Hello Fabio,

Am 09.01.2020 um 12:14 schrieb Fabio Estevam:
Hi Heiko,

On Thu, Jan 9, 2020 at 5:26 AM Heiko Schocher <[email protected]> wrote:

Hmm.. I wonder ... if you want to detect the revd1, you must
access the pmic in SPL, so you need a DTS in which it is
configured, also DM PMIC support in SPL ... which introduces a
lot of dependencies starting with enabling CONFIG_SPL_DM and
blows up SPL ... :-(

Yes, as we are very memory limited in SPL, so what about just probing
the I2C bus directly at 0x8 via I2C API to detect the presence of the
PMIC?

This way we do not need DM PMIC support in SPL.

Yes, i had such a hack also ...

Do we need to mark I2C with 'u-boot,dm-pre-reloc;' too and create a
arch/arm/dts/imx6qdl-wandboard-u-boot.dtsi ?

see my patches, I added there such u-boot files. Unfortunately a
imx6qdl-wandboard-u-boot.dtsi did not worked, I needed 2 files.

2 problems I see:

- reorder board_fit_config_name_match

    see attached patch: 0001-wandboard-reorder-board_fit_config_name_match.patch

    With this patch (based on your patches) and hack [2] U-Boot works also 
again.

- detect rev D1 board (remaining problem)

    board_fit_config_name_match() is called from board_fit_config_name_match,
    so from SPL where you have no access (yet?) to pmic_get(), and so
    is_revd1() is always 0 -> which leads to wrong DTB selection.

    First question: other possibility to detect revision D1 ?

    may only probing the chip is enough ?

As far as I know probing the PMIC chip is the only way to detect D1.

Ok, so we must find a way for it ...

    Should we use instead CONFIG_DTB_RESELECT ?

Not familiar with CONFIG_DTB_RESELECT, sorry.


    This is the way to go I think, added patches:
    0002-wandboard-enable-CONFIG_DTB_RESELECT.patch
    0003-wandboard-use-imx6dl-wandboard-revd1-as-default-DTB.patch
    0004-wandboard-add-u-boot-specific-wandboard-revd1-u-boot.patch
    0005-wandboard-in-SPL-use-only-D1-DTB.patch

    with them, after a soft reset all works fine, see [3] but
    on power on I see [4] :-(

    Any idea, why after a power on, pmic does not work?

Interesting, I do not see this behavior with a imx6qp wandboard revd1.

I have seen I2C errors when booting with an HDMI cable connected:
https://lists.denx.de/pipermail/u-boot/2019-December/393503.html

,but haven't had a chance to debug this yet.

Ok, may I find more time for it...

If you have time, may I can ask, if you can test my patches, if they
do not break other board revisions?

Many thanks!

bye,
Heiko
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