Dear all I managed to get this driver and Sergio's userspace one working on an A20 tablet (a A70x). I thought to post back with my findings.
First of all although fw_extractor does a great job, there is not a lot of consistency in how firmwares in the Android kernel driver start and finish and so it is natural that it is going to be misguided for some firmwares (I found firmwares that started f0 00 00 00 97 00 00 00, f0 00 00 00 03 00 00 00 and f0 00 00 00 00 00 00 00 and I found firmwares that ended both 7c 00 00 00 00 00 00 00 as well as 7c 00 00 00 16 ff ff ff). The most reliable way I found of identifying the start and end of each firmware was to use "readelf -s" to extract the lengths of the objects directly (I used "readelf -s | grep -i fw" but bear in mind that I was running on an arm system and readelf may not necessarily produce correct results with arm binaries on an x86 system unless you tell it that you are dealing with an arm binary. Actually, that might be an idea to update fw_extractor to use readelf ... hmm. When working out which firmware to use, the gslx680 does not seem to like being uploaded with different firmwares and will stop responding (neither driver will, however, report any errors). It took me about 20 hours to work this out! If you try a firmware the device must be fully switched off (a reboot is not sufficient) before trying another one. For me, non-working firmwares just produced no output. Fourthly, as identified earlier, the i2c incomplete xfer stuff is caused by a recent(ish) patch to the 3.4 sunxi kernel changing the default transfer speed to 100khz. The file to change is arch/arm/plat-sunxi/include/plat/i2c.h (towards the end). I think the patch should be reverted. This certainly affected Joe's driver (kernel). I did not investigate whether the change to the default speed was needed for Sergio's (user space) driver. Fifthly, for Joe's driver, the previous comment about 'With A20, I think you should remove "IRQF_TRIGGER_FALLING |"' is important. Finally, thanks to both Joe and Sergio. Great work, saved me a bunch of time. In passing, I identified some possibly useful changes to both drivers, are you accepting pull requests? Have fun BBUK > -- You received this message because you are subscribed to the Google Groups "linux-sunxi" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. For more options, visit https://groups.google.com/d/optout.
