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diff --git a/Documentation/media/v4l-drivers/imx-uapi.rst b/Documentation/media/v4l-drivers/imx-uapi.rst deleted file mode 100644 index 8d47712dea9f..000000000000 --- a/Documentation/media/v4l-drivers/imx-uapi.rst +++ /dev/null @@ -1,125 +0,0 @@ -.. SPDX-License-Identifier: GPL-2.0 - -========================= -i.MX Video Capture Driver -========================= - -Events -====== - -.. _imx_api_ipuX_csiY: - -ipuX_csiY ---------- - -This subdev can generate the following event when enabling the second -IDMAC source pad: - -- V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR - -The user application can subscribe to this event from the ipuX_csiY -subdev node. This event is generated by the Frame Interval Monitor -(see below for more on the FIM). - -Controls -======== - -.. _imx_api_FIM: - -Frame Interval Monitor in ipuX_csiY ------------------------------------ - -The adv718x decoders can occasionally send corrupt fields during -NTSC/PAL signal re-sync (too little or too many video lines). When -this happens, the IPU triggers a mechanism to re-establish vertical -sync by adding 1 dummy line every frame, which causes a rolling effect -from image to image, and can last a long time before a stable image is -recovered. Or sometimes the mechanism doesn't work at all, causing a -permanent split image (one frame contains lines from two consecutive -captured images). - -From experiment it was found that during image rolling, the frame -intervals (elapsed time between two EOF's) drop below the nominal -value for the current standard, by about one frame time (60 usec), -and remain at that value until rolling stops. - -While the reason for this observation isn't known (the IPU dummy -line mechanism should show an increase in the intervals by 1 line -time every frame, not a fixed value), we can use it to detect the -corrupt fields using a frame interval monitor. If the FIM detects a -bad frame interval, the ipuX_csiY subdev will send the event -V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR. Userland can register with -the FIM event notification on the ipuX_csiY subdev device node. -Userland can issue a streaming restart when this event is received -to correct the rolling/split image. - -The ipuX_csiY subdev includes custom controls to tweak some dials for -FIM. If one of these controls is changed during streaming, the FIM will -be reset and will continue at the new settings. - -- V4L2_CID_IMX_FIM_ENABLE - -Enable/disable the FIM. - -- V4L2_CID_IMX_FIM_NUM - -How many frame interval measurements to average before comparing against -the nominal frame interval reported by the sensor. This can reduce noise -caused by interrupt latency. - -- V4L2_CID_IMX_FIM_TOLERANCE_MIN - -If the averaged intervals fall outside nominal by this amount, in -microseconds, the V4L2_EVENT_IMX_FRAME_INTERVAL_ERROR event is sent. - -- V4L2_CID_IMX_FIM_TOLERANCE_MAX - -If any intervals are higher than this value, those samples are -discarded and do not enter into the average. This can be used to -discard really high interval errors that might be due to interrupt -latency from high system load. - -- V4L2_CID_IMX_FIM_NUM_SKIP - -How many frames to skip after a FIM reset or stream restart before -FIM begins to average intervals. - -- V4L2_CID_IMX_FIM_ICAP_CHANNEL / V4L2_CID_IMX_FIM_ICAP_EDGE - -These controls will configure an input capture channel as the method -for measuring frame intervals. This is superior to the default method -of measuring frame intervals via EOF interrupt, since it is not subject -to uncertainty errors introduced by interrupt latency. - -Input capture requires hardware support. A VSYNC signal must be routed -to one of the i.MX6 input capture channel pads. - -V4L2_CID_IMX_FIM_ICAP_CHANNEL configures which i.MX6 input capture -channel to use. This must be 0 or 1. - -V4L2_CID_IMX_FIM_ICAP_EDGE configures which signal edge will trigger -input capture events. By default the input capture method is disabled -with a value of IRQ_TYPE_NONE. Set this control to IRQ_TYPE_EDGE_RISING, -IRQ_TYPE_EDGE_FALLING, or IRQ_TYPE_EDGE_BOTH to enable input capture, -triggered on the given signal edge(s). - -When input capture is disabled, frame intervals will be measured via -EOF interrupt. - - -File list ---------- - -drivers/staging/media/imx/ -include/media/imx.h -include/linux/imx-media.h - - -Authors -------- - -- Steve Longerbeam <steve_longerbeam@mentor.com> -- Philipp Zabel <kernel@pengutronix.de> -- Russell King <linux@armlinux.org.uk> - -Copyright (C) 2012-2017 Mentor Graphics Inc. |