I2C Detect Slave Method?

Jeff Seese

In case any body else is looking for this.

If for example you wanted two I2C busses, you would do that like this.

Example: using GPIO 14 for the second SDA and GPIO 16 for the 2nd SCL

insmod i2c-gpio-custom bus0=1,5,4 bus1=2,14,16

and you can then verify them with

i2cdetect -y 1

and

i2cdetect -y 2

Jan Breuer

@UFD Please have a look at my pull request https://github.com/openwrt/openwrt/pull/831
It should fix all issues with I2C. It is using real I2C hardware of the chip (no bit-banging).

UFD

Hi,

Im glad you guys found this useful!

@Jeff-Seese Thanks for the additional information on spinning up multiple I2C channels (useful when you have fixed I2C address based devices).

@Jan-Breuer I will certainly look into this. It would be amazing if "real" I2C worked on the Omega.

Kind Regards,
UFD

Sergiy Tarasov

@UFD said in I2C Detect Slave Method?:
Hello everyone!

How I can use these kmod's with another version of kernel?
Now I have latest firmware and the kernel version is 4.4.74.

George Gerber

Is it possible to give links to newer compiled versions of (?):

kmod-i2c-gpio-custom_4.4.46-2_mipsel_24kc.ipk
kmod-i2c-gpio_4.4.46-1_mipsel_24kc.ipk
kmod-i2c-algo-bit_4.4.46-1_mipsel_24kc.ipk

There is no longer a b160 image at: http://repo.onion.io/omega2/images/ for some mysterious reason.

I have tried b159, but it gives me an "unable to open mmap file" error when I run "omega2-ctrl gpiomux set i2c gpio".

b175 gives me a "failed to find i2c-algo-bit" error when I run "insmod i2c-algo-bit"

UFD

@George-Gerber, it is there, you may miss it because it falls under 0.1.10 i.e. omega2p-v0.1.10-b160.bin

@Sergiy-Tarasov, I have had some success using what is most likely a hack and not recommended.

Uncomment line 1 "reboot_core" in the file /etc/opkg/distfeeds.conf
opkg update
opkg --force-depends install kmod-i2c-gpio-custom
Now the hack, because it was for a higher kenel version the libraries are installed to /lib/module/<kenel-version> so we need to copy them across to the current version, in my case:
cp /lib/modules/4.4.131/* /lib/4.47/

Then proceed with the insmod as before.

Regards,
UFD

Lazar Demin

@UFD we fixed the driver for the hardware I2C controller. The main enhancements are:

The i2cdetect command is now supported
clock stretching is supported
support for unlimited message length
support for repeated start sequences

Check out this blog post for more details

UFD

@Lazar-Demin, Awesome news, thanks for letting me know. I will test very soon.

Ammar Assad

@Lazar-Demin Dear,
Thank you for your support, but Clock stretching is not clear; i.e how to change clock for i2c, in my case it is 100 kHz and I wan to chage it
what are the instructions for that,
thank you in all cases.

Lazar Demin

@Ammar-Assad the underlying driver supports clock stretching and will do so automatically, you don't have to specifically configure it.
As far as I remember, the Omega2 should support all I2C devices running from 100 kHz to 400 kHz out of the box.

Ammar Assad

@Lazar-Demin
Acutally I have upgraded my omega for that, it is still unclear for me how to controll clock speed, it is alway 100 kHz, the device is MPU9250

György Farkas

@Ammar-Assad Omega2(+)'s SCL clock frequency is 100kHz by default. According to its datasheet it's good for an MPU9250 slave.
Do you want a slower (eg. 10kHz) or a faster (eg. 400kHz) bus?
What is your real problem?

@Ammar-Assad wrote

it is still unclear for me how to controll clock speed, it is alway 100 kHz

Clock stretching is not clear; i.e how to change clock for i2c, in my case it is 100 kHz and I wan to chage it

As you know the original I2C communication speed (I2C Standard mode) was defined with a maximum of 100 kbit per second and the SCL clock is always determined / generated by the I2C master.
The clock stretching is a completely different thing.

Ammar Assad

@György-Farkas Thanks for your concern, Actually I want to faster it if it is possible.

György Farkas

@Ammar-Assad
MediaTek MT7688 Datasheet
5.10 I2C Controller
Module name: I2C Base address: (+10000900h)
Address 10000940 SM0CFG1 SERIAL INTERFACE MASTER 0 CONFIG 1 REGISTER
bit 27:16 SM0_CLK_DIV SIF master 0 clock divide value
This is used to set the divider to generate expected SCL.

Omega2(+) default 100kHz
40MHz / 400 = 100kHz
400 = 0x190
0x8190800F

devmem 0x10000940
0x8190800F

set to 400kHz
40MHz / 100 = 400kHz
100 = 0x64
0x8064800F

devmem 0x10000940 32 0x8064800F

devmem 0x10000940
0x8064800F

Good luck!

Ammar Assad

@György-Farkas said in I2C Detect Slave Method?:

0x10000940

Ooops! devmem not found unfortunately !

György Farkas

@Ammar-Assad Here you are a quick 'proof-of-concept' with a "full" BusyBox.

# Omega2+
root@Omega-99A5:/# oupgrade -v
> Device Firmware Version: 0.2.2 b200

root@Omega-99A5:/# cd ~
root@Omega-99A5:~# wget https://www.busybox.net/downloads/binaries/1.28.1-defconfig-multiarch/busybox-mipsel
root@Omega-99A5:~# chmod +x busybox-mipsel

root@Omega-99A5:~# ./busybox-mipsel
BusyBox v1.28.1 (2018-02-15 14:34:02 CET) multi-call binary.
BusyBox is copyrighted by many authors between 1998-2015.
Licensed under GPLv2. See source distribution for detailed
copyright notices.

