Merge branch 'linus' into core/rcu

9 files changed, 1823 insertions, 55 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index 008c38ba774..dbd42d6c93a 100644
--- a/drivers/gpio/Kconfig
+++ b/drivers/gpio/Kconfig
@@ -2,15 +2,40 @@
 # GPIO infrastructure and expanders
 #
 
-config HAVE_GPIO_LIB
+config ARCH_WANT_OPTIONAL_GPIOLIB
 	bool
 	help
+	  Select this config option from the architecture Kconfig, if
+	  it is possible to use gpiolib on the architecture, but let the
+	  user decide whether to actually build it or not.
+	  Select this instead of ARCH_REQUIRE_GPIOLIB, if your architecture does
+	  not depend on GPIOs being available, but rather let the user
+	  decide whether he needs it or not.
+
+config ARCH_REQUIRE_GPIOLIB
+	bool
+	select GPIOLIB
+	help
 	  Platforms select gpiolib if they use this infrastructure
 	  for all their GPIOs, usually starting with ones integrated
 	  into SOC processors.
+	  Selecting this from the architecture code will cause the gpiolib
+	  code to always get built in.
+
+
+
+menuconfig GPIOLIB
+	bool "GPIO Support"
+	depends on ARCH_WANT_OPTIONAL_GPIOLIB || ARCH_REQUIRE_GPIOLIB
+	select GENERIC_GPIO
+	help
+	  This enables GPIO support through the generic GPIO library.
+	  You only need to enable this, if you also want to enable
+	  one or more of the GPIO expansion card drivers below.
+
+	  If unsure, say N.
 
-menu "GPIO Support"
-	depends on HAVE_GPIO_LIB
+if GPIOLIB
 
 config DEBUG_GPIO
 	bool "Debug GPIO calls"
@@ -23,10 +48,44 @@ config DEBUG_GPIO
 	  slower.  The diagnostics help catch the type of setup errors
 	  that are most common when setting up new platforms or boards.
 
+config GPIO_SYSFS
+	bool "/sys/class/gpio/... (sysfs interface)"
+	depends on SYSFS && EXPERIMENTAL
+	help
+	  Say Y here to add a sysfs interface for GPIOs.
+
+	  This is mostly useful to work around omissions in a system's
+	  kernel support.  Those are common in custom and semicustom
+	  hardware assembled using standard kernels with a minimum of
+	  custom patches.  In those cases, userspace code may import
+	  a given GPIO from the kernel, if no kernel driver requested it.
+
+	  Kernel drivers may also request that a particular GPIO be
+	  exported to userspace; this can be useful when debugging.
+
 # put expanders in the right section, in alphabetical order
 
 comment "I2C GPIO expanders:"
 
+config GPIO_MAX732X
+	tristate "MAX7319, MAX7320-7327 I2C Port Expanders"
+	depends on I2C
+	help
+	  Say yes here to support the MAX7319, MAX7320-7327 series of I2C
+	  Port Expanders. Each IO port on these chips has a fixed role of
+	  Input (designated by 'I'), Push-Pull Output ('O'), or Open-Drain
+	  Input and Output (designed by 'P'). The combinations are listed
+	  below:
+
+	  8 bits:	max7319 (8I), max7320 (8O), max7321 (8P),
+		  	max7322 (4I4O), max7323 (4P4O)
+
+	  16 bits:	max7324 (8I8O), max7325 (8P8O),
+		  	max7326 (4I12O), max7327 (4P12O)
+
+	  Board setup code must specify the model to use, and the start
+	  number for these GPIOs.
+
 config GPIO_PCA953X
 	tristate "PCA953x, PCA955x, and MAX7310 I/O ports"
 	depends on I2C
@@ -45,7 +104,7 @@ config GPIO_PCA953X
 	  will be called pca953x.
 
 config GPIO_PCF857X
-	tristate "PCF857x, PCA857x, and PCA967x I2C GPIO expanders"
+	tristate "PCF857x, PCA{85,96}7x, and MAX732[89] I2C GPIO expanders"
 	depends on I2C
 	help
 	  Say yes here to provide access to most "quasi-bidirectional" I2C
@@ -54,7 +113,8 @@ config GPIO_PCF857X
 	  some of them.  Compatible models include:
 
 	  8 bits:   pcf8574, pcf8574a, pca8574, pca8574a,
-	            pca9670, pca9672, pca9674, pca9674a
+	            pca9670, pca9672, pca9674, pca9674a,
+	  	    max7328, max7329
 
 	  16 bits:  pcf8575, pcf8575c, pca8575,
 	            pca9671, pca9673, pca9675
@@ -67,8 +127,32 @@ config GPIO_PCF857X
 	  This driver provides an in-kernel interface to those GPIOs using
 	  platform-neutral GPIO calls.
 
+comment "PCI GPIO expanders:"
+
+config GPIO_BT8XX
+	tristate "BT8XX GPIO abuser"
+	depends on PCI && VIDEO_BT848=n
+	help
+	  The BT8xx frame grabber chip has 24 GPIO pins than can be abused
+	  as a cheap PCI GPIO card.
+
+	  This chip can be found on Miro, Hauppauge and STB TV-cards.
+
+	  The card needs to be physically altered for using it as a
+	  GPIO card. For more information on how to build a GPIO card
+	  from a BT8xx TV card, see the documentation file at
+	  Documentation/bt8xxgpio.txt
+
+	  If unsure, say N.
+
 comment "SPI GPIO expanders:"
 
+config GPIO_MAX7301
+	tristate "Maxim MAX7301 GPIO expander"
+	depends on SPI_MASTER
+	help
+	  gpio driver for Maxim MAX7301 SPI GPIO expander.
+
 config GPIO_MCP23S08
 	tristate "Microchip MCP23S08 I/O expander"
 	depends on SPI_MASTER
@@ -76,4 +160,4 @@ config GPIO_MCP23S08
 	  SPI driver for Microchip MCP23S08 I/O expander.  This provides
 	  a GPIO interface supporting inputs and outputs.
 
-endmenu
+endif
diff --git a/drivers/gpio/Makefile b/drivers/gpio/Makefile
index fdde9923cf3..01b4bbde195 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -2,8 +2,11 @@
 
