Update gpiommc to use configfs

git-svn-id: svn://svn.openwrt.org/openwrt/trunk@11887 3c298f89-4303-0410-b956-a3cf2f4a3e73

6 files changed, 638 insertions, 236 deletions

diff --git a/package/mmc_over_gpio/Makefile b/package/mmc_over_gpio/Makefile
index 20b7b6ac4..954ccfa9c 100644
--- a/package/mmc_over_gpio/Makefile
+++ b/package/mmc_over_gpio/Makefile
@@ -16,7 +16,7 @@ include $(INCLUDE_DIR)/package.mk
 define KernelPackage/mmc-over-gpio
   SUBMENU:=Other modules
   DEPENDS:=@GPIO_SUPPORT +kmod-mmc-spi +kmod-spi-gpio
-  KCONFIG:=CONFIG_GPIOMMC
+  KCONFIG:=CONFIG_GPIOMMC CONFIG_CONFIGFS_FS=y
   TITLE:=MMC/SD card over GPIO support
   FILES:=$(LINUX_DIR)/drivers/mmc/host/gpiommc.$(LINUX_KMOD_SUFFIX)
   AUTOLOAD:=$(call AutoLoad,93,spi_gpio gpiommc)
diff --git a/package/mmc_over_gpio/files/mmc_over_gpio.init b/package/mmc_over_gpio/files/mmc_over_gpio.init
index 57c5695d1..e276dfd1c 100644
--- a/package/mmc_over_gpio/files/mmc_over_gpio.init
+++ b/package/mmc_over_gpio/files/mmc_over_gpio.init
@@ -2,20 +2,59 @@
 # Copyright (C) 2008 OpenWrt.org
 START=90
 
-SYSFS="/sys"
-SYSFS_DRIVERDIR="$SYSFS/bus/platform/drivers/gpiommc"
+CONFIGFS_DIR="/config/gpiommc"
 
 # add_device(name, DI_pin, DO_pin, CLK_pin, CS_pin, mode)
 add_device() {
-	echo -n "$1" "$2" "$3" "$4" "$5" "$6" > $SYSFS_DRIVERDIR/add
+	local dir="$CONFIGFS_DIR/$1"
+
+	mkdir $dir
+	[ $? -eq 0 ] || return 1
+	echo $2 > $dir/gpio_data_in
+	[ $? -eq 0 ] || return 1
+	echo $3 > $dir/gpio_data_out
+	[ $? -eq 0 ] || return 1
+	echo $4 > $dir/gpio_clock
+	[ $? -eq 0 ] || return 1
+	echo $5 > $dir/gpio_chipselect
+	[ $? -eq 0 ] || return 1
+	echo $6 > $dir/spi_mode
+	[ $? -eq 0 ] || return 1
+	# XXX We have more config options available. Use defaults for now.
+
+	echo 1 > $dir/register
+	[ $? -eq 0 ] || return 1
+
+	return 0
 }
 
 # remove_device(name)
 remove_device() {
-	echo -n "$1" > $SYSFS_DRIVERDIR/remove
+	local dir="$CONFIGFS_DIR/$1"
+
+	rmdir $dir
+}
+
+mount_configfs() {
+	# FIXME: This should probably be done somewhere else.
+	mount | grep configfs
+	if [ $? -eq 0 ]; then
+		# already mounted
+		return 0
+	fi
+	mkdir -p /config
+	[ $? -eq 0 ] || return 1
+	mount configfs -t configfs /config
+	[ $? -eq 0 ] || return 1
+
+	return 0
 }
 
 start() {
+	# Make sure configfs is mounted
+	mount_configfs
+	[ $? -eq 0 ] || return 1
+
 	#FIXME we should use a config file, but I dunno how that parser works.
 	add_device "default" 5 4 3 7 0
 }
diff --git a/target/linux/brcm47xx/patches-2.6.25/710-add-gpio-is-valid.patch b/target/linux/brcm47xx/patches-2.6.25/710-add-gpio-is-valid.patch
new file mode 100644
index 000000000..bca3b4eaa
--- /dev/null
+++ b/target/linux/brcm47xx/patches-2.6.25/710-add-gpio-is-valid.patch
@@ -0,0 +1,44 @@
+Add gpio_is_valid() for bcm47xx
+Index: linux-2.6.25.10/arch/mips/bcm47xx/gpio.c
+===================================================================
+--- linux-2.6.25.10.orig/arch/mips/bcm47xx/gpio.c	2008-07-20 20:48:44.000000000 +0200
++++ linux-2.6.25.10/arch/mips/bcm47xx/gpio.c	2008-07-20 20:57:55.000000000 +0200
+@@ -77,3 +77,15 @@ int bcm47xx_gpio_direction_output(unsign
+ }
+ EXPORT_SYMBOL_GPL(bcm47xx_gpio_direction_output);
+ 
++int bcm47xx_gpio_is_valid(int gpio)
++{
++	if (ssb_bcm47xx.chipco.dev) {
++		if (gpio >= 0 && gpio < BCM47XX_CHIPCO_GPIO_LINES)
++			return 1;
++	} else if (ssb_bcm47xx.extif.dev) {
++		if (gpio >= 0 && gpio < BCM47XX_EXTIF_GPIO_LINES)
++			return 1;
++	}
++	return 0;
++}
++EXPORT_SYMBOL_GPL(bcm47xx_gpio_is_valid);
+Index: linux-2.6.25.10/include/asm-mips/mach-bcm47xx/gpio.h
+===================================================================
+--- linux-2.6.25.10.orig/include/asm-mips/mach-bcm47xx/gpio.h	2008-07-20 20:48:44.000000000 +0200
++++ linux-2.6.25.10/include/asm-mips/mach-bcm47xx/gpio.h	2008-07-20 20:49:20.000000000 +0200
+@@ -17,6 +17,7 @@ extern int bcm47xx_gpio_get_value(unsign
+ extern void bcm47xx_gpio_set_value(unsigned gpio, int value);
+ extern int bcm47xx_gpio_direction_input(unsigned gpio);
+ extern int bcm47xx_gpio_direction_output(unsigned gpio, int value);
++extern int bcm47xx_gpio_is_valid(int gpio);
+ 
+ static inline int gpio_request(unsigned gpio, const char *label)
+ {
+@@ -52,6 +53,10 @@ static inline int gpio_direction_output(
+ 	return bcm47xx_gpio_direction_output(gpio, value);
+ }
+ 
++static inline int gpio_is_valid(int gpio)
++{
