diff --git a/drivers/gpio/gpio-mcp23s08.c b/drivers/gpio/gpio-mcp23s08.c
new file mode 100644
index 0000000..0083ec0
--- /dev/null
+++ b/drivers/gpio/gpio-mcp23s08.c
@@ -0,0 +1,530 @@
+/*
+ * MCP23S08 SPI gpio expander driver
+ */
+
+#include <linux/kernel.h>
+#include <linux/device.h>
+#include <linux/workqueue.h>
+#include <linux/mutex.h>
+#include <linux/gpio.h>
+#include <linux/spi/spi.h>
+#include <linux/spi/mcp23s08.h>
+#include <linux/slab.h>
+#include <asm/byteorder.h>
+
+/**
+ * MCP types supported by driver
+ */
+#define MCP_TYPE_S08	0
+#define MCP_TYPE_S17	1
+
+/* Registers are all 8 bits wide.
+ *
+ * The mcp23s17 has twice as many bits, and can be configured to work
+ * with either 16 bit registers or with two adjacent 8 bit banks.
+ *
+ * Also, there are I2C versions of both chips.
+ */
+#define MCP_IODIR	0x00		/* init/reset:  all ones */
+#define MCP_IPOL	0x01
+#define MCP_GPINTEN	0x02
+#define MCP_DEFVAL	0x03
+#define MCP_INTCON	0x04
+#define MCP_IOCON	0x05
+#	define IOCON_SEQOP	(1 << 5)
+#	define IOCON_HAEN	(1 << 3)
+#	define IOCON_ODR	(1 << 2)
+#	define IOCON_INTPOL	(1 << 1)
+#define MCP_GPPU	0x06
+#define MCP_INTF	0x07
+#define MCP_INTCAP	0x08
+#define MCP_GPIO	0x09
+#define MCP_OLAT	0x0a
+
+struct mcp23s08;
+
+struct mcp23s08_ops {
+	int	(*read)(struct mcp23s08 *mcp, unsigned reg);
+	int	(*write)(struct mcp23s08 *mcp, unsigned reg, unsigned val);
+	int	(*read_regs)(struct mcp23s08 *mcp, unsigned reg,
+			     u16 *vals, unsigned n);
+};
+
+struct mcp23s08 {
+	struct spi_device	*spi;
+	u8			addr;
+
+	u16			cache[11];
+	/* lock protects the cached values */
+	struct mutex		lock;
+
+	struct gpio_chip	chip;
+
+	struct work_struct	work;
+
+	const struct mcp23s08_ops	*ops;
+};
+
+/* A given spi_device can represent up to eight mcp23sxx 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[8];
+	struct mcp23s08		chip[];
+};
+
+static int mcp23s08_read(struct mcp23s08 *mcp, unsigned reg)
+{
+	u8	tx[2], rx[1];
+	int	status;
+
+	tx[0] = mcp->addr | 0x01;
+	tx[1] = reg;
+	status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
+	return (status < 0) ? status : rx[0];
+}
+
+static int mcp23s08_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
+{
+	u8	tx[3];
+
+	tx[0] = mcp->addr;
+	tx[1] = reg;
+	tx[2] = val;
+	return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
+}
+
+static int
+mcp23s08_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
+{
+	u8	tx[2], *tmp;
+	int	status;
+
+	if ((n + reg) > sizeof mcp->cache)
+		return -EINVAL;
+	tx[0] = mcp->addr | 0x01;
+	tx[1] = reg;
+
+	tmp = (u8 *)vals;
+	status = spi_write_then_read(mcp->spi, tx, sizeof tx, tmp, n);
+	if (status >= 0) {
+		while (n--)
+			vals[n] = tmp[n]; /* expand to 16bit */
+	}
+	return status;
+}
+
+static int mcp23s17_read(struct mcp23s08 *mcp, unsigned reg)
+{
+	u8	tx[2], rx[2];
+	int	status;
+
+	tx[0] = mcp->addr | 0x01;
+	tx[1] = reg << 1;
+	status = spi_write_then_read(mcp->spi, tx, sizeof tx, rx, sizeof rx);
+	return (status < 0) ? status : (rx[0] | (rx[1] << 8));
+}
+
