[v2,2/4] dt-bindings: bus: Add Baikal-T1 APB-bus binding

Commit Message

Serge Semin May 7, 2020, 10:41 p.m. UTC

Baikal-T1 CPU or DMAC MMIO requests are handled by the AMBA 3 AXI
Interconnect which routes them to the AXI-APB bridge, which in turn
serializes accesses and routes them to the corresponding APB slave device.
This binding describes the AXI-APB bridge considered as the APB-bus. It is
supposed to be compatible with "be,bt1-apb" and "simple-bus" drivers,
should be equipped with EHB MMIO region and a region with no slave device
mapped, interrupts line number, APB reference clock and domain reset line.

Signed-off-by: Serge Semin <[e-mail]>
Cc: Alexey Malahov <[e-mail]>
Cc: Paul Burton <[e-mail]>
Cc: Ralf Baechle <[e-mail]>
Cc: Tony Lindgren <[e-mail]>
Cc: Tero Kristo <[e-mail]>
Cc: Manivannan Sadhasivam <[e-mail]>
Cc: Jeffrey Hugo <[e-mail]>
Cc: Linus Walleij <[e-mail]>
Cc: Olof Johansson <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]

---

Rob, I had to remove your Reviewed-by tag, since new changes had been
introduced.

Changelog v2:
- Move driver to the bus subsystem.
- Don't use a multi-arg clock phandle reference in the examples dt-bindings
  property. Thus redundant include statement can be removed.
- Use dual GPL/BSD license.
- Use single lined copyright header.
- Lowercase the unit-address.
- Convert a dedicated EHB block binding to the Baikal-T1 APB-bus one.
- Add APB reference clock and reset support.
- Replace "additionalProperties: false" property with
  "unevaluatedProperties: false".
- Add reg-names property.
---
 .../bindings/bus/baikal,bt1-apb.yaml          | 90 +++++++++++++++++++
 1 file changed, 90 insertions(+)
 create mode 100644 Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml

Comments

Rob Herring (Arm) May 15, 2020, 3:13 a.m. UTC | #1

On Fri, 8 May 2020 01:41:14 +0300, Serge Semin wrote:
> Baikal-T1 CPU or DMAC MMIO requests are handled by the AMBA 3 AXI
> Interconnect which routes them to the AXI-APB bridge, which in turn
> serializes accesses and routes them to the corresponding APB slave device.
> This binding describes the AXI-APB bridge considered as the APB-bus. It is
> supposed to be compatible with "be,bt1-apb" and "simple-bus" drivers,
> should be equipped with EHB MMIO region and a region with no slave device
> mapped, interrupts line number, APB reference clock and domain reset line.
> 
> Signed-off-by: Serge Semin <[e-mail]>
> Cc: Alexey Malahov <[e-mail]>
> Cc: Paul Burton <[e-mail]>
> Cc: Ralf Baechle <[e-mail]>
> Cc: Tony Lindgren <[e-mail]>
> Cc: Tero Kristo <[e-mail]>
> Cc: Manivannan Sadhasivam <[e-mail]>
> Cc: Jeffrey Hugo <[e-mail]>
> Cc: Linus Walleij <[e-mail]>
> Cc: Olof Johansson <[e-mail]>
> Cc: [e-mail]
> Cc: [e-mail]
> 
> ---
> 
> Rob, I had to remove your Reviewed-by tag, since new changes had been
> introduced.
> 
> Changelog v2:
> - Move driver to the bus subsystem.
> - Don't use a multi-arg clock phandle reference in the examples dt-bindings
>   property. Thus redundant include statement can be removed.
> - Use dual GPL/BSD license.
> - Use single lined copyright header.
> - Lowercase the unit-address.
> - Convert a dedicated EHB block binding to the Baikal-T1 APB-bus one.
> - Add APB reference clock and reset support.
> - Replace "additionalProperties: false" property with
>   "unevaluatedProperties: false".
> - Add reg-names property.
> ---
>  .../bindings/bus/baikal,bt1-apb.yaml          | 90 +++++++++++++++++++
>  1 file changed, 90 insertions(+)
>  create mode 100644 Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml
> 

Reviewed-by: Rob Herring <[e-mail]>

Patch

diff --git a/Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml b/Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml
new file mode 100644
index 000000000000..d6a3b71ea835
--- /dev/null
+++ b/Documentation/devicetree/bindings/bus/baikal,bt1-apb.yaml
@@ -0,0 +1,90 @@ 
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+# Copyright (C) 2020 BAIKAL ELECTRONICS, JSC
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/bus/baikal,bt1-apb.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Baikal-T1 APB-bus
+
+maintainers:
+  - Serge Semin <[e-mail]>
+
+description: |
+  Baikal-T1 CPU or DMAC MMIO requests are handled by the AMBA 3 AXI Interconnect
+  which routes them to the AXI-APB bridge. This interface is a single master
+  multiple slaves bus in turn serializing IO accesses and routing them to the
+  addressed APB slave devices. In case of any APB protocol collisions, slave
+  device not responding on timeout an IRQ is raised with an erroneous address
+  reported to the APB terminator (APB Errors Handler Block).
+
+allOf:
+ - $ref: /schemas/simple-bus.yaml#
+
+properties:
+  compatible:
+    contains:
+      const: baikal,bt1-apb
+
+  reg:
+    items:
+      - description: APB EHB MMIO registers
+      - description: APB MMIO region with no any device mapped
+
+  reg-names:
+    items:
+      - const: ehb
+      - const: nodev
+
+  interrupts:
+    maxItems: 1
+
+  clocks:
+    items:
+      - description: APB reference clock
+
+  clock-names:
+    items:
+      - const: pclk
+
+  resets:
+    items:
+      - description: APB domain reset line
+
+  reset-names:
+    items:
+      - const: prst
+
+unevaluatedProperties: false
+
+required:
+  - compatible
+  - reg
+  - reg-names
+  - interrupts
+  - clocks
+  - clock-names
+
+examples:
+  - |
+    #include <dt-bindings/interrupt-controller/mips-gic.h>
+
+    bus@1f059000 {
+      compatible = "baikal,bt1-apb", "simple-bus";
+      reg = <0 0x1f059000 0 0x1000>,
+            <0 0x1d000000 0 0x2040000>;
+      reg-names = "ehb", "nodev";
+      #address-cells = <1>;
+      #size-cells = <1>;
+
+      ranges;
+
+      interrupts = <GIC_SHARED 16 IRQ_TYPE_LEVEL_HIGH>;
+
+      clocks = <&ccu_sys 1>;
+      clock-names = "pclk";
+
+      resets = <&ccu_sys 1>;
+      reset-names = "prst";
+    };
+...