Re: [PATCH v3 2/2] mtd: spi-nor: add initial sysfs support

[Michael Walle]

Hi Alex,

Am 2021-04-29 18:23, schrieb Alexander Williams:
> On Thu, Apr 29, 2021 at 8:57 AM Michael Walle <michael@xxxxxxxx> 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@xxxxxxxx>
> > ---
> > 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@xxxxxxxxxxxxxxxxxxx
> > +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@xxxxxxxxxxxxxxxxxxx
> > +Description:   (RO) Manufacturer of the SPI NOR flash.
> > +
> > +
> > +What:          /sys/bus/spi/devices/.../partname
> > +Date:          April 2021
> > +KernelVersion: 5.14
> > +Contact:       linux-mtd@xxxxxxxxxxxxxxxxxxx
> > +Description:   (RO) Part name of the SPI NOR flash.
> > +
> > +
> > +What:          /sys/bus/spi/devices/.../sfdp
> > +Date:          April 2021
> > +KernelVersion: 5.14
> > +Contact:       linux-mtd@xxxxxxxxxxxxxxxxxxx
> > +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