[PATCH v2 1/3] dt-bindings: spi: add spi-rx-bus-channels peripheral property

[David Lechner <dlechner@baylibre.com>]

This adds a new spi-rx-bus-channels property to the generic spi
peripheral property bindings. This property is used to describe
devices that have parallel data output channels.

This property is different from spi-rx-bus-width in that the latter
means that we are reading multiple bits of a single word at one time
while the former means that we are reading single bits of multiple words
at the same time.

Signed-off-by: David Lechner <dlechner@baylibre.com>
---

v2 changes: new patch in v2

 .../devicetree/bindings/spi/spi-peripheral-props.yaml        | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
index 15938f81fdce..1c8e71c18234 100644
--- a/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
+++ b/Documentation/devicetree/bindings/spi/spi-peripheral-props.yaml
@@ -67,6 +67,18 @@ properties:
     enum: [0, 1, 2, 4, 8]
     default: 1
 
+  spi-rx-bus-channels:
+    description:
+      The number of parallel channels for read transfers. The difference between
+      this and spi-rx-bus-width is that a value N for spi-rx-bus-channels means
+      the SPI bus is receiving one bit each of N different words at the same
+      time whereas a value M for spi-rx-bus-width means that the bus is
+      receiving M bits of a single word at the same time. It is also possible to
+      use both properties at the same time, meaning the bus is receiving M bits
+      of N different words at the same time.
+    $ref: /schemas/types.yaml#/definitions/uint32
+    default: 1
+
   spi-rx-delay-us:
     description:
       Delay, in microseconds, after a read transfer.

-- 
2.34.1