++	return bcm47xx_gpio_is_valid(gpio);
++}
+ 
+ /* cansleep wrappers */
+ #include <asm-generic/gpio.h>
diff --git a/target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch b/target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch
new file mode 100644
index 000000000..966270b78
--- /dev/null
+++ b/target/linux/generic-2.6/patches-2.6.25/920-backport-gpio-is-valid.patch
@@ -0,0 +1,18 @@
+Backport gpio_is_valid() for gpiolib from linux-2.6.26
+Index: linux-2.6.25.10/include/asm-generic/gpio.h
+===================================================================
+--- linux-2.6.25.10.orig/include/asm-generic/gpio.h	2008-07-03 05:46:47.000000000 +0200
++++ linux-2.6.25.10/include/asm-generic/gpio.h	2008-07-20 20:32:12.000000000 +0200
+@@ -16,6 +16,12 @@
+ #define ARCH_NR_GPIOS		256
+ #endif
+ 
++static inline int gpio_is_valid(int number)
++{
++	/* only some non-negative numbers are valid */
++	return ((unsigned)number) < ARCH_NR_GPIOS;
++}
++
+ struct seq_file;
+ 
+ /**
diff --git a/target/linux/generic-2.6/patches-2.6.25/921-gpio_spi_driver.patch b/target/linux/generic-2.6/patches-2.6.25/921-gpio_spi_driver.patch
index 264386f33..1249a6318 100644
--- a/target/linux/generic-2.6/patches-2.6.25/921-gpio_spi_driver.patch
+++ b/target/linux/generic-2.6/patches-2.6.25/921-gpio_spi_driver.patch
@@ -1,8 +1,8 @@
 Index: linux-2.6.25.10/include/linux/spi/spi_gpio.h
 ===================================================================
 --- /dev/null	1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.25.10/include/linux/spi/spi_gpio.h	2008-07-18 18:19:56.000000000 +0200
-@@ -0,0 +1,67 @@
++++ linux-2.6.25.10/include/linux/spi/spi_gpio.h	2008-07-20 20:10:21.000000000 +0200
+@@ -0,0 +1,73 @@
 +/*
 + * spi_gpio interface to platform code
 + *
@@ -20,7 +20,9 @@ Index: linux-2.6.25.10/include/linux/spi/spi_gpio.h
 +#include <linux/spi/spi.h>
 +
 +
-+/** struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
++/**
++ * struct spi_gpio_platform_data - Data definitions for a SPI-GPIO device.
++ *
 + * This structure holds information about a GPIO-based SPI device.
 + *
 + * @pin_clk: The GPIO pin number of the CLOCK pin.
@@ -56,13 +58,17 @@ Index: linux-2.6.25.10/include/linux/spi/spi_gpio.h
 +	void *boardinfo_setup_data;
 +};
 +
-+/** SPI_GPIO_PLATDEV_NAME - The platform device name string.
++/**
++ * SPI_GPIO_PLATDEV_NAME - The platform device name string.
++ *
 + * The name string that has to be used for platform_device_alloc
 + * when allocating a spi-gpio device.
 + */
 +#define SPI_GPIO_PLATDEV_NAME	"spi-gpio"
 +
-+/** spi_gpio_next_id - Get another platform device ID number.
++/**
++ * spi_gpio_next_id - Get another platform device ID number.
++ *
 + * This returns the next platform device ID number that has to be used
 + * for platform_device_alloc. The ID is opaque and should not be used for
 + * anything else.
@@ -73,7 +79,7 @@ Index: linux-2.6.25.10/include/linux/spi/spi_gpio.h
 Index: linux-2.6.25.10/drivers/spi/spi_gpio.c
 ===================================================================
 --- /dev/null	1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.25.10/drivers/spi/spi_gpio.c	2008-07-18 18:19:56.000000000 +0200
++++ linux-2.6.25.10/drivers/spi/spi_gpio.c	2008-07-20 20:10:21.000000000 +0200
 @@ -0,0 +1,251 @@
 +/*
 + * Bitbanging SPI bus driver using GPIO API
@@ -328,8 +334,8 @@ Index: linux-2.6.25.10/drivers/spi/spi_gpio.c
 +MODULE_LICENSE("GPL v2");
 Index: linux-2.6.25.10/drivers/spi/Kconfig
 ===================================================================
---- linux-2.6.25.10.orig/drivers/spi/Kconfig	2008-07-18 18:19:43.000000000 +0200
-+++ linux-2.6.25.10/drivers/spi/Kconfig	2008-07-18 18:19:56.000000000 +0200
+--- linux-2.6.25.10.orig/drivers/spi/Kconfig	2008-07-20 20:09:48.000000000 +0200
++++ linux-2.6.25.10/drivers/spi/Kconfig	2008-07-20 20:11:48.000000000 +0200
 @@ -100,6 +100,19 @@ config SPI_BUTTERFLY
  	  inexpensive battery powered microcontroller evaluation board.
  	  This same cable can be used to flash new firmware.
@@ -341,7 +347,7 @@ Index: linux-2.6.25.10/drivers/spi/Kconfig
 +	help
 +	  This is a platform driver that can be used for bitbanging
 +	  an SPI bus over GPIO pins.
-+	  Select this, if you have any SPI device that is connected via
++	  Select this if you have any SPI device that is connected via
 +	  GPIO pins.
 +	  The module will be called spi_gpio.
