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From:   Alexander Williams <awill@google.com>
Date:   Thu, 29 Apr 2021 09:23:26 -0700
Message-ID: <CACqsJN8mrHUB9Ls3PG5R_B84+xUjf-2VakA=09mP_bodWnUgmw@mail.gmail.com>
Subject: Re: [PATCH v3 2/2] mtd: spi-nor: add initial sysfs support
To:     Michael Walle <michael@walle.cc>
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>
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Hi Michael,

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?

- Alex