 				int (*match)(struct gpio_chip *chip,
-					     const void *data))
+					     void *data))
 {
 	struct gpio_chip *chip = NULL;
 	unsigned long flags;
diff --git a/include/asm-generic/gpio.h b/include/asm-generic/gpio.h
index 5f52690..1cb3dd1 100644
--- a/include/asm-generic/gpio.h
+++ b/include/asm-generic/gpio.h
@@ -144,7 +144,7 @@ extern int gpiochip_add(struct gpio_chip *chip);
 extern int __must_check gpiochip_remove(struct gpio_chip *chip);
 extern struct gpio_chip *gpiochip_find(const void *data,
 					int (*match)(struct gpio_chip *chip,
-						     const void *data));
+						     void *data));
 
 
 /* Always use the library code for GPIO management calls,
diff --git a/include/linux/of_gpio.h b/include/linux/of_gpio.h
index 81733d1..c454f57 100644
--- a/include/linux/of_gpio.h
+++ b/include/linux/of_gpio.h
@@ -58,7 +58,6 @@ extern int of_mm_gpiochip_add(struct device_node *np,
 
 extern void of_gpiochip_add(struct gpio_chip *gc);
 extern void of_gpiochip_remove(struct gpio_chip *gc);
-extern struct gpio_chip *of_node_to_gpiochip(struct device_node *np);
 extern int of_gpio_simple_xlate(struct gpio_chip *gc,
 				const struct of_phandle_args *gpiospec,
 				u32 *flags);
-- 
1.7.9.5

[PATCH 2/2] gpio: Device tree support for LPC32xx

[Roland Stigge]

This patch adds device tree support for gpio-lpc32xx.c.

To register the various GPIO banks as (struct) gpio_chips via the same DT
gpio-controller, we utilize the adjusted of_xlate API to manipulate the
actually used struct gpio_chip.

Signed-off-by: Roland Stigge <stigge@antcom.de>
Reviewed-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

---

Thanks to Jean-Christophe PLAGNIOL-VILLARD, Grant Likely, Arnd Bergmann, Jon
Smirl, Mark Brown for reviewing!

You can also pull from:
  git://git.antcom.de/linux-2.6.git dt/gpio
  http://git.antcom.de/linux-2.6.git dt/gpio
  http://git.antcom.de/?p=linux-2.6.git;a=shortlog;h=refs/heads/dt/gpio

 Documentation/devicetree/bindings/gpio/gpio_lpc32xx.txt |   43 +++++++++++++
 arch/arm/mach-lpc32xx/include/mach/gpio.h               |    9 ++
 drivers/gpio/gpio-lpc32xx.c                             |   52 +++++++++++++++-
 3 files changed, 102 insertions(+), 2 deletions(-)

--- /dev/null
+++ linux-2.6/Documentation/devicetree/bindings/gpio/gpio_lpc32xx.txt
@@ -0,0 +1,43 @@
+NXP LPC32xx SoC GPIO controller
+
+Required properties:
+- compatible: must be "nxp,lpc3220-gpio"
+- reg: Physical base address and length of the controller's registers.
+- gpio-controller: Marks the device node as a GPIO controller.
+- #gpio-cells: Should be 3:
+   1) bank:
+      0: GPIO P0
+      1: GPIO P1
+      2: GPIO P2
+      3: GPIO P3
+      4: GPI P3
+      5: GPO P3
+   2) pin number
+   3) optional parameters:
+      - bit 0 specifies polarity (0 for normal, 1 for inverted)
+- reg: Index of the GPIO group
+
+Example:
+
+	gpio: gpio@40028000 {
+		compatible = "nxp,lpc3220-gpio";
+		reg = <0x40028000 0x1000>;
+		gpio-controller;
+		#gpio-cells = <3>; /* bank, pin, flags */
+	};
+
+	leds {
+		compatible = "gpio-leds";
+
+		led0 {
+			gpios = <&gpio 5 1 1>; /* GPO_P3 1, active low */
+			linux,default-trigger = "heartbeat";
+			default-state = "off";
+		};
+
+		led1 {
+			gpios = <&gpio 5 14 1>; /* GPO_P3 14, active low */
+			linux,default-trigger = "timer";
+			default-state = "off";
+		};
+	};
--- linux-2.6.orig/arch/arm/mach-lpc32xx/include/mach/gpio.h
+++ linux-2.6/arch/arm/mach-lpc32xx/include/mach/gpio.h
@@ -1 +1,8 @@
-/* empty */
+#ifndef __MACH_GPIO_H
+#define __MACH_GPIO_H
+
+#include "gpio-lpc32xx.h"
+
+#define ARCH_NR_GPIOS (LPC32XX_GPO_P3_GRP + LPC32XX_GPO_P3_MAX)
+
+#endif /* __MACH_GPIO_H */
--- linux-2.6.orig/drivers/gpio/gpio-lpc32xx.c
+++ linux-2.6/drivers/gpio/gpio-lpc32xx.c
@@ -21,6 +21,9 @@
 #include <linux/io.h>
 #include <linux/errno.h>
 #include <linux/gpio.h>
+#include <linux/of_gpio.h>
+#include <linux/platform_device.h>
+#include <linux/module.h>
 
