On 18/07/2022 15:46, Ivan Bornyakov wrote:

On Mon, Jul 18, 2022 at 03:06:18PM +0200, Krzysztof Kozlowski wrote:

quoted

On 15/07/2022 12:03, Ivan Bornyakov wrote:

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On Fri, Jul 15, 2022 at 11:33:54AM +0200, Krzysztof Kozlowski wrote:

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On 14/07/2022 14:26, Ivan Bornyakov wrote:

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Add Device Tree Binding doc for Lattice ECP5 FPGA manager using slave
SPI to load .bit formatted uncompressed bitstream image.

Signed-off-by: Ivan Bornyakov <redacted>
---
 .../fpga/lattice,ecp5-spi-fpga-mgr.yaml       | 71 +++++++++++++++++++
 1 file changed, 71 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml

diff --git a/Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml b/Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml
new file mode 100644
index 000000000000..79868f9c84e2
--- /dev/null
+++ b/Documentation/devicetree/bindings/fpga/lattice,ecp5-spi-fpga-mgr.yaml

@@ -0,0 +1,71 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/fpga/lattice,ecp5-spi-fpga-mgr.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Lattice ECP5 FPGA manager.
+
+maintainers:
+  - Ivan Bornyakov <i.bornyakov@metrotek.ru>
+
+description:
+  Device Tree Bindings for Lattice ECP5 FPGA Manager using slave SPI to
+  load the uncompressed bitstream in .bit format.

s/Device Tree Bindings for//

Instead describe the hardware you are adding bindings for. What is a
"Manager"? It is so broad and unspecific... It is some dedicated
hardware to communicate with FPGA or you just called this regular FPGA
interface exposed to the CPU/SoC?

"FPGA Manager" is a kernel subsystem that exports a set of functions for
programming an FPGA with a bitstream image.
See Documentation/driver-api/fpga/fpga-mgr.rst

This is what you want to include in the bindings document? How is it
related to bindings? We do not talk about driver API but we talk about
hardware. Bindings are for the hardware.

I've send out v3 not too long ago. If you found the wording there not
good enough, could you look through
Documentation/devicetree/bindings/fpga/ and point me to a proper example?

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+
+properties:
+  compatible:
+    enum:
+      - lattice,ecp5-spi-fpga-mgr

Do not encode interface name in compatible so no "spi".

Recently when I submitted FPGA manager for Microchip PolarFire, I was
asked the opposite, to add "spi" in compatible. The reason was that FPGA
can be programmed through other interfaces as well.

I don't see such comment from Rob (DT maintainer):
https://lore.kernel.org/all/?q=%22dt-bindings%3A+fpga%3A+add+binding+doc+for+microchip-spi+fpga+mgr%22

Can you point me to it?

Yeah, it was not Rob but other developer:
https://lore.kernel.org/all/79328410-e56f-7c8a-9d17-de9bfdb98f51@microchip.com/ (local)

The type of bus should not be included in the compatible. It's obvious
by looking at the parent, so Conor's comment was not helpful, IMO.

And at that point I had not even written the bindings doc, so neither
you nor Rob weren't in the Cc.

But eventually Rob reviewed DT bindings doc for PolarFire with
compatible string to be "microchip,mpf-spi-fpga-mgr"
https://lore.kernel.org/all/YkORrgC1FdzaKCMW@robh.at.kernel.org/ (local)

So I thought it was OK.

If spi was at the end, probably would be easier to spot thus would
trigger a comment.


Best regards,
Krzysztof