 +
@@ -352,8 +358,8 @@ Index: linux-2.6.25.10/drivers/spi/Kconfig
  	depends on SPI_MASTER && ARCH_IMX && EXPERIMENTAL
 Index: linux-2.6.25.10/drivers/spi/Makefile
 ===================================================================
---- linux-2.6.25.10.orig/drivers/spi/Makefile	2008-07-18 18:19:43.000000000 +0200
-+++ linux-2.6.25.10/drivers/spi/Makefile	2008-07-18 18:19:56.000000000 +0200
+--- linux-2.6.25.10.orig/drivers/spi/Makefile	2008-07-20 20:09:48.000000000 +0200
++++ linux-2.6.25.10/drivers/spi/Makefile	2008-07-20 20:10:21.000000000 +0200
 @@ -16,6 +16,7 @@ obj-$(CONFIG_SPI_BFIN)			+= spi_bfin5xx.
  obj-$(CONFIG_SPI_BITBANG)		+= spi_bitbang.o
  obj-$(CONFIG_SPI_AU1550)		+= au1550_spi.o
@@ -364,8 +370,8 @@ Index: linux-2.6.25.10/drivers/spi/Makefile
  obj-$(CONFIG_SPI_PXA2XX)		+= pxa2xx_spi.o
 Index: linux-2.6.25.10/MAINTAINERS
 ===================================================================
---- linux-2.6.25.10.orig/MAINTAINERS	2008-07-03 05:46:47.000000000 +0200
-+++ linux-2.6.25.10/MAINTAINERS	2008-07-18 18:20:28.000000000 +0200
+--- linux-2.6.25.10.orig/MAINTAINERS	2008-07-20 20:09:48.000000000 +0200
++++ linux-2.6.25.10/MAINTAINERS	2008-07-20 20:10:59.000000000 +0200
 @@ -3685,6 +3685,11 @@ M:	dbrownell@users.sourceforge.net
  L:	spi-devel-general@lists.sourceforge.net
  S:	Maintained
diff --git a/target/linux/generic-2.6/patches-2.6.25/922-gpiommc.patch b/target/linux/generic-2.6/patches-2.6.25/922-gpiommc.patch
index 8253202c0..8bb4c99bc 100644
--- a/target/linux/generic-2.6/patches-2.6.25/922-gpiommc.patch
+++ b/target/linux/generic-2.6/patches-2.6.25/922-gpiommc.patch
@@ -1,12 +1,12 @@
 Index: linux-2.6.25.10/drivers/mmc/host/gpiommc.c
 ===================================================================
 --- /dev/null	1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.25.10/drivers/mmc/host/gpiommc.c	2008-07-18 22:31:00.000000000 +0200
-@@ -0,0 +1,328 @@
++++ linux-2.6.25.10/drivers/mmc/host/gpiommc.c	2008-07-20 20:49:16.000000000 +0200
+@@ -0,0 +1,608 @@
 +/*
 + * Driver an MMC/SD card on a bitbanging GPIO SPI bus.
 + * This module hooks up the mmc_spi and spi_gpio modules and also
-+ * provides a sysfs interface.
++ * provides a configfs interface.
 + *
 + * Copyright 2008 Michael Buesch <mb@bu3sch.de>
 + *
@@ -18,10 +18,13 @@ Index: linux-2.6.25.10/drivers/mmc/host/gpiommc.c
 +#include <linux/list.h>
 +#include <linux/mutex.h>
 +#include <linux/spi/spi_gpio.h>
++#include <linux/configfs.h>
++#include <linux/gpio.h>
++#include <asm/atomic.h>
 +
 +
 +#define PFX				"gpio-mmc: "
-+#define GPIOMMC_MAX_NAMELEN_STR		__stringify(GPIOMMC_MAX_NAMELEN)
++
 +
 +struct gpiommc_device {
 +	struct platform_device *pdev;
@@ -63,6 +66,14 @@ Index: linux-2.6.25.10/drivers/mmc/host/gpiommc.c
 +	if (!mmc_pdata)
 +		goto error;
 +
++#ifdef CONFIG_MMC_SPI_MODULE
++	err = request_module("mmc_spi");
++	if (err) {
++		printk(KERN_WARNING PFX
++		       "Failed to request mmc_spi module.\n");
++	}
++#endif /* CONFIG_MMC_SPI_MODULE */
++
 +	/* Allocate the GPIO-MMC device */
 +	err = -ENOMEM;
 +	d = kzalloc(sizeof(*d), GFP_KERNEL);
@@ -121,152 +132,438 @@ Index: linux-2.6.25.10/drivers/mmc/host/gpiommc.c
 +	struct gpiommc_platform_data *pdata = d->pdev->dev.platform_data;
 +
 +	platform_device_unregister(d->spi_pdev);
-+	printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n", pdata->name);
++	printk(KERN_INFO PFX "GPIO based MMC-Card \"%s\" removed\n",
++	       pdata->name);
 +	platform_device_put(d->spi_pdev);
 +
 +	return 0;
 +}
 +
-+/* Wrapper for the platform data with context data for the sysfs interface. */
-+struct gpiommc_sysfs_platform_data {
-+	struct gpiommc_platform_data p; /* Keep as first element */
++#ifdef CONFIG_GPIOMMC_CONFIGFS
 +
-+	/* The platform device that we allocated. */
++/* A device that was created through configfs */
++struct gpiommc_configfs_device {
++	struct config_item item;
++	/* The platform device, after registration. */
 +	struct platform_device *pdev;
-+	/* gpiommc_sysfs_list */
-+	struct list_head list;
++	/* The configuration */
++	struct gpiommc_platform_data pdata;
 +};
 +
-+static LIST_HEAD(gpiommc_sysfs_list);
-+static DEFINE_MUTEX(gpiommc_sysfs_mutex);
++#define GPIO_INVALID	-1
++
++static inline bool gpiommc_is_registered(struct gpiommc_configfs_device *dev)
++{
++	return (dev->pdev != NULL);
++}
 +
-+static struct gpiommc_sysfs_platform_data *gpiommc_sysfs_find_dev(const char *name)
++static inline struct gpiommc_configfs_device *ci_to_gpiommc(struct config_item *item)
 +{
-+	struct gpiommc_sysfs_platform_data *pdata;
++	return item ? container_of(item, struct gpiommc_configfs_device, item) : NULL;
++}
 +
-+	list_for_each_entry(pdata, &gpiommc_sysfs_list, list) {
-+		if (strcmp(pdata->p.name, name) == 0)
-+			return pdata;
-+	}
++static struct configfs_attribute gpiommc_attr_DI = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "gpio_data_in",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