+static int mcp23s17_write(struct mcp23s08 *mcp, unsigned reg, unsigned val)
+{
+	u8	tx[4];
+
+	tx[0] = mcp->addr;
+	tx[1] = reg << 1;
+	tx[2] = val;
+	tx[3] = val >> 8;
+	return spi_write_then_read(mcp->spi, tx, sizeof tx, NULL, 0);
+}
+
+static int
+mcp23s17_read_regs(struct mcp23s08 *mcp, unsigned reg, u16 *vals, unsigned n)
+{
+	u8	tx[2];
+	int	status;
+
+	if ((n + reg) > sizeof mcp->cache)
+		return -EINVAL;
+	tx[0] = mcp->addr | 0x01;
+	tx[1] = reg << 1;
+
+	status = spi_write_then_read(mcp->spi, tx, sizeof tx,
+				     (u8 *)vals, n * 2);
+	if (status >= 0) {
+		while (n--)
+			vals[n] = __le16_to_cpu((__le16)vals[n]);
+	}
+
+	return status;
+}
+
+static const struct mcp23s08_ops mcp23s08_ops = {
+	.read		= mcp23s08_read,
+	.write		= mcp23s08_write,
+	.read_regs	= mcp23s08_read_regs,
+};
+
+static const struct mcp23s08_ops mcp23s17_ops = {
+	.read		= mcp23s17_read,
+	.write		= mcp23s17_write,
+	.read_regs	= mcp23s17_read_regs,
+};
+
+
+/*----------------------------------------------------------------------*/
+
+static int mcp23s08_direction_input(struct gpio_chip *chip, unsigned offset)
+{
+	struct mcp23s08	*mcp = container_of(chip, struct mcp23s08, chip);
+	int status;
+
+	mutex_lock(&mcp->lock);
+	mcp->cache[MCP_IODIR] |= (1 << offset);
+	status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
+	mutex_unlock(&mcp->lock);
+	return status;
+}
+
+static int mcp23s08_get(struct gpio_chip *chip, unsigned offset)
+{
+	struct mcp23s08	*mcp = container_of(chip, struct mcp23s08, chip);
+	int status;
+
+	mutex_lock(&mcp->lock);
+
+	/* REVISIT reading this clears any IRQ ... */
+	status = mcp->ops->read(mcp, MCP_GPIO);
+	if (status < 0)
+		status = 0;
+	else {
+		mcp->cache[MCP_GPIO] = status;
+		status = !!(status & (1 << offset));
+	}
+	mutex_unlock(&mcp->lock);
+	return status;
+}
+
+static int __mcp23s08_set(struct mcp23s08 *mcp, unsigned mask, int value)
+{
+	unsigned olat = mcp->cache[MCP_OLAT];
+
+	if (value)
+		olat |= mask;
+	else
+		olat &= ~mask;
+	mcp->cache[MCP_OLAT] = olat;
+	return mcp->ops->write(mcp, MCP_OLAT, olat);
+}
+
+static void mcp23s08_set(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct mcp23s08	*mcp = container_of(chip, struct mcp23s08, chip);
+	unsigned mask = 1 << offset;
+
+	mutex_lock(&mcp->lock);
+	__mcp23s08_set(mcp, mask, value);
+	mutex_unlock(&mcp->lock);
+}
+
+static int
+mcp23s08_direction_output(struct gpio_chip *chip, unsigned offset, int value)
+{
+	struct mcp23s08	*mcp = container_of(chip, struct mcp23s08, chip);
+	unsigned mask = 1 << offset;
+	int status;
+
+	mutex_lock(&mcp->lock);
+	status = __mcp23s08_set(mcp, mask, value);
+	if (status == 0) {
+		mcp->cache[MCP_IODIR] &= ~mask;
+		status = mcp->ops->write(mcp, MCP_IODIR, mcp->cache[MCP_IODIR]);
+	}
+	mutex_unlock(&mcp->lock);
+	return status;
+}
+
+/*----------------------------------------------------------------------*/
+
+#ifdef CONFIG_DEBUG_FS
+
+#include <linux/seq_file.h>
+
+/*
+ * This shows more info than the generic gpio dump code:
+ * pullups, deglitching, open drain drive.
