PS I2C on Xillinux

I take look at http://www.zedboard.org/content/zedboard-out-box-sd-card-image-and-source.
Looks like, the MIO configuration is stored in the FSBL.
Is it right?
How can I modifi FSBL?

I have some progress. FSBL is possible to create from SDK. I tried to add UART0 and I2C0 both connected to the MIO. I adjusted DTS. UART works well, but I2C is still not accessible from linux. /dev/i2c-0 does not exists.

Vatu,

Did you recompile Linux and create the dtb file form the ./scripts directory based on your updated dts file?

There are two ways to come around this:

(1) If you don't need the card's sound capability, and you're fine with using PL pins from the chip, you may "steal" the I2C interface used to program the sound chip. Just reLOC the relevant pins to your application logic, and disable the sound subsystem as described in the Getting Started Guide for Linux.

(2) If you want the native I2C Linux driver to run the relevant PL lines, you'll need to modify the DTS file, and compile it into a DTB, and then copy it to the SD card's first partition. The entry you need to add tells the kernel that an I2C hardware element is available, and also its attributes. I've never done this, but this is the flow. There shouldn't be a need to recompile the kernel, I believe.

   Eli

Thanks for answer.
I decompile DTB on first partition of SD using DTC -I dtb -O dts -o devicetree.dts devicetree.dtb. I add UART0 and I2C0 in to DTS. Last step is compiling DTB using DTC -I dts -O dtb -o devicetree.dtb devicetree.dts. Uart works fine but I2C does not.

Two possible reasons:
1. Wrong entry for I2C0 in DTS
2. Driver for I2C not found or does not exist in Xillinux.

I am linux newbie and I am not sure how to verify this.
I tried list modules by lsmod and modprobe -l. But nothing look like I2C driver. I thing that I2C driver is not instaled. I believe that it is not need recompile entire kernel. I read in  "Getting started with Xillybus on a Linux host" about compiling single module respective specified folder. This is what I tryed, but no success yet.

I think choose 2 is right way.

Thanks.

Hi Tim,
I am recompile kernel. I am use git clone https://github.com/Digilent/linux-3.3-digilent.git to get sources. I am apply 6 patches from /usr/src/xillinux/kernel-patches successfly. I am recompile kernel using by make. Then I copy zImage from arch/arm/boot to first partition on SD.

I am decompile DTB on first partition of SD using DTC -I dtb -O dts -o devicetree.dts devicetree.dtb. I add UART0 and I2C0 in to DTS.

ttserial@e0000000 {
tttclock = <0x2faf080>;
tttcompatible = "xlnx,ps7-uart-1.00.a", "xlnx,xuartps";
tttdevice_type = "serial";
tttinterrupt-parent = <0x1>;
tttinterrupts = <0x0 0x1b 0x0>;
tttreg = <0xe0000000 0x1000>;
tttxlnx,has-modem = <0x0>;
tttxlnx,uart-clk-freq-hz = <0x2faf080>;
tt};


tti2c0: i2c@e0004000 {
tttcompatible = "xlnx,ps7-i2c-1.00.a";
tttreg = <0xE0004000 0x1000>;
tttinterrupts = <0 25 0>;
tttinterrupt-parent = <1>;
tttbus-id = <0>;
tttinput-clk = <50000000>;
ttti2c-clk = <100000>;
ttt
ttt#address-cells = <1>;
ttt#size-cells = <0>;
tt};

Last step is compiling DTB using DTC -I dts -O dtb -o devicetree.dtb devicetree.dts.

After power off and power on zedboard boot successfly.





U-Boot 2012.04.01 (Oct 16 2012 - 17:41:50)

DRAM:  512 MiB
WARNING: Caches not enabled
MMC:   SDHCI: 0
Using default environment

In:    serial
Out:   serial
Err:   serial
Net:   zynq_gem
Hit any key to stop autoboot:  0
Copying Linux from SD to RAM...
Device: SDHCI
Manufacturer ID: 1d
OEM: 4144
Name: SD
Tran Speed: 25000000
Rd Block Len: 512
SD version 2.0
High Capacity: Yes
Capacity: 15 GiB
Bus Width: 4-bit
reading zImage

