Re: [PATCH v12 5/6] ARM: socfpga: add bindings document for fpga bridge drivers

From: Rob Herring
Date: Wed Oct 28 2015 - 19:45:11 EST


On Tue, Oct 27, 2015 at 5:09 PM, <atull@xxxxxxxxxxxxxxxxxxxxx> wrote:
> From: Alan Tull <atull@xxxxxxxxxxxxxxxxxxxxx>
>
> Add bindings documentation for Altera SOCFPGA bridges:
> * fpga2sdram
> * fpga2hps
> * hps2fpga
> * lwhps2fpga
>
> Signed-off-by: Alan Tull <dinguyen@xxxxxxxxxxxxxxxxxxxxx>

Oops...

> Signed-off-by: Dinh Nguyen <dinguyen@xxxxxxxxxxxxxxxxxxxxx>
> Signed-off-by: Matthew Gerlach <mgerlach@xxxxxxxxxx>

These should be roughly in order of who did modifications. I'd expect
you to be last.

> ---
> v2: separate into 2 documents for the 2 drivers
> v12: bump version to line up with simple-fpga-bus version
> remove Linux specific notes such as references to sysfs
> move non-DT specific documentation elsewhere
> remove bindings that would have been used to pass configuration
> clean up formatting
> ---
> .../bindings/fpga/altera-fpga2sdram-bridge.txt | 18 ++++++++++
> .../bindings/fpga/altera-hps2fpga-bridge.txt | 36 ++++++++++++++++++++
> 2 files changed, 54 insertions(+)
> create mode 100644 Documentation/devicetree/bindings/fpga/altera-fpga2sdram-bridge.txt
> create mode 100644 Documentation/devicetree/bindings/fpga/altera-hps2fpga-bridge.txt
>
> diff --git a/Documentation/devicetree/bindings/fpga/altera-fpga2sdram-bridge.txt b/Documentation/devicetree/bindings/fpga/altera-fpga2sdram-bridge.txt
> new file mode 100644
> index 0000000..11eb5b7
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/altera-fpga2sdram-bridge.txt
> @@ -0,0 +1,18 @@
> +Altera FPGA To SDRAM Bridge Driver
> +
> +Required properties:
> +- compatible : Should contain "altr,socfpga-fpga2sdram-bridge"
> +
> +Optional properties:
> +- label : User-readable name for this bridge.
> + Default is br<device#>

Why does the user need label? We generally use label to match physical
labels like "Rear USB port" or "disk LED" or something.

> +- init-val : 0 if driver should disable bridge at startup
> + 1 if driver should enable bridge at startup

Perhaps "bridge-enable" would be a more descriptive name.

And to comment on other replies, I have no problem with this type of
property in the DT. But yes, configuration type properties will get
more scrutiny.

> + Default is to leave bridge in current state.
> +
> +Example:
> + fpga2sdram_br: fpgabridge@3 {
> + compatible = "altr,socfpga-fpga2sdram-bridge";
> + label = "fpga2sdram";
> + init-val = <0>;
> + };
> diff --git a/Documentation/devicetree/bindings/fpga/altera-hps2fpga-bridge.txt b/Documentation/devicetree/bindings/fpga/altera-hps2fpga-bridge.txt
> new file mode 100644
> index 0000000..eb52f3b
> --- /dev/null
> +++ b/Documentation/devicetree/bindings/fpga/altera-hps2fpga-bridge.txt
> @@ -0,0 +1,36 @@
> +Altera FPGA/HPS Bridge Driver
> +
> +Required properties:
> +- compatible : Should contain one of:
> + "altr,socfpga-hps2fpga-bridge",
> + "altr,socfpga-lwhps2fpga-bridge", or
> + "altr,socfpga-fpga2hps-bridge"
> +- clocks : Clocks used by this module.
> +
> +Optional properties:
> +- label : User-readable name for this bridge.
> + Default is br<device#>
> +- init-val : 0 if driver should disable bridge at startup.
> + 1 if driver should enable bridge at startup.
> + Default is to leave bridge in its current state.
> +
> +Example:
> + hps_fpgabridge0: fpgabridge@0 {
> + compatible = "altr,socfpga-hps2fpga-bridge";
> + label = "hps2fpga";
> + clocks = <&l4_main_clk>;
> + init-val = <1>;
> + };
> +
> + hps_fpgabridge1: fpgabridge@1 {
> + compatible = "altr,socfpga-lwhps2fpga-bridge";
> + label = "lwhps2fpga";
> + clocks = <&l4_main_clk>;
> + init-val = <0>;
> + };
> +
> + hps_fpgabridge2: fpgabridge@2 {
> + compatible = "altr,socfpga-fpga2hps-bridge";
> + label = "fpga2hps";
> + clocks = <&l4_main_clk>;
> + };
> --
> 1.7.9.5
>
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