Messages in this thread | | | Date | Sat, 5 Aug 2023 15:50:41 +0100 | From | Daniel Golle <> | Subject | Re: [PATCH v7 6/7] ABI: sysfs-nvmem-cells: Expose cells through sysfs |
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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
> + 00000000 54 4e 34 38 4d 2d 50 2d 44 4e |TN48M-P-DN| > + 0000000a > -- > 2.34.1 >
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