linux-kernel - Re: [RFC v3 2/6] mmc: core: allow to match the device tree to apply quirks

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Date:   Wed, 3 Nov 2021 14:36:21 +0100
From:   "H. Nikolaus Schaller" <hns@...delico.com>
To:     Jérôme Pouiller <jerome.pouiller@...abs.com>
Cc:     Ulf Hansson <ulf.hansson@...aro.org>,
        Avri Altman <avri.altman@....com>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Tony Lindgren <tony@...mide.com>,
        Bean Huo <beanhuo@...ron.com>, notasas@...il.com,
        linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org,
        letux-kernel@...nphoenux.org, kernel@...a-handheld.com
Subject: Re: [RFC v3 2/6] mmc: core: allow to match the device tree to apply
 quirks

Hi jerome,


> Am 03.11.2021 um 14:24 schrieb Jérôme Pouiller <jerome.pouiller@...abs.com>:
> 
> Hi Nikolaus,
> 
> On Wednesday 3 November 2021 14:00:10 CET H. Nikolaus Schaller wrote:
>> From: Jérôme Pouiller <jerome.pouiller@...abs.com>
>> 
>> MMC subsystem provides a way to apply quirks when a device match some
>> properties (VID, PID, etc...) Unfortunately, some SDIO devices does not
>> comply with the SDIO specification and does not provide reliable VID/PID
>> (eg. Silabs WF200).
>> 
>> So, the drivers for these devices rely on device tree to identify the
>> device.
>> 
>> This patch allows the MMC to also rely on the device tree to apply a
>> quirk.
>> 
>> Signed-off-by: Jérôme Pouiller <jerome.pouiller@...abs.com>
>> ---
>> drivers/mmc/core/card.h   |  3 +++
>> drivers/mmc/core/quirks.h | 18 ++++++++++++++++++
>> 2 files changed, 21 insertions(+)
>> 
>> diff --git a/drivers/mmc/core/card.h b/drivers/mmc/core/card.h
>> index 7bd392d55cfa5..2f73f8567e14f 100644
>> --- a/drivers/mmc/core/card.h
>> +++ b/drivers/mmc/core/card.h
>> @@ -59,6 +59,9 @@ struct mmc_fixup {
>>        /* for MMC cards */
>>        unsigned int ext_csd_rev;
>> 
>> +       /* Match against functions declared in device tree */
>> +       const char *const *of_compatible;
>> +
>>        void (*vendor_fixup)(struct mmc_card *card, int data);
>>        int data;
>> };
>> diff --git a/drivers/mmc/core/quirks.h b/drivers/mmc/core/quirks.h
>> index c7ef2d14b359f..a8b82b34dcfd2 100644
>> --- a/drivers/mmc/core/quirks.h
>> +++ b/drivers/mmc/core/quirks.h
>> @@ -10,6 +10,7 @@
>>  *
>>  */
>> 
>> +#include <linux/of.h>
>> #include <linux/mmc/sdio_ids.h>
>> 
>> #include "card.h"
>> @@ -145,6 +146,20 @@ static const struct mmc_fixup __maybe_unused sdio_fixup_methods[] = {
>>        END_FIXUP
>> };
>> 
>> +static inline bool mmc_fixup_of_compatible_match(struct mmc_card *card,
>> +                                                const char *const *compat_list)
>> +{
>> +       struct device_node *of_node;
>> +       int i;
>> +
>> +       for (i = 0; i < 7; i++) {
>> +               of_node = mmc_of_find_child_device(card->host, i);
>> +               if (of_node && of_device_compatible_match(of_node, compat_list))
>> +                       return true;
>> +       }
>> +       return false;
>> +}
>> +
>> static inline void mmc_fixup_device(struct mmc_card *card,
>>                                    const struct mmc_fixup *table)
>> {
>> @@ -173,6 +188,9 @@ static inline void mmc_fixup_device(struct mmc_card *card,
>>                        continue;
>>                if (rev < f->rev_start || rev > f->rev_end)
>>                        continue;
>> +               if (f->of_compatible &&
>> +                   !mmc_fixup_of_compatible_match(card, f->of_compatible))
>> +                       continue;
>> 
>>                dev_dbg(&card->dev, "calling %ps\n", f->vendor_fixup);
>>                f->vendor_fixup(card, f->data);
>> --
>> 2.33.0
>> 
>> 
> 
> Thanks to take care of this. Do you know if the comments for Ulf[1]
> are still relevant?
> 
> [1]: https://lore.kernel.org/lkml/CAPDyKFpr0kpRXoUACNNSwe8pL1S9wJPjnX+GFGS1PNezKCDYzQ@mail.gmail.com/

Ah yes. I think so.

Especially the comment about doing the loop over the child nodes...

I'll make a note for v4.

BR and thanks,
Nikolaus