drivers: video: emul_rx/emul_imager: Explicitly set init priority

The Emul Rx needs to be initialized after the camera sensor which
is generally initialized with CONFIG_VIDEO_INIT_PRIORITY.

This is currently true "by chance" due to the order the linker links the
object files. This linker order is not easily controlled, so use an
explicit priority value to ensure this requirement.

Co-authored-by: Phi Bang Nguyen <[email protected]>
Signed-off-by: Josuah Demangeon <[email protected]>

Author: josuah

drivers/video/Kconfig

@@ -23,6 +23,14 @@ config VIDEO_INIT_PRIORITY
 	help
 	  System initialization priority for video drivers.
 
+config VIDEO_IMAGER_INIT_PRIORITY
+	int "Imager (image sensor) init priority"
+	default 65
+	help
+	  System initialization priority for imager (image sensor) drivers.
+	  The default value is there to allow other drivers to have a default
+	  init priority placed before (< 65) or after (> 65) the imagers.
+
 config VIDEO_BUFFER_POOL_SZ_MAX
 	int "Size of the largest buffer in the video pool"
 	default 1048576

drivers/video/Kconfig.emul_rx

@@ -8,3 +8,15 @@ config VIDEO_EMUL_RX
 	default y
 	help
 	  Enable driver for the MIPI RX emulated DMA engine.
+
+if VIDEO_EMUL_RX
+
+config VIDEO_EMUL_RX_INIT_PRIORITY
+	int "Emul Rx init priority"
+	default 67
+	help
+	  Initialization priority for the emulated Rx device.
+	  The default value is set to preserve the initialization dependency,
+	  placing it after the imagers (65), such as the emulated imager.
+
+endif

drivers/video/video_emul_imager.c

@@ -420,8 +420,8 @@ int emul_imager_init(const struct device *dev)
 	};                                                                                         \
                                                                                                    \
 	DEVICE_DT_INST_DEFINE(inst, &emul_imager_init, NULL, &emul_imager_data_##inst,             \
-			      &emul_imager_cfg_##inst, POST_KERNEL, CONFIG_VIDEO_INIT_PRIORITY,    \
-			      &emul_imager_driver_api);
+			      &emul_imager_cfg_##inst, POST_KERNEL,                                \
+			      CONFIG_VIDEO_IMAGER_INIT_PRIORITY, &emul_imager_driver_api);
 
 DT_INST_FOREACH_STATUS_OKAY(EMUL_IMAGER_DEFINE)
 

drivers/video/video_emul_rx.c

@@ -296,6 +296,7 @@ int emul_rx_init(const struct device *dev)
 	};                                                                                         \
                                                                                                    \
 	DEVICE_DT_INST_DEFINE(n, &emul_rx_init, NULL, &emul_rx_data_##n, &emul_rx_cfg_##n,         \
-			      POST_KERNEL, CONFIG_VIDEO_INIT_PRIORITY, &emul_rx_driver_api);
+			      POST_KERNEL, CONFIG_VIDEO_EMUL_RX_INIT_PRIORITY,                     \
+			      &emul_rx_driver_api);
 
 DT_INST_FOREACH_STATUS_OKAY(EMUL_RX_DEFINE)