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add support for Janz MODULbus devices

From:  "Ira W. Snyder" <iws@ovro.caltech.edu>
To:  linux-kernel@vger.kernel.org
Subject:  [PATCH 0/3 RFCv4] add support for Janz MODULbus devices
Date:  Tue, 2 Mar 2010 13:22:06 -0800
Message-ID:  <1267564929-9324-1-git-send-email-iws@ovro.caltech.edu>
Archive-link:  Article, Thread

This patch series adds support for the Janz CMOD-IO carrier board, as well
as the Janz VMOD-ICAN3 Intelligent CAN controller and the Janz VMOD-TTL
Digital IO controller. The CMOD-IO carrier board is a PCI to MODULbus
bridge, into which plug MODULbus daughterboards.  I only have access to two
types of daughtercards, the VMOD-ICAN3 and VMOD-TTL boards mentioned above.

The CAN driver has been tested under high loads. I am able to generate ~60%
bus utilization. With two VMOD-ICAN3 boards looped back to each other,
neither one loses any packets when only a single board is generating
packets at maximum speed. Once both boards start generating packets, one
board will sometimes loose arbitration, and cause some lost packets.

RFCv3 -> RFCv4:
- addressed many review comments
- switch to NAPI
- add TX flow control
- mark functions with __devinit and __devexit
- add sysfs readout of MODULbus number (hex switch)
- implement GPIO driver for VMOD-TTL

RFCv2 -> RFCv3:
- addressed many review comments
- correct CAN bus error handling
- use struct device to track subdevices
- use structures for register layout
- add lots of #defines for register values
- use better function prefixes

RFCv1 -> RFCv2:
- converted to a multi-driver model
- addressed many review comments
- added CAN bus error handling
- use a work function only instead of work + NAPI
- use SJA1000 bittiming calculation code

I appreciate any review you can offer.

Thanks,
Ira
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