Usage: busybox [function [arguments]...]
   or: busybox --list[-full]
   or: busybox --install [-s] [DIR]
   or: function [arguments]...

	BusyBox is a multi-call binary that combines many common Unix
	utilities into a single executable.  Most people will create a
	link to busybox for each function they wish to use and BusyBox
	will act like whatever it was invoked as.

Currently defined functions:
	[, [[, acpid, add-shell, addgroup, adduser, adjtimex, arch, arp, arping, ash, awk, base64, basename, beep, blkdiscard, blkid,
	blockdev, bootchartd, brctl, bunzip2, bzcat, bzip2, cal, cat, chat, chattr, chgrp, chmod, chown, chpasswd, chpst, chroot,
	chrt, chvt, cksum, clear, cmp, comm, conspy, cp, cpio, crond, crontab, cryptpw, cttyhack, cut, date, dc, dd, deallocvt,
	delgroup, deluser, depmod, devmem, df, dhcprelay, diff, dirname, dmesg, dnsd, dnsdomainname, dos2unix, dpkg, dpkg-deb, du,
	dumpkmap, dumpleases, echo, ed, egrep, eject, env, envdir, envuidgid, ether-wake, expand, expr, factor, fakeidentd, fallocate,
	false, fatattr, fbset, fbsplash, fdflush, fdformat, fdisk, fgconsole, fgrep, find, findfs, flock, fold, free, freeramdisk,
	fsck, fsck.minix, fsfreeze, fstrim, fsync, ftpd, ftpget, ftpput, fuser, getopt, getty, grep, groups, gunzip, gzip, halt, hd,
	hdparm, head, hexdump, hexedit, hostid, hostname, httpd, hush, hwclock, i2cdetect, i2cdump, i2cget, i2cset, id, ifconfig,
	ifdown, ifenslave, ifplugd, ifup, inetd, init, insmod, install, ionice, iostat, ip, ipaddr, ipcalc, ipcrm, ipcs, iplink,
	ipneigh, iproute, iprule, iptunnel, kbd_mode, kill, killall, killall5, klogd, last, less, link, linux32, linux64, linuxrc, ln,
	loadfont, loadkmap, logger, login, logname, logread, losetup, lpd, lpq, lpr, ls, lsattr, lsmod, lsof, lspci, lsscsi, lsusb,
	lzcat, lzma, lzop, makedevs, makemime, man, md5sum, mdev, mesg, microcom, mkdir, mkdosfs, mke2fs, mkfifo, mkfs.ext2,
	mkfs.minix, mkfs.vfat, mknod, mkpasswd, mkswap, mktemp, modinfo, modprobe, more, mount, mountpoint, mpstat, mt, mv, nameif,
	nanddump, nandwrite, nbd-client, nc, netstat, nice, nl, nmeter, nohup, nproc, nsenter, nslookup, ntpd, nuke, od, openvt,
	partprobe, passwd, paste, patch, pgrep, pidof, ping, ping6, pipe_progress, pivot_root, pkill, pmap, popmaildir, poweroff,
	powertop, printenv, printf, ps, pscan, pstree, pwd, pwdx, raidautorun, rdate, rdev, readahead, readlink, readprofile,
	realpath, reboot, reformime, remove-shell, renice, reset, resize, resume, rev, rm, rmdir, rmmod, route, rpm, rpm2cpio,
	rtcwake, run-init, run-parts, runlevel, runsv, runsvdir, rx, script, scriptreplay, sed, sendmail, seq, setarch, setconsole,
	setfattr, setfont, setkeycodes, setlogcons, setpriv, setserial, setsid, setuidgid, sh, sha1sum, sha256sum, sha3sum, sha512sum,
	showkey, shred, shuf, slattach, sleep, smemcap, softlimit, sort, split, ssl_client, start-stop-daemon, stat, strings, stty,
	su, sulogin, sum, sv, svc, svlogd, swapoff, swapon, switch_root, sync, sysctl, syslogd, tac, tail, tar, taskset, tcpsvd, tee,
	telnet, telnetd, test, tftp, tftpd, time, timeout, top, touch, tr, traceroute, traceroute6, true, truncate, tty, ttysize,
	tunctl, ubiattach, ubidetach, ubimkvol, ubirename, ubirmvol, ubirsvol, ubiupdatevol, udhcpc, udhcpd, udpsvd, uevent, umount,
	uname, unexpand, uniq, unix2dos, unlink, unlzma, unshare, unxz, unzip, uptime, users, usleep, uudecode, uuencode, vconfig, vi,
	vlock, volname, w, wall, watch, watchdog, wc, wget, which, who, whoami, whois, xargs, xxd, xz, xzcat, yes, zcat, zcip

root@Omega-99A5:~# ./busybox-mipsel devmem 0x10000940
0x818F800F

root@Omega-99A5:~# ./busybox-mipsel devmem 0x10000940 32 0x8064800F
root@Omega-99A5:~# ./busybox-mipsel devmem 0x10000940
0x8064800F

FW 0.2.2 b200 - presently the divider is '0x18F = 399' instead of '0x190 = 400'.
Please ask one of Onion administrators ( @Zheng-Han @Lazar-Demin @Pavel-Metrokhin) why

Ammar Assad

@György-Farkas said in I2C Detect Slave Method?:

./busybox-mipsel devmem 0x10000940 32 0x8064800F

I am very grateful to you, it worked fine ...