 #include <mach/hardware.h>
 #include <mach/platform.h>
@@ -454,10 +457,57 @@ static struct lpc32xx_gpio_chip lpc32xx_
 	},
 };
 
+/* Empty now, can be removed later when mach-lpc32xx is finally switched over
+ * to DT support
+ */
 void __init lpc32xx_gpio_init(void)
 {
+}
+
+static int lpc32xx_of_xlate(struct gpio_chip *gc,
+			    const struct of_phandle_args *gpiospec, u32 *flags)
+{
+	/* Is this the correct bank? */
+	u32 bank = gpiospec->args[0];
+	if ((bank > ARRAY_SIZE(lpc32xx_gpiochip) ||
+	    (gc != &lpc32xx_gpiochip[bank].chip)))
+		return -EINVAL;
+
+	if (flags)
+		*flags = gpiospec->args[2];
+	return gpiospec->args[1];
+}
+
+static int __devinit lpc32xx_gpio_probe(struct platform_device *pdev)
+{
 	int i;
 
-	for (i = 0; i < ARRAY_SIZE(lpc32xx_gpiochip); i++)
+	for (i = 0; i < ARRAY_SIZE(lpc32xx_gpiochip); i++) {
+		if (pdev->dev.of_node) {
+			lpc32xx_gpiochip[i].chip.of_xlate = lpc32xx_of_xlate;
+			lpc32xx_gpiochip[i].chip.of_gpio_n_cells = 3;
+			lpc32xx_gpiochip[i].chip.of_node = pdev->dev.of_node;
+		}
 		gpiochip_add(&lpc32xx_gpiochip[i].chip);
+	}
+
+	return 0;
 }
+
+#ifdef CONFIG_OF
+static struct of_device_id lpc32xx_gpio_of_match[] __devinitdata = {
+	{ .compatible = "nxp,lpc3220-gpio", },
+	{ },
+};
+#endif
+
+static struct platform_driver lpc32xx_gpio_driver = {
+	.driver		= {
+		.name	= "lpc32xx-gpio",
+		.owner	= THIS_MODULE,
+		.of_match_table = of_match_ptr(lpc32xx_gpio_of_match),
+	},
+	.probe		= lpc32xx_gpio_probe,
+};
+
+module_platform_driver(lpc32xx_gpio_driver);

Re: [PATCH 1/2] gpio: Adjust of_xlate API to support multiple GPIO chips

[Arnd Bergmann]

On Friday 18 May 2012, Roland Stigge wrote:
> From: Grant Likely <grant.likely@secretlab.ca>
> 
> This patch changes the of_xlate API to make it possible for multiple
> gpio_chips to refer to the same device tree node.  This is useful for
> banked GPIO controllers that use multiple gpio_chips for a single
> device.  With this change the core code will try calling of_xlate on
> each gpio_chip that references the device_node and will return the
> gpio number for the first one to return 'true'.
> 
> Cc: Roland Stigge <stigge@antcom.de>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>
> Tested-by: Roland Stigge <stigge@antcom.de>
> 

Acked-by: Arnd Bergmann <arnd@arndb.de>

Re: [PATCH 2/2] gpio: Device tree support for LPC32xx

[Grant Likely]

On Fri, 18 May 2012 10:19:52 +0200, Roland Stigge <stigge@antcom.de> wrote:
> This patch adds device tree support for gpio-lpc32xx.c.
> 
> To register the various GPIO banks as (struct) gpio_chips via the same DT
> gpio-controller, we utilize the adjusted of_xlate API to manipulate the
> actually used struct gpio_chip.
> 
> Signed-off-by: Roland Stigge <stigge@antcom.de>
> Reviewed-by: Arnd Bergmann <arnd@arndb.de>
> Signed-off-by: Grant Likely <grant.likely@secretlab.ca>

Applied, thanks.

g.

