Received-SPF: pass (google.com: domain of linux-kernel-owner@vger.kernel.org designates 2620:137:e000::1:20 as permitted sender) client-ip=2620:137:e000::1:20;
From:   Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
To:     Mark Brown <broonie@kernel.org>, Rob Herring <robh+dt@kernel.org>,
        Krzysztof Kozlowski <krzysztof.kozlowski+dt@linaro.org>,
        Conor Dooley <conor+dt@kernel.org>,
        Linus Walleij <linus.walleij@linaro.org>
Cc:     linux-spi@vger.kernel.org, devicetree@vger.kernel.org,
        linux-arm-kernel@lists.infradead.org, linux-kernel@vger.kernel.org,
        linux@ew.tq-group.com,
        Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
Subject: [PATCH 1/2] spi: dt-bindings: introduce linux,use-rt-queue flag
Date:   Fri,  2 Jun 2023 13:52:00 +0200
Message-Id: <20230602115201.415718-1-matthias.schiffer@ew.tq-group.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit
Precedence: bulk

We have seen a number of downstream patches that allow enabling the
realtime feature of the SPI subsystem to reduce latency. These were
usually implemented for a specific SPI driver, even though the actual
handling of the rt flag is happening in the generic SPI controller code.

Introduce a generic linux,use-rt-queue flag that can be used with any
controller driver. The now redundant driver-specific pl022,rt flag is
marked as deprecated.

Signed-off-by: Matthias Schiffer <matthias.schiffer@ew.tq-group.com>
---
 Documentation/devicetree/bindings/spi/spi-controller.yaml | 6 ++++++
 Documentation/devicetree/bindings/spi/spi-pl022.yaml      | 4 +++-
 2 files changed, 9 insertions(+), 1 deletion(-)

diff --git a/Documentation/devicetree/bindings/spi/spi-controller.yaml b/Documentation/devicetree/bindings/spi/spi-controller.yaml
index 524f6fe8c27b4..a24b4ea87443b 100644
--- a/Documentation/devicetree/bindings/spi/spi-controller.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-controller.yaml
@@ -79,6 +79,12 @@ properties:
     description:
       The SPI controller acts as a slave, instead of a master.
 
+  linux,use-rt-queue:
+    $ref: /schemas/types.yaml#/definitions/flag
+    description:
+      Indicates that the controller should run the message pump with realtime
+      priority to minimise the transfer latency on the bus.
+
   slave:
     type: object
 
diff --git a/Documentation/devicetree/bindings/spi/spi-pl022.yaml b/Documentation/devicetree/bindings/spi/spi-pl022.yaml
index 91e540a92fafe..3c43fcc007e1f 100644
--- a/Documentation/devicetree/bindings/spi/spi-pl022.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-pl022.yaml
@@ -49,8 +49,10 @@ properties:
 
   pl022,rt:
     description: indicates the controller should run the message pump with realtime
-      priority to minimise the transfer latency on the bus (boolean)
+      priority to minimise the transfer latency on the bus (deprecated, use the
+      generic linux,use-rt-queue property)
     type: boolean
+    deprecated: true
 
   dmas:
     description:
-- 
TQ-Systems GmbH | Mühlstraße 2, Gut Delling | 82229 Seefeld, Germany
Amtsgericht München, HRB 105018
Geschäftsführer: Detlef Schneider, Rüdiger Stahl, Stefan Schneider
http://www.tq-group.com/