Merge branch 'linus' into x86/x2apic

Conflicts:

	arch/x86/kernel/genapic_64.c

Manual merge:

	arch/x86/kernel/genx2apic_uv_x.c

Signed-off-by: Ingo Molnar <mingo@elte.hu>

8 files changed, 1445 insertions, 49 deletions

diff --git a/drivers/gpio/Kconfig b/drivers/gpio/Kconfig
index fced1909cbba..dbd42d6c93a7 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.
 
-menu "GPIO Support"
-        depends on HAVE_GPIO_LIB
+          If unsure, say N.
+
+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
@@ -68,6 +127,24 @@ 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
@@ -83,4 +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 16e796dc5410..01b4bbde1956 100644
--- a/drivers/gpio/Makefile
+++ b/drivers/gpio/Makefile
@@ -2,9 +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 000000000000..7a1168249dd5
--- /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 beaf6b3a37dc..8d2940517c99 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/max732x.c b/drivers/gpio/max732x.c
new file mode 100644
index 000000000000..b51c8135ca28
--- /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 7f92fdd5f0e2..8a1b405fefda 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 a380730b61ab..cc8468692ae0 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 d25d356c4f20..fc9c6ae739ee 100644
--- a/drivers/gpio/pcf857x.c
+++ b/drivers/gpio/pcf857x.c
@@ -200,6 +200,7 @@ static int pcf857x_probe(struct i2c_client *client,
 
         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