A20 Rev L : Kernel error every 5 secs: axp_mfd 0-0034 : failed reading from...

[att2]

Hello,
We have the following configuration:
Hardware: T2-OLinuXino-LIME2-e8Gs16M-IND rev.L
Lot code: P15389
+ Olimex LCD-Display 7"
Software:
root@A20-OLinuXino:~# uname -a
Linux A20-OLinuXino 3.4.103-00033-g9a1cd034181a-dirty #49 SMP PREEMPT Fri May 18 16:07:20 EEST 2018 armv7l GNU/Linux

Yes, we used some old image, still works.. EXCEPT now we get errors every 5 seconds from the kernel :

[  884.275677] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading from 0x03
[  884.282757] axp_mfd 0-0034: failed reading from 0x03
<4>i2c-0, xfer timeout
[  889.285472] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading from 0x00
[  889.292552] axp_mfd 0-0034: failed reading from 0x00
<4>i2c-0, xfer timeout
[  894.295276] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading at 0x33
[  894.302183] axp_mfd 0-0034: failed reading at 0x33
<4>i2c-0, xfer timeout
[  899.305057] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading from 0x56
[  899.312139] axp_mfd 0-0034: failed reading from 0x56
<4>i2c-0, xfer timeout
[  904.314847] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading from 0x78
[  904.321925] axp_mfd 0-0034: failed reading from 0x78
<4>i2c-0, xfer timeout
[  909.324643] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading from 0x5e
[  909.331728] axp_mfd 0-0034: failed reading from 0x5e
<4>i2c-0, xfer timeout
[  914.334441] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading at 0xb9
[  914.341346] axp_mfd 0-0034: failed reading at 0xb9
<4>i2c-0, xfer timeout
[  919.344232] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading at 0x30
[  919.351137] axp_mfd 0-0034: failed reading at 0x30
<4>i2c-0, xfer timeout
[  934.383620] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading from 0xb0
[  934.390698] axp_mfd 0-0034: failed reading from 0xb0
<4>i2c-0, xfer timeout
[  939.393410] i2c-0, xfer timeout
<3>axp_mfd 0-0034: failed reading at 0x84
[  939.400308] axp_mfd 0-0034: failed reading at 0x84

Please kindly advise of how to get rid of these kernel errors every 5 seconds, preferably not changing to a new image or new kernel, if possible....
Thanks!

[LubOlimex]

It seems errors are related to i2c0 line. The i2c-0 is connected to the AXP209 chip - this is the chip that handles the power supplies; but these pins are also routed to the GPIO-2 extension. Do you have anything connected to pin #5 and/or pin #7 of the GPIO-2 connector? It might influence i2c-0...

[att2]

Yes. WE did not insert this AXP209 chip in Revision L - OLIMEX did insert this chip.
Why, I don't know. You are welcome to tell me your reasons why you added another chip that obviously was not needed in previous revisions.
You are also welcome to tell me WHY these pins are also routed to the GPIO-2 extension!
I don't see any need for this chip nor for that routing !

[LubOlimex]

What?? This reply is very confusing. AXP209 had been there since beginning of time... It is the main PMU it is essential for the design. It had been basically in every Olimex design with A20 chip.

Can you try how it goes with the latest 3.4.x image:

https://ftp.olimex.com/Allwinner_Images/A20-OLinuXino-LIME2/Debian/sd/a20-lime2_mainline_uboot_sunxi_kernel_3.4.103_jessie_eMMC_rel_16.zip

[att2]

Are you even reading my stuff?
I said:

root@A20-OLinuXino:~# uname -a
Linux A20-OLinuXino 3.4.103-00033-g9a1cd034181a-dirty #49 SMP PREEMPT Fri May 18 16:07:20 EEST 2018 armv7l GNU/Linux

[LubOlimex]

Yes, but just want to make sure if the behavior remains with the unmodified image.

[LubOlimex]

I tested with same board T2-OLinuXino-LIME2-e8Gs16M-IND from revision L and same Linux image and I get no such error.