# I2C Interface (Header P22) - I can\`t use this interface. **URL:** \ **Category:** Linux\ **Tags:** hardware\ **Created:** [September 14, 2010, 10:05am UTC](https://forums.digi.com/t/i2c-interface-header-p22-i-can-t-use-this-interface/11179 "2010-09-14T10:05:41Z")\ **Posts on this page:** 1\ **Page:** 1
**Author:** ![song0369](https://avatars.discourse-cdn.com/v4/letter/s/5daacb/32.png) [@song0369](https://forums.digi.com/u/song0369)\ **Post date:** [September 14, 2010, 10:05am UTC](https://forums.digi.com/t/i2c-interface-header-p22-i-can-t-use-this-interface/11179/1 "2010-09-14T10:05:41Z")
Hi. nice to meet you. I don`t speak english very well. please, understand it. I use Digi ConnectCore i.mx51. I want use I2C interface(Header P22). (Connect to PCA9554 expander) I have next setting setp. 1)setting to kernel config. device driver -\> GPIO support -\> PCA953x, PCA955x, TCA64xx, and MAX7310 I/O ports device driver -\> i2c support -\> i2c system bus driver -\> mxc i2c support device driver -\> i2c support -\> i2c device interface system type -\> Freescale MXC Implementations -\> I2C interface optoin -\> Enable I2C1 module system type -\> Freescale MXC Implementations -\> I2C interface optoin -\> Enable I2C2 module 2)testing in board.(I use i2c-tools) Explan to english is very hard. so, See you that I input command. [root /]# ls /dev/i2c-\* -al crw-rw---- 1 root root 89, 0 Jan 4 23:26 /dev/i2c-0 crw-rw---- 1 root root 89, 1 Jan 4 23:26 /dev/i2c-1 [root /]# i2cdetect -l i2c-0 i2c mxc\_i2c I2C adapter i2c-1 i2c mxc\_i2c I2C adapter [root /]# i2cdetect 0 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-0. I will probe address range 0x03-0x77. Continue? [Y/n] 0 1 2 3 4 5 6 7 8 i2c-adapter i2c-0: Bus Arbitration lost 9 a b c d e f 00: i2c-adapter i2c-0: Could not grab Bus ownership – i2c-adapter i2c-0: Bus Arbitration lost i2c-adapter i2c-0: Could not grab Bus ownership – i2c-adapter i2c-0: Bus Arbitration lost … – i2c-adapter i2c-0: Bus Arbitration lost i2c-adapter i2c-0: Could not grab Bus ownership – i2c-adapter i2c-0: Bus Arbitration lost i2c-adapter i2c-0: Could not grab Bus ownership [root /]# i2cdetect 1 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will probe file /dev/i2c-1. I will probe address range 0x03-0x77. Continue? [Y/n] y 0 1 2 3 4 5 6 7 8 i2c-adapter i2c-1: Could not grab Bus ownership 9 a b c d e f 00: i2c-adapter i2c-1: Could not grab Bus ownership – – i2c-adapter i2c-1: Could not grab Bus ownership – i2c-adapter i2c-1: Could not grab Bus ownership … – i2c-adapter i2c-1: Could not grab Bus ownership [root /]# find /sys/bus/i2c/drivers /sys/bus/i2c/drivers /sys/bus/i2c/drivers/dummy /sys/bus/i2c/drivers/dummy/uevent /sys/bus/i2c/drivers/dummy/unbind /sys/bus/i2c/drivers/dummy/bind /sys/bus/i2c/drivers/dev\_driver /sys/bus/i2c/drivers/dev\_driver/uevent /sys/bus/i2c/drivers/dev\_driver/unbind /sys/bus/i2c/drivers/dev\_driver/bind /sys/bus/i2c/drivers/pca953x /sys/bus/i2c/drivers/pca953x/module /sys/bus/i2c/drivers/pca953x/uevent /sys/bus/i2c/drivers/pca953x/unbind /sys/bus/i2c/drivers/pca953x/bind [root /]# find /sys/bus/i2c/devices/ /sys/bus/i2c/devices/ [root /]# cat /proc/devices Character devices: 1 mem 4 /dev/vc/0 4 tty 5 /dev/tty 5 /dev/console 5 /dev/ptmx 7 vcs 10 misc 13 input 29 fb 89 i2c 90 mtd 108 ppp 128 ptm 136 pts 153 spi 180 usb 189 usb\_device 207 ttymxc 252 mxc\_vpu 253 mxc\_ipu 254 rtc Block devices: 259 blkext 7 loop 8 sd 31 mtdblock 65 sd 66 sd 67 sd 68 sd 69 sd 70 sd 71 sd 128 sd 129 sd 130 sd 131 sd 132 sd 133 sd 134 sd 135 sd 179 mmc [root /]# i2cset 1 0x40 0x00 0x00 WARNING! This program can confuse your I2C bus, cause data loss and worse! I will write to device file /dev/i2c-1, chip address 0x40, data address 0x00, data 0x00, mode byte. Continue? [Y/n] y i2c-adapter i2c-1: Could not grab Bus ownership Error: Write failed and, I tested next module. but not work. kernel/drivers/i2c/busses/i2c-gpio.ko kernel/drivers/i2c/busses/mxc\_i2c.ko kernel/drivers/i2c/algos/i2c-algo-bit.ko kernel/drivers/i2c/i2c-dev.ko kernel/drivers/i2c-slave/i2c\_slave.ko kernel/drivers/i2c-slave/mxc\_i2c\_slave.ko kernel/drivers/i2c-slave/i2c\_slave\_client.ko I think, I2C interface(header P22) setting is GPIO. so,can`t connect PCA9554 expander. (it is Just my think) I want really it! (PCA9554 expander connect to I2C interface header P22, and PCA9554 control.) do you any have idea? help me please~~