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

From: Florian Fainelli
Date: Tue Jul 26 2022 - 13:27:47 EST


On 7/26/22 02:34, Krzysztof Kozlowski wrote:
> On 25/07/2022 18:07, Florian Fainelli wrote:
>> 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.
>
> The path should be much more specific so include at least:
> rdb/rdb:memory_controllers/rdb:memory_controllers:memc@*/
> (or some variations of it if pieces of name change)
>
> However looking at the driver, this is regular platform driver, thus it
> will appear as:
> /sys/bus/platform/9902000.memc-ddr

There is a missing /devices in the path, but yet that will work too:

/sys/bus/platform/devices/9902000.memc-ddr

Thanks!
--
Florian

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