From: Jose Abreu <Jose.Abreu@xxxxxxxxxxxx>
A new helper function was introduced to facilitate the calculation
of time per frame value whenever we have access to the full
v4l2_dv_timings structure.
This should be used only for receivers and only when there is
enough accuracy in the measured pixel clock value as well as in
the horizontal/vertical values.
Signed-off-by: Jose Abreu <joabreu@xxxxxxxxxxxx>
Cc: Carlos Palminha <palminha@xxxxxxxxxxxx>
Signed-off-by: Hans Verkuil <hans.verkuil@xxxxxxxxx>
---
drivers/media/v4l2-core/v4l2-dv-timings.c | 39 +++++++++++++++++++++++
include/media/v4l2-dv-timings.h | 11 +++++++
2 files changed, 50 insertions(+)
diff --git a/drivers/media/v4l2-core/v4l2-dv-timings.c b/drivers/media/v4l2-core/v4l2-dv-timings.c
index c81faea96fba..8f52353b0881 100644
--- a/drivers/media/v4l2-core/v4l2-dv-timings.c
+++ b/drivers/media/v4l2-core/v4l2-dv-timings.c
@@ -373,6 +373,45 @@ struct v4l2_fract v4l2_dv_timings_aspect_ratio(const struct v4l2_dv_timings *t)
}
EXPORT_SYMBOL_GPL(v4l2_dv_timings_aspect_ratio);
+/** v4l2_calc_timeperframe - helper function to calculate timeperframe based
+ * v4l2_dv_timings fields.
+ * @t - Timings for the video mode.
+ *
+ * Calculates the expected timeperframe using the pixel clock value and
+ * horizontal/vertical measures. This means that v4l2_dv_timings structure
+ * must be correctly and fully filled.
+ */
+struct v4l2_fract v4l2_calc_timeperframe(const struct v4l2_dv_timings *t)
+{
+ const struct v4l2_bt_timings *bt = &t->bt;
+ struct v4l2_fract fps_fract = { 1, 1 };
+ unsigned long n, d;
+ u32 htot, vtot, fps;
+ u64 pclk;
+
+ if (t->type != V4L2_DV_BT_656_1120)
+ return fps_fract;
+
+ htot = V4L2_DV_BT_FRAME_WIDTH(bt);
+ vtot = V4L2_DV_BT_FRAME_HEIGHT(bt);
+ pclk = bt->pixelclock;
+
+ if ((bt->flags & V4L2_DV_FL_CAN_DETECT_REDUCED_FPS) &&
+ (bt->flags & V4L2_DV_FL_REDUCED_FPS))
+ pclk = div_u64(pclk * 1000ULL, 1001);
+
+ fps = (htot * vtot) > 0 ? div_u64((100 * pclk), (htot * vtot)) : 0;
+ if (!fps)
+ return fps_fract;
+
+ rational_best_approximation(fps, 100, fps, 100, &n, &d);
+
+ fps_fract.numerator = d;
+ fps_fract.denominator = n;
+ return fps_fract;
+}
+EXPORT_SYMBOL_GPL(v4l2_calc_timeperframe);
+
/*
* CVT defines
* Based on Coordinated Video Timings Standard
diff --git a/include/media/v4l2-dv-timings.h b/include/media/v4l2-dv-timings.h
index 17cb27df1b81..fb355d9577a4 100644
--- a/include/media/v4l2-dv-timings.h
+++ b/include/media/v4l2-dv-timings.h
@@ -10,6 +10,17 @@
#include <linux/videodev2.h>
+/**
+ * v4l2_calc_timeperframe - helper function to calculate timeperframe based
+ * v4l2_dv_timings fields.
+ * @t: Timings for the video mode.
+ *
+ * Calculates the expected timeperframe using the pixel clock value and
+ * horizontal/vertical measures. This means that v4l2_dv_timings structure
+ * must be correctly and fully filled.
+ */
+struct v4l2_fract v4l2_calc_timeperframe(const struct v4l2_dv_timings *t);
+
/*
* v4l2_dv_timings_presets: list of all dv_timings presets.
*/
--
2.18.0
