Messages in this thread | | | Date | Mon, 7 Aug 2023 11:20:40 +0200 | From | Miquel Raynal <> | Subject | Re: [PATCH v8 0/8] NVMEM cells in sysfs |
| |
Hi Chen-Yu,
wenst@chromium.org wrote on Mon, 7 Aug 2023 16:57:03 +0800:
> On Mon, Aug 7, 2023 at 4:24 PM Miquel Raynal <miquel.raynal@bootlin.com> wrote: > > > > Hello, > > > > As part of a previous effort, support for dynamic NVMEM layouts was > > brought into mainline, helping a lot in getting information from NVMEM > > devices at non-static locations. One common example of NVMEM cell is the > > MAC address that must be used. Sometimes the cell content is mainly (or > > only) useful to the kernel, and sometimes it is not. Users might also > > want to know the content of cells such as: the manufacturing place and > > date, the hardware version, the unique ID, etc. Two possibilities in > > this case: either the users re-implement their own parser to go through > > the whole device and search for the information they want, or the kernel > > can expose the content of the cells if deemed relevant. This second > > approach sounds way more relevant than the first one to avoid useless > > code duplication, so here is a series bringing NVMEM cells content to > > the user through sysfs. > > > > Here is a real life example with a Marvell Armada 7040 TN48m switch: > > > > $ nvmem=/sys/bus/nvmem/devices/1-00563/ > > $ for i in `ls -1 $nvmem/cells/*`; do basename $i; hexdump -C $i | head -n1; done > > country-code@77 > > 00000000 54 57 |TW| > > crc32@88 > > 00000000 bb cd 51 98 |..Q.| > > device-version@49 > > 00000000 02 |.| > > diag-version@80 > > 00000000 56 31 2e 30 2e 30 |V1.0.0| > > label-revision@4c > > 00000000 44 31 |D1| > > mac-address@2c > > 00000000 18 be 92 13 9a 00 |......| > > manufacture-date@34 > > 00000000 30 32 2f 32 34 2f 32 30 32 31 20 31 38 3a 35 39 |02/24/2021 18:59| > > manufacturer@72 > > 00000000 44 4e 49 |DNI| > > num-macs@6e > > 00000000 00 40 |.@| > > onie-version@61 > > 00000000 32 30 32 30 2e 31 31 2d 56 30 31 |2020.11-V01| > > platform-name@50 > > 00000000 38 38 46 37 30 34 30 2f 38 38 46 36 38 32 30 |88F7040/88F6820| > > product-name@d > > 00000000 54 4e 34 38 4d 2d 50 2d 44 4e |TN48M-P-DN| > > serial-number@19 > > 00000000 54 4e 34 38 31 50 32 54 57 32 30 34 32 30 33 32 |TN481P2TW2042032| > > vendor@7b > > 00000000 44 4e 49 |DNI| > > > > This layout with a cells/ folder containing one file per cell has been > > legitimately challenged by John Thomson. I am not against the idea of > > having a sub-folder per cell but I did not find a relevant way to do > > that so for know I did not change the sysfs organization. If someone > > really wants this other layout, please provide a code snipped which I > > can integrate. > > > > Current support does not include: > > * The knowledge of the type of data (binary vs. ASCII), so by default > > all cells are exposed in binary form. > > * Write support. > > > > Changes in v8: > > * Fix a compilation warning whith !CONFIG_NVMEM_SYSFS. > > * Add a patch to return NULL when no layout is found (reported by Dan > > Carpenter). > > * Fixed the documentation as well as the cover letter regarding the > > addition of addresses in the cell names. > > It seems this version no longer creates cells for legacy DT layout formats? > So while I assume the issue I ran into is fixed, I don't see any cells > created on the MT8183 either. > > Is this intended?
Not at all, but I am surprised they are no longer created. I will add fake cells and see how it behaves.
Thanks for the feedback! Miquèl
| |