i2c-dev

i2c-dev

[John de la Garza]

I have my kernel built with dev-i2c and i2c_i801 but do not have
a /dev entry.

lspci shows this:
00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 06)

dmesg shows this:
[    1.566003] i801_smbus 0000:00:1f.3: enabling device (0000 -> 0003)

ls /sys/bus/i2c/devices/ shows nothing...

on running this on a MacBookPro6,2


What am I missing?  Shouldn't I see a i2c device?  I think SMBus is
a subset of i2c and I should be able to use that subset, right?

i2c-dev

[Paul Bolle]

Having looked into this a bit, but failing to come up with something
helpful, I decided to ask some additional info.

On Tue, 2014-10-21 at 21:54 -0400, John de la Garza wrote:
> I have my kernel

Which version (roughly)?

>  built with dev-i2c and i2c_i801

.config, please?

>  but do not have
> a /dev entry.
> 
> lspci shows this:
> 00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 06)

What are the PCI vendor and device codes? See "lspci -nn".

> dmesg shows this:
> [    1.566003] i801_smbus 0000:00:1f.3: enabling device (0000 -> 0003)
> 
> ls /sys/bus/i2c/devices/ shows nothing...
> 
> on running this on a MacBookPro6,2
> 
> What am I missing?  Shouldn't I see a i2c device?  I think SMBus is
> a subset of i2c and I should be able to use that subset, right?


Paul Bolle

i2c-dev

[Paul Bolle]

On Wed, 2014-10-22 at 13:27 -0400, John de la Garza wrote:
> On Wed, Oct 22, 2014 at 06:35:02PM +0200, Paul Bolle wrote:
> > Having looked into this a bit, but failing to come up with something
> > helpful, I decided to ask some additional info.
> > 
> > On Tue, 2014-10-21 at 21:54 -0400, John de la Garza wrote:
> > > I have my kernel
> > 
> > Which version (roughly)?
> 
> Linux vega 3.18.0-rc1+ #71 SMP Wed Oct 22 00:49:21 EDT 2014 x86_64 GNU/Linux
> > 
> > >  built with dev-i2c and i2c_i801
> > 
> > .config, please?
> > 
> see below
> 
> > >  but do not have
> > > a /dev entry.
> > > 
> > > lspci shows this:
> > > 00:1f.3 SMBus: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller (rev 06)
> > 
> > What are the PCI vendor and device codes? See "lspci -nn".
> > 
> 00:1f.3 SMBus [0c05]: Intel Corporation 5 Series/3400 Series Chipset SMBus Controller [8086:3b30] (rev 06)
> > > dmesg shows this:
> > > [    1.566003] i801_smbus 0000:00:1f.3: enabling device (0000 -> 0003)

I'm afraid I can't really help you here, sorry. That is, except for the
obvious question whether this is a regression (ie, do releases v3.17 or
earlier show something in /sys/bus/i2c/devices/?) or a configuration
issue (perhaps a distribution provided kernel does show what you want).

Hope this helps,


Paul Bolle

i2c-dev

[John de la Garza]

On Thu, Oct 23, 2014 at 08:15:53PM +0200, Paul Bolle wrote:
> I'm afraid I can't really help you here, sorry. That is, except for the
> obvious question whether this is a regression (ie, do releases v3.17 or
> earlier show something in /sys/bus/i2c/devices/?) or a configuration
> issue (perhaps a distribution provided kernel does show what you want).
> 

I didn't have any devices drivers loaded for things that had
i2c devices.  I loaded the i915 gpu driver and now I see stuff.

root at vega:/home/john/linux# i2cdetect  -l
i2c-0	i2c       	i915 gmbus ssc                  	I2C adapter
i2c-1	i2c       	i915 gmbus vga                  	I2C adapter
i2c-2	i2c       	i915 gmbus panel                	I2C adapter
i2c-3	i2c       	i915 gmbus dpc                  	I2C adapter
i2c-4	i2c       	i915 gmbus dpb                  	I2C adapter
i2c-5	i2c       	i915 gmbus dpd                  	I2C adapter
i2c-6	i2c       	DPDDC-B                         	I2C adapter