[PATCH v3 07/10] Documentation: dt-bindings: Add documents for PECI hwmon client drivers

On Tue, Apr 17, 2018 at 3:40 PM, Jae Hyun Yoo
[off-list ref] wrote:

On 4/16/2018 4:51 PM, Jae Hyun Yoo wrote:

quoted

On 4/16/2018 4:22 PM, Jae Hyun Yoo wrote:

quoted

On 4/16/2018 11:14 AM, Rob Herring wrote:

quoted

On Tue, Apr 10, 2018 at 11:32:09AM -0700, Jae Hyun Yoo wrote:

quoted

This commit adds dt-bindings documents for PECI cputemp and dimmtemp
client
drivers.

[...]

quoted

quoted

quoted

quoted

+Example:
+    peci-bus at 0 {
+        #address-cells = <1>;
+        #size-cells = <0>;
+        < more properties >
+
+        peci-dimmtemp at cpu0 {

unit-address is wrong.

Will fix it using the reg value.

quoted

It is a different bus from cputemp? Otherwise, you have conflicting
addresses. If that's the case, probably should make it clear by showing
different host adapters for each example.

It could be the same bus with cputemp. Also, client address sharing is
possible by PECI core if the functionality is different. I mean, cputemp and
dimmtemp targeting the same client is possible case like this.
peci-cputemp at 30
peci-dimmtemp at 30

Oh, I got your point. Probably, I should change these separate settings
into one like

peci-client at 30 {
     compatible = "intel,peci-client";
     reg = <0x30>;
};

Then cputemp and dimmtemp drivers could refer the same compatible string.
Will rewrite it.

I've checked it again and realized that it should use function based node
name like:

peci-cputemp at 30
peci-dimmtemp at 30

If it use the same string like 'peci-client at 30', the drivers cannot be
selectively enabled. The client address sharing way is well handled in PECI
core and this way would be better for the future implementations of other
PECI functional drivers such as crash dump driver and so on. So I'm going
change the unit-address only.

2 nodes at the same address is wrong (and soon dtc will warn you on
this). You have 2 potential options. The first is you need additional
address information in the DT if these are in fact 2 independent
devices. This could be something like a function number to use
something from PCI addressing. From what I found on PECI, it doesn't
seem to have anything like that. The 2nd option is you have a single
DT node which registers multiple hwmon devices. DT nodes and drivers
don't have to be 1-1. Don't design your DT nodes from how you want to
partition drivers in some OS.

Rob