mfd: Add HTCPLD driver

This change introduces a driver for the HTC PLD chip found
on some smartphones, such as the HTC Wizard and HTC Herald.
It works through the I2C bus and acts as a GPIO extender.
Specifically:

 * it can have several sub-devices, each with its own I2C
   address
 * Each sub-device provides 8 output and 8 input pins
 * The chip attaches to one GPIO to signal when any of the
   input GPIOs change -- at which point all chips must be
   scanned for changes

This driver implements the GPIOs throught the kernel's
GPIO and IRQ framework.  This allows any GPIO-servicing
drivers to operate on htcpld pins, such as the gpio-keys
and gpio-leds drivers.

Signed-off-by: Cory Maccarrone <darkstar6262@gmail.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>
diff --git a/include/linux/htcpld.h b/include/linux/htcpld.h
new file mode 100644
index 0000000..ab3f6cb4
--- /dev/null
+++ b/include/linux/htcpld.h
@@ -0,0 +1,24 @@
+#ifndef __LINUX_HTCPLD_H
+#define __LINUX_HTCPLD_H
+
+struct htcpld_chip_platform_data {
+	unsigned int addr;
+	unsigned int reset;
+	unsigned int num_gpios;
+	unsigned int gpio_out_base;
+	unsigned int gpio_in_base;
+	unsigned int irq_base;
+	unsigned int num_irqs;
+};
+
+struct htcpld_core_platform_data {
+	unsigned int                      int_reset_gpio_hi;
+	unsigned int                      int_reset_gpio_lo;
+	unsigned int                      i2c_adapter_id;
+
+	struct htcpld_chip_platform_data  *chip;
+	unsigned int                      num_chip;
+};
+
+#endif /* __LINUX_HTCPLD_H */
+