> 
> ---
> 
> Thanks to Jean-Christophe PLAGNIOL-VILLARD, Grant Likely, Arnd Bergmann, Jon
> Smirl, Mark Brown for reviewing!
> 
> You can also pull from:
>   git://git.antcom.de/linux-2.6.git dt/gpio
>   http://git.antcom.de/linux-2.6.git dt/gpio
>   http://git.antcom.de/?p=linux-2.6.git;a=shortlog;h=refs/heads/dt/gpio
> 
>  Documentation/devicetree/bindings/gpio/gpio_lpc32xx.txt |   43 +++++++++++++
>  arch/arm/mach-lpc32xx/include/mach/gpio.h               |    9 ++
>  drivers/gpio/gpio-lpc32xx.c                             |   52 +++++++++++++++-
>  3 files changed, 102 insertions(+), 2 deletions(-)
> 
> --- /dev/null
> +++ linux-2.6/Documentation/devicetree/bindings/gpio/gpio_lpc32xx.txt
> @@ -0,0 +1,43 @@
> +NXP LPC32xx SoC GPIO controller
> +
> +Required properties:
> +- compatible: must be "nxp,lpc3220-gpio"
> +- reg: Physical base address and length of the controller's registers.
> +- gpio-controller: Marks the device node as a GPIO controller.
> +- #gpio-cells: Should be 3:
> +   1) bank:
> +      0: GPIO P0
> +      1: GPIO P1
> +      2: GPIO P2
> +      3: GPIO P3
> +      4: GPI P3
> +      5: GPO P3
> +   2) pin number
> +   3) optional parameters:
> +      - bit 0 specifies polarity (0 for normal, 1 for inverted)
> +- reg: Index of the GPIO group
> +
> +Example:
> +
> +	gpio: gpio@40028000 {
> +		compatible = "nxp,lpc3220-gpio";
> +		reg = <0x40028000 0x1000>;
> +		gpio-controller;
> +		#gpio-cells = <3>; /* bank, pin, flags */
> +	};
> +
> +	leds {
> +		compatible = "gpio-leds";
> +
> +		led0 {
> +			gpios = <&gpio 5 1 1>; /* GPO_P3 1, active low */
> +			linux,default-trigger = "heartbeat";
> +			default-state = "off";
> +		};
> +
> +		led1 {
> +			gpios = <&gpio 5 14 1>; /* GPO_P3 14, active low */
> +			linux,default-trigger = "timer";
> +			default-state = "off";
> +		};
> +	};
> --- linux-2.6.orig/arch/arm/mach-lpc32xx/include/mach/gpio.h
> +++ linux-2.6/arch/arm/mach-lpc32xx/include/mach/gpio.h
> @@ -1 +1,8 @@
> -/* empty */
> +#ifndef __MACH_GPIO_H
> +#define __MACH_GPIO_H
> +
> +#include "gpio-lpc32xx.h"
> +
> +#define ARCH_NR_GPIOS (LPC32XX_GPO_P3_GRP + LPC32XX_GPO_P3_MAX)
> +
> +#endif /* __MACH_GPIO_H */
> --- linux-2.6.orig/drivers/gpio/gpio-lpc32xx.c
> +++ linux-2.6/drivers/gpio/gpio-lpc32xx.c
> @@ -21,6 +21,9 @@
>  #include <linux/io.h>
>  #include <linux/errno.h>
>  #include <linux/gpio.h>
> +#include <linux/of_gpio.h>
> +#include <linux/platform_device.h>
> +#include <linux/module.h>
>  
>  #include <mach/hardware.h>
>  #include <mach/platform.h>
> @@ -454,10 +457,57 @@ static struct lpc32xx_gpio_chip lpc32xx_
>  	},
>  };
>  
> +/* Empty now, can be removed later when mach-lpc32xx is finally switched over
> + * to DT support
> + */
>  void __init lpc32xx_gpio_init(void)
>  {
> +}
> +
> +static int lpc32xx_of_xlate(struct gpio_chip *gc,
> +			    const struct of_phandle_args *gpiospec, u32 *flags)
> +{
> +	/* Is this the correct bank? */
> +	u32 bank = gpiospec->args[0];
> +	if ((bank > ARRAY_SIZE(lpc32xx_gpiochip) ||
> +	    (gc != &lpc32xx_gpiochip[bank].chip)))
> +		return -EINVAL;
> +
> +	if (flags)
> +		*flags = gpiospec->args[2];
> +	return gpiospec->args[1];
> +}
> +
> +static int __devinit lpc32xx_gpio_probe(struct platform_device *pdev)
> +{
>  	int i;
>  
> -	for (i = 0; i < ARRAY_SIZE(lpc32xx_gpiochip); i++)
> +	for (i = 0; i < ARRAY_SIZE(lpc32xx_gpiochip); i++) {
> +		if (pdev->dev.of_node) {
> +			lpc32xx_gpiochip[i].chip.of_xlate = lpc32xx_of_xlate;
> +			lpc32xx_gpiochip[i].chip.of_gpio_n_cells = 3;
> +			lpc32xx_gpiochip[i].chip.of_node = pdev->dev.of_node;
> +		}
>  		gpiochip_add(&lpc32xx_gpiochip[i].chip);
> +	}
> +
> +	return 0;
>  }
> +
> +#ifdef CONFIG_OF
> +static struct of_device_id lpc32xx_gpio_of_match[] __devinitdata = {
> +	{ .compatible = "nxp,lpc3220-gpio", },
> +	{ },
> +};
> +#endif
> +
> +static struct platform_driver lpc32xx_gpio_driver = {
> +	.driver		= {
> +		.name	= "lpc32xx-gpio",
> +		.owner	= THIS_MODULE,
> +		.of_match_table = of_match_ptr(lpc32xx_gpio_of_match),
> +	},
> +	.probe		= lpc32xx_gpio_probe,
> +};
> +
> +module_platform_driver(lpc32xx_gpio_driver);

-- 
Grant Likely, B.Sc, P.Eng.
Secret Lab Technologies, Ltd.