+ */
+static void mcp23s08_dbg_show(struct seq_file *s, struct gpio_chip *chip)
+{
+	struct mcp23s08	*mcp;
+	char		bank;
+	int		t;
+	unsigned	mask;
+
+	mcp = container_of(chip, struct mcp23s08, chip);
+
+	/* NOTE: we only handle one bank for now ... */
+	bank = '0' + ((mcp->addr >> 1) & 0x7);
+
+	mutex_lock(&mcp->lock);
+	t = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
+	if (t < 0) {
+		seq_printf(s, " I/O ERROR %d\n", t);
+		goto done;
+	}
+
+	for (t = 0, mask = 1; t < chip->ngpio; t++, mask <<= 1) {
+		const char	*label;
+
+		label = gpiochip_is_requested(chip, t);
+		if (!label)
+			continue;
+
+		seq_printf(s, " gpio-%-3d P%c.%d (%-12s) %s %s %s",
+			chip->base + t, bank, t, label,
+			(mcp->cache[MCP_IODIR] & mask) ? "in " : "out",
+			(mcp->cache[MCP_GPIO] & mask) ? "hi" : "lo",
+			(mcp->cache[MCP_GPPU] & mask) ? "  " : "up");
+		/* NOTE:  ignoring the irq-related registers */
+		seq_printf(s, "\n");
+	}
+done:
+	mutex_unlock(&mcp->lock);
+}
+
+#else
+#define mcp23s08_dbg_show	NULL
+#endif
+
+/*----------------------------------------------------------------------*/
+
+static int mcp23s08_probe_one(struct spi_device *spi, unsigned addr,
+			      unsigned type, unsigned base, unsigned pullups)
+{
+	struct mcp23s08_driver_data	*data = spi_get_drvdata(spi);
+	struct mcp23s08			*mcp = data->mcp[addr];
+	int				status;
+
+	mutex_init(&mcp->lock);
+
+	mcp->spi = spi;
+	mcp->addr = 0x40 | (addr << 1);
+
+	mcp->chip.direction_input = mcp23s08_direction_input;
+	mcp->chip.get = mcp23s08_get;
+	mcp->chip.direction_output = mcp23s08_direction_output;
+	mcp->chip.set = mcp23s08_set;
+	mcp->chip.dbg_show = mcp23s08_dbg_show;
+
+	if (type == MCP_TYPE_S17) {
+		mcp->ops = &mcp23s17_ops;
+		mcp->chip.ngpio = 16;
+		mcp->chip.label = "mcp23s17";
+	} else {
+		mcp->ops = &mcp23s08_ops;
+		mcp->chip.ngpio = 8;
+		mcp->chip.label = "mcp23s08";
+	}
+	mcp->chip.base = base;
+	mcp->chip.can_sleep = 1;
+	mcp->chip.dev = &spi->dev;
+	mcp->chip.owner = THIS_MODULE;
+
+	/* verify MCP_IOCON.SEQOP = 0, so sequential reads work,
+	 * and MCP_IOCON.HAEN = 1, so we work with all chips.