 ccflags-$(CONFIG_DEBUG_GPIO)	+= -DDEBUG
 
-obj-$(CONFIG_HAVE_GPIO_LIB)	+= gpiolib.o
+obj-$(CONFIG_GPIOLIB)		+= gpiolib.o
 
+obj-$(CONFIG_GPIO_MAX7301)	+= max7301.o
+obj-$(CONFIG_GPIO_MAX732X)	+= max732x.o
 obj-$(CONFIG_GPIO_MCP23S08)	+= mcp23s08.o
 obj-$(CONFIG_GPIO_PCA953X)	+= pca953x.o
 obj-$(CONFIG_GPIO_PCF857X)	+= pcf857x.o
+obj-$(CONFIG_GPIO_BT8XX)	+= bt8xxgpio.o
diff --git a/drivers/gpio/bt8xxgpio.c b/drivers/gpio/bt8xxgpio.c
new file mode 100644
index 00000000000..7a1168249dd
--- /dev/null
+++ b/drivers/gpio/bt8xxgpio.c
@@ -0,0 +1,348 @@
+/*
+
+    bt8xx GPIO abuser
+
+    Copyright (C) 2008 Michael Buesch <mb@bu3sch.de>
+
+    Please do _only_ contact the people listed _above_ with issues related to this driver.
+    All the other people listed below are not related to this driver. Their names
+    are only here, because this driver is derived from the bt848 driver.
+
+
+    Derived from the bt848 driver:
+
+    Copyright (C) 1996,97,98 Ralph  Metzler
+			   & Marcus Metzler
+    (c) 1999-2002 Gerd Knorr
+
+    some v4l2 code lines are taken from Justin's bttv2 driver which is
+    (c) 2000 Justin Schoeman
+
+    V4L1 removal from:
+    (c) 2005-2006 Nickolay V. Shmyrev
+
+    Fixes to be fully V4L2 compliant by
+    (c) 2006 Mauro Carvalho Chehab
+
+    Cropping and overscan support
+    Copyright (C) 2005, 2006 Michael H. Schimek
+    Sponsored by OPQ Systems AB
+
+    This program is free software; you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation; either version 2 of the License, or
+    (at your option) any later version.
+
+    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., 675 Mass Ave, Cambridge, MA 02139, USA.
+*/
+
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/spinlock.h>
+
+#include <asm/gpio.h>
+
+/* Steal the hardware definitions from the bttv driver. */
+#include "../media/video/bt8xx/bt848.h"
+
+
+#define BT8XXGPIO_NR_GPIOS		24 /* We have 24 GPIO pins */
+
+
+struct bt8xxgpio {
+	spinlock_t lock;
+
+	void __iomem *mmio;
+	struct pci_dev *pdev;
+	struct gpio_chip gpio;
+
+#ifdef CONFIG_PM
+	u32 saved_outen;
+	u32 saved_data;
+#endif
+};
+
+#define bgwrite(dat, adr)	writel((dat), bg->mmio+(adr))
+#define bgread(adr)		readl(bg->mmio+(adr))
+
+
+static int modparam_gpiobase = -1/* dynamic */;
+module_param_named(gpiobase, modparam_gpiobase, int, 0444);
+MODULE_PARM_DESC(gpiobase, "The GPIO number base. -1 means dynamic, which is the default.");
+
+
+static int bt8xxgpio_gpio_direction_input(struct gpio_chip *gpio, unsigned nr)
+{
+	struct bt8xxgpio *bg = container_of(gpio, struct bt8xxgpio, gpio);
+	unsigned long flags;
+	u32 outen, data;
+
+	spin_lock_irqsave(&bg->lock, flags);
+
+	data = bgread(BT848_GPIO_DATA);
+	data &= ~(1 << nr);
+	bgwrite(data, BT848_GPIO_DATA);
+
+	outen = bgread(BT848_GPIO_OUT_EN);
+	outen &= ~(1 << nr);
+	bgwrite(outen, BT848_GPIO_OUT_EN);
+
+	spin_unlock_irqrestore(&bg->lock, flags);
+
+	return 0;
+}
+
+static int bt8xxgpio_gpio_get(struct gpio_chip *gpio, unsigned nr)
+{
+	struct bt8xxgpio *bg = container_of(gpio, struct bt8xxgpio, gpio);
+	unsigned long flags;
+	u32 val;
+
+	spin_lock_irqsave(&bg->lock, flags);
+	val = bgread(BT848_GPIO_DATA);
+	spin_unlock_irqrestore(&bg->lock, flags);
+
+	return !!(val & (1 << nr));
+}
+
+static int bt8xxgpio_gpio_direction_output(struct gpio_chip *gpio,
+					unsigned nr, int val)
+{
+	struct bt8xxgpio *bg = container_of(gpio, struct bt8xxgpio, gpio);
+	unsigned long flags;
+	u32 outen, data;
+
+	spin_lock_irqsave(&bg->lock, flags);
+
+	outen = bgread(BT848_GPIO_OUT_EN);
+	outen |= (1 << nr);
+	bgwrite(outen, BT848_GPIO_OUT_EN);
+
+	data = bgread(BT848_GPIO_DATA);
+	if (val)
+		data |= (1 << nr);
+	else
+		data &= ~(1 << nr);
+	bgwrite(data, BT848_GPIO_DATA);
+
+	spin_unlock_irqrestore(&bg->lock, flags);
+
+	return 0;
+}
+
+static void bt8xxgpio_gpio_set(struct gpio_chip *gpio,
+			    unsigned nr, int val)
+{
+	struct bt8xxgpio *bg = container_of(gpio, struct bt8xxgpio, gpio);
+	unsigned long flags;
+	u32 data;
+
+	spin_lock_irqsave(&bg->lock, flags);
+
+	data = bgread(BT848_GPIO_DATA);
+	if (val)
+		data |= (1 << nr);
+	else
+		data &= ~(1 << nr);
+	bgwrite(data, BT848_GPIO_DATA);
+
+	spin_unlock_irqrestore(&bg->lock, flags);
+}
+
+static void bt8xxgpio_gpio_setup(struct bt8xxgpio *bg)
+{
+	struct gpio_chip *c = &bg->gpio;
+
+	c->label = bg->pdev->dev.bus_id;
+	c->owner = THIS_MODULE;
+	c->direction_input = bt8xxgpio_gpio_direction_input;
+	c->get = bt8xxgpio_gpio_get;
+	c->direction_output = bt8xxgpio_gpio_direction_output;
+	c->set = bt8xxgpio_gpio_set;
+	c->dbg_show = NULL;
+	c->base = modparam_gpiobase;
+	c->ngpio = BT8XXGPIO_NR_GPIOS;
+	c->can_sleep = 0;
+}
+
+static int bt8xxgpio_probe(struct pci_dev *dev,
+			const struct pci_device_id *pci_id)
+{
+	struct bt8xxgpio *bg;
+	int err;
+
+	bg = kzalloc(sizeof(*bg), GFP_KERNEL);
+	if (!bg)
+		return -ENOMEM;
+
+	bg->pdev = dev;
+	spin_lock_init(&bg->lock);
+
+	err = pci_enable_device(dev);
+	if (err) {
+		printk(KERN_ERR "bt8xxgpio: Can't enable device.\n");
+		goto err_freebg;
+	}
+	if (!request_mem_region(pci_resource_start(dev, 0),
+				pci_resource_len(dev, 0),
+				"bt8xxgpio")) {
+		printk(KERN_WARNING "bt8xxgpio: Can't request iomem (0x%llx).\n",
+		       (unsigned long long)pci_resource_start(dev, 0));
+		err = -EBUSY;
+		goto err_disable;
+	}
+	pci_set_master(dev);
+	pci_set_drvdata(dev, bg);
+
+	bg->mmio = ioremap(pci_resource_start(dev, 0), 0x1000);
+	if (!bg->mmio) {
+		printk(KERN_ERR "bt8xxgpio: ioremap() failed\n");
+		err = -EIO;
+		goto err_release_mem;
+	}
+
+	/* Disable interrupts */
+	bgwrite(0, BT848_INT_MASK);
+
+	/* gpio init */
+	bgwrite(0, BT848_GPIO_DMA_CTL);
+	bgwrite(0, BT848_GPIO_REG_INP);
+	bgwrite(0, BT848_GPIO_OUT_EN);
+
+	bt8xxgpio_gpio_setup(bg);
+	err = gpiochip_add(&bg->gpio);
+	if (err) {
+		printk(KERN_ERR "bt8xxgpio: Failed to register GPIOs\n");
+		goto err_release_mem;
+	}
+
+	printk(KERN_INFO "bt8xxgpio: Abusing BT8xx card for GPIOs %d to %d\n",
+	       bg->gpio.base, bg->gpio.base + BT8XXGPIO_NR_GPIOS - 1);
+
+	return 0;
+
+err_release_mem:
+	release_mem_region(pci_resource_start(dev, 0),
+			   pci_resource_len(dev, 0));
+	pci_set_drvdata(dev, NULL);
+err_disable:
+	pci_disable_device(dev);
+err_freebg:
+	kfree(bg);
+
+	return err;
+}
+
+static void bt8xxgpio_remove(struct pci_dev *pdev)
+{
+	struct bt8xxgpio *bg = pci_get_drvdata(pdev);
+
+	gpiochip_remove(&bg->gpio);
+
+	bgwrite(0, BT848_INT_MASK);
+	bgwrite(~0x0, BT848_INT_STAT);
+	bgwrite(0x0, BT848_GPIO_OUT_EN);
+
+	iounmap(bg->mmio);
+	release_mem_region(pci_resource_start(pdev, 0),
+			   pci_resource_len(pdev, 0));
+	pci_disable_device(pdev);
+
+	pci_set_drvdata(pdev, NULL);
+	kfree(bg);
+}
+
+#ifdef CONFIG_PM
+static int bt8xxgpio_suspend(struct pci_dev *pdev, pm_message_t state)
+{
+	struct bt8xxgpio *bg = pci_get_drvdata(pdev);
+	unsigned long flags;
+
+	spin_lock_irqsave(&bg->lock, flags);
+
+	bg->saved_outen = bgread(BT848_GPIO_OUT_EN);
+	bg->saved_data = bgread(BT848_GPIO_DATA);
+
+	bgwrite(0, BT848_INT_MASK);
+	bgwrite(~0x0, BT848_INT_STAT);
+	bgwrite(0x0, BT848_GPIO_OUT_EN);
+
+	spin_unlock_irqrestore(&bg->lock, flags);
+
+	pci_save_state(pdev);
+	pci_disable_device(pdev);
+	pci_set_power_state(pdev, pci_choose_state(pdev, state));
+
+	return 0;
+}
+
+static int bt8xxgpio_resume(struct pci_dev *pdev)
+{
+	struct bt8xxgpio *bg = pci_get_drvdata(pdev);
+	unsigned long flags;
+	int err;
+
+	pci_set_power_state(pdev, 0);
+	err = pci_enable_device(pdev);
+	if (err)
+		return err;
+	pci_restore_state(pdev);
+
+	spin_lock_irqsave(&bg->lock, flags);
+
+	bgwrite(0, BT848_INT_MASK);
+	bgwrite(0, BT848_GPIO_DMA_CTL);
+	bgwrite(0, BT848_GPIO_REG_INP);
+	bgwrite(bg->saved_outen, BT848_GPIO_OUT_EN);
+	bgwrite(bg->saved_data & bg->saved_outen,
+		BT848_GPIO_DATA);
+
+	spin_unlock_irqrestore(&bg->lock, flags);
+
+	return 0;
+}
+#else
+#define bt8xxgpio_suspend NULL
+#define bt8xxgpio_resume NULL
+#endif /* CONFIG_PM */
+
+static struct pci_device_id bt8xxgpio_pci_tbl[] = {
+	{ PCI_DEVICE(PCI_VENDOR_ID_BROOKTREE, PCI_DEVICE_ID_BT848) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_BROOKTREE, PCI_DEVICE_ID_BT849) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_BROOKTREE, PCI_DEVICE_ID_BT878) },
+	{ PCI_DEVICE(PCI_VENDOR_ID_BROOKTREE, PCI_DEVICE_ID_BT879) },
+	{ 0, },
+};
+MODULE_DEVICE_TABLE(pci, bt8xxgpio_pci_tbl);
+
+static struct pci_driver bt8xxgpio_pci_driver = {
+	.name		= "bt8xxgpio",
+	.id_table	= bt8xxgpio_pci_tbl,
+	.probe		= bt8xxgpio_probe,
+	.remove		= bt8xxgpio_remove,
+	.suspend	= bt8xxgpio_suspend,
+	.resume		= bt8xxgpio_resume,
+};
+
+static int bt8xxgpio_init(void)
+{
+	return pci_register_driver(&bt8xxgpio_pci_driver);
+}
+module_init(bt8xxgpio_init)
+
+static void bt8xxgpio_exit(void)
+{
+	pci_unregister_driver(&bt8xxgpio_pci_driver);
+}
+module_exit(bt8xxgpio_exit)
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Michael Buesch");
+MODULE_DESCRIPTION("Abuse a BT8xx framegrabber card as generic GPIO card");
diff --git a/drivers/gpio/gpiolib.c b/drivers/gpio/gpiolib.c
index beaf6b3a37d..8d2940517c9 100644
--- a/drivers/gpio/gpiolib.c
+++ b/drivers/gpio/gpiolib.c
@@ -2,8 +2,11 @@
 #include <linux/module.h>
 #include <linux/irq.h>
 #include <linux/spinlock.h>
-
-#include <asm/gpio.h>
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+#include <linux/gpio.h>
 
