diff options
| -rw-r--r-- | drivers/media/v4l2-core/v4l2-dv-timings.c | 39 | ||||
| -rw-r--r-- | include/media/v4l2-dv-timings.h | 11 |
2 files changed, 50 insertions, 0 deletions
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. */ |