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micksulley
Posts: 188
Joined: Sat Mar 03, 2012 11:48 am
Location: Melton Mowbray, England

/dev/i2c missing

Sun Jan 25, 2015 12:04 pm

I am trying to add a owfs system to a Pi, which I have done on other Pi's, but this time I do not have /dev/i2c
I have updated /etc/modprobe.d/raspi-blacklist.conf and commented out the i2c line
I have added i2c-dev to /etc/modules
I have rebooted
It is a fresh install of Raspian

What have I missed?

Thanks
Mick


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micksulley
Posts: 188
Joined: Sat Mar 03, 2012 11:48 am
Location: Melton Mowbray, England

Re: /dev/i2c missing

Sun Jan 25, 2015 12:44 pm

Yes adding
dtparam=i2c1=on
dtparam=i2c0=on
to config.txt has fixed it, thank you. Why has this changed? I have done this many time before and never added anything to config.txt.

Mick

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joan
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Location: UK

Re: /dev/i2c missing

Sun Jan 25, 2015 12:46 pm

micksulley wrote:Yes adding
dtparam=i2c1=on
dtparam=i2c0=on
to config.txt has fixed it, thank you. Why has this changed? I have done this many time before and never added anything to config.txt.

Mick
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DougieLawson
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Re: /dev/i2c missing

Sun Jan 25, 2015 7:08 pm

micksulley wrote:Why has this changed? I have done this many time before and never added anything to config.txt.
Because you've been running sudo rpi-update when you don't need to . That's pushed you to the 3.18.3+ kernel which has the new device tree support.
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ShiftPlusOne
Raspberry Pi Engineer & Forum Moderator
Raspberry Pi Engineer & Forum Moderator
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Re: /dev/i2c missing

Sun Jan 25, 2015 7:12 pm

As for why this has changed at all, I think that thread explains how it came about pretty well.

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borlandoflorida
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Joined: Sat Jan 05, 2013 6:41 pm
Location: Derby

Re: /dev/i2c missing

Mon Jan 26, 2015 11:51 am

I had the exact same issue on Saturday 24 January 2015 and only just found this thread after being pointed here by a really helpful user over on Redditt.

My fix was to install the latest Raspbian image (December 2014) and not updating the firmware with rpi-update. My Pi works fine as it is, but it's good to know for future reference as I was pulling my hair out with this!

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