+	 */
+	status = mcp->ops->read(mcp, MCP_IOCON);
+	if (status < 0)
+		goto fail;
+	if ((status & IOCON_SEQOP) || !(status & IOCON_HAEN)) {
+		/* mcp23s17 has IOCON twice, make sure they are in sync */
+		status &= ~(IOCON_SEQOP | (IOCON_SEQOP << 8));
+		status |= IOCON_HAEN | (IOCON_HAEN << 8);
+		status = mcp->ops->write(mcp, MCP_IOCON, status);
+		if (status < 0)
+			goto fail;
+	}
+
+	/* configure ~100K pullups */
+	status = mcp->ops->write(mcp, MCP_GPPU, pullups);
+	if (status < 0)
+		goto fail;
+
+	status = mcp->ops->read_regs(mcp, 0, mcp->cache, ARRAY_SIZE(mcp->cache));
+	if (status < 0)
+		goto fail;
+
+	/* disable inverter on input */
+	if (mcp->cache[MCP_IPOL] != 0) {
+		mcp->cache[MCP_IPOL] = 0;
+		status = mcp->ops->write(mcp, MCP_IPOL, 0);
+		if (status < 0)
+			goto fail;
+	}
+
+	/* disable irqs */
+	if (mcp->cache[MCP_GPINTEN] != 0) {
+		mcp->cache[MCP_GPINTEN] = 0;
+		status = mcp->ops->write(mcp, MCP_GPINTEN, 0);
+		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, type;
+	unsigned			base;
+
+	type = spi_get_device_id(spi)->driver_data;
+
+	pdata = spi->dev.platform_data;
+	if (!pdata || !gpio_is_valid(pdata->base)) {
+		dev_dbg(&spi->dev, "invalid or missing platform data\n");
+		return -EINVAL;
+	}
+
+	for (addr = 0; addr < ARRAY_SIZE(pdata->chip); addr++) {
+		if (!pdata->chip[addr].is_present)
+			continue;
+		chips++;
+		if ((type == MCP_TYPE_S08) && (addr > 3)) {
+			dev_err(&spi->dev,
+				"mcp23s08 only supports address 0..3\n");
+			return -EINVAL;
+		}
+	}
+	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 < ARRAY_SIZE(pdata->chip); addr++) {
+		if (!pdata->chip[addr].is_present)
+			continue;
+		chips--;
+		data->mcp[addr] = &data->chip[chips];
+		status = mcp23s08_probe_one(spi, addr, type, base,
+					    pdata->chip[addr].pullups);
+		if (status < 0)
+			goto fail;
+
+		base += (type == MCP_TYPE_S17) ? 16 : 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
+	 * handled here...
+	 */
+
+	if (pdata->setup) {
+		status = pdata->setup(spi,
+				pdata->base, data->ngpio,
+				pdata->context);
+		if (status < 0)
+			dev_dbg(&spi->dev, "setup --> %d\n", status);
+	}
+
+	return 0;
+
+fail:
+	for (addr = 0; addr < ARRAY_SIZE(data->mcp); 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_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,
+				pdata->base, data->ngpio,
+				pdata->context);
+		if (status < 0) {
+			dev_err(&spi->dev, "%s --> %d\n", "teardown", status);
+			return status;
+		}
+	}
+
+	for (addr = 0; addr < ARRAY_SIZE(data->mcp); 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(data);
+	return status;
+}
+
+static const struct spi_device_id mcp23s08_ids[] = {
+	{ "mcp23s08", MCP_TYPE_S08 },
+	{ "mcp23s17", MCP_TYPE_S17 },
+	{ },
+};
+MODULE_DEVICE_TABLE(spi, mcp23s08_ids);
+
+static struct spi_driver mcp23s08_driver = {
+	.probe		= mcp23s08_probe,
+	.remove		= mcp23s08_remove,
+	.id_table	= mcp23s08_ids,
+	.driver = {
+		.name	= "mcp23s08",
+		.owner	= THIS_MODULE,
+	},
+};
+
+/*----------------------------------------------------------------------*/
+
+static int __init mcp23s08_init(void)
+{
+	return spi_register_driver(&mcp23s08_driver);
+}
+/* register after spi postcore initcall and before
+ * subsys initcalls that may rely on these GPIOs
+ */
+subsys_initcall(mcp23s08_init);
+
+static void __exit mcp23s08_exit(void)
+{
+	spi_unregister_driver(&mcp23s08_driver);
+}
+module_exit(mcp23s08_exit);
+
+MODULE_LICENSE("GPL");