Messages in this thread | | | Date | Mon, 7 Aug 2023 09:20:47 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH v7 6/7] ABI: sysfs-nvmem-cells: Expose cells through sysfs |
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Hi Daniel,
daniel@makrotopia.org wrote on Sat, 5 Aug 2023 15:50:41 +0100:
> On Tue, Aug 01, 2023 at 08:21:31PM +0200, Miquel Raynal wrote: > > The binary content of nvmem devices is available to the user so in the > > easiest cases, finding the content of a cell is rather easy as it is > > just a matter of looking at a known and fixed offset. However, nvmem > > layouts have been recently introduced to cope with more advanced > > situations, where the offset and size of the cells is not known in > > advance or is dynamic. When using layouts, more advanced parsers are > > used by the kernel in order to give direct access to the content of each > > cell regardless of their position/size in the underlying device, but > > these information were not accessible to the user. > > > > By exposing the nvmem cells to the user through a dedicated cell/ folder > > containing one file per cell, we provide a straightforward access to > > useful user information without the need for re-writing a userland > > parser. Content of nvmem cells is usually: product names, manufacturing > > date, MAC addresses, etc, > > > > Signed-off-by: Miquel Raynal <miquel.raynal@bootlin.com> > > Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> > > --- > > Documentation/ABI/testing/sysfs-nvmem-cells | 21 +++++++++++++++++++++ > > 1 file changed, 21 insertions(+) > > create mode 100644 Documentation/ABI/testing/sysfs-nvmem-cells > > > > diff --git a/Documentation/ABI/testing/sysfs-nvmem-cells b/Documentation/ABI/testing/sysfs-nvmem-cells > > new file mode 100644 > > index 000000000000..a1d140dcbd5d > > --- /dev/null > > +++ b/Documentation/ABI/testing/sysfs-nvmem-cells > > @@ -0,0 +1,21 @@ > > +What: /sys/bus/nvmem/devices/.../cells/<cell-name> > > +Date: May 2023 > > +KernelVersion: 6.5 > > +Contact: Miquel Raynal <miquel.raynal@bootlin.com> > > +Description: > > + The "cells" folder contains one file per cell exposed by the > > + NVMEM device. The name of the file is: <name>@<where>, with > > + <name> being the cell name and <where> its location in the NVMEM > > + device, in hexadecimal (without the '0x' prefix, to mimic device > > + tree node names). The length of the file is the size of the cell > > + (when known). The content of the file is the binary content of > > + the cell (may sometimes be ASCII, likely without trailing > > + character). > > + Note: This file is only present if CONFIG_NVMEM_SYSFS > > + is enabled. > > + > > + Example:: > > + > > + hexdump -C /sys/bus/nvmem/devices/1-00563/cells/product-name > > Location is missing here, should be something like > hexdump -C /sys/bus/nvmem/devices/1-00563/cells/product-name@f00
Yes. I forgot to update the cover letter as well. I will do it in next version.
Thanks, Miquèl
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