 +
-+	return NULL;
++static struct configfs_attribute gpiommc_attr_DO = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "gpio_data_out",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_CLK = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "gpio_clock",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_CS = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "gpio_chipselect",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_CS_activelow = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "gpio_chipselect_activelow",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_spimode = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "spi_mode",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_spidelay = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "spi_delay",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_max_bus_speed = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "max_bus_speed",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute gpiommc_attr_register = {
++	.ca_owner = THIS_MODULE,
++	.ca_name = "register",
++	.ca_mode = S_IRUGO | S_IWUSR,
++};
++
++static struct configfs_attribute *gpiommc_config_attrs[] = {
++	&gpiommc_attr_DI,
++	&gpiommc_attr_DO,
++	&gpiommc_attr_CLK,
++	&gpiommc_attr_CS,
++	&gpiommc_attr_CS_activelow,
++	&gpiommc_attr_spimode,
++	&gpiommc_attr_spidelay,
++	&gpiommc_attr_max_bus_speed,
++	&gpiommc_attr_register,
++	NULL,
++};
++
++static ssize_t gpiommc_config_attr_show(struct config_item *item,
++					struct configfs_attribute *attr,
++					char *page)
++{
++	struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
++	ssize_t count = 0;
++	unsigned int gpio;
++	int err = 0;
++
++	if (attr == &gpiommc_attr_DI) {
++		gpio = dev->pdata.pins.gpio_di;
++		if (gpio == GPIO_INVALID)
++			count = snprintf(page, PAGE_SIZE, "not configured\n");
++		else
++			count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_DO) {
++		gpio = dev->pdata.pins.gpio_do;
++		if (gpio == GPIO_INVALID)
++			count = snprintf(page, PAGE_SIZE, "not configured\n");
++		else
++			count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_CLK) {
++		gpio = dev->pdata.pins.gpio_clk;
++		if (gpio == GPIO_INVALID)
++			count = snprintf(page, PAGE_SIZE, "not configured\n");
++		else
++			count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_CS) {
++		gpio = dev->pdata.pins.gpio_cs;
++		if (gpio == GPIO_INVALID)
++			count = snprintf(page, PAGE_SIZE, "not configured\n");
++		else
++			count = snprintf(page, PAGE_SIZE, "%u\n", gpio);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_CS_activelow) {
++		count = snprintf(page, PAGE_SIZE, "%u\n",
++				 dev->pdata.pins.cs_activelow);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_spimode) {
++		count = snprintf(page, PAGE_SIZE, "%u\n",
++				 dev->pdata.mode);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_spidelay) {
++		count = snprintf(page, PAGE_SIZE, "%u\n",
++				 !dev->pdata.no_spi_delay);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_max_bus_speed) {
++		count = snprintf(page, PAGE_SIZE, "%u\n",
++				 dev->pdata.max_bus_speed);
++		goto out;
++	}
++	if (attr == &gpiommc_attr_register) {
++		count = snprintf(page, PAGE_SIZE, "%u\n",
++				 gpiommc_is_registered(dev));
++		goto out;
++	}
++	WARN_ON(1);
++	err = -ENOSYS;
++out:
++	return err ? err : count;
 +}
 +
-+static ssize_t gpiommc_add_store(struct device_driver *drv,
-+				 const char *buf, size_t count)
++static int gpiommc_do_register(struct gpiommc_configfs_device *dev,
++			       const char *name)
 +{
-+	int res, err;
-+	struct gpiommc_sysfs_platform_data pdata_local, *pdata;
-+	struct platform_device *pdev;
-+	unsigned int no_spi_delay = 0, mode = 0, csactivelow = 0;
-+
-+	mutex_lock(&gpiommc_sysfs_mutex);
-+
-+	pdata = &pdata_local;
-+	memset(pdata, 0, sizeof(*pdata));
-+
-+	err = -EINVAL;
-+	res = sscanf(buf, "%" GPIOMMC_MAX_NAMELEN_STR "s %u %u %u %u %u %u %u %u",
-+		     pdata->p.name,
-+		     &pdata->p.pins.gpio_di,
-+		     &pdata->p.pins.gpio_do,
-+		     &pdata->p.pins.gpio_clk,
-+		     &pdata->p.pins.gpio_cs,
-+		     &mode,
-+		     &pdata->p.max_bus_speed,
-+		     &no_spi_delay,
-+		     &csactivelow);
-+	pdata->p.mode = mode;
-+	pdata->p.no_spi_delay = !!no_spi_delay;
-+	pdata->p.pins.cs_activelow = !!csactivelow;
-+	if (res < 9)
-+		pdata->p.pins.cs_activelow = 1; /* Default: CS = activelow */
-+	if (res < 8)
-+		pdata->p.no_spi_delay = 0; /* Default: Delay turned on */
-+	if (res < 7)
-+		pdata->p.max_bus_speed = 5000000; /* Default: 5Mhz */
-+	if (res < 6)
-+		pdata->p.mode = 0; /* Default: SPI mode 0 */
-+	if (res < 5 || res > 9)
-+		goto out; /* First 5 args are mandatory. */
-+
-+	/* Convert mode so that the SPI subsystem does understand it. */
-+	switch (pdata->p.mode) {
-+	case 0:
-+		pdata->p.mode = SPI_MODE_0;
-+		break;
-+	case 1:
-+		pdata->p.mode = SPI_MODE_1;
-+		break;
-+	case 2:
-+		pdata->p.mode = SPI_MODE_2;
-+		break;