2674504 bytes read
reading devicetree.dtb

6483 bytes read
reading ramdisk8M.image.gz

** Unable to read "ramdisk8M.image.gz" from mmc 0:1 **
## Starting application at 0x00008000 ...
Uncompressing Linux... done, booting the kernel.
[    0.000000] Booting Linux on physical CPU 0
[    0.000000] Linux version 3.3.0-xillinux-1.0+ (root@arbot2) (gcc version 4.6.3 (Ubuntu/Linaro 4.6.3-1ubuntu5) ) #1 SMP PREEMPT Sat Nov 10 20:54:10 UTC 2012
[    0.000000] CPU: ARMv7 Processor [413fc090] revision 0 (ARMv7), cr=18c5387d
[    0.000000] CPU: PIPT / VIPT nonaliasing data cache, VIPT aliasing instruction cache
[    0.000000] Machine: Xilinx Zynq Platform, model: Xillinux for Zedboard
[    0.000000] bootconsole [earlycon0] enabled
[    0.000000] Memory policy: ECC disabled, Data cache writealloc
[    0.000000] BUG: mapping for 0xf8f00000 at 0xfe00c000 out of vmalloc space
[    0.000000] BUG: mapping for 0xe0000000 at 0xfe000000 out of vmalloc space
[    0.000000] BUG: mapping for 0xffff1000 at 0xfe200000 out of vmalloc space
[    0.000000] PERCPU: Embedded 7 pages/cpu @c09c0000 s5440 r8192 d15040 u32768
[    0.000000] Built 1 zonelists in Zone order, mobility grouping on.  Total pages: 125824
[    0.000000] Kernel command line: consoleblank=0 root=/dev/mmcblk0p2 rw rootwait earlyprintk
[    0.000000] PID hash table entries: 2048 (order: 1, 8192 bytes)
[    0.000000] Dentry cache hash table entries: 65536 (order: 6, 262144 bytes)
[    0.000000] Inode-cache hash table entries: 32768 (order: 5, 131072 bytes)
[    0.000000] Memory: 240MB 256MB = 496MB total
[    0.000000] Memory: 497428k/497428k available, 26860k reserved, 0K highmem
[    0.000000] Virtual kernel memory layout:
[    0.000000]     vector  : 0xffff0000 - 0xffff1000   (   4 kB)
[    0.000000]     fixmap  : 0xfff00000 - 0xfffe0000   ( 896 kB)
[    0.000000]     vmalloc : 0xe0800000 - 0xfd000000   ( 456 MB)
[    0.000000]     lowmem  : 0xc0000000 - 0xe0000000   ( 512 MB)
[    0.000000]     pkmap   : 0xbfe00000 - 0xc0000000   (   2 MB)
[    0.000000]     modules : 0xbf000000 - 0xbfe00000   (  14 MB)
[    0.000000]       .text : 0xc0008000 - 0xc04bf650   (4830 kB)
[    0.000000]       .init : 0xc04c0000 - 0xc04e9540   ( 166 kB)
[    0.000000]       .data : 0xc04ea000 - 0xc051bfa0   ( 200 kB)
[    0.000000]        .bss : 0xc051bfc4 - 0xc0538028   ( 113 kB)
[    0.000000] Preemptible hierarchical RCU implementation.
[    0.000000]  Verbose stalled-CPUs detection is disabled.
[    0.000000] NR_IRQS:128
[    0.000000] xlnx,ps7-ttc-1.00.a #0 at 0xe0800000, irq=43
[    0.000000] Console: colour dummy device 80x30
[    0.000000] console [tty0] enabled, bootconsole disabled

Ubuntu 12.04 LTS arbot2 ttyPS0

arbot2 login: root (automatic login)

Last login: Sun Nov 11 08:00:07 UTC 2012 from 192.168.10.100 on pts/1
Welcome to the Xillinux distribution for Zynq-7000 EPP.

You may communicate data with standard FPGA FIFOs in the logic fabric by
writing to or reading from the /dev/xillybus_* device files. Additional
pipe files of that sort can be set up at request of a custom Xillybus IP core.

For more information: http://www.xillybus.com.

To start a graphical X-Windows session, type "startx" at shell prompt.



But without i2c. :-(
i2cdetect -l returns nothing.

I found log entry in /var/log/dmesg

[    1.430000] xi2cps e0004000.i2c: 100 kHz mmio e0004000 irq 57

But /dev/i2c-0 still does not exists.
I have no idea.
Any suggestions?

Thanks

Solved. It is easy. I2C-dev module must be installed (by default is disabled). It is controlled by option CONFIG_I2C_CHARDEV in .config.


Vatu

There is detailed procedure how to get working PS I2C.

http://www.arbot.cz/post/2012/11/14/PS-I2C-in-Xillinux.aspx


Vatu