How to set imx6dl board gpio default low level in uboot once power on

[mrleo]

HI,all

I  found that imx6 some gpio default is output high level once power on.

example：GPIO_2（GPIO_1_2)），NANDF_D5（GPIO_2_5）

My custom imx6dl board is used these two gpio  to control  lcd power and lcd reset.

These two gpio are default high level.

If I want these two gpio are default low level,what should I do?

Who can give me a help? Or give me an advices?

Thanks,

Leo

[igorpadykov · Accepted solution]

Hi Leo

if one uses plugin mode, this can be added to dcd header.

Otherwise, for uboot 2009 this may be lowlevel_init.S,

for later uboot versions seems in miscellaneous functions

like board_xx_init_yy in   ..freescale/mx6sabresd/mx6sabresd.c

Best regards

igor

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[mrleo]

Hi igorpadyov,

I have added to uboot 2009 in lowlevel_init.S( lowlevel_init below,befor inv_dcache).

But it will have a very shorter time high level then (in lowlevel_init.S set to low level) low level once power on.

Thanks,

Leo

Re: How to set imx6dl board gpio default low level in uboot once power on

[igorpadykov]

Hi Leo

default pad state after reset is not possible to change, so

there always will be short time until software change pin state.

This is inevitable.

~igor