i2c almost working for me, was Re: i2c still not working for me

[Emmanuel Vadot]

On Fri, 19 Apr 2019 10:20:47 +0300
Daniel Braniss <danny at cs.huji.ac.il> wrote:

> 
> 
> > On 18 Apr 2019, at 17:19, Ian Lepore <ian at freebsd.org> wrote:
> > 
> > On Thu, 2019-04-18 at 10:12 +0300, Daniel Braniss wrote:
> >>> On 17 Apr 2019, at 23:26, Emmanuel Vadot <manu at bidouilliste.com>
> >>> wrote:
> >>> 
> >>> On Tue, 16 Apr 2019 09:16:02 +0300
> >>> Daniel Braniss <danny at cs.huji.ac.il <mailto:danny at cs.huji.ac.il>>
> >>> wrote:
> >>> 
> >>>> 
> >>>> 
> >>>>> On 11 Apr 2019, at 09:56, Daniel Braniss <danny at cs.huji.ac.il>
> >>>>> wrote:
> >>>>> 
> >>>>> if no device is connected, I2CRDWR hangs, 
> >>>>> it also happens with i2c(8) -s, only reboot helps.
> >>>>> 
> >>>>> ichb1: twsi_reset: Using IIC_FASTEST/UNKNOWN mode with speed
> >>>>> param=2a
> >>>>> iichb1: TWSI_WRITE: Writing 0 to 18
> >>>>> iichb1: TWSI_WRITE: Writing 2a to 14
> >>>>> iichb1: TWSI_WRITE: Writing 40 to c
> >>>>> iichb1: TWSI_WRITE: Writing c4 to c
> >>>>> iichb1: twsi_transfer: transmitting 2 messages
> >>>>> iichb1: TWSI_READ: read f8 from 10
> >>>>> iichb1: twsi_transfer: status=f8
> >>>>> iichb1: twsi_transfer: msg[0] flags: 0
> >>>>> iichb1: twsi_transfer: msg[0] len: 9
> >>>>> iichb1: TWSI_WRITE: Writing e4 to c
> >>>>> 
> >>>>> and now it?s hung
> >>>> 
> >>>> [?]
> >>> 
> >>> I don't see that on my OrangePi One or Pine64-LTS.
> >> 
> >> well, mine is are Nanopi Neo, maybe it?s a dts issue?
> >> I also have a orangepi-zero but it will take me some time to make
> >> a sdcard
> 
> I managed to boot my OrangePi Zero, and i2c -s has no issues, does not hang.
> still, with the latest (r346368) my NanoPi Neo hangs when no i2c device is present,
> so what is the difference? or where can I look?

 Are you using the same i2c controller on both ?
 Could you paste somewhere the overlays or dts patches ?

> 
> >>> 
> >>>> 
> >>>> even with a working device, this happens sometimes:
> >>>> 
> >>>> my app gets ENXIO from the ioctl(fd, I2CRDWR, &data) and on the
> >>>> console:
> >>>> ?
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 38 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> gic0: Spurious interrupt detected: last irq: 29 on CPU2
> >>>> 
> >>>> the good news: my app is killable :-)
> >>> 
> >>> I would need more details for this.
> >> 
> >> it was caused by i2c issues - the cable was a bit too long.
> >> BTW, does changing the frequency work? ie dev.iicbus.0.frequency
> > 
> > It looks like that driver does not honor the frequency sysctl/tunable.
> 
> > 
> > You can often compensate for a too-long cable by adding some stronger
> > pullups.  It's typical for a SOM to have pullups in the 4.7K range on
> > i2c.  You can add your own 1K pullups to see if that helps the rise
> > times on the bus.
> 
> well, at the moment it works ok with a 6m cable, i?ll try your suggestion soon.
> 
> > 
> > -- Ian
> > 
> 
> 
> cheers,
> 	danny


-- 
Emmanuel Vadot <manu at bidouilliste.com> <manu at freebsd.org>