 
 /* Optional implementation infrastructure for GPIO interfaces.
@@ -44,6 +47,8 @@ struct gpio_desc {
 #define FLAG_REQUESTED	0
 #define FLAG_IS_OUT	1
 #define FLAG_RESERVED	2
+#define FLAG_EXPORT	3	/* protected by sysfs_lock */
+#define FLAG_SYSFS	4	/* exported via /sys/class/gpio/control */
 
 #ifdef CONFIG_DEBUG_FS
 	const char		*label;
@@ -151,6 +156,482 @@ err:
 	return ret;
 }
 
+#ifdef CONFIG_GPIO_SYSFS
+
+/* lock protects against unexport_gpio() being called while
+ * sysfs files are active.
+ */
+static DEFINE_MUTEX(sysfs_lock);
+
+/*
+ * /sys/class/gpio/gpioN... only for GPIOs that are exported
+ *   /direction
+ *      * MAY BE OMITTED if kernel won't allow direction changes
+ *      * is read/write as "in" or "out"
+ *      * may also be written as "high" or "low", initializing
+ *        output value as specified ("out" implies "low")
+ *   /value
+ *      * always readable, subject to hardware behavior
+ *      * may be writable, as zero/nonzero
+ *
+ * REVISIT there will likely be an attribute for configuring async
+ * notifications, e.g. to specify polling interval or IRQ trigger type
+ * that would for example trigger a poll() on the "value".
+ */
+
+static ssize_t gpio_direction_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	const struct gpio_desc	*desc = dev_get_drvdata(dev);
+	ssize_t			status;
+
+	mutex_lock(&sysfs_lock);
+
+	if (!test_bit(FLAG_EXPORT, &desc->flags))
+		status = -EIO;
+	else
+		status = sprintf(buf, "%s\n",
+			test_bit(FLAG_IS_OUT, &desc->flags)
+				? "out" : "in");
+
+	mutex_unlock(&sysfs_lock);
+	return status;
+}
+
+static ssize_t gpio_direction_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	const struct gpio_desc	*desc = dev_get_drvdata(dev);
+	unsigned		gpio = desc - gpio_desc;
+	ssize_t			status;
+
+	mutex_lock(&sysfs_lock);
+
+	if (!test_bit(FLAG_EXPORT, &desc->flags))
+		status = -EIO;
+	else if (sysfs_streq(buf, "high"))
+		status = gpio_direction_output(gpio, 1);
+	else if (sysfs_streq(buf, "out") || sysfs_streq(buf, "low"))
+		status = gpio_direction_output(gpio, 0);
+	else if (sysfs_streq(buf, "in"))
+		status = gpio_direction_input(gpio);
+	else
+		status = -EINVAL;
+
+	mutex_unlock(&sysfs_lock);
+	return status ? : size;
+}
+
+static const DEVICE_ATTR(direction, 0644,
+		gpio_direction_show, gpio_direction_store);
+
+static ssize_t gpio_value_show(struct device *dev,
+		struct device_attribute *attr, char *buf)
+{
+	const struct gpio_desc	*desc = dev_get_drvdata(dev);
+	unsigned		gpio = desc - gpio_desc;
+	ssize_t			status;
+
+	mutex_lock(&sysfs_lock);
+
+	if (!test_bit(FLAG_EXPORT, &desc->flags))
+		status = -EIO;
+	else
+		status = sprintf(buf, "%d\n", gpio_get_value_cansleep(gpio));
+
+	mutex_unlock(&sysfs_lock);
+	return status;
+}
+
+static ssize_t gpio_value_store(struct device *dev,
+		struct device_attribute *attr, const char *buf, size_t size)
+{
+	const struct gpio_desc	*desc = dev_get_drvdata(dev);
+	unsigned		gpio = desc - gpio_desc;
+	ssize_t			status;
+
+	mutex_lock(&sysfs_lock);
+
+	if (!test_bit(FLAG_EXPORT, &desc->flags))
+		status = -EIO;
+	else if (!test_bit(FLAG_IS_OUT, &desc->flags))
+		status = -EPERM;
+	else {
+		long		value;
+
+		status = strict_strtol(buf, 0, &value);
+		if (status == 0) {
+			gpio_set_value_cansleep(gpio, value != 0);
+			status = size;
+		}
+	}
+
+	mutex_unlock(&sysfs_lock);
+	return status;
+}
+
+static /*const*/ DEVICE_ATTR(value, 0644,
+		gpio_value_show, gpio_value_store);
+
+static const struct attribute *gpio_attrs[] = {
+	&dev_attr_direction.attr,
+	&dev_attr_value.attr,
+	NULL,
+};
+
+static const struct attribute_group gpio_attr_group = {
+	.attrs = (struct attribute **) gpio_attrs,
+};
+
+/*
+ * /sys/class/gpio/gpiochipN/
+ *   /base ... matching gpio_chip.base (N)
+ *   /label ... matching gpio_chip.label
+ *   /ngpio ... matching gpio_chip.ngpio
+ */
+
+static ssize_t chip_base_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	const struct gpio_chip	*chip = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%d\n", chip->base);
+}
+static DEVICE_ATTR(base, 0444, chip_base_show, NULL);
+
+static ssize_t chip_label_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	const struct gpio_chip	*chip = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%s\n", chip->label ? : "");
+}
+static DEVICE_ATTR(label, 0444, chip_label_show, NULL);
+
+static ssize_t chip_ngpio_show(struct device *dev,
+			       struct device_attribute *attr, char *buf)
+{
+	const struct gpio_chip	*chip = dev_get_drvdata(dev);
+
+	return sprintf(buf, "%u\n", chip->ngpio);
+}
+static DEVICE_ATTR(ngpio, 0444, chip_ngpio_show, NULL);
+
+static const struct attribute *gpiochip_attrs[] = {
+	&dev_attr_base.attr,
+	&dev_attr_label.attr,
+	&dev_attr_ngpio.attr,
+	NULL,
+};
+
+static const struct attribute_group gpiochip_attr_group = {
+	.attrs = (struct attribute **) gpiochip_attrs,
+};
+
+/*
+ * /sys/class/gpio/export ... write-only
+ *	integer N ... number of GPIO to export (full access)
+ * /sys/class/gpio/unexport ... write-only
+ *	integer N ... number of GPIO to unexport
+ */
+static ssize_t export_store(struct class *class, const char *buf, size_t len)
+{
+	long	gpio;
+	int	status;
+
+	status = strict_strtol(buf, 0, &gpio);
+	if (status < 0)
+		goto done;
+
+	/* No extra locking here; FLAG_SYSFS just signifies that the
+	 * request and export were done by on behalf of userspace, so
+	 * they may be undone on its behalf too.
+	 */
+
+	status = gpio_request(gpio, "sysfs");
+	if (status < 0)
+		goto done;
+
+	status = gpio_export(gpio, true);
+	if (status < 0)
+		gpio_free(gpio);
+	else
+		set_bit(FLAG_SYSFS, &gpio_desc[gpio].flags);
+
+done:
+	if (status)
+		pr_debug("%s: status %d\n", __func__, status);
+	return status ? : len;
+}
+
+static ssize_t unexport_store(struct class *class, const char *buf, size_t len)
+{
+	long	gpio;
+	int	status;
+
+	status = strict_strtol(buf, 0, &gpio);
+	if (status < 0)
+		goto done;
+
+	status = -EINVAL;
+
+	/* reject bogus commands (gpio_unexport ignores them) */
+	if (!gpio_is_valid(gpio))
+		goto done;
+
+	/* No extra locking here; FLAG_SYSFS just signifies that the
+	 * request and export were done by on behalf of userspace, so
+	 * they may be undone on its behalf too.
+	 */
+	if (test_and_clear_bit(FLAG_SYSFS, &gpio_desc[gpio].flags)) {
+		status = 0;
+		gpio_free(gpio);
+	}
+done:
+	if (status)
+		pr_debug("%s: status %d\n", __func__, status);
+	return status ? : len;
+}
+
+static struct class_attribute gpio_class_attrs[] = {
+	__ATTR(export, 0200, NULL, export_store),
+	__ATTR(unexport, 0200, NULL, unexport_store),
+	__ATTR_NULL,
+};
+
+static struct class gpio_class = {
+	.name =		"gpio",
+	.owner =	THIS_MODULE,
+
+	.class_attrs =	gpio_class_attrs,
+};
+
+
+/**
+ * gpio_export - export a GPIO through sysfs
+ * @gpio: gpio to make available, already requested
+ * @direction_may_change: true if userspace may change gpio direction
+ * Context: arch_initcall or later
+ *
+ * When drivers want to make a GPIO accessible to userspace after they
+ * have requested it -- perhaps while debugging, or as part of their
