Quoting Stefan Roese <sr@xxxxxxx>:
This patch adds a driver for the I2C controller found on the MediaTek
MT7621/7628/7688 SoC's. The base version of this driver was done by
Steven Liu (according to the copyright and MODULE_AUTHOR lines). It
can be found in the OpenWRT repositories (v4.14 at the time I looked).
The base driver had many issues, which are disccussed here:
https://en.forum.labs.mediatek.com/t/openwrt-15-05-loads-non-working-i2c-kernel-module-for-mt7688/1286/3
1From this link an enhanced driver version (complete rewrite, mayor
changes: support clock stretching, repeated start, ACK handling and
unlimited message length) from Jan Breuer can be found here:
https://gist.github.com/j123b567/9b555b635c2b4069d716b24198546954
This patch now adds this enhanced I2C driver to mainline.
Changes by Stefan Roese for upstreaming:
- Add devicetree bindings
- checkpatch clean
- Use module_platform_driver()
- Minor cosmetic enhancements
Signed-off-by: Stefan Roese <sr@xxxxxxx>
Cc: Steven Liu <steven_liu@xxxxxxxxxxxx>
Cc: Jan Breuer <jan.breuer@xxxxxxxxx>
Cc: John Crispin <john@xxxxxxxxxxx>
Cc: Wolfram Sang <wsa+renesas@xxxxxxxxxxxxxxxxxxxx>
---
v2:
- Configure I2C controller to open-drain instead of push-pull, as
noticed and suggested by Jan (misleading bit description)
Hi Stefan,
I am using the openwrt version for a while on my Ubiquity ER-X-SFP
router on top of the net-next tree.
But I was unable to readout the SFP module because i2c message size
limit of 64 bytes.
Without additional patches my console was spamming me with -EOPNOTSUPP
because SFP code tries to read +90 bytes in one go.
With this driver the sfp code can readout the module successfully.
Both the SFP module and the GPIO expander on the bus are working.
Tested-by: René van Dorst <opensource@xxxxxxxxxx>
Greats,
René
