topic Re: How to change GPIO default state in uboot in i.MX Processors

How to change GPIO default state in uboot

ravirajns — Wed, 26 Sep 2018 07:22:32 GMT

Hi All,

We are using IMX6DL and facing issue in uboot to configure I2C2 signal to default pulled down. Below are details.

I2C 2 signals are connected peripheral and want this signal default to pulled down in IMX uboot.

1. MX6_PAD_KEY_COL3__GPIO4_IO12

2. MX6_PAD_KEY_ROW3__GPIO4_IO13

We have done changes in board_init function(board/freescale/mx6sabresd/mx6sabresd.c file) but still for ~200msec I2C signal are high.

As per our observation system takes ~200msec to reach board_init() function where we have added code and due to this default I2C signals are high, once our added code execute signals goes low.

But we need default I2C signals should configure low.

What is the default I2C2 signal configurations?

How I can configure above I2C2 signals default pulled down.

Please provide inputs to resolve this issue.

Thanks,

Raviraj

Re: How to change GPIO default state in uboot

igorpadykov — Thu, 27 Sep 2018 01:41:50 GMT

Hi Raviraj

one can try to change gpio state in plugin:

uboot/board/freescale/mx6sabresd/plugin.S

plugin.S\mx6sabresd\freescale\board - uboot-imx - i.MX U-Boot

described in sect.8.7 Plugin image i.MX6DQ Reference Manual
https://www.nxp.com/docs/en/reference-manual/IMX6DQRM.pdf

Best regards
igor
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Re: How to change GPIO default state in uboot

ravirajns — Thu, 27 Sep 2018 10:43:03 GMT

Thanks for your inputs.

Where exactly need to add in board/freescale/mx6sabresd/plugin.S file, this is assembly file.

What is the default state of I2C2 pinmux?

Thanks,

Raviraj

Re: How to change GPIO default state in uboot

igorpadykov — Fri, 28 Sep 2018 01:40:25 GMT

Hi Raviraj

default pin state is described in Table 96. 21 x 21 mm Functional Contact Assignments

i.MX6DQ Datasheet

http://www.nxp.com/docs/en/data-sheet/IMX6DQCEC.pdf

https://community.nxp.com/thread/452162

Best regards
igor