drivers: video_sw_generator: Add support to change frame rate

Add code to to set / get / enumerate frame rates (intervals).

Signed-off-by: Phi Bang Nguyen <[email protected]>

Author: ngphibang

drivers/video/video_sw_generator.c

@@ -13,7 +13,15 @@
 LOG_MODULE_REGISTER(video_sw_generator, CONFIG_VIDEO_LOG_LEVEL);
 
 #define VIDEO_PATTERN_COLOR_BAR 0
-#define VIDEO_PATTERN_FPS       30
+#define DEFAULT_FRAME_RATE      30
+/*
+ * The pattern generator needs about 1.5 ms to fill out a 320x160 RGB565
+ * buffer and 25 ms for a 720p XRGB32 buffer (tested on i.MX RT1064). So,
+ * the max frame rate actually varies between 40 and 666 fps depending on
+ * the buffer format. There is no way to determine this value for each
+ * format. 60 fps is therefore chosen as a common value in practice.
+ */
+#define MAX_FRAME_RATE          60
 
 struct video_sw_generator_data {
 	const struct device *dev;
@@ -26,6 +34,7 @@ struct video_sw_generator_data {
 	bool ctrl_hflip;
 	bool ctrl_vflip;
 	struct k_poll_signal *signal;
+	uint32_t frame_rate;
 };
 
 static const struct video_format_cap fmts[] = {{
@@ -93,7 +102,7 @@ static int video_sw_generator_stream_start(const struct device *dev)
 {
 	struct video_sw_generator_data *data = dev->data;
 
-	k_work_schedule(&data->buf_work, K_MSEC(1000 / VIDEO_PATTERN_FPS));
+	k_work_schedule(&data->buf_work, K_MSEC(1000 / data->frame_rate));
 
 	return 0;
 }
@@ -145,7 +154,7 @@ static void __buffer_work(struct k_work *work)
 
 	data = CONTAINER_OF(dwork, struct video_sw_generator_data, buf_work);
 
-	k_work_reschedule(&data->buf_work, K_MSEC(1000 / VIDEO_PATTERN_FPS));
+	k_work_reschedule(&data->buf_work, K_MSEC(1000 / data->frame_rate));
 
 	vbuf = k_fifo_get(&data->fifo_in, K_NO_WAIT);
 	if (vbuf == NULL) {
@@ -262,6 +271,67 @@ static inline int video_sw_generator_set_ctrl(const struct device *dev, unsigned
 	return 0;
 }
 
+static int video_sw_generator_set_frmival(const struct device *dev, enum video_endpoint_id ep,
+					  struct video_frmival *frmival)
+{
+	struct video_sw_generator_data *data = dev->data;
+
+	if (frmival->denominator && frmival->numerator) {
+		data->frame_rate = MIN(DIV_ROUND_CLOSEST(frmival->denominator, frmival->numerator),
+				       MAX_FRAME_RATE);
+	} else {
+		return -EINVAL;
+	}
+
+	frmival->numerator = 1;
+	frmival->denominator = data->frame_rate;
+
+	return 0;
+}
+
+static int video_sw_generator_get_frmival(const struct device *dev, enum video_endpoint_id ep,
+					  struct video_frmival *frmival)
+{
+	struct video_sw_generator_data *data = dev->data;
+
+	frmival->numerator = 1;
+	frmival->denominator = data->frame_rate;
+
+	return 0;
+}
+
+static int video_sw_generator_enum_frmival(const struct device *dev, enum video_endpoint_id ep,
+					   struct video_frmival_enum *fie)
+{
+	int i = 0;
+
+	if (ep != VIDEO_EP_OUT || fie->index) {
+		return -EINVAL;
+	}
+
+	while (fmts[i].pixelformat && (fmts[i].pixelformat != fie->format->pixelformat)) {
+		i++;
+	}
+
+	if ((i == ARRAY_SIZE(fmts)) || (fie->format->width > fmts[i].width_max) ||
+	    (fie->format->width < fmts[i].width_min) ||
+	    (fie->format->height > fmts[i].height_max) ||
+	    (fie->format->height < fmts[i].height_min)) {
+		return -EINVAL;
+	}
+
+	fie->type = VIDEO_FRMIVAL_TYPE_STEPWISE;
+	fie->stepwise.min.numerator = 1;
+	fie->stepwise.min.denominator = MAX_FRAME_RATE;
+	fie->stepwise.max.numerator = UINT32_MAX;
+	fie->stepwise.max.denominator = 1;
+	/* The frame interval step size is the minimum resolution of K_MSEC(), which is 1ms */
+	fie->stepwise.step.numerator = 1;
+	fie->stepwise.step.denominator = 1000;
+
+	return 0;
+}
+
 static const struct video_driver_api video_sw_generator_driver_api = {
 	.set_format = video_sw_generator_set_fmt,
 	.get_format = video_sw_generator_get_fmt,
@@ -272,6 +342,9 @@ static const struct video_driver_api video_sw_generator_driver_api = {
 	.dequeue = video_sw_generator_dequeue,
 	.get_caps = video_sw_generator_get_caps,
 	.set_ctrl = video_sw_generator_set_ctrl,
+	.set_frmival = video_sw_generator_set_frmival,
+	.get_frmival = video_sw_generator_get_frmival,
+	.enum_frmival = video_sw_generator_enum_frmival,
 #ifdef CONFIG_POLL
 	.set_signal = video_sw_generator_set_signal,
 #endif
@@ -282,6 +355,7 @@ static struct video_sw_generator_data video_sw_generator_data_0 = {
 	.fmt.height = 160,
 	.fmt.pitch = 320 * 2,
 	.fmt.pixelformat = VIDEO_PIX_FMT_RGB565,
+	.frame_rate = DEFAULT_FRAME_RATE,
 };
 
 static int video_sw_generator_init(const struct device *dev)