Re: [PATCH v2 2/2] dt-bindings: net: bluetooth: Add device property nvm-postfix for QCA6174

[Rocky Liao]

On 2019-04-09 22:03, Rob Herring wrote:
> On Tue, Apr 9, 2019 at 5:15 AM Rocky Liao <rjliao@xxxxxxxxxxxxxx> 
> wrote:
> > On 2019-04-04 20:32, Marc Gonzalez wrote:
> > > +robh
> > >
> > > On 04/04/2019 11:08, Rocky Liao wrote:
> > >
> > >> This patchs patch adds an optional device property nvm-postfix to
> > >> allow the
> > >> driver to load customized nvm file based on this property
> > >
> > > While text /before/ is indeed called a "prefix", text /after/ is not a
> > > "postfix",
> > > but a "suffix".
> > >
> > >
> > >>  Documentation/devicetree/bindings/net/qualcomm-bluetooth.txt | 2 ++
> > >>  1 file changed, 2 insertions(+)
> > >>
> > >> diff --git
> > >> a/Documentation/devicetree/bindings/net/qualcomm-bluetooth.txt
> > >> b/Documentation/devicetree/bindings/net/qualcomm-bluetooth.txt
> > >> index 824c0e2..70cda4b 100644
> > >> --- a/Documentation/devicetree/bindings/net/qualcomm-bluetooth.txt
> > >> +++ b/Documentation/devicetree/bindings/net/qualcomm-bluetooth.txt
> > >> @@ -16,6 +16,7 @@ Optional properties for compatible string
> > >> qcom,qca6174-bt:
> > >>
> > >>   - enable-gpios: gpio specifier used to enable chip
> > >>   - clocks: clock provided to the controller (SUSCLK_32KHZ)
> > >> + - nvm-postfix: nvm file postfix to load customized nvm file
> > >
> > > The device tree is supposed to describe hardware.
> > >
> > > The name of which file to load can hardly be considered part of the HW.
> > >
> > > Possible solutions:
> > > 1) derive the file name from the compatible string
> > > 2) pass the name as a module parameter
> > > 3) something else
> > >
> > >
> > >> @@ -39,6 +40,7 @@ serial@7570000 {
> > >>
> > >>              enable-gpios = <&pm8994_gpios 19 GPIO_ACTIVE_HIGH>;
> > >>              clocks = <&divclk4>;
> > >> +            nvm-postfix = "i2s";
> > >>      };
> > >>  };
> > >
> > > If one provides the entire suffix, including the underscore, then you
> > > can
> > > simplify the code:
> > >
> > >       snprintf(config.fwname, sizeof(config.fwname), "qca/nvm_%08x%s.bin",
> > > soc_ver, suffix ? suffix : "");
> > >
> > > Regards
> > .
> > Hi Marc,
> >
> > The major purpose for that property is about the BT audio bus type, 
> > can
> > it be considered as part of the HW? If yes maybe we can use a property
> > name "audio-bus" to reflect that.
> >
> > If not then I will adopt the solution 1 to add a new compatible string
> > "{ .compatible = "qcom,qca6174-bt-i2s" }" and load specific nvm for 
> > this
> > compatible string, please feel free to let me know if any other
> > concerns.
>
> I don't think the suggestion was to add the nvm string to the
> compatible, but rather compatible strings serve as a map key. Having
> board specific firmware files for wifi/bt is pretty common, but
> parameters for 'i2s' is a bit strange. So a better explanation of what
> parameters this contains would help. How/when does it vary, for
> example?
>
> Also, if it is only a handful of parameters, making them DT properties
> is preferred.
>
> Rob

Ok, I prefer to go with adding a device property "firmware-name" with 
full firmware name as you suggested in previous comment.
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