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Date:      Thu, 03 Sep 2020 15:02:27 +0400
From:      Alexander Mishin <mishin@mh.net.ru>
To:        freebsd-arm@freebsd.org
Subject:   Re: Re: Re: Re: Re: Kmod driver at iicbus. attach() and config_intrhook(9)
Message-ID:  <8c4593191cccecfe6927c6628e62c742@mh.net.ru>
In-Reply-To: <7498213a-28d8-f20c-35ae-97aaf2796c1e@FreeBSD.org>
References:  <0496ebc5628a015c005c150549e1e70a@mh.net.ru> <20200901221839.GY4213@funkthat.com> <7498213a-28d8-f20c-35ae-97aaf2796c1e@FreeBSD.org>

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Andriy Gapon писал 2020-09-03 11:29:
> On 02/09/2020 01:18, John-Mark Gurney wrote:
>> So my reading of the twsi driver is that it handles things correctly
>> allowing devices pre-interrupts to attach, and using interrupts for
>> transfers post-cold.
> 
> I just want to note that twsi uses _completely_ different code for 
> polled and
> interrupt modes.  So, while either mode should be active at correct 
> times, I
> cannot certify that the polled mode works correctly for all transfer 
> types.
> I haven't reviewed the polled mode code.

This adds some more light on my question.

As a result:
For twsi I use iicbb_transfer() (as Emmanuel Vadot recommended to 
someone on the mailing list).
It is definitely not works for my driver, until interrupts went enabled. 
But it works perfectly well with the config_intrhook().

I have never tried iicbus_write() at boot time yet, but I think I'll 
try, just to know for the future.

Thanks



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