-+	case 3:
-+		pdata->p.mode = SPI_MODE_3;
-+		break;
-+	default:
-+		goto out; /* Invalid mode */
++	int err;
++
++	if (gpiommc_is_registered(dev))
++		return 0;
++
++	if (!gpio_is_valid(dev->pdata.pins.gpio_di) ||
++	    !gpio_is_valid(dev->pdata.pins.gpio_do) ||
++	    !gpio_is_valid(dev->pdata.pins.gpio_clk) ||
++	    !gpio_is_valid(dev->pdata.pins.gpio_cs)) {
++		printk(KERN_ERR PFX
++		       "configfs: Invalid GPIO pin number(s)\n");
++		return -EINVAL;
 +	}
 +
-+	err = -EEXIST;
-+	if (gpiommc_sysfs_find_dev(pdata->p.name))
-+		goto out;
++	strlcpy(dev->pdata.name, name,
++		sizeof(dev->pdata.name));
++
++	dev->pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME,
++					  gpiommc_next_id());
++	if (!dev->pdev)
++		return -ENOMEM;
++	err = platform_device_add_data(dev->pdev, &dev->pdata,
++				       sizeof(dev->pdata));
++	if (err) {
++		platform_device_put(dev->pdev);
++		return err;
++	}
++	err = platform_device_add(dev->pdev);
++	if (err) {
++		platform_device_put(dev->pdev);
++		return err;
++	}
 +
-+	err = -ENOMEM;
-+	pdev = platform_device_alloc(GPIOMMC_PLATDEV_NAME, gpiommc_next_id());
-+	if (!pdev)
-+		goto out;
++	return 0;
++}
 +
-+	err = platform_device_add_data(pdev, pdata, sizeof(*pdata));
-+	if (err)
-+		goto err_free_pdev;
-+	pdata = pdev->dev.platform_data;
++static void gpiommc_do_unregister(struct gpiommc_configfs_device *dev)
++{
++	if (!gpiommc_is_registered(dev))
++		return;
 +
-+	err = platform_device_add(pdev);
-+	if (err)
-+		goto err_free_pdev;
++	platform_device_unregister(dev->pdev);
++	dev->pdev = NULL;
++}
++
++static ssize_t gpiommc_config_attr_store(struct config_item *item,
++					 struct configfs_attribute *attr,
++					 const char *page, size_t count)
++{
++	struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
++	int err = -EINVAL;
++	unsigned long data;
++
++	if (attr == &gpiommc_attr_register) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (data == 1)
++			err = gpiommc_do_register(dev, item->ci_name);
++		if (data == 0) {
++			gpiommc_do_unregister(dev);
++			err = 0;
++		}
++		goto out;
++	}
 +
-+	pdata->pdev = pdev;
-+	INIT_LIST_HEAD(&pdata->list);
-+	list_add(&pdata->list, &gpiommc_sysfs_list);
++	if (gpiommc_is_registered(dev)) {
++		/* The rest of the config parameters can only be set
++		 * as long as the device is not registered, yet. */
++		err = -EBUSY;
++		goto out;
++	}
 +
-+	err = 0;
++	if (attr == &gpiommc_attr_DI) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (!gpio_is_valid(data))
++			goto out;
++		dev->pdata.pins.gpio_di = data;
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_DO) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (!gpio_is_valid(data))
++			goto out;
++		dev->pdata.pins.gpio_do = data;
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_CLK) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (!gpio_is_valid(data))
++			goto out;
++		dev->pdata.pins.gpio_clk = data;
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_CS) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (!gpio_is_valid(data))
++			goto out;
++		dev->pdata.pins.gpio_cs = data;
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_CS_activelow) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (data != 0 && data != 1)
++			goto out;
++		dev->pdata.pins.cs_activelow = data;
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_spimode) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		switch (data) {
++		case 0:
++			dev->pdata.mode = SPI_MODE_0;
++			break;
++		case 1:
++			dev->pdata.mode = SPI_MODE_1;
++			break;
++		case 2:
++			dev->pdata.mode = SPI_MODE_2;
++			break;
++		case 3:
++			dev->pdata.mode = SPI_MODE_3;
++			break;
++		default:
++			goto out;
++		}
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_spidelay) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (data != 0 && data != 1)
++			goto out;
++		dev->pdata.no_spi_delay = !data;
++		err = 0;
++		goto out;
++	}
++	if (attr == &gpiommc_attr_max_bus_speed) {
++		err = strict_strtoul(page, 10, &data);
++		if (err)
++			goto out;
++		err = -EINVAL;
++		if (data > UINT_MAX)
++			goto out;
++		dev->pdata.max_bus_speed = data;
++		err = 0;
++		goto out;
++	}
++	WARN_ON(1);
++	err = -ENOSYS;
 +out:
-+	mutex_unlock(&gpiommc_sysfs_mutex);
-+
 +	return err ? err : count;
++}
 +
-+err_free_pdev:
-+	platform_device_put(pdev);
-+	goto out;
++static void gpiommc_config_item_release(struct config_item *item)
++{
++	struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
++
++	kfree(dev);
 +}
 +
-+static ssize_t gpiommc_remove_store(struct device_driver *drv,
-+				    const char *buf, size_t count)
++static struct configfs_item_operations gpiommc_config_item_ops = {
++	.release		= gpiommc_config_item_release,
++	.show_attribute		= gpiommc_config_attr_show,
++	.store_attribute	= gpiommc_config_attr_store,
++};
++
++static struct config_item_type gpiommc_dev_ci_type = {
++	.ct_item_ops	= &gpiommc_config_item_ops,
