[SRU][P:raspi][PATCH 1/1] dtoverlays: ov9281: Add continuous clock option as an override

[Juerg Haefliger]

From: Dave Stevenson <dave.stevenson at raspberrypi.com>

BugLink: https://bugs.launchpad.net/bugs/2116543

The previous change to make ov9281 always run in continuous clock
mode causes problems on Pi3 for reasons that aren't fully
understood. Pi4 is quite happy with it.

Change the default back to being non-continuous clock, and add
an override to select continuous clock mode and its slightly
greater max frame rate.

https://forums.raspberrypi.com/viewtopic.php?p=2300215

Signed-off-by: Dave Stevenson <dave.stevenson at raspberrypi.com>
(cherry picked from commit 57b1d68461521424a4bae79ec77446d49ce7211f rpi-6.14.y)
Signed-off-by: Juerg Haefliger <juerg.haefliger at canonical.com>
---
 arch/arm/boot/dts/overlays/README             |  3 +++
 arch/arm/boot/dts/overlays/ov9281-overlay.dts | 15 +++++++++++++++
 2 files changed, 18 insertions(+)

diff --git a/arch/arm/boot/dts/overlays/README b/arch/arm/boot/dts/overlays/README
index b82ff0b70271..04604a61456c 100644
--- a/arch/arm/boot/dts/overlays/README
+++ b/arch/arm/boot/dts/overlays/README
@@ -3623,6 +3623,9 @@ Params: rotation                Mounting rotation of the camera sensor (0 or
                                 Compute Module (CSI0, i2c_vc, and cam0_reg).
         arducam                 Slow down the regulator for slow Arducam
                                 modules.
+        clk-continuous          Switch to continuous mode on the CSI clock lane,
+                                which increases the maximum frame rate slightly.
+                                Appears not to work on Pi3.
 
 
 Name:   papirus
diff --git a/arch/arm/boot/dts/overlays/ov9281-overlay.dts b/arch/arm/boot/dts/overlays/ov9281-overlay.dts
index ff70628415f8..82dd992fdb7e 100644
--- a/arch/arm/boot/dts/overlays/ov9281-overlay.dts
+++ b/arch/arm/boot/dts/overlays/ov9281-overlay.dts
@@ -70,6 +70,20 @@ __dormant__ {
 		};
 	};
 
+	fragment at 7 {
+		target = <&csi_ep>;
+		__overlay__ {
+			clock-noncontinuous;
+		};
+	};
+
+	fragment at 8 {
+		target = <&cam_endpoint>;
+		__overlay__ {
+			clock-noncontinuous;
+		};
+	};
+
 	__overrides__ {
 		rotation = <&cam_node>,"rotation:0";
 		orientation = <&cam_node>,"orientation:0";
@@ -81,6 +95,7 @@ __overrides__ {
 		       <&cam_node>, "avdd-supply:0=",<&cam0_reg>,
 		       <&reg_frag>, "target:0=",<&cam0_reg>;
 		arducam = <0>, "+6";
+		clk-continuous = <0>, "-7-8";
 	};
 };
 
-- 
2.48.1