+ * public interface -- they may use this routine.  If the GPIO can
+ * change direction (some can't) and the caller allows it, userspace
+ * will see "direction" sysfs attribute which may be used to change
+ * the gpio's direction.  A "value" attribute will always be provided.
+ *
+ * Returns zero on success, else an error.
+ */
+int gpio_export(unsigned gpio, bool direction_may_change)
+{
+	unsigned long		flags;
+	struct gpio_desc	*desc;
+	int			status = -EINVAL;
+
+	/* can't export until sysfs is available ... */
+	if (!gpio_class.p) {
+		pr_debug("%s: called too early!\n", __func__);
+		return -ENOENT;
+	}
+
+	if (!gpio_is_valid(gpio))
+		goto done;
+
+	mutex_lock(&sysfs_lock);
+
+	spin_lock_irqsave(&gpio_lock, flags);
+	desc = &gpio_desc[gpio];
+	if (test_bit(FLAG_REQUESTED, &desc->flags)
+			&& !test_bit(FLAG_EXPORT, &desc->flags)) {
+		status = 0;
+		if (!desc->chip->direction_input
+				|| !desc->chip->direction_output)
+			direction_may_change = false;
+	}
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	if (status == 0) {
+		struct device	*dev;
+
+		dev = device_create(&gpio_class, desc->chip->dev, MKDEV(0, 0),
+					desc, "gpio%d", gpio);
+		if (dev) {
+			if (direction_may_change)
+				status = sysfs_create_group(&dev->kobj,
+						&gpio_attr_group);
+			else
+				status = device_create_file(dev,
+						&dev_attr_value);
+			if (status != 0)
+				device_unregister(dev);
+		} else
+			status = -ENODEV;
+		if (status == 0)
+			set_bit(FLAG_EXPORT, &desc->flags);
+	}
+
+	mutex_unlock(&sysfs_lock);
+
+done:
+	if (status)
+		pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+
+	return status;
+}
+EXPORT_SYMBOL_GPL(gpio_export);
+
+static int match_export(struct device *dev, void *data)
+{
+	return dev_get_drvdata(dev) == data;
+}
+
+/**
+ * gpio_unexport - reverse effect of gpio_export()
+ * @gpio: gpio to make unavailable
+ *
+ * This is implicit on gpio_free().
+ */
+void gpio_unexport(unsigned gpio)
+{
+	struct gpio_desc	*desc;
+	int			status = -EINVAL;
+
+	if (!gpio_is_valid(gpio))
+		goto done;
+
+	mutex_lock(&sysfs_lock);
+
+	desc = &gpio_desc[gpio];
+	if (test_bit(FLAG_EXPORT, &desc->flags)) {
+		struct device	*dev = NULL;
+
+		dev = class_find_device(&gpio_class, NULL, desc, match_export);
+		if (dev) {
+			clear_bit(FLAG_EXPORT, &desc->flags);
+			put_device(dev);
+			device_unregister(dev);
+			status = 0;
+		} else
+			status = -ENODEV;
+	}
+
+	mutex_unlock(&sysfs_lock);
+done:
+	if (status)
+		pr_debug("%s: gpio%d status %d\n", __func__, gpio, status);
+}
+EXPORT_SYMBOL_GPL(gpio_unexport);
+
+static int gpiochip_export(struct gpio_chip *chip)
+{
+	int		status;
+	struct device	*dev;
+
+	/* Many systems register gpio chips for SOC support very early,
+	 * before driver model support is available.  In those cases we
+	 * export this later, in gpiolib_sysfs_init() ... here we just
+	 * verify that _some_ field of gpio_class got initialized.
+	 */
+	if (!gpio_class.p)
+		return 0;
+
+	/* use chip->base for the ID; it's already known to be unique */
+	mutex_lock(&sysfs_lock);
+	dev = device_create(&gpio_class, chip->dev, MKDEV(0, 0), chip,
+				"gpiochip%d", chip->base);
+	if (dev) {
+		status = sysfs_create_group(&dev->kobj,
+				&gpiochip_attr_group);
+	} else
+		status = -ENODEV;
+	chip->exported = (status == 0);
+	mutex_unlock(&sysfs_lock);
+
+	if (status) {
+		unsigned long	flags;
+		unsigned	gpio;
+
+		spin_lock_irqsave(&gpio_lock, flags);
+		gpio = chip->base;
+		while (gpio_desc[gpio].chip == chip)
+			gpio_desc[gpio++].chip = NULL;
+		spin_unlock_irqrestore(&gpio_lock, flags);
+
+		pr_debug("%s: chip %s status %d\n", __func__,
+				chip->label, status);
+	}
+
+	return status;
+}
+
+static void gpiochip_unexport(struct gpio_chip *chip)
+{
+	int			status;
+	struct device		*dev;
+
+	mutex_lock(&sysfs_lock);
+	dev = class_find_device(&gpio_class, NULL, chip, match_export);
+	if (dev) {
+		put_device(dev);
+		device_unregister(dev);
+		chip->exported = 0;
+		status = 0;
+	} else
+		status = -ENODEV;
+	mutex_unlock(&sysfs_lock);
+
+	if (status)
+		pr_debug("%s: chip %s status %d\n", __func__,
+				chip->label, status);
+}
+
+static int __init gpiolib_sysfs_init(void)
+{
+	int		status;
+	unsigned long	flags;
+	unsigned	gpio;
+
+	status = class_register(&gpio_class);
+	if (status < 0)
+		return status;
+
+	/* Scan and register the gpio_chips which registered very
+	 * early (e.g. before the class_register above was called).
+	 *
+	 * We run before arch_initcall() so chip->dev nodes can have
+	 * registered, and so arch_initcall() can always gpio_export().
+	 */
+	spin_lock_irqsave(&gpio_lock, flags);
+	for (gpio = 0; gpio < ARCH_NR_GPIOS; gpio++) {
+		struct gpio_chip	*chip;
+
+		chip = gpio_desc[gpio].chip;
+		if (!chip || chip->exported)
+			continue;
+
+		spin_unlock_irqrestore(&gpio_lock, flags);
+		status = gpiochip_export(chip);
+		spin_lock_irqsave(&gpio_lock, flags);
+	}
+	spin_unlock_irqrestore(&gpio_lock, flags);
+
+
+	return status;
+}
+postcore_initcall(gpiolib_sysfs_init);
+
+#else
+static inline int gpiochip_export(struct gpio_chip *chip)
+{
+	return 0;
+}
+
+static inline void gpiochip_unexport(struct gpio_chip *chip)
+{
+}
+
+#endif /* CONFIG_GPIO_SYSFS */
+
 /**
  * gpiochip_add() - register a gpio_chip
  * @chip: the chip to register, with chip->base initialized
@@ -160,6 +641,11 @@ err:
  * because the chip->base is invalid or already associated with a
  * different chip.  Otherwise it returns zero as a success code.
  *
+ * When gpiochip_add() is called very early during boot, so that GPIOs
+ * can be freely used, the chip->dev device must be registered before
+ * the gpio framework's arch_initcall().  Otherwise sysfs initialization
+ * for GPIOs will fail rudely.
+ *
  * If chip->base is negative, this requests dynamic assignment of
  * a range of valid GPIOs.
  */
@@ -182,7 +668,7 @@ int gpiochip_add(struct gpio_chip *chip)
 		base = gpiochip_find_base(chip->ngpio);
 		if (base < 0) {
 			status = base;
-			goto fail_unlock;
+			goto unlock;
 		}
 		chip->base = base;
 	}
@@ -197,12 +683,23 @@ int gpiochip_add(struct gpio_chip *chip)
 	if (status == 0) {
 		for (id = base; id < base + chip->ngpio; id++) {
 			gpio_desc[id].chip = chip;
-			gpio_desc[id].flags = 0;
+
+			/* REVISIT:  most hardware initializes GPIOs as
+			 * inputs (often with pullups enabled) so power
+			 * usage is minimized.  Linux code should set the
+			 * gpio direction first thing; but until it does,
+			 * we may expose the wrong direction in sysfs.
+			 */
+			gpio_desc[id].flags = !chip->direction_input
+				? (1 << FLAG_IS_OUT)
+				: 0;
 		}
 	}
 
-fail_unlock:
+unlock:
 	spin_unlock_irqrestore(&gpio_lock, flags);
+	if (status == 0)
+		status = gpiochip_export(chip);
 fail:
 	/* failures here can mean systems won't boot... */
 	if (status)
@@ -239,6 +736,10 @@ int gpiochip_remove(struct gpio_chip *chip)
 	}
 
 	spin_unlock_irqrestore(&gpio_lock, flags);
+
+	if (status == 0)
+		gpiochip_unexport(chip);
+
 	return status;
 }
 EXPORT_SYMBOL_GPL(gpiochip_remove);
@@ -296,6 +797,8 @@ void gpio_free(unsigned gpio)
 		return;
 	}
 