++	.ct_attrs	= gpiommc_config_attrs,
++	.ct_owner	= THIS_MODULE,
++};
++
++static struct config_item *gpiommc_make_item(struct config_group *group,
++					     const char *name)
 +{
-+	struct gpiommc_sysfs_platform_data *pdata;
-+	int err;
++	struct gpiommc_configfs_device *dev;
 +
-+	mutex_lock(&gpiommc_sysfs_mutex);
++	if (strlen(name) > GPIOMMC_MAX_NAMELEN) {
++		printk(KERN_ERR PFX "configfs: device name too long\n");
++		return NULL;
++	}
 +
-+	err = -ENODEV;
-+	pdata = gpiommc_sysfs_find_dev(buf);
-+	if (!pdata)
-+		goto out;
++	dev = kzalloc(sizeof(*dev), GFP_KERNEL);
++	if (!dev)
++		return NULL;
 +
-+	list_del(&pdata->list);
-+	platform_device_unregister(pdata->pdev);
++	config_item_init_type_name(&dev->item, name,
++				   &gpiommc_dev_ci_type);
 +
-+out:
-+	mutex_unlock(&gpiommc_sysfs_mutex);
++	/* Assign default configuration */
++	dev->pdata.pins.gpio_di = GPIO_INVALID;
++	dev->pdata.pins.gpio_do = GPIO_INVALID;
++	dev->pdata.pins.gpio_clk = GPIO_INVALID;
++	dev->pdata.pins.gpio_cs = GPIO_INVALID;
++	dev->pdata.pins.cs_activelow = 1;
++	dev->pdata.mode = SPI_MODE_0;
++	dev->pdata.no_spi_delay = 0;
++	dev->pdata.max_bus_speed = 5000000; /* 5 MHz */
 +
-+	return err ? err : count;
++	return &(dev->item);
 +}
 +
-+static DRIVER_ATTR(add, 0200,
-+		   NULL, gpiommc_add_store);
-+static DRIVER_ATTR(remove, 0200,
-+		   NULL, gpiommc_remove_store);
++static void gpiommc_drop_item(struct config_group *group,
++			      struct config_item *item)
++{
++	struct gpiommc_configfs_device *dev = ci_to_gpiommc(item);
++
++	gpiommc_do_unregister(dev);
++	kfree(dev);
++}
++
++static struct configfs_group_operations gpiommc_ct_group_ops = {
++	.make_item	= gpiommc_make_item,
++	.drop_item	= gpiommc_drop_item,
++};
++
++static struct config_item_type gpiommc_ci_type = {
++	.ct_group_ops	= &gpiommc_ct_group_ops,
++	.ct_owner	= THIS_MODULE,
++};
++
++static struct configfs_subsystem gpiommc_subsys = {
++	.su_group = {
++		.cg_item = {
++			.ci_namebuf = GPIOMMC_PLATDEV_NAME,
++			.ci_type = &gpiommc_ci_type,
++		},
++	},
++	.su_mutex = __MUTEX_INITIALIZER(gpiommc_subsys.su_mutex),
++};
++
++#endif /* CONFIG_GPIOMMC_CONFIGFS */
 +
 +static struct platform_driver gpiommc_plat_driver = {
 +	.probe	= gpiommc_probe,
@@ -292,50 +589,33 @@ Index: linux-2.6.25.10/drivers/mmc/host/gpiommc.c
 +	err = platform_driver_register(&gpiommc_plat_driver);
 +	if (err)
 +		return err;
-+	err = driver_create_file(&gpiommc_plat_driver.driver,
-+				 &driver_attr_add);
-+	if (err)
-+		goto err_drv_unreg;
-+	err = driver_create_file(&gpiommc_plat_driver.driver,
-+				 &driver_attr_remove);
-+	if (err)
-+		goto err_remove_add;
 +
-+	return 0;
++#ifdef CONFIG_GPIOMMC_CONFIGFS
++	config_group_init(&gpiommc_subsys.su_group);
++	err = configfs_register_subsystem(&gpiommc_subsys);
++	if (err) {
++		platform_driver_unregister(&gpiommc_plat_driver);
++		return err;
++	}
++#endif /* CONFIG_GPIOMMC_CONFIGFS */
 +
-+err_remove_add:
-+	driver_remove_file(&gpiommc_plat_driver.driver,
-+			   &driver_attr_add);
-+err_drv_unreg:
-+	platform_driver_unregister(&gpiommc_plat_driver);
-+	return err;
++	return 0;
 +}
 +module_init(gpiommc_modinit);
 +
 +static void __exit gpiommc_modexit(void)
 +{
-+	struct gpiommc_sysfs_platform_data *pdata, *pdata_tmp;
-+
-+	driver_remove_file(&gpiommc_plat_driver.driver,
-+			   &driver_attr_remove);
-+	driver_remove_file(&gpiommc_plat_driver.driver,
-+			   &driver_attr_add);
-+
-+	mutex_lock(&gpiommc_sysfs_mutex);
-+	list_for_each_entry_safe(pdata, pdata_tmp, &gpiommc_sysfs_list, list) {
-+		list_del(&pdata->list);
-+		platform_device_unregister(pdata->pdev);
-+	}
-+	mutex_unlock(&gpiommc_sysfs_mutex);
-+
++#ifdef CONFIG_GPIOMMC_CONFIGFS
++	configfs_unregister_subsystem(&gpiommc_subsys);
++#endif
 +	platform_driver_unregister(&gpiommc_plat_driver);
 +}
 +module_exit(gpiommc_modexit);
 Index: linux-2.6.25.10/drivers/mmc/host/Kconfig
 ===================================================================
---- linux-2.6.25.10.orig/drivers/mmc/host/Kconfig	2008-07-18 22:30:36.000000000 +0200
-+++ linux-2.6.25.10/drivers/mmc/host/Kconfig	2008-07-18 22:31:00.000000000 +0200
-@@ -130,3 +130,23 @@ config MMC_SPI
+--- linux-2.6.25.10.orig/drivers/mmc/host/Kconfig	2008-07-20 20:32:22.000000000 +0200
++++ linux-2.6.25.10/drivers/mmc/host/Kconfig	2008-07-20 20:33:20.000000000 +0200
+@@ -130,3 +130,27 @@ config MMC_SPI
  
  	  If unsure, or if your system has no SPI master driver, say N.
  
@@ -347,8 +627,8 @@ Index: linux-2.6.25.10/drivers/mmc/host/Kconfig
 +	  MMC/SD cards can be used on a GPIO based bus by bitbanging
 +	  the SPI protocol in software.
 +
-+	  This driver provides a sysfs interface to dynamically create
-+	  and destroy GPIO-based MMC/SD card interfaces. It also provides
++	  This driver provides a configfs interface to dynamically create
++	  and destroy GPIO-based MMC/SD card devices. It also provides
 +	  a platform device interface API.
