[PATCH v2 1/5] dt-bindings: aspeed: Add eSPI controller

Hi Rob,

-----Original Message-----
From: Rob Herring <robh@kernel.org>
Sent: Saturday, August 21, 2021 4:02 AM
To: ChiaWei Wang <redacted>
Cc: joel at jms.id.au; andrew at aj.id.au; linux-aspeed at lists.ozlabs.org;
openbmc at lists.ozlabs.org; devicetree at vger.kernel.org;
linux-arm-kernel at lists.infradead.org; linux-kernel at vger.kernel.org; Ryan Chen
[off-list ref]
Subject: Re: [PATCH v2 1/5] dt-bindings: aspeed: Add eSPI controller

On Thu, Aug 19, 2021 at 04:00:36PM +0800, Chia-Wei Wang wrote:

quoted

Add dt-bindings for Aspeed eSPI controller

Signed-off-by: Chia-Wei Wang <redacted>
---
 .../devicetree/bindings/soc/aspeed/espi.yaml  | 158
++++++++++++++++++
 1 file changed, 158 insertions(+)
 create mode 100644
Documentation/devicetree/bindings/soc/aspeed/espi.yaml

diff --git a/Documentation/devicetree/bindings/soc/aspeed/espi.yaml

b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml
new file mode 100644
index 000000000000..fec3d37f3ffd

--- /dev/null
+++ b/Documentation/devicetree/bindings/soc/aspeed/espi.yaml

@@ -0,0 +1,158 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause) # #
+Copyright (c) 2021 Aspeed Technology Inc.
+%YAML 1.2
+---
+$id: "http://devicetree.org/schemas/soc/aspeed/espi.yaml#"
+$schema: "http://devicetree.org/meta-schemas/core.yaml#"
+
+title: Aspeed eSPI Controller
+
+maintainers:
+  - Chia-Wei Wang <chiawei_wang@aspeedtech.com>
+  - Ryan Chen <ryan_chen@aspeedtech.com>
+
+description:
+  Aspeed eSPI controller implements a slave side eSPI endpoint device
+  supporting the four eSPI channels, namely peripheral, virtual wire,
+  out-of-band, and flash.
+
+properties:
+  compatible:
+    items:
+      - enum:
+          - aspeed,ast2500-espi
+          - aspeed,ast2600-espi
+      - const: simple-mfd
+      - const: syscon

Is this really 2 sub devices that could be used individually or in a different
combination? If not, then I'd make all this 1 node.

espi-mmbi has individual function and control registers.
However, espi-mmbi is also a feature extended based on the memory cycle of eSPI peripheral channel.
Thereby, it has dependency on the eSPI channel initialization conducted by espi-ctrl.
The scenario is similar to the lpc-ctrl and other lpc-xxx drivers of Aspeed SoCs.

Chiawei