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+ C2 port support
+ ---------------
+(C) Copyright 2007 Rodolfo Giometti <>
+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
+GNU General Public License for more details.
+This driver implements the support for Linux of Silicon Labs (Silabs)
+C2 Interface used for in-system programming of micro controllers.
+By using this driver you can reprogram the in-system flash without EC2
+or EC3 debug adapter. This solution is also useful in those systems
+where the micro controller is connected via special GPIOs pins.
+The C2 Interface main references are at (
+Silicon Laboratories site], see:
+- AN127: FLASH Programming via the C2 Interface at
+, and
+- C2 Specification at
+however it implements a two wire serial communication protocol (bit
+banging) designed to enable in-system programming, debugging, and
+boundary-scan testing on low pin-count Silicon Labs devices. Currently
+this code supports only flash programming but extensions are easy to
+Using the driver
+Once the driver is loaded you can use sysfs support to get C2port's
+info or read/write in-system flash.
+# ls /sys/class/c2port/c2port0/
+access flash_block_size flash_erase rev_id
+dev_id flash_blocks_num flash_size subsystem/
+flash_access flash_data reset uevent
+Initially the C2port access is disabled since you hardware may have
+such lines multiplexed with other devices so, to get access to the
+C2port, you need the command:
+# echo 1 > /sys/class/c2port/c2port0/access
+after that you should read the device ID and revision ID of the
+connected micro controller:
+# cat /sys/class/c2port/c2port0/dev_id
+# cat /sys/class/c2port/c2port0/rev_id
+However, for security reasons, the in-system flash access in not
+enabled yet, to do so you need the command:
+# echo 1 > /sys/class/c2port/c2port0/flash_access
+After that you can read the whole flash:
+# cat /sys/class/c2port/c2port0/flash_data > image
+erase it:
+# echo 1 > /sys/class/c2port/c2port0/flash_erase
+and write it:
+# cat image > /sys/class/c2port/c2port0/flash_data
+after writing you have to reset the device to execute the new code:
+# echo 1 > /sys/class/c2port/c2port0/reset