[lm-sensors] some quesions from the tools

lei yang yanglei.fage at gmail.com
Tue Apr 27 18:57:22 CEST 2010


Hi Experts

I'm new to i2c, I have some questions in the end, can you help me explain
them to me

root at mpc8313erdb:/root> sensors
lm75-i2c-0-48
Adapter: MPC adapter
temp1:       +21.0?C  (high = +80.0?C, hyst = +75.0?C)
root at mpc8313erdb:/root> ./i2cdetect -l
i2c-0   i2c             MPC adapter                             I2C adapter
i2c-1   i2c             MPC adapter                             I2C adapter
root at mpc8313erdb:/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] y
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- 0c -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
50: 50 -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- UU -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
root at mpc8313erdb:/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  9  a  b  c  d  e  f
00:          -- -- -- -- -- -- -- -- -- -- -- -- --
10: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
20: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
30: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
40: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
70: -- -- -- -- -- -- -- --
root at mpc8313erdb:/root>


Q1:use i2cdetect -l, I can see it detects i2c-0 and i2c-0 why "sensors"
comand just output lm75-i2c-0-48?


Q2:Use ./i2cdetect 0 it detect three adrees :0x48 0x50 0x68, i just know
0x48 is a temperature sensors,how do I know 0x50 and 0x68?
and from demsg |grep 68 I got

root at mpc8313erdb:/root> dmesg |grep 68
On node 0 totalpages: 32768
Inode-cache hash table entries: 8192 (order: 3, 32768 bytes)
Memory: 125268k/131072k available (4072k kernel code, 5656k reserved, 140k
data, 126k bss, 188k init)
TCP established hash table entries: 4096 (order: 3, 32768 bytes)
rtc-ds1307 0-0068: rtc core: registered ds1339 as rtc0
rtc-ds1307 0-0068: setting system clock to 2010-04-27 23:41:40 UTC
(1272411700)

so 0x68 is rtc device, i can't know 0x50 from demsg,can you show me the way


Q3:Why I got to i2c bus? but why it can't detect one address on bus 1 with
./i2cdetect 1?


Q4:I want to do a full test for the i2c driver of my board, is there some
points about the test?


Thanks
Lei
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