drivers: video: dcmipp: add functions for external ISP functions usage

Add weak functions and their call within the dcmipp driver so that
externally provided ISP control functions can be called by the
driver at right timing in order to perform the control of the
ISP part of the DCMIPP.

Signed-off-by: Alain Volmat <alain.volmat@foss.st.com>

Author: Alain Volmat

drivers/video/video_stm32_dcmipp.c

@@ -19,6 +19,7 @@
 
 #include "video_ctrls.h"
 #include "video_device.h"
+#include "video_stm32_dcmipp.h"
 
 #define DT_DRV_COMPAT st_stm32_dcmipp
 
@@ -36,6 +37,26 @@
 #define STM32_DCMIPP_HAS_PIXEL_PIPES
 #endif
 
+/* Weak function declaration in order to interface with external ISP handler */
+void __weak stm32_dcmipp_isp_vsync_update(DCMIPP_HandleTypeDef *hdcmipp, uint32_t Pipe)
+{
+}
+
+int __weak stm32_dcmipp_isp_init(DCMIPP_HandleTypeDef *hdcmipp, const struct device *sensor)
+{
+	return 0;
+}
+
+int __weak stm32_dcmipp_isp_start(void)
+{
+	return 0;
+}
+
+int __weak stm32_dcmipp_isp_stop(void)
+{
+	return 0;
+}
+
 LOG_MODULE_REGISTER(stm32_dcmipp, CONFIG_VIDEO_LOG_LEVEL);
 
 typedef void (*irq_config_func_t)(const struct device *dev);
@@ -152,6 +173,12 @@ void HAL_DCMIPP_PIPE_VsyncEventCallback(DCMIPP_HandleTypeDef *hdcmipp, uint32_t
 	struct stm32_dcmipp_pipe_data *pipe = dcmipp->pipe[Pipe];
 	int ret;
 
+	/*
+	 * Let the external ISP handler know that a VSYNC happened a new statistics are
+	 * thus available
+	 */
+	stm32_dcmipp_isp_vsync_update(hdcmipp, Pipe);
+
 	if (pipe->state != STM32_DCMIPP_RUNNING) {
 		return;
 	}
@@ -529,9 +556,64 @@ static int stm32_dcmipp_set_fmt(const struct device *dev, struct video_format *f
 	return ret;
 }
 
+#if defined(STM32_DCMIPP_HAS_PIXEL_PIPES)
+static void stm32_dcmipp_get_isp_decimation(struct stm32_dcmipp_data *dcmipp)
+{
+	DCMIPP_DecimationConfTypeDef ispdec_cfg;
+	uint32_t is_enabled;
+
+	is_enabled = HAL_DCMIPP_PIPE_IsEnabledISPDecimation(&dcmipp->hdcmipp, DCMIPP_PIPE1);
+	if (is_enabled == 0) {
+		dcmipp->isp_dec_hratio = 1;
+		dcmipp->isp_dec_vratio = 1;
+	} else {
+		HAL_DCMIPP_PIPE_GetISPDecimationConfig(&dcmipp->hdcmipp, DCMIPP_PIPE1, &ispdec_cfg);
+		dcmipp->isp_dec_hratio = 1 << (ispdec_cfg.HRatio >> DCMIPP_P1DECR_HDEC_Pos);
+		dcmipp->isp_dec_vratio = 1 << (ispdec_cfg.VRatio >> DCMIPP_P1DECR_VDEC_Pos);
+	}
+}
+#endif
+
 static int stm32_dcmipp_get_fmt(const struct device *dev, struct video_format *fmt)
 {
 	struct stm32_dcmipp_pipe_data *pipe = dev->data;
+#if defined(STM32_DCMIPP_HAS_PIXEL_PIPES)
+	struct stm32_dcmipp_data *dcmipp = pipe->dcmipp;
+	const struct stm32_dcmipp_config *config = dev->config;
+	static atomic_t isp_init_once;
+	int ret;
+
+	/* Initialize the external ISP handling stack */
+	/*
+	 * TODO - this is not the right place to do that, however we need to know
+	 * the sensor format before calling the isp_init handler hence can't
+	 * do that within the stm32_dcmipp_init function due to unknown
+	 * driver initialization order
+	 *
+	 * Would need an ops that get called when both side of an endpoint get
+	 * initiialized
+	 */
+	if (atomic_cas(&isp_init_once, 0, 1) &&
+	    (pipe->id == DCMIPP_PIPE1 || pipe->id == DCMIPP_PIPE2)) {
+		/*
+		 * It is necessary to perform a dummy configuration here otherwise any
+		 * ISP related configuration done by the stm32_dcmipp_isp_init will
+		 * fail due to the HAL DCMIPP driver not being in READY state
+		 */
+		ret = stm32_dcmipp_conf_parallel(dcmipp->dev, &stm32_dcmipp_input_fmt_desc[0]);
+		if (ret < 0) {
+			LOG_ERR("Failed to perform dummy parallel configuration");
+			return ret;
+		}
+
+		ret = stm32_dcmipp_isp_init(&dcmipp->hdcmipp, config->sensor_dev);
+		if (ret < 0) {
+			LOG_ERR("Failed to initialize the ISP");
+			return ret;
+		}
+		stm32_dcmipp_get_isp_decimation(dcmipp);
+	}
+#endif
 