 +	  See Documentation/gpiommc.txt for details.
 +
@@ -356,23 +636,28 @@ Index: linux-2.6.25.10/drivers/mmc/host/Kconfig
 +
 +	  If unsure, say N.
 +
-+config MMC_S3C
-+	tristate "Samsung S3C SD/MMC Card Interface support"
-+	depends on ARCH_S3C2410 && MMC
++config GPIOMMC_CONFIGFS
++	bool
++	depends on GPIOMMC && CONFIGFS_FS
++	default y
++	help
++	  This option automatically enables configfs support for gpiommc
++	  if configfs is available.
 Index: linux-2.6.25.10/drivers/mmc/host/Makefile
 ===================================================================
---- linux-2.6.25.10.orig/drivers/mmc/host/Makefile	2008-07-18 22:30:36.000000000 +0200
-+++ linux-2.6.25.10/drivers/mmc/host/Makefile	2008-07-18 22:31:20.000000000 +0200
-@@ -18,3 +18,4 @@ obj-$(CONFIG_MMC_AT91)		+= at91_mci.o
+--- linux-2.6.25.10.orig/drivers/mmc/host/Makefile	2008-07-20 20:32:22.000000000 +0200
++++ linux-2.6.25.10/drivers/mmc/host/Makefile	2008-07-20 20:33:20.000000000 +0200
+@@ -17,4 +17,4 @@ obj-$(CONFIG_MMC_OMAP)		+= omap.o
+ obj-$(CONFIG_MMC_AT91)		+= at91_mci.o
  obj-$(CONFIG_MMC_TIFM_SD)	+= tifm_sd.o
  obj-$(CONFIG_MMC_SPI)		+= mmc_spi.o
- 
+-
 +obj-$(CONFIG_GPIOMMC)		+= gpiommc.o
 Index: linux-2.6.25.10/include/linux/mmc/gpiommc.h
 ===================================================================
 --- /dev/null	1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.25.10/include/linux/mmc/gpiommc.h	2008-07-18 22:31:00.000000000 +0200
-@@ -0,0 +1,62 @@
++++ linux-2.6.25.10/include/linux/mmc/gpiommc.h	2008-07-20 20:33:20.000000000 +0200
+@@ -0,0 +1,71 @@
 +/*
 + * Device driver for MMC/SD cards driven over a GPIO bus.
 + *
@@ -387,8 +672,11 @@ Index: linux-2.6.25.10/include/linux/mmc/gpiommc.h
 +
 +
 +#define GPIOMMC_MAX_NAMELEN		15
++#define GPIOMMC_MAX_NAMELEN_STR		__stringify(GPIOMMC_MAX_NAMELEN)
 +
-+/** struct gpiommc_pins - Hardware pin assignments
++/**
++ * struct gpiommc_pins - Hardware pin assignments
++ *
 + * @gpio_di: The GPIO number of the DATA IN pin
 + * @gpio_do: The GPIO number of the DATA OUT pin
 + * @gpio_clk: The GPIO number of the CLOCK pin
@@ -403,7 +691,9 @@ Index: linux-2.6.25.10/include/linux/mmc/gpiommc.h
 +	bool cs_activelow;
 +};
 +
-+/** struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
++/**
++ * struct gpiommc_platform_data - Platform data for a MMC-over-SPI-GPIO device.
++ *
 + * @name: The unique name string of the device.
 + * @pins: The hardware pin assignments.
 + * @mode: The hardware mode. This is either SPI_MODE_0,
@@ -421,13 +711,17 @@ Index: linux-2.6.25.10/include/linux/mmc/gpiommc.h
 +	unsigned int max_bus_speed;
 +};
 +
-+/** GPIOMMC_PLATDEV_NAME - The platform device name string.
++/**
++ * GPIOMMC_PLATDEV_NAME - The platform device name string.
++ *
 + * The name string that has to be used for platform_device_alloc
 + * when allocating a gpiommc device.
 + */
 +#define GPIOMMC_PLATDEV_NAME	"gpiommc"
 +
-+/** gpiommc_next_id - Get another platform device ID number.
++/**
++ * gpiommc_next_id - Get another platform device ID number.
++ *
 + * This returns the next platform device ID number that has to be used
 + * for platform_device_alloc. The ID is opaque and should not be used for
 + * anything else.
@@ -438,16 +732,16 @@ Index: linux-2.6.25.10/include/linux/mmc/gpiommc.h
 Index: linux-2.6.25.10/Documentation/gpiommc.txt
 ===================================================================
 --- /dev/null	1970-01-01 00:00:00.000000000 +0000
-+++ linux-2.6.25.10/Documentation/gpiommc.txt	2008-07-18 22:31:00.000000000 +0200
-@@ -0,0 +1,96 @@
++++ linux-2.6.25.10/Documentation/gpiommc.txt	2008-07-20 20:33:20.000000000 +0200
+@@ -0,0 +1,97 @@
 +GPIOMMC - Driver for an MMC/SD card on a bitbanging GPIO SPI bus
 +================================================================
 +
 +The gpiommc module hooks up the mmc_spi and spi_gpio modules for running an
 +MMC or SD card on GPIO pins.
 +
-+Two interfaces for registering a new MMC/SD card device are provided.
-+A static platform-device based mechanism and a dynamic sysfs based interface.
++Two interfaces for registering a new MMC/SD card device are provided:
++A static platform-device based mechanism and a dynamic configfs based interface.
 +
 +
 +Registering devices via platform-device
@@ -457,7 +751,7 @@ Index: linux-2.6.25.10/Documentation/gpiommc.txt
 +part of the hardware platform. This is most useful only for embedded machines
 +with MMC/SD devices statically connected to the platform GPIO bus.
 +
-+The data structures are declared in <linux/mmc/gpiommc.h>
++The data structures are declared in <linux/mmc/gpiommc.h>.
 +
 +To register a new device, define an instance of struct gpiommc_platform_data.
