AM6442: How can I reset the PHY on SK-AM64B using IO expander

Hi Timothy,

Thanks for your question.

So essentially TCA6424a is a I2C bus and can be controlled via SoC_I2C1. Well I can point you to a detailed FAQ which I created a while ago. This FAQ explains how to set a pin to:

1. High or Low mode.
2. Input or Output mode.

Here is the FAQ:

https://e2e.ti.com/support/processors-group/processors/f/processors-forum/1326205/faq-processor-sdk-am64x-how-to-program-tca6424a-using-soc_i2c1?tisearch=e2e-sitesearch&keymatch=TCA6424#

I am pretty sure that this FAQ will solve your concern here.

Regards,

Vaibhav

Hi,

This IO ex pander is not the TCA6424A but rather the TCA9538.  (Or is that part number incorrect and it is the TCA6424 as per block diagram?  I assume schematic is correct).

It appears I don't see any i2c stuff on i2c bus 1.

# i2cdetect 1
Warning: Can't use SMBus Quick Write command, will skip some addresses
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]
     0  1  2  3  4  5  6  7  8  9  a  b  c  d  e  f
00:
10:
20:
30: -- -- -- -- -- -- -- --
40:
50: -- -- -- -- -- -- -- -- -- -- -- -- -- -- -- --
60:
70:

Note that I do see things on I2C bus 0:

# i2cdetect 0
Warning: Can't use SMBus Quick Write command, will skip some addresses
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:
10:
20:
30: 30 -- -- -- -- -- -- --
40:
50: -- 51 -- -- -- -- -- -- -- -- -- -- -- -- -- --
60:
70:

Am I able to control for reset with the i2ctools?

i2cget/i2cset for example?

73,
Timothy

Hi Timothy,

Please expect responses in few business days.

Regards,

Vaibhav

Hi Timothy,

I referred the schematics for SK-AM64B and found out that SoC_I2C1 indeed goes to TCA9538PWR. So I think your schematics is correct.

 Before we move forward, can you please specify which exact EVM you are using:

1. https://www.ti.com/tool/TMDS64EVM

2. https://www.ti.com/tool/SK-AM64B

I am  assuming it is SK-AM64B. If so then we have to look at TCA9538PWR.

On that note, would you like me to send you a cpiece of working code which basically sets one of the ports to HIGH?

If that is the case, then which port/pin do you want to be driven HIGH?

Regards,

Vaibhav

Hi,

Vaibhav Kumar said:

 Before we move forward, can you please specify which exact EVM you are using:

I am using the red SK-AM64B you have.

Vaibhav Kumar said:

On that note, would you like me to send you a cpiece of working code which basically sets one of the ports to HIGH?

Sure, however it would be more convenient if you could share commands using i2ctools or devmem2 or something like that so I wouldn't have to compile a program.  Of course if you send me code, I fear that because i2ctools can't find this another C program would fail....

BTW, attached is my dts file.  Perhaps there is some issue with it?

https://e2e.ti.com/cfs-file/__key/communityserver-discussions-components-files/791/0333.k3_2D00_am642_2D00_sk.dts

73,
Timothy

Hi Timothy,

I have assigned this thread to the correct expert. Please expect responses in few business days.

Regards,

Vaibhav