+	gpio_unexport(gpio);
+
 	spin_lock_irqsave(&gpio_lock, flags);
 
 	desc = &gpio_desc[gpio];
@@ -534,10 +1037,6 @@ EXPORT_SYMBOL_GPL(gpio_set_value_cansleep);
 
 #ifdef CONFIG_DEBUG_FS
 
-#include <linux/debugfs.h>
-#include <linux/seq_file.h>
-
-
 static void gpiolib_dbg_show(struct seq_file *s, struct gpio_chip *chip)
 {
 	unsigned		i;
@@ -614,17 +1113,28 @@ static int gpiolib_show(struct seq_file *s, void *unused)
 	/* REVISIT this isn't locked against gpio_chip removal ... */
 
 	for (gpio = 0; gpio_is_valid(gpio); gpio++) {
+		struct device *dev;
+
 		if (chip == gpio_desc[gpio].chip)
 			continue;
 		chip = gpio_desc[gpio].chip;
 		if (!chip)
 			continue;
 
-		seq_printf(s, "%sGPIOs %d-%d, %s%s:\n",
+		seq_printf(s, "%sGPIOs %d-%d",
 				started ? "\n" : "",
-				chip->base, chip->base + chip->ngpio - 1,
-				chip->label ? : "generic",
-				chip->can_sleep ? ", can sleep" : "");
+				chip->base, chip->base + chip->ngpio - 1);
+		dev = chip->dev;
+		if (dev)
+			seq_printf(s, ", %s/%s",
+				dev->bus ? dev->bus->name : "no-bus",
+				dev->bus_id);
+		if (chip->label)
+			seq_printf(s, ", %s", chip->label);
+		if (chip->can_sleep)
+			seq_printf(s, ", can sleep");
+		seq_printf(s, ":\n");
+
 		started = 1;
 		if (chip->dbg_show)
 			chip->dbg_show(s, chip);
diff --git a/drivers/gpio/max7301.c b/drivers/gpio/max7301.c
new file mode 100644
index 00000000000..39c795ad831
--- /dev/null
+++ b/drivers/gpio/max7301.c
@@ -0,0 +1,339 @@
+/**
+ * drivers/gpio/max7301.c
+ *
+ * Copyright (C) 2006 Juergen Beisert, Pengutronix
+ * Copyright (C) 2008 Guennadi Liakhovetski, Pengutronix
+ *
+ * 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.
+ *
+ * The Maxim's MAX7301 device is an SPI driven GPIO expander. There are
+ * 28 GPIOs. 8 of them can trigger an interrupt. See datasheet for more
+ * details
+ * Note:
+ * - DIN must be stable at the rising edge of clock.
+ * - when writing:
+ *   - always clock in 16 clocks at once
+ *   - at DIN: D15 first, D0 last
+ *   - D0..D7 = databyte, D8..D14 = commandbyte
+ *   - D15 = low -> write command
+ * - when reading
+ *   - always clock in 16 clocks at once
+ *   - at DIN: D15 first, D0 last
+ *   - D0..D7 = dummy, D8..D14 = register address
+ *   - D15 = high -> read command
+ *   - raise CS and assert it again
+ *   - always clock in 16 clocks at once
+ *   - at DOUT: D15 first, D0 last
+ *   - D0..D7 contains the data from the first cycle
+ *
+ * The driver exports a standard gpiochip interface
+ */
+
+#include <linux/init.h>
+#include <linux/platform_device.h>
+#include <linux/mutex.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/max7301.h>
+#include <linux/gpio.h>
+
+#define DRIVER_NAME "max7301"
+
+/*
+ * Pin configurations, see MAX7301 datasheet page 6
+ */
+#define PIN_CONFIG_MASK 0x03
+#define PIN_CONFIG_IN_PULLUP 0x03
+#define PIN_CONFIG_IN_WO_PULLUP 0x02
+#define PIN_CONFIG_OUT 0x01
+
+#define PIN_NUMBER 28
+
+
+/*
+ * Some registers must be read back to modify.
+ * To save time we cache them here in memory
+ */
+struct max7301 {
+	struct mutex	lock;
+	u8		port_config[8];	/* field 0 is unused */
+	u32		out_level;	/* cached output levels */
+	struct gpio_chip chip;
+	struct spi_device *spi;
+};
+
+/**
+ * max7301_write - Write a new register content
+ * @spi: The SPI device
+ * @reg: Register offset
+ * @val: Value to write
+ *
+ * A write to the MAX7301 means one message with one transfer
+ *
+ * Returns 0 if successful or a negative value on error
+ */
+static int max7301_write(struct spi_device *spi, unsigned int reg, unsigned int val)
+{
+	u16 word = ((reg & 0x7F) << 8) | (val & 0xFF);
+	return spi_write(spi, (const u8 *)&word, sizeof(word));
+}
+
+/**
+ * max7301_read - Read back register content
+ * @spi: The SPI device
+ * @reg: Register offset
+ *
+ * A read from the MAX7301 means two transfers; here, one message each
+ *
+ * Returns positive 8 bit value from device if successful or a
+ * negative value on error
+ */
+static int max7301_read(struct spi_device *spi, unsigned int reg)
+{
+	int ret;
+	u16 word;
+
+	word = 0x8000 | (reg << 8);
+	ret = spi_write(spi, (const u8 *)&word, sizeof(word));
+	if (ret)
+		return ret;
+	/*
+	 * This relies on the fact, that a transfer with NULL tx_buf shifts out
+	 * zero bytes (=NOOP for MAX7301)
+	 */
+	ret = spi_read(spi, (u8 *)&word, sizeof(word));
+	if (ret)
+		return ret;
+	return word & 0xff;
+}
+
+static int max7301_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct max7301 *ts = container_of(chip, struct max7301, chip);
+	u8 *config;
+	int ret;
+
+	/* First 4 pins are unused in the controller */
+	offset += 4;
+
+	config = &ts->port_config[offset >> 2];
+
+	mutex_lock(&ts->lock);
+
+	/* Standard GPIO API doesn't support pull-ups, has to be extended.
+	 * Hard-coding no pollup for now. */
+	*config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3));
+
+	ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config);
+
+	mutex_unlock(&ts->lock);
+
+	return ret;
+}
+
+static int __max7301_set(struct max7301 *ts, unsigned offset, int value)
+{
+	if (value) {
+		ts->out_level |= 1 << offset;
+		return max7301_write(ts->spi, 0x20 + offset, 0x01);
+	} else {
+		ts->out_level &= ~(1 << offset);
+		return max7301_write(ts->spi, 0x20 + offset, 0x00);
+	}
+}
+
+static int max7301_direction_output(struct gpio_chip *chip, unsigned offset,
+				    int value)
+{
+	struct max7301 *ts = container_of(chip, struct max7301, chip);
+	u8 *config;
+	int ret;
+
+	/* First 4 pins are unused in the controller */
+	offset += 4;
+
+	config = &ts->port_config[offset >> 2];
+
+	mutex_lock(&ts->lock);
+
+	*config = (*config & ~(3 << (offset & 3))) | (1 << (offset & 3));
+
+	ret = __max7301_set(ts, offset, value);
+
+	if (!ret)
+		ret = max7301_write(ts->spi, 0x08 + (offset >> 2), *config);
+
+	mutex_unlock(&ts->lock);
+
+	return ret;
+}
+
+static int max7301_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct max7301 *ts = container_of(chip, struct max7301, chip);
+	int config, level = -EINVAL;
+
+	/* First 4 pins are unused in the controller */
+	offset += 4;
+
+	mutex_lock(&ts->lock);
+
+	config = (ts->port_config[offset >> 2] >> ((offset & 3) * 2)) & 3;
+
+	switch (config) {
+	case 1:
+		/* Output: return cached level */
+		level =  !!(ts->out_level & (1 << offset));
+		break;
+	case 2:
+	case 3:
+		/* Input: read out */
+		level = max7301_read(ts->spi, 0x20 + offset) & 0x01;
+	}
+	mutex_unlock(&ts->lock);
+
+	return level;
+}
+
+static void max7301_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct max7301 *ts = container_of(chip, struct max7301, chip);
+
+	/* First 4 pins are unused in the controller */
+	offset += 4;
+
+	mutex_lock(&ts->lock);
+
+	__max7301_set(ts, offset, value);
+
+	mutex_unlock(&ts->lock);
+}
+
+static int __devinit max7301_probe(struct spi_device *spi)
+{
+	struct max7301 *ts;
+	struct max7301_platform_data *pdata;
+	int i, ret;
+
+	pdata = spi->dev.platform_data;
+	if (!pdata || !pdata->base)
+		return -ENODEV;
+
+	/*
+	 * bits_per_word cannot be configured in platform data
+	 */
+	spi->bits_per_word = 16;
+
+	ret = spi_setup(spi);
+	if (ret < 0)
+		return ret;
+
+	ts = kzalloc(sizeof(struct max7301), GFP_KERNEL);
+	if (!ts)
+		return -ENOMEM;
+
+	mutex_init(&ts->lock);
+
+	dev_set_drvdata(&spi->dev, ts);
+
+	/* Power up the chip and disable IRQ output */
+	max7301_write(spi, 0x04, 0x01);
+
+	ts->spi = spi;
+
+	ts->chip.label = DRIVER_NAME,
+
+	ts->chip.direction_input = max7301_direction_input;
+	ts->chip.get = max7301_get;
+	ts->chip.direction_output = max7301_direction_output;
+	ts->chip.set = max7301_set;
+
+	ts->chip.base = pdata->base;
+	ts->chip.ngpio = PIN_NUMBER;
+	ts->chip.can_sleep = 1;
+	ts->chip.dev = &spi->dev;
+	ts->chip.owner = THIS_MODULE;
+
+	ret = gpiochip_add(&ts->chip);
+	if (ret)
+		goto exit_destroy;
+
+	/*
+	 * tristate all pins in hardware and cache the
+	 * register values for later use.
+	 */
+	for (i = 1; i < 8; i++) {
+		int j;
+		/* 0xAA means input with internal pullup disabled */
+		max7301_write(spi, 0x08 + i, 0xAA);
+		ts->port_config[i] = 0xAA;
+		for (j = 0; j < 4; j++) {
+			int idx = ts->chip.base + (i - 1) * 4 + j;
+			ret = gpio_direction_input(idx);
+			if (ret)
+				goto exit_remove;
+			gpio_free(idx);
+		}
+	}
+	return ret;
+
+exit_remove:
+	gpiochip_remove(&ts->chip);
+exit_destroy:
+	dev_set_drvdata(&spi->dev, NULL);
+	mutex_destroy(&ts->lock);
+	kfree(ts);
+	return ret;
+}
+
+static int max7301_remove(struct spi_device *spi)
+{
+	struct max7301 *ts;
+	int ret;
+
+	ts = dev_get_drvdata(&spi->dev);
+	if (ts == NULL)
+		return -ENODEV;
+
+	dev_set_drvdata(&spi->dev, NULL);
+
+	/* Power down the chip and disable IRQ output */
+	max7301_write(spi, 0x04, 0x00);
+
+	ret = gpiochip_remove(&ts->chip);
+	if (!ret) {
+		mutex_destroy(&ts->lock);
+		kfree(ts);
+	} else
+		dev_err(&spi->dev, "Failed to remove the GPIO controller: %d\n",
+			ret);
+
+	return ret;
+}
+
+static struct spi_driver max7301_driver = {
+	.driver = {
+		.name		= DRIVER_NAME,
+		.owner		= THIS_MODULE,
+	},
+	.probe		= max7301_probe,
+	.remove		= __devexit_p(max7301_remove),
+};
+
+static int __init max7301_init(void)
+{
+	return spi_register_driver(&max7301_driver);
+}
+
+static void __exit max7301_exit(void)
+{
+	spi_unregister_driver(&max7301_driver);
+}
+
+module_init(max7301_init);
+module_exit(max7301_exit);
+
+MODULE_AUTHOR("Juergen Beisert");
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("MAX7301 SPI based GPIO-Expander");
diff --git a/drivers/gpio/max732x.c b/drivers/gpio/max732x.c
new file mode 100644
index 00000000000..b51c8135ca2
--- /dev/null
+++ b/drivers/gpio/max732x.c
@@ -0,0 +1,385 @@
+/*
+ *  max732x.c - I2C Port Expander with 8/16 I/O
+ *
+ *  Copyright (C) 2007 Marvell International Ltd.
+ *  Copyright (C) 2008 Jack Ren <jack.ren@marvell.com>