 	*fmt = pipe->fmt;
 
@@ -869,6 +951,12 @@ static int stm32_dcmipp_stream_enable(const struct device *dev)
 	}
 #endif
 
+	/* Initialize the external ISP handling stack */
+	ret = stm32_dcmipp_isp_init(&dcmipp->hdcmipp, config->sensor_dev);
+	if (ret < 0) {
+		goto out;
+	}
+
 	/* Enable the DCMIPP Pipeline */
 	if (config->bus_type == VIDEO_BUS_TYPE_PARALLEL) {
 		ret = HAL_DCMIPP_PIPE_Start(&dcmipp->hdcmipp, pipe->id,
@@ -914,6 +1002,12 @@ static int stm32_dcmipp_stream_enable(const struct device *dev)
 		}
 	}
 
+	/* Start the external ISP handling */
+	ret = stm32_dcmipp_isp_start();
+	if (ret < 0) {
+		goto out;
+	}
+
 	pipe->state = STM32_DCMIPP_RUNNING;
 	pipe->is_streaming = true;
 	dcmipp->enabled_pipe++;
@@ -938,6 +1032,12 @@ static int stm32_dcmipp_stream_disable(const struct device *dev)
 		goto out;
 	}
 
+	/* Stop the external ISP handling */
+	ret = stm32_dcmipp_isp_stop();
+	if (ret < 0) {
+		goto out;
+	}
+
 	/* Disable the DCMIPP Pipeline */
 	if (config->bus_type == VIDEO_BUS_TYPE_PARALLEL) {
 		ret = HAL_DCMIPP_PIPE_Stop(&dcmipp->hdcmipp, pipe->id);

drivers/video/video_stm32_dcmipp.h

@@ -0,0 +1,16 @@
+/*
+ * Copyright (c) 2025 STMicroelectronics.
+ *
+ * SPDX-License-Identifier: Apache-2.0
+ */
+
+#ifndef ZEPHYR_INCLUDE_VIDEO_DCMIPP_H_
+#define ZEPHYR_INCLUDE_VIDEO_DCMIPP_H_
+
+/* Prototypes of ISP external handler weak functions */
+void stm32_dcmipp_isp_vsync_update(DCMIPP_HandleTypeDef *hdcmipp, uint32_t Pipe);
+int stm32_dcmipp_isp_init(DCMIPP_HandleTypeDef *hdcmipp, const struct device *sensor);
+int stm32_dcmipp_isp_start(void);
+int stm32_dcmipp_isp_stop(void);
+
+#endif /* ZEPHYR_INCLUDE_VIDEO_DCMIPP_H_ */