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From: "H. Nikolaus Schaller" <firstname.lastname@example.org>
To: Ulf Hansson <email@example.com>
Cc: Jerome Pouiller <Jerome.Pouiller@silabs.com>,
Avri Altman <firstname.lastname@example.org>,
Shawn Lin <email@example.com>,
Linus Walleij <firstname.lastname@example.org>,
Bean Huo <email@example.com>,
Discussions about the Letux Kernel
firstname.lastname@example.org, Tony Lindgren <email@example.com>,
Subject: Re: [RFC] mmc: core: transplant ti,wl1251 quirks from to be retired omap_hsmmc
Date: Thu, 28 Oct 2021 09:08:50 +0200 [thread overview]
Message-ID: <470A96FD-DB24-4C32-BC9F-AE2F617FBF2D@goldelico.com> (raw)
> Am 27.10.2021 um 23:31 schrieb Ulf Hansson <firstname.lastname@example.org>:
> On Wed, 27 Oct 2021 at 19:01, H. Nikolaus Schaller <email@example.com> wrote:
>> Hi Ulf,
>>> Am 26.10.2021 um 20:08 schrieb H. Nikolaus Schaller <firstname.lastname@example.org>:
>>> Hi Uf,
>>>> As a matter of fact, the similar problem that you are looking to
>>>> address (applying card quirks based on DT compatibility strings), is
>>>> partly being taken care of in another series , being discussed
>>>> right now. I think the solution for the ti,wl1251 should be based upon
>>>> that too. Please have a look and see if you can play with that!?
>>> That is interesting.
>>> Yes, maybe it can be the basis. At least for finding the chip and driver.
>> I have done a first experiment.
>> It seems as if the series  does the opposite of what we need... It just
>> skips entries in struct mmc_fixup if the DT does *not* match.
> Ohh, I didn't look that close. In that case the code isn't doing what
> it *should*. The point is really to match on the compatible string and
> then add quirks if that is found.
That is what I had expected.
> Let me have a closer look - and for sure, I am willing to help if needed.
>> This new match is not even tried in the wl1251 case since card->cis.vendor
>> and card->cis.device are not properly initialized when mmc_fixup_device() is called.
>> (in the upstream code the init_card function sets these and also sets MMC_QUIRK_NONSTD_SDIO
>> to early abort before sdio_read_cccr, sdio_read_common_cis, and mmc_fixup_device).
> We can call mmc_fixup_device() more than once during initialization
> and provide different struct mmc_fixup* - if that is needed.
Ah, looks good.
>> What I don't get from the code is how cis.vendor or cis.device can be
>> initialized from device tree for a specific device. As far as I see it can
>> only be checked for and some quirks can be set from a table if vendor and
>> device read from the CIS registers do match.
> Yes. I thought that should be possible, but maybe it is not?
It seems to be a hen or egg issue here. MMC_QUIRK_NONSTD_SDIO should be set
before we can match by vendor and device or compatible. But it can't be set
>> Instead, we want to match DT and define some values for an otherwise unknown
>> device (i.e. we can't match by vendor or other methods) to help to initialize
>> the interface. So in mmc_fixup_device it is too late and we need something
>> running earlier, based purely on device tree information...
> Okay, I will have a closer look. Maybe we need to extend the card
> quirks interface a bit to make it suitable for this case too.
Combining your suggestions we could do roughly:
Next we need a location for the sdio_prepare_fixups_methods table and functions.
For "ti,wl1251" we would then provide the entry in the table and a function doing
the setup. But where should these be defined? Likely not in a header file like
quirks.h? But there is no quirks.c.
next prev parent reply other threads:[~2021-10-28 7:09 UTC|newest]
Thread overview: 14+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-06 11:25 H. Nikolaus Schaller
2021-10-26 17:12 ` Ulf Hansson
2021-10-26 18:08 ` H. Nikolaus Schaller
2021-10-27 17:00 ` H. Nikolaus Schaller
2021-10-27 21:31 ` Ulf Hansson
2021-10-28 7:08 ` H. Nikolaus Schaller [this message]
2021-10-28 8:59 ` Jérôme Pouiller
2021-10-28 9:31 ` Ulf Hansson
2021-10-28 9:40 ` H. Nikolaus Schaller
2021-10-28 9:43 ` H. Nikolaus Schaller
2021-10-28 9:51 ` Ulf Hansson
2021-10-28 9:55 ` Jérôme Pouiller
2021-10-28 10:07 ` H. Nikolaus Schaller
2021-11-01 9:12 ` H. Nikolaus Schaller
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