+ *  Copyright (C) 2008 Eric Miao <eric.miao@marvell.com>
+ *
+ *  Derived from drivers/gpio/pca953x.c
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; version 2 of the License.
+ */
+
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/slab.h>
+#include <linux/string.h>
+#include <linux/gpio.h>
+
+#include <linux/i2c.h>
+#include <linux/i2c/max732x.h>
+
+
+/*
+ * Each port of MAX732x (including MAX7319) falls into one of the
+ * following three types:
+ *
+ *   - Push Pull Output
+ *   - Input
+ *   - Open Drain I/O
+ *
+ * designated by 'O', 'I' and 'P' individually according to MAXIM's
+ * datasheets.
+ *
+ * There are two groups of I/O ports, each group usually includes
+ * up to 8 I/O ports, and is accessed by a specific I2C address:
+ *
+ *   - Group A : by I2C address 0b'110xxxx
+ *   - Group B : by I2C address 0b'101xxxx
+ *
+ * where 'xxxx' is decided by the connections of pin AD2/AD0.  The
+ * address used also affects the initial state of output signals.
+ *
+ * Within each group of ports, there are five known combinations of
+ * I/O ports: 4I4O, 4P4O, 8I, 8P, 8O, see the definitions below for
+ * the detailed organization of these ports.
+ *
+ * GPIO numbers start from 'gpio_base + 0' to 'gpio_base + 8/16',
+ * and GPIOs from GROUP_A are numbered before those from GROUP_B
+ * (if there are two groups).
+ *
+ * NOTE: MAX7328/MAX7329 are drop-in replacements for PCF8574/a, so
+ * they are not supported by this driver.
+ */
+
+#define PORT_NONE	0x0	/* '/' No Port */
+#define PORT_OUTPUT	0x1	/* 'O' Push-Pull, Output Only */
+#define PORT_INPUT	0x2	/* 'I' Input Only */
+#define PORT_OPENDRAIN	0x3	/* 'P' Open-Drain, I/O */
+
+#define IO_4I4O		0x5AA5	/* O7 O6 I5 I4 I3 I2 O1 O0 */
+#define IO_4P4O		0x5FF5	/* O7 O6 P5 P4 P3 P2 O1 O0 */
+#define IO_8I		0xAAAA	/* I7 I6 I5 I4 I3 I2 I1 I0 */
+#define IO_8P		0xFFFF	/* P7 P6 P5 P4 P3 P2 P1 P0 */
+#define IO_8O		0x5555	/* O7 O6 O5 O4 O3 O2 O1 O0 */
+
+#define GROUP_A(x)	((x) & 0xffff)	/* I2C Addr: 0b'110xxxx */
+#define GROUP_B(x)	((x) << 16)	/* I2C Addr: 0b'101xxxx */
+
+static const struct i2c_device_id max732x_id[] = {
+	{ "max7319", GROUP_A(IO_8I) },
+	{ "max7320", GROUP_B(IO_8O) },
+	{ "max7321", GROUP_A(IO_8P) },
+	{ "max7322", GROUP_A(IO_4I4O) },
+	{ "max7323", GROUP_A(IO_4P4O) },
+	{ "max7324", GROUP_A(IO_8I) | GROUP_B(IO_8O) },
+	{ "max7325", GROUP_A(IO_8P) | GROUP_B(IO_8O) },
+	{ "max7326", GROUP_A(IO_4I4O) | GROUP_B(IO_8O) },
+	{ "max7327", GROUP_A(IO_4P4O) | GROUP_B(IO_8O) },
+	{ },
+};
+MODULE_DEVICE_TABLE(i2c, max732x_id);
+
+struct max732x_chip {
+	struct gpio_chip gpio_chip;
+
+	struct i2c_client *client;	/* "main" client */
+	struct i2c_client *client_dummy;
+	struct i2c_client *client_group_a;
+	struct i2c_client *client_group_b;
+
+	unsigned int	mask_group_a;
+	unsigned int	dir_input;
+	unsigned int	dir_output;
+
+	struct mutex	lock;
+	uint8_t		reg_out[2];
+};
+
+static int max732x_write(struct max732x_chip *chip, int group_a, uint8_t val)
+{
+	struct i2c_client *client;
+	int ret;
+
+	client = group_a ? chip->client_group_a : chip->client_group_b;
+	ret = i2c_smbus_write_byte(client, val);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed writing\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int max732x_read(struct max732x_chip *chip, int group_a, uint8_t *val)
+{
+	struct i2c_client *client;
+	int ret;
+
+	client = group_a ? chip->client_group_a : chip->client_group_b;
+	ret = i2c_smbus_read_byte(client);
+	if (ret < 0) {
+		dev_err(&client->dev, "failed reading\n");
+		return ret;
+	}
+
+	*val = (uint8_t)ret;
+	return 0;
+}
+
+static inline int is_group_a(struct max732x_chip *chip, unsigned off)
+{
+	return (1u << off) & chip->mask_group_a;
+}
+
+static int max732x_gpio_get_value(struct gpio_chip *gc, unsigned off)
+{
+	struct max732x_chip *chip;
+	uint8_t reg_val;
+	int ret;
+
+	chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+	ret = max732x_read(chip, is_group_a(chip, off), &reg_val);
+	if (ret < 0)
+		return 0;
+
+	return reg_val & (1u << (off & 0x7));
+}
+
+static void max732x_gpio_set_value(struct gpio_chip *gc, unsigned off, int val)
+{
+	struct max732x_chip *chip;
+	uint8_t reg_out, mask = 1u << (off & 0x7);
+	int ret;
+
+	chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+	mutex_lock(&chip->lock);
+
+	reg_out = (off > 7) ? chip->reg_out[1] : chip->reg_out[0];
+	reg_out = (val) ? reg_out | mask : reg_out & ~mask;
+
+	ret = max732x_write(chip, is_group_a(chip, off), reg_out);
+	if (ret < 0)
+		goto out;
+
+	/* update the shadow register then */
+	if (off > 7)
+		chip->reg_out[1] = reg_out;
+	else
+		chip->reg_out[0] = reg_out;
+out:
+	mutex_unlock(&chip->lock);
+}
+
+static int max732x_gpio_direction_input(struct gpio_chip *gc, unsigned off)
+{
+	struct max732x_chip *chip;
+	unsigned int mask = 1u << off;
+
+	chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+	if ((mask & chip->dir_input) == 0) {
+		dev_dbg(&chip->client->dev, "%s port %d is output only\n",
+			chip->client->name, off);
+		return -EACCES;
+	}
+
+	return 0;
+}
+
+static int max732x_gpio_direction_output(struct gpio_chip *gc,
+		unsigned off, int val)
+{
+	struct max732x_chip *chip;
+	unsigned int mask = 1u << off;
+
+	chip = container_of(gc, struct max732x_chip, gpio_chip);
+
+	if ((mask & chip->dir_output) == 0) {
+		dev_dbg(&chip->client->dev, "%s port %d is input only\n",
+			chip->client->name, off);
+		return -EACCES;
+	}
+
+	max732x_gpio_set_value(gc, off, val);
+	return 0;
+}
+
+static int __devinit max732x_setup_gpio(struct max732x_chip *chip,
+					const struct i2c_device_id *id,
+					unsigned gpio_start)
+{
+	struct gpio_chip *gc = &chip->gpio_chip;
+	uint32_t id_data = id->driver_data;
+	int i, port = 0;
+
+	for (i = 0; i < 16; i++, id_data >>= 2) {
+		unsigned int mask = 1 << port;
+
+		switch (id_data & 0x3) {
+		case PORT_OUTPUT:
+			chip->dir_output |= mask;
+			break;
+		case PORT_INPUT:
+			chip->dir_input |= mask;
+			break;
+		case PORT_OPENDRAIN:
+			chip->dir_output |= mask;
+			chip->dir_input |= mask;
+			break;
+		default:
+			continue;
+		}
+
+		if (i < 8)
+			chip->mask_group_a |= mask;
+		port++;
+	}
+
+	if (chip->dir_input)
+		gc->direction_input = max732x_gpio_direction_input;
+	if (chip->dir_output) {
+		gc->direction_output = max732x_gpio_direction_output;
+		gc->set = max732x_gpio_set_value;
+	}
+	gc->get = max732x_gpio_get_value;
+	gc->can_sleep = 1;
+
+	gc->base = gpio_start;
+	gc->ngpio = port;
+	gc->label = chip->client->name;
+	gc->owner = THIS_MODULE;
+
+	return port;
+}
+
+static int __devinit max732x_probe(struct i2c_client *client,
+				   const struct i2c_device_id *id)
+{
+	struct max732x_platform_data *pdata;
+	struct max732x_chip *chip;
+	struct i2c_client *c;
+	uint16_t addr_a, addr_b;
+	int ret, nr_port;
+
+	pdata = client->dev.platform_data;
+	if (pdata == NULL)
+		return -ENODEV;
+
+	chip = kzalloc(sizeof(struct max732x_chip), GFP_KERNEL);
+	if (chip == NULL)
+		return -ENOMEM;
+	chip->client = client;
+
+	nr_port = max732x_setup_gpio(chip, id, pdata->gpio_base);
+
+	addr_a = (client->addr & 0x0f) | 0x60;
+	addr_b = (client->addr & 0x0f) | 0x50;
+
+	switch (client->addr & 0x70) {
+	case 0x60:
+		chip->client_group_a = client;
+		if (nr_port > 7) {
+			c = i2c_new_dummy(client->adapter, addr_b);
+			chip->client_group_b = chip->client_dummy = c;
+		}
+		break;
+	case 0x50:
+		chip->client_group_b = client;
+		if (nr_port > 7) {
+			c = i2c_new_dummy(client->adapter, addr_a);
+			chip->client_group_a = chip->client_dummy = c;
+		}
+		break;
+	default:
+		dev_err(&client->dev, "invalid I2C address specified %02x\n",
+				client->addr);
+		ret = -EINVAL;
+		goto out_failed;
+	}
+
+	mutex_init(&chip->lock);
+
+	max732x_read(chip, is_group_a(chip, 0), &chip->reg_out[0]);
+	if (nr_port > 7)
+		max732x_read(chip, is_group_a(chip, 8), &chip->reg_out[1]);
+
+	ret = gpiochip_add(&chip->gpio_chip);
+	if (ret)
+		goto out_failed;
+
+	if (pdata->setup) {
+		ret = pdata->setup(client, chip->gpio_chip.base,
+				chip->gpio_chip.ngpio, pdata->context);
+		if (ret < 0)
+			dev_warn(&client->dev, "setup failed, %d\n", ret);
+	}
+
+	i2c_set_clientdata(client, chip);
+	return 0;
+
+out_failed:
+	kfree(chip);
+	return ret;
+}
+
+static int __devexit max732x_remove(struct i2c_client *client)
+{
+	struct max732x_platform_data *pdata = client->dev.platform_data;
+	struct max732x_chip *chip = i2c_get_clientdata(client);
+	int ret;
+
+	if (pdata->teardown) {
+		ret = pdata->teardown(client, chip->gpio_chip.base,
+				chip->gpio_chip.ngpio, pdata->context);
+		if (ret < 0) {
+			dev_err(&client->dev, "%s failed, %d\n",
+					"teardown", ret);
+			return ret;
+		}
+	}
+
+	ret = gpiochip_remove(&chip->gpio_chip);
+	if (ret) {
+		dev_err(&client->dev, "%s failed, %d\n",
+				"gpiochip_remove()", ret);
+		return ret;
+	}
+
+	/* unregister any dummy i2c_client */
+	if (chip->client_dummy)
+		i2c_unregister_device(chip->client_dummy);
+
+	kfree(chip);
+	return 0;
+}
+
+static struct i2c_driver max732x_driver = {
+	.driver = {
+		.name	= "max732x",
+		.owner	= THIS_MODULE,
+	},
+	.probe		= max732x_probe,
+	.remove		= __devexit_p(max732x_remove),
+	.id_table	= max732x_id,
+};
+
+static int __init max732x_init(void)
+{
+	return i2c_add_driver(&max732x_driver);
+}
+module_init(max732x_init);
+
+static void __exit max732x_exit(void)
+{
+	i2c_del_driver(&max732x_driver);
+}
+module_exit(max732x_exit);
+
+MODULE_AUTHOR("Eric Miao <eric.miao@marvell.com>");
+MODULE_DESCRIPTION("GPIO expander driver for MAX732X");
+MODULE_LICENSE("GPL");
diff --git a/drivers/gpio/mcp23s08.c b/drivers/gpio/mcp23s08.c
index 7f92fdd5f0e..8a1b405fefd 100644
--- a/drivers/gpio/mcp23s08.c
+++ b/drivers/gpio/mcp23s08.c
@@ -40,15 +40,26 @@ struct mcp23s08 {
 	struct spi_device	*spi;
 	u8			addr;
 