 +This structure holds any information about how the device is hooked up to the
@@ -474,72 +768,73 @@ Index: linux-2.6.25.10/Documentation/gpiommc.txt
 +
 +	err = platform_device_add_data(pdev, pdata, sizeof(struct gpiommc_platform_data));
 +
-+You may free the local instance of struct gpiommc_platform_data now.
++You may free the local instance of struct gpiommc_platform_data now. (So the
++struct may be allocated on the stack, too).
 +Now simply register the platform device.
 +
 +	err = platform_device_add(pdev);
 +
-+Done. The gpiommc probe routine should be called and you should see a dmesg
-+message for the added device.
++Done. The gpiommc probe routine will be invoked now and you should see a kernel
++log message for the added device.
 +
 +
-+Registering devices via sysfs
-+=============================
++Registering devices via configfs
++================================
 +
-+MMC/SD cards connected via GPIO often are a pretty dynamic thing. For example
++MMC/SD cards connected via GPIO often are a pretty dynamic thing, as for example
 +selfmade hacks for soldering an MMC/SD card to standard GPIO pins on embedded
 +hardware are a common situation.
 +So we provide a dynamic interface to conveniently handle adding and removing
 +devices from userspace, without the need to recompile the kernel.
 +
-+There are two sysfs files responsible for that:
-+export ADD=/sys/bus/platform/drivers/gpiommc/add
-+export REMOVE=/sys/bus/platform/drivers/gpiommc/remove
-+
-+To add a new device, simply echo the configuration string to the "add" file.
-+The config string is composed out of the following elements:
-+
-+DEVNAME DIpin DOpin CLKpin CSpin SPIMODE MAXBUSSPEED NO_SPI_DELAY CSACTIVELOW
-+
-+DEVNAME is a unique name string for the device.
-+DIpin is the SPI DI GPIO pin.
-+DOpin is the SPI DO GPIO pin.
-+CLKpin is the SPI CLOCK GPIO pin.
-+CSpin is the SPI CHIPSELECT GPIO pin.
-+SPIMODE is the hardware mode the device will run at. Can be 0-3.
-+MAXBUSSPEED is the maximum bus speed in Hertz.
-+NO_SPI_DELAY can be 1 or 0. If it is 1, then the lowlevel SPI delay
-+will not be performed. This is not standards compliant, but may be required
-+to gain reasonable speeds on embedded hardware.
-+CSACTIVELOW can be 1 or 0. If it is 1, the chip is considered to be selected, if CS
-+is at a logical 0.
-+
-+Note that the elements SPIMODE, MAXBUSSPEED and NO_SPI_DELAY are optional
-+and can be omitted.
-+SPIMODE will default to 0.
-+MAXBUSSSPEED will default to 5Mhz.
-+NO_SPI_DELAY will default to 0.
-+CSACTIVELOW will default to 1.
-+
-+Example:
-+
-+	echo -n "my_device 5 4 3 7 0 1000000 1" > $ADD
-+
-+This will add a new device called "my_device" with the GPIO pins assigned as
-+DI=5, DO=4, CLK=3, CS=7
-+The hardware mode will be SPI_MODE_0.
-+The maximum bus speed will be 1000000 Hz (1Mhz)
-+And the explicit SPI delay at the lowlevel bitbang loop will be switched off.
-+
-+To remove a device, simply echo the device name string to the "remove" file.
-+
-+Example:
-+
-+	echo -n "my_device" > $REMOVE
++The "gpiommc" subdirectory at the configfs mountpoint is used for handling
++the dynamic configuration.
++
++To create a new device, it must first be allocated with mkdir.
++The following command will allocate a device named "my_mmc":
++	mkdir /config/gpiommc/my_mmc
++
++There are several configuration files available in the new
++/config/gpiommc/my_mmc/ directory:
++
++gpio_data_in			= The SPI data-IN GPIO pin number.
++gpio_data_out			= The SPI data-OUT GPIO pin number.
++gpio_clock			= The SPI Clock GPIO pin number.
++gpio_chipselect			= The SPI Chipselect GPIO pin number.
++gpio_chipselect_activelow	= Boolean. If 0, Chipselect is active-HIGH.
++				  If 1, Chipselect is active-LOW.
++spi_mode			= The SPI data mode. Can be 0-3.
++spi_delay			= Enable all delays in the lowlevel bitbanging.
++max_bus_speed			= The maximum SPI bus speed. In Hertz.
++
++register			= Not a configuration parameter.
++				  Used to register the configured card
++				  with the kernel.
++
++The device must first get configured and then registered by writing "1" to
++the "register" file.
++The configuration parameters "gpio_data_in", "gpio_data_out", "gpio_clock"
++and "gpio_chipselect" are essential and _must_ be configured before writing
++"1" to the "register" file. The registration will fail, otherwise.
++
++The default values for the other parameters are:
++gpio_chipselect_activelow	= 1		(CS active-LOW)
++spi_mode			= 0		(SPI_MODE_0)
++spi_delay			= 1		(enabled)
++max_bus_speed			= 5000000	(5 Mhz)
++
++Configuration values can not be changed after registration. To unregister
++the device, write a "0" to the "register" file. The configuration can be
++changed again after unregistering.
++
++To completely remove the device, simply rmdir the directory
++(/config/gpiommc/my_mmc in this example).
++There's no need to first unregister the device before removing it. That will
++be done automatically.
 Index: linux-2.6.25.10/MAINTAINERS
 ===================================================================
---- linux-2.6.25.10.orig/MAINTAINERS	2008-07-18 22:30:41.000000000 +0200
-+++ linux-2.6.25.10/MAINTAINERS	2008-07-18 22:31:00.000000000 +0200
+--- linux-2.6.25.10.orig/MAINTAINERS	2008-07-20 20:33:20.000000000 +0200
++++ linux-2.6.25.10/MAINTAINERS	2008-07-20 20:33:20.000000000 +0200
 @@ -1736,6 +1736,11 @@ L:	gigaset307x-common@lists.sourceforge.
  W:	http://gigaset307x.sourceforge.net/
  S:	Maintained