Re: [PATCH net-next 1/7] dt-binding: ti: am65x: document common platform time sync cpts module

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On 06/05/2020 22:07, Rob Herring wrote:
On Tue, May 5, 2020 at 10:01 AM Grygorii Strashko
<grygorii.strashko@xxxxxx> wrote:



On 05/05/2020 07:04, Rob Herring wrote:
On Fri, May 01, 2020 at 11:50:05PM +0300, Grygorii Strashko wrote:
Document device tree bindings for TI AM654/J721E SoC The Common Platform
Time Sync (CPTS) module. The CPTS module is used to facilitate host control
of time sync operations. Main features of CPTS module are:
    - selection of multiple external clock sources
    - 64-bit timestamp mode in ns with ppm and nudge adjustment.
    - control of time sync events via interrupt or polling
    - hardware timestamp of ext. events (HWx_TS_PUSH)
    - periodic generator function outputs (TS_GENFx)
    - PPS in combination with timesync router
    - Depending on integration it enables compliance with the IEEE 1588-2008
standard for a precision clock synchronization protocol, Ethernet Enhanced
Scheduled Traffic Operations (CPTS_ESTFn) and PCIe Subsystem Precision Time
Measurement (PTM).

Signed-off-by: Grygorii Strashko <grygorii.strashko@xxxxxx>
---
   .../bindings/net/ti,k3-am654-cpsw-nuss.yaml   |   7 +
   .../bindings/net/ti,k3-am654-cpts.yaml        | 152 ++++++++++++++++++
   2 files changed, 159 insertions(+)
   create mode 100644 Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml

diff --git a/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml b/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml
index 78bf511e2892..0f3fde45e200 100644
--- a/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml
+++ b/Documentation/devicetree/bindings/net/ti,k3-am654-cpsw-nuss.yaml
@@ -144,6 +144,13 @@ patternProperties:
       description:
         CPSW MDIO bus.

+  "^cpts$":

ok


Fixed strings go under 'properties'.

+    type: object
+    allOf:
+      - $ref: "ti,am654-cpts.yaml#"
+    description:
+      CPSW Common Platform Time Sync (CPTS) module.
+
   required:
     - compatible
     - reg
diff --git a/Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml b/Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml
new file mode 100644
index 000000000000..1b535d41e5c6
--- /dev/null
+++ b/Documentation/devicetree/bindings/net/ti,k3-am654-cpts.yaml
@@ -0,0 +1,152 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/net/ti,am654-cpts.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: The TI AM654x/J721E Common Platform Time Sync (CPTS) module Device Tree Bindings
+
+maintainers:
+  - Grygorii Strashko <grygorii.strashko@xxxxxx>
+  - Sekhar Nori <nsekhar@xxxxxx>
+
+description: |+
+  The TI AM654x/J721E CPTS module is used to facilitate host control of time
+  sync operations.
+  Main features of CPTS module are
+  - selection of multiple external clock sources
+  - Software control of time sync events via interrupt or polling
+  - 64-bit timestamp mode in ns with PPM and nudge adjustment.
+  - hardware timestamp push inputs (HWx_TS_PUSH)
+  - timestamp counter compare output (TS_COMP)
+  - timestamp counter bit output (TS_SYNC)
+  - periodic Generator function outputs (TS_GENFx)
+  - Ethernet Enhanced Scheduled Traffic Operations (CPTS_ESTFn) (TSN)
+  - external hardware timestamp push inputs (HWx_TS_PUSH) timestamping
+
+   Depending on integration it enables compliance with the IEEE 1588-2008
+   standard for a precision clock synchronization protocol, Ethernet Enhanced
+   Scheduled Traffic Operations (CPTS_ESTFn) and PCIe Subsystem Precision Time
+   Measurement (PTM).
+
+  TI AM654x/J721E SoCs has several similar CPTS modules integrated into the
+  different parts of the system which could be synchronized with each other
+  - Main CPTS
+  - MCU CPSW CPTS with IEEE 1588-2008 support
+  - PCIe subsystem CPTS for PTM support
+
+  Depending on CPTS module integration and when CPTS is integral part of
+  another module (MCU CPSW for example) "compatible" and "reg" can
+  be omitted - parent module is fully responsible for CPTS enabling and
+  configuration.

That's fine, but you should still have compatible and reg.

I'll add reg as below. But compatible is an issue, because
k3-am654-cpsw-nuss call of_platform_populate() to create mdio device.
But for CPTS I do not want to create device as k3-am654-cpsw-nuss uses direct
function calls to CPTS.

Will it be correct to switch to of_platform_device_create() instead of
of_platform_populate()?

That should be fine I think.

Thanks. I've sent follow up patches.

--
Best regards,
grygorii



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