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Date:   Thu, 29 Apr 2021 18:44:38 +0200
From:   Michael Walle <michael@walle.cc>
To:     Alexander Williams <awill@google.com>
Cc:     linux-kernel@vger.kernel.org, linux-mtd@lists.infradead.org,
        Tudor Ambarus <tudor.ambarus@microchip.com>,
        Pratyush Yadav <p.yadav@ti.com>,
        Miquel Raynal <miquel.raynal@bootlin.com>,
        Richard Weinberger <richard@nod.at>,
        Vignesh Raghavendra <vigneshr@ti.com>,
        Yicong Yang <yangyicong@hisilicon.com>,
        Heiko Thiery <heiko.thiery@gmail.com>
Subject: Re: [PATCH v3 2/2] mtd: spi-nor: add initial sysfs support
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 <20210429155713.28808-3-michael@walle.cc>
 <CACqsJN8mrHUB9Ls3PG5R_B84+xUjf-2VakA=09mP_bodWnUgmw@mail.gmail.com>
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Hi Alex,

Am 2021-04-29 18:23, schrieb Alexander Williams:
> On Thu, Apr 29, 2021 at 8:57 AM Michael Walle <michael@walle.cc> wrote:
>> 
>> Add support to show the manufacturer, the partname and JEDEC 
>> identifier
>> as well as to dump the SFDP table. Not all flashes list their SFDP 
>> table
>> contents in their datasheet. So having that is useful. It might also 
>> be
>> helpful in bug reports from users.
>> 
>> Signed-off-by: Michael Walle <michael@walle.cc>
>> ---
>> Pratyush, Heiko, I've dropped your Acked and Tested-by because there
>> were some changes.
>> 
>>  .../ABI/testing/sysfs-bus-spi-devices-spi-nor | 31 +++++++
>>  drivers/mtd/spi-nor/Makefile                  |  2 +-
>>  drivers/mtd/spi-nor/core.c                    |  1 +
>>  drivers/mtd/spi-nor/core.h                    |  2 +
>>  drivers/mtd/spi-nor/sysfs.c                   | 92 
>> +++++++++++++++++++
>>  5 files changed, 127 insertions(+), 1 deletion(-)
>>  create mode 100644 
>> Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
>>  create mode 100644 drivers/mtd/spi-nor/sysfs.c
>> 
>> diff --git a/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor 
>> b/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
>> new file mode 100644
>> index 000000000000..4c88307759e2
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-bus-spi-devices-spi-nor
>> @@ -0,0 +1,31 @@
>> +What:          /sys/bus/spi/devices/.../jedec_id
>> +Date:          April 2021
>> +KernelVersion: 5.14
>> +Contact:       linux-mtd@lists.infradead.org
>> +Description:   (RO) The JEDEC ID of the SPI NOR flash as reported by 
>> the
>> +               flash device.
>> +
>> +
>> +What:          /sys/bus/spi/devices/.../manufacturer
>> +Date:          April 2021
>> +KernelVersion: 5.14
>> +Contact:       linux-mtd@lists.infradead.org
>> +Description:   (RO) Manufacturer of the SPI NOR flash.
>> +
>> +
>> +What:          /sys/bus/spi/devices/.../partname
>> +Date:          April 2021
>> +KernelVersion: 5.14
>> +Contact:       linux-mtd@lists.infradead.org
>> +Description:   (RO) Part name of the SPI NOR flash.
>> +
>> +
>> +What:          /sys/bus/spi/devices/.../sfdp
>> +Date:          April 2021
>> +KernelVersion: 5.14
>> +Contact:       linux-mtd@lists.infradead.org
>> +Description:   (RO) This attribute is only present if the SPI NOR 
>> flash
>> +               device supports the "Read SFDP" command (5Ah).
>> +
>> +               If present, it contains the complete SFDP (serial 
>> flash
>> +               discoverable parameters) binary data of the flash.
>> diff --git a/drivers/mtd/spi-nor/Makefile 
>> b/drivers/mtd/spi-nor/Makefile
>> index 136f245c91dc..6b904e439372 100644
>> --- a/drivers/mtd/spi-nor/Makefile
>> +++ b/drivers/mtd/spi-nor/Makefile
>> @@ -1,6 +1,6 @@
>>  # SPDX-License-Identifier: GPL-2.0
>> 
>> -spi-nor-objs                   := core.o sfdp.o swp.o otp.o
>> +spi-nor-objs                   := core.o sfdp.o swp.o otp.o sysfs.o
>>  spi-nor-objs                   += atmel.o
>>  spi-nor-objs                   += catalyst.o
>>  spi-nor-objs                   += eon.o
>> diff --git a/drivers/mtd/spi-nor/core.c b/drivers/mtd/spi-nor/core.c
>> index 20c7ee604731..57d8a4dae5fd 100644
>> --- a/drivers/mtd/spi-nor/core.c
>> +++ b/drivers/mtd/spi-nor/core.c
>> @@ -3349,6 +3349,7 @@ static struct spi_mem_driver spi_nor_driver = {
>>                 .driver = {
>>                         .name = "spi-nor",
>>                         .of_match_table = spi_nor_of_table,
>> +                       .dev_groups = spi_nor_sysfs_groups,
> 
> Putting these in the driver's dev_groups does create a divergence 
> between
> different spi-nor controllers. For all the controllers supported in
> drivers/mtd/spi-nor/controllers/, would their drivers need to add the 
> same sysfs
> groups to get the same support?

Well, one supports it and one does not, no? If support is added later,
we should keep an eye on it. Unfortunately, I don't have any hardware
to see if just adding the .dev_groups to another driver will just work.

-michael