has anyone got a linux kernel driver for mcp79410 rtc  -solved

Hi Tim!

You want the ds1307 driver, however it sort of depends which kernel you're running, the patch to add the mcp7941x series isn't in the 3.1.9+ kernel that's default in most of the current distros.  If you're ok with patching your kernel and re-compling it then you can find the patch here: http://git.kernel.org/?p=linux/kernel/git/torvalds/linux.git;a=commitdiff;h=43fcb81550f7a16be192b19c77a379c9b27b1585 but be aware that it may not apply cleanly to the older kernel depending on what other changes there were.

However the patch did make it into 3.2, so if you don't want to mess with kernel compiling then have a look at Chris Boots kernel http://www.bootc.net/projects/raspberry-pi-kernel/

I'd also suggest asking Raspberry Pi questions over in the Raspberry Pi section http://www.element14.com/community/groups/raspberry-pi?ICID=technologies_rpi_menubar. There's a fair number of us over there willing to help, but we're not necessarily going to see stuff here in the Experts section.

thanks very much selsinork.

My next challenge will be to get the 3.1.9 kernel source for my current armedslack install on my raspberrypi, as the source is not at kernel.org anymore;

or, find out the config with special raspberrypi blobs and patches and see if I can get the 3.6rc1 kernel built instead. I'll post in the raspberry pi section in future, but there still seams to be a problem with posts dissapearing entirely on all the forums here at element14/farnell

http://www.kernel.org/pub/linux/kernel/v3.x/linux-3.1.9.tar.gz still seems to be there..

'official' 3.1.9 kernel source for the Pi is available here https://github.com/raspberrypi/linux and this will include all the necessary drivers.

You're unlikely to get 3.6rc1 working, there are too many missing pieces and there's a lot of changes to arm code between 3.1.9 and 3.6 making forward porting it far from simple..

That said, if you're a wizard kernel developer then you should go look at  https://github.com/lp0/linux Simon Arlott and Chris Boot have done a bunch of work in this direction. You'll need this too https://github.com/raspberrypi/linux/wiki/Device-Tree-port and you probably want to sign up to the mailing list http://lists.infradead.org/mailman/listinfo/linux-rpi-kernel

It appears that either an admin moved the thread into the Raspberry Pi area, or it magically disappeared only to turn up in the right place on it's own

well I'm not a wizard kernel developer, I've compiled a few custom kernels for pc's but that's about it. Thanks for the pointer to the 3.1.9 kernel source. I should have hunted further on the site. I'l get that downloaded and see I can get the rtc module happy.

just an update. I tried the patch on the kernel and it didn't like it, so I manually put in the changes roughly comparing them with the 3.6rc1. with modifying the include/linux/vermagic.h I can get the module to compile, but when I try insmod rtc-ds1307.ko it complains of an "-1 unknown symbol in module". the joys :-(

What version of the kernel were you modifying for those changes in 3.6rc1?  The Foundation's 3.1.9+?

(btw, in case it's any help, I wrote this document awhile back http://www.element14.com/community/docs/DOC-44948/l/compiling-linux-kernel-staging-driver-modules)

yes, the 3.1.9+ one from github/raspberrypi/linux, although it looks like it may now have moved up a subversion - see https://github.com/raspberrypi/linux/blob/rpi-3.2.27/Makefile

I'll have a look at your kernel (cross) compiling guide drew, and try that. I think part of the problem is that my slackware distribution was using the 3.1.9 kernel, but still had 2.6.38.4 source present as well. (in /usr/src). I used david (spencer's) kernel+installer from http://www.daves-collective.co.uk/raspi/images/raspi-slack-installer_01Aug12.img.xz

since this post slackware 14.0 (and armedslack 14.0 ) has come out. this updates the source framework to 3.4.11

hopefully dave will update his kernel installer/package for slackware from the 3.1.9 version to a 3.2.x or higher, as I belive that is required to add the rtc device to the kernel using the method posted http://www.element14.com/community/groups/raspberry-pi/blog/2012/07/19/what-time-is-it-adding-a-rtc-to-the-raspberry-pi-via-i2c 

I am looking forward to testing the little module I made to see if it works!

yes, the 3.1.9+ one from github/raspberrypi/linux, although it looks like it may now have moved up a subversion - see https://github.com/raspberrypi/linux/blob/rpi-3.2.27/Makefile

I'll have a look at your kernel (cross) compiling guide drew, and try that. I think part of the problem is that my slackware distribution was using the 3.1.9 kernel, but still had 2.6.38.4 source present as well. (in /usr/src). I used david (spencer's) kernel+installer from http://www.daves-collective.co.uk/raspi/images/raspi-slack-installer_01Aug12.img.xz

since this post slackware 14.0 (and armedslack 14.0 ) has come out. this updates the source framework to 3.4.11

hopefully dave will update his kernel installer/package for slackware from the 3.1.9 version to a 3.2.x or higher, as I belive that is required to add the rtc device to the kernel using the method posted http://www.element14.com/community/groups/raspberry-pi/blog/2012/07/19/what-time-is-it-adding-a-rtc-to-the-raspberry-pi-via-i2c 

I am looking forward to testing the little module I made to see if it works!