The first patch adds printing a warning in v4l2_get_link_freq() if V4L2_CID_LINK_FREQ isn't implemented (this is a mandatory control for CSI-2 transmitter drivers [1], but many sensor drivers don't have it currently). The second patch is the start of the work discussed in the "[RFC] Repurpose V4L2_CID_PIXEL_RATE for the sampling rate in the pixel array" thread [2]. I'll send the similar patches for the rest of CSI receiver drivers which use V4L2_CID_PIXEL_RATE to calculate the link frequency as a separate patchset following this one: I don't have the hardware to test the changes to these drivers, so the second patchset will be build tested only. The third patch in this series is the patch by Vladimir Lypak [3] rebased onto the changes done by the second patch. By replacing getting the pixel clock with v4l2_get_link_freq() the second patch also fixes the integer overflow which Vladimir's patch addresses. So the third patch only needs to fix drivers/media/platform/qcom/camss/camss-vfe.c which the second patch doesn't touch. The resulting patchset is free from the "undefined reference to `__udivdi3'" issue [4] as the u64 value is only divided by a power of 2, which doesn't need do_div(). This patchset has been tested on db410c board with imx219 and ov5647 sensors (RPi camera modules v2 and v1) attached to AISTARVISION MIPI Adapter V2.0. [1] https://linuxtv.org/downloads/v4l-dvb-apis-new/driver-api/csi2.html [2] https://www.spinics.net/lists/linux-media/msg183183.html [3] https://www.spinics.net/lists/linux-media/msg186875.html [4] https://www.spinics.net/lists/linux-media/msg186918.html Changes in v2: * Added [PATCH 1/3] v4l: common: v4l2_get_link_freq: add printing a warning * camss_get_link_freq() changed to take the actual number of lanes as the third arg vs the number of lanes multiplied by 2 in the first version * Fixed checkpatch warnings and bad indentation Changes in v3: * The warning message in v4l2_get_link_freq() improved as suggested by Jacopo Mondi
