Re: [PATCH v2 2/3] Documentation: sysfs: Document Broadcom STB memc sysfs knobs

From: Florian Fainelli
Date: Mon Jul 25 2022 - 12:07:47 EST


On 7/23/22 10:59, Krzysztof Kozlowski wrote:
> On 22/07/2022 22:10, Florian Fainelli wrote:
>> Document the "srpd" and "frequency" sysfs attributes exposed by
>> the brcmstb_memc driver.
>>
>> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>
>> ---
>> .../ABI/testing/sysfs-platform-brcmstb-memc | 15 +++++++++++++++
>> 1 file changed, 15 insertions(+)
>> create mode 100644 Documentation/ABI/testing/sysfs-platform-brcmstb-memc
>>
>> diff --git a/Documentation/ABI/testing/sysfs-platform-brcmstb-memc b/Documentation/ABI/testing/sysfs-platform-brcmstb-memc
>> new file mode 100644
>> index 000000000000..2bf0f58e412c
>> --- /dev/null
>> +++ b/Documentation/ABI/testing/sysfs-platform-brcmstb-memc
>> @@ -0,0 +1,15 @@
>> +What: /sys/devices/platform/*/*/*/*/srpd
>
> That's a lot of */. Are you sure it is correct path? Didn't you include
> here some driver-related path components? Can you paste in email full
> path as an example?

Yes this is the correct path:

/sys/devices/platform/rdb/rdb:memory_controllers/rdb:memory_controllers:memc@0/9902000.memc-ddr/

the 'rdb' node is our top level bus node, the 'rdb:memory_controllers' is an encapsulating node that groups all of the possible memory controllers in a system (there can be between 1 and 3), the rdb:memory_controllers@0 is the first of those memory controller and finally the 9902000.memc-ddr is the sub-node that contains the register controls of interest, since the memory controller aggregates different functions (arbitration, configuration, statistics, DDR PHY SHIM layer, etc.). Maybe I should provide a more complete binding while I am it.

>
>> +Date: July 2022
>> +KernelVersion: 5.21
>> +Contact: Florian Fainelli <f.fainelli@xxxxxxxxx>
>> +Description:
>> + Self Refresh Power Down (SRPD) inactivity timeout counted in
>> + internal DDR controller clock cycles. Possible values range
>> + from 0 (disable inactivity timeout) to 65535 (0xffff).
>
> Using hex suggests one should write there hex? If so, skip decimal...
> You describe the user interface, not hardware registers.

Fair enough.
--
Florian