[PATCH 3/6] dt-bindings: connector: Add Toradex camera connector

[Ernest Van Hoecke]

From: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>

Toradex boards route the sideband signals of their 24-pin camera
connectors to different GPIO controllers. Camera overlays which name
those controllers directly must therefore be duplicated for each host
board.

Describe reset, power-down, detection and power-control as
connector-local GPIO functions. This lets an accessory overlay remain
independent of the host wiring. MIPI CSI-2, I2C, clocks and supplies
remain described separately because the GPIO nexus does not abstract
them.

Signed-off-by: Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
---
 .../connector/toradex,camera-connector.yaml        | 86 ++++++++++++++++++++++
 1 file changed, 86 insertions(+)

diff --git a/Documentation/devicetree/bindings/connector/toradex,camera-connector.yaml b/Documentation/devicetree/bindings/connector/toradex,camera-connector.yaml
new file mode 100644
index 000000000000..06e6836e1aa6
--- /dev/null
+++ b/Documentation/devicetree/bindings/connector/toradex,camera-connector.yaml
@@ -0,0 +1,86 @@
+# SPDX-License-Identifier: (GPL-2.0-only OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/connector/toradex,camera-connector.yaml#
+$schema: http://devicetree.org/meta-schemas/base.yaml#
+
+title: Toradex camera connector GPIO nexus
+
+maintainers:
+  - Ernest Van Hoecke <ernest.vanhoecke@xxxxxxxxxxx>
+  - Toradex Linux BSP Team <linux-bsp@xxxxxxxxxxx>
+
+description: |
+  Toradex boards provide 24-pin camera connectors carrying MIPI CSI-2, I2C,
+  clock, power, and sideband GPIO signals. This binding describes the sideband
+  signals as a GPIO nexus. The other connector resources remain described by
+  the surrounding board device tree.
+
+  The nexus exposes connector-local GPIO function numbers to camera overlays
+  and maps the functions wired by a carrier board to their GPIO controllers.
+  GPIO specifiers contain a function number followed by standard GPIO flags.
+  A board may omit functions which it does not wire.
+
+  The function numbers are:
+    - 0: Camera reset, connector pin 11
+    - 1: Camera power-down, connector pin 22
+    - 2: Camera identification, connector pin 23
+    - 3: Camera power control, connector pin 24
+
+properties:
+  compatible:
+    const: toradex,camera-connector
+
+  "#gpio-cells":
+    const: 2
+
+  gpio-map:
+    minItems: 1
+    maxItems: 4
+
+  gpio-map-mask:
+    items:
+      - const: 0xffffffff
+      - const: 0
+
+  gpio-map-pass-thru:
+    items:
+      - const: 0
+      - const: 0xffffffff
+
+required:
+  - compatible
+  - "#gpio-cells"
+  - gpio-map
+  - gpio-map-mask
+  - gpio-map-pass-thru
+
+additionalProperties: false
+
+examples:
+  - |
+    #include <dt-bindings/gpio/gpio.h>
+
+    camera-connector {
+        compatible = "toradex,camera-connector";
+        #gpio-cells = <2>;
+        /*
+         * 0: Camera reset, connector pin 11
+         * 1: Camera power-down, connector pin 22
+         * 2: Camera identification, connector pin 23
+         * 3: Camera power control, connector pin 24
+         */
+        gpio-map = <0 0 &gpio1 0 GPIO_ACTIVE_HIGH>,
+                   <1 0 &gpio1 1 GPIO_ACTIVE_HIGH>,
+                   <2 0 &gpio1 2 GPIO_ACTIVE_HIGH>,
+                   <3 0 &gpio1 3 GPIO_ACTIVE_HIGH>;
+        gpio-map-mask = <0xffffffff 0x0>;
+        gpio-map-pass-thru = <0x0 0xffffffff>;
+    };
+
+    gpio1: gpio-controller {
+        #gpio-cells = <2>;
+        gpio-controller;
+    };
+
+...

-- 
2.43.0