+	u8			cache[11];
 	/* lock protects the cached values */
 	struct mutex		lock;
-	u8			cache[11];
 
 	struct gpio_chip	chip;
 
 	struct work_struct	work;
 };
 
+/* A given spi_device can represent up to four mcp23s08 chips
+ * sharing the same chipselect but using different addresses
+ * (e.g. chips #0 and #3 might be populated, but not #1 or $2).
+ * Driver data holds all the per-chip data.
+ */
+struct mcp23s08_driver_data {
+	unsigned		ngpio;
+	struct mcp23s08		*mcp[4];
+	struct mcp23s08		chip[];
+};
+
 static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
 {
 	u8	tx[2], rx[1];
@@ -208,25 +219,18 @@ done:
 
 /*----------------------------------------------------------------------*/
 
-static int mcp23s08_probe(struct spi_device *spi)
+static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
+		unsigned base, unsigned pullups)
 {
-	struct mcp23s08			*mcp;
-	struct mcp23s08_platform_data	*pdata;
+	struct mcp23s08_driver_data	*data = spi_get_drvdata(spi);
+	struct mcp23s08			*mcp = data->mcp[addr];
 	int				status;
 	int				do_update = 0;
 
-	pdata = spi->dev.platform_data;
-	if (!pdata || pdata->slave > 3 || !pdata->base)
-		return -ENODEV;
-
-	mcp = kzalloc(sizeof *mcp, GFP_KERNEL);
-	if (!mcp)
-		return -ENOMEM;
-
 	mutex_init(&mcp->lock);
 
 	mcp->spi = spi;
-	mcp->addr = 0x40 | (pdata->slave << 1);
+	mcp->addr = 0x40 | (addr << 1);
 
 	mcp->chip.label = "mcp23s08",
 
@@ -236,26 +240,28 @@ static int mcp23s08_probe(struct spi_device *spi)
 	mcp->chip.set = mcp23s08_set;
 	mcp->chip.dbg_show = mcp23s08_dbg_show;
 
-	mcp->chip.base = pdata->base;
+	mcp->chip.base = base;
 	mcp->chip.ngpio = 8;
 	mcp->chip.can_sleep = 1;
+	mcp->chip.dev = &spi->dev;
 	mcp->chip.owner = THIS_MODULE;
 
-	spi_set_drvdata(spi, mcp);
-
-	/* verify MCP_IOCON.SEQOP = 0, so sequential reads work */
+	/* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
+	 * and MCP_IOCON.HAEN = 1, so we work with all chips.
+	 */
 	status = mcp23s08_read(mcp, MCP_IOCON);
 	if (status < 0)
 		goto fail;
-	if (status & IOCON_SEQOP) {
+	if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
 		status &= ~IOCON_SEQOP;
+		status |= IOCON_HAEN;
 		status = mcp23s08_write(mcp, MCP_IOCON, (u8) status);
 		if (status < 0)
 			goto fail;
 	}
 
