HID: mcp2221: add usb to i2c-smbus host bridge

MCP2221 is a USB HID to I2C/SMbus host bridge device. This
commit implements i2c and smbus host adapter support. 7-bit
address and i2c multi-message transaction is also supported.

Signed-off-by: Rishi Gupta <gupt21@gmail.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

MAINTAINERS

@@ -10236,6 +10236,13 @@ F:	drivers/net/can/m_can/m_can.c
 F:	drivers/net/can/m_can/m_can.h
 F:	drivers/net/can/m_can/m_can_platform.c
 
+MCP2221A MICROCHIP USB-HID TO I2C BRIDGE DRIVER
+M:	Rishi Gupta <gupt21@gmail.com>
+L:	linux-i2c@vger.kernel.org
+L:	linux-input@vger.kernel.org
+S:	Maintained
+F:	drivers/hid/hid-mcp2221.c
+
 MCP4018 AND MCP4531 MICROCHIP DIGITAL POTENTIOMETER DRIVERS
 M:	Peter Rosin <peda@axentia.se>
 L:	linux-iio@vger.kernel.org

drivers/hid/Kconfig

@@ -1145,6 +1145,16 @@ config HID_ALPS
 	Say Y here if you have a Alps touchpads over i2c-hid or usbhid
 	and want support for its special functionalities.
 
+config HID_MCP2221
+	tristate "Microchip MCP2221 HID USB-to-I2C/SMbus host support"
+	depends on USB_HID && I2C
+	---help---
+	Provides I2C and SMBUS host adapter functionality over USB-HID
+	through MCP2221 device.
+
+	To compile this driver as a module, choose M here: the module
+	will be called hid-mcp2221.ko.
+
 endmenu
 
 endif # HID

drivers/hid/Makefile

@@ -70,6 +70,7 @@ obj-$(CONFIG_HID_LOGITECH_HIDPP)	+= hid-logitech-hidpp.o
 obj-$(CONFIG_HID_MACALLY)	+= hid-macally.o
 obj-$(CONFIG_HID_MAGICMOUSE)	+= hid-magicmouse.o
 obj-$(CONFIG_HID_MALTRON)	+= hid-maltron.o
+obj-$(CONFIG_HID_MCP2221)	+= hid-mcp2221.o
 obj-$(CONFIG_HID_MAYFLASH)	+= hid-mf.o
 obj-$(CONFIG_HID_MICROSOFT)	+= hid-microsoft.o
 obj-$(CONFIG_HID_MONTEREY)	+= hid-monterey.o

drivers/hid/hid-ids.h

@@ -819,6 +819,7 @@
 #define USB_DEVICE_ID_PICK16F1454	0x0042
 #define USB_DEVICE_ID_PICK16F1454_V2	0xf2f7
 #define USB_DEVICE_ID_LUXAFOR		0xf372
+#define USB_DEVICE_ID_MCP2221		0x00dd
 
 #define USB_VENDOR_ID_MICROSOFT		0x045e
 #define USB_DEVICE_ID_SIDEWINDER_GV	0x003b