AM1808 PInmux configuration on u-Boot

Carmelo Garcia

Prodigy 105 points

Other Parts Discussed in Thread: AM1808

Hello!

I'm currently working on the development of a new custom board for AM1808 with Linux.

I have used Pin Setup tool for Am1808 but I can't find how to use the header file it brings as output.

It's something like this:

#define PINMUX0_VALUE 0x44080800
#define PINMUX1_VALUE 0x88888000
#define PINMUX2_VALUE 0x88888880
#define PINMUX3_VALUE 0x88888888
#define PINMUX4_VALUE 0x22222288
#define PINMUX5_VALUE 0x11111112
#define PINMUX6_VALUE 0x00000000
#define PINMUX7_VALUE 0x10110010
#define PINMUX8_VALUE 0x00000000
#define PINMUX9_VALUE 0x11111111
#define PINMUX10_VALUE 0x22222222
#define PINMUX11_VALUE 0x88888888
#define PINMUX12_VALUE 0x81188888
#define PINMUX13_VALUE 0x88808801
#define PINMUX14_VALUE 0x44444400
#define PINMUX15_VALUE 0x44444444
#define PINMUX16_VALUE 0x22222244
#define PINMUX17_VALUE 0x22222222
#define PINMUX18_VALUE 0x22022222
#define PINMUX19_VALUE 0x02022222

It seems it should be used somehow in the u-Boot compilation, so the pins are configured right after the bootloader and the kernel can locate all the buses and devices.

However, I haven't been able to find it.

Any help on this please?

Thank you!

over 13 years ago

0 Michael T over 13 years ago

TI__Expert 6735 points

Carmelo:

The pin mux settings for AM180x are setup in the U-Boot code at ./board/davinci/da8xxevm/da850.c

Regards,

Michael T

0 Carmelo Garcia over 13 years ago in reply to Michael T

Prodigy 105 points

Hello Michael.

I have already found that pinmux settings, but they look nothing but the information I get from the pin setup tool.

This program seems to give me the content of the pinmux registers.

How could I make that conversion?

Thanks for your support!

Carmelo

0 Michael T over 13 years ago in reply to Carmelo Garcia

TI__Expert 6735 points

Carmelo:

The Pin Setup tool provides a way to trade-off different pin mux configurations and resolve

conflicts, but it cannot directly generate source code. The output register values provide a

reference for what needs to go into the source code.

Regards,

Michael T

0 Carmelo Garcia over 13 years ago in reply to Michael T

Prodigy 105 points

Hello Michael.

Pin Setup tool is in fact a very useful way to check pin configurations.

But it is capable of exporting these configurations to a header file (.h), and this file should be used for something.

I have been researching in the Processors Wiki, and the Pin Setup Tool for ARM Processors also exports to header files.

However, this one gives us two files, with a full explanation on how to use them in u-boot in this link:

http://processors.wiki.ti.com/index.php/Pin_Mux_Utility_for_ARM_MPU_Processors

This tool can not be used with AM1808, so I'm stuck.

Any ideas?

0 Michael T over 13 years ago in reply to Carmelo Garcia

TI__Expert 6735 points

The header files from Pin Mux Utility are really just reference code that is close to the implementation

used on AM35x and AM37x. Pinmux implementation varies a lot across platforms and is generally

not in a form that can be automatically generated for any pin mux configuration.

Yes, AM180x uses the separate program called Pin Setup.

Michael T

0 Carmelo Garcia over 13 years ago in reply to Michael T

Prodigy 105 points

So there is one more question about pinmux.

I have found some pinmux references in the file /arch/arm/configs/board-da850-evm.c.

Should I configure pinmux registers just in U-Boot (within the file /board/davinci/da8xxevm/da850evm.c), or is it necessary to modify code in the kernel too?

I'm pretty confused about pinmux initialisation in a kernel environment.

Thanks again.

0 Sudhakar Rajashekhara over 13 years ago in reply to Carmelo Garcia

TI__Expert 5170 points

Hi,

Ideally pinmuxing of peripherals which are accessed in U-Boot will be done in U-Boot, else it'll be done in the kernel.

Regards, Sudhakar

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AM1808 PInmux configuration on u-Boot