 	/* configure ~100K pullups */
-	status = mcp23s08_write(mcp, MCP_GPPU, pdata->pullups);
+	status = mcp23s08_write(mcp, MCP_GPPU, pullups);
 	if (status < 0)
 		goto fail;
 
@@ -282,11 +288,58 @@ static int mcp23s08_probe(struct spi_device *spi)
 		tx[1] = MCP_IPOL;
 		memcpy(&tx[2], &mcp->cache[MCP_IPOL], sizeof(tx) - 2);
 		status = spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
-
-		/* FIXME check status... */
+		if (status < 0)
+			goto fail;
 	}
 
 	status = gpiochip_add(&mcp->chip);
+fail:
+	if (status < 0)
+		dev_dbg(&spi->dev, "can't setup chip %d, --> %d\n",
+				addr, status);
+	return status;
+}
+
+static int mcp23s08_probe(struct spi_device *spi)
+{
+	struct mcp23s08_platform_data	*pdata;
+	unsigned			addr;
+	unsigned			chips = 0;
+	struct mcp23s08_driver_data	*data;
+	int				status;
+	unsigned			base;
+
+	pdata = spi->dev.platform_data;
+	if (!pdata || !gpio_is_valid(pdata->base))
+		return -ENODEV;
+
+	for (addr = 0; addr < 4; addr++) {
+		if (!pdata->chip[addr].is_present)
+			continue;
+		chips++;
+	}
+	if (!chips)
+		return -ENODEV;
+
+	data = kzalloc(sizeof *data + chips * sizeof(struct mcp23s08),
+			GFP_KERNEL);
+	if (!data)
+		return -ENOMEM;
+	spi_set_drvdata(spi, data);
+
+	base = pdata->base;
+	for (addr = 0; addr < 4; addr++) {
+		if (!pdata->chip[addr].is_present)
+			continue;
+		chips--;
+		data->mcp[addr] = &data->chip[chips];
+		status = mcp23s08_probe_one(spi, addr, base,
+				pdata->chip[addr].pullups);
+		if (status < 0)
+			goto fail;
+		base += 8;
+	}
+	data->ngpio = base - pdata->base;
 
 	/* NOTE:  these chips have a relatively sane IRQ framework, with
 	 * per-signal masking and level/edge triggering.  It's not yet
@@ -294,8 +347,9 @@ static int mcp23s08_probe(struct spi_device *spi)
 	 */
 
 	if (pdata->setup) {
-		status = pdata->setup(spi, mcp->chip.base,
-				mcp->chip.ngpio, pdata->context);
+		status = pdata->setup(spi,
+				pdata->base, data->ngpio,
+				pdata->context);
 		if (status < 0)
 			dev_dbg(&spi->dev, "setup --> %d\n", status);
 	}
@@ -303,19 +357,29 @@ static int mcp23s08_probe(struct spi_device *spi)
 	return 0;
 
 fail:
-	kfree(mcp);
+	for (addr = 0; addr < 4; addr++) {
+		int tmp;
+
+		if (!data->mcp[addr])
+			continue;
+		tmp = gpiochip_remove(&data->mcp[addr]->chip);
+		if (tmp < 0)
+			dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
+	}
+	kfree(data);
 	return status;
 }
 
 static int mcp23s08_remove(struct spi_device *spi)
 {
-	struct mcp23s08			*mcp = spi_get_drvdata(spi);
+	struct mcp23s08_driver_data	*data = spi_get_drvdata(spi);
 	struct mcp23s08_platform_data	*pdata = spi->dev.platform_data;
+	unsigned			addr;
 	int				status = 0;
 
 	if (pdata->teardown) {
 		status = pdata->teardown(spi,
-				mcp->chip.base, mcp->chip.ngpio,
+				pdata->base, data->ngpio,
 				pdata->context);
 		if (status < 0) {
 			dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
@@ -323,11 +387,20 @@ static int mcp23s08_remove(struct spi_device *spi)
 		}
 	}
 
-	status = gpiochip_remove(&mcp->chip);
+	for (addr = 0; addr < 4; addr++) {
+		int tmp;
+
+		if (!data->mcp[addr])
+			continue;
+
+		tmp = gpiochip_remove(&data->mcp[addr]->chip);
+		if (tmp < 0) {
+			dev_err(&spi->dev, "%s --> %d\n", "remove", tmp);
+			status = tmp;
+		}
+	}
 	if (status == 0)
-		kfree(mcp);
-	else
-		dev_err(&spi->dev, "%s --> %d\n", "remove", status);
+		kfree(data);
 	return status;
 }
 
@@ -355,4 +428,3 @@ static void __exit mcp23s08_exit(void)
 module_exit(mcp23s08_exit);
 
 MODULE_LICENSE("GPL");
-
diff --git a/drivers/gpio/pca953x.c b/drivers/gpio/pca953x.c
index a380730b61a..cc8468692ae 100644
--- a/drivers/gpio/pca953x.c
+++ b/drivers/gpio/pca953x.c
@@ -188,6 +188,7 @@ static void pca953x_setup_gpio(struct pca953x_chip *chip, int gpios)
 	gc->base = chip->gpio_start;
 	gc->ngpio = gpios;
 	gc->label = chip->client->name;
+	gc->dev = &chip->client->dev;
 	gc->owner = THIS_MODULE;
 }
 
diff --git a/drivers/gpio/pcf857x.c b/drivers/gpio/pcf857x.c
index aa6cc8b2a2b..fc9c6ae739e 100644
--- a/drivers/gpio/pcf857x.c
+++ b/drivers/gpio/pcf857x.c
@@ -37,6 +37,8 @@ static const struct i2c_device_id pcf857x_id[] = {
 	{ "pca9671", 16 },
 	{ "pca9673", 16 },
 	{ "pca9675", 16 },
+	{ "max7328", 8 },
+	{ "max7329", 8 },
 	{ }
 };
 MODULE_DEVICE_TABLE(i2c, pcf857x_id);
@@ -56,6 +58,7 @@ MODULE_DEVICE_TABLE(i2c, pcf857x_id);
 struct pcf857x {
 	struct gpio_chip	chip;
 	struct i2c_client	*client;
+	struct mutex		lock;		/* protect 'out' */
 	unsigned		out;		/* software latch */
 };
 
@@ -66,9 +69,14 @@ struct pcf857x {
 static int pcf857x_input8(struct gpio_chip *chip, unsigned offset)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
+	int		status;
 
+	mutex_lock(&gpio->lock);
 	gpio->out |= (1 << offset);
-	return i2c_smbus_write_byte(gpio->client, gpio->out);
+	status = i2c_smbus_write_byte(gpio->client, gpio->out);
+	mutex_unlock(&gpio->lock);
+
+	return status;
 }
 
 static int pcf857x_get8(struct gpio_chip *chip, unsigned offset)
@@ -84,12 +92,17 @@ static int pcf857x_output8(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
 	unsigned	bit = 1 << offset;
+	int		status;
 
+	mutex_lock(&gpio->lock);
 	if (value)
 		gpio->out |= bit;
 	else
 		gpio->out &= ~bit;
-	return i2c_smbus_write_byte(gpio->client, gpio->out);
+	status = i2c_smbus_write_byte(gpio->client, gpio->out);
+	mutex_unlock(&gpio->lock);
+
+	return status;
 }
 
 static void pcf857x_set8(struct gpio_chip *chip, unsigned offset, int value)
@@ -124,9 +137,14 @@ static int i2c_read_le16(struct i2c_client *client)
 static int pcf857x_input16(struct gpio_chip *chip, unsigned offset)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
+	int		status;
 
+	mutex_lock(&gpio->lock);
 	gpio->out |= (1 << offset);
-	return i2c_write_le16(gpio->client, gpio->out);
+	status = i2c_write_le16(gpio->client, gpio->out);
+	mutex_unlock(&gpio->lock);
+
+	return status;
 }
 
 static int pcf857x_get16(struct gpio_chip *chip, unsigned offset)
@@ -142,12 +160,17 @@ static int pcf857x_output16(struct gpio_chip *chip, unsigned offset, int value)
 {
 	struct pcf857x	*gpio = container_of(chip, struct pcf857x, chip);
 	unsigned	bit = 1 << offset;
+	int		status;
 
+	mutex_lock(&gpio->lock);
 	if (value)
 		gpio->out |= bit;
 	else
 		gpio->out &= ~bit;
-	return i2c_write_le16(gpio->client, gpio->out);
+	status = i2c_write_le16(gpio->client, gpio->out);
+	mutex_unlock(&gpio->lock);
+
+	return status;
 }
 
 static void pcf857x_set16(struct gpio_chip *chip, unsigned offset, int value)
@@ -173,8 +196,11 @@ static int pcf857x_probe(struct i2c_client *client,
 	if (!gpio)
 		return -ENOMEM;
 
+	mutex_init(&gpio->lock);
+
 	gpio->chip.base = pdata->gpio_base;
 	gpio->chip.can_sleep = 1;
+	gpio->chip.dev = &client->dev;
 	gpio->chip.owner = THIS_MODULE;
 
 	/* NOTE:  the OnSemi jlc1562b is also largely compatible with