linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
* [PATCH v2 0/3] media: qcom: camss: V4L2_CID_PIXEL_RATE/LINK_FREQ fixes
@ 2021-02-17 22:11 Andrey Konovalov
  2021-02-17 22:11 ` [PATCH v2 1/3] v4l: common: v4l2_get_link_freq: add printing a warning Andrey Konovalov
                   ` (2 more replies)
  0 siblings, 3 replies; 9+ messages in thread
From: Andrey Konovalov @ 2021-02-17 22:11 UTC (permalink / raw)
  To: junak.pub, robert.foss, sakari.ailus
  Cc: todor.too, agross, bjorn.andersson, mchehab, laurent.pinchart,
	jacopo, linux-media, linux-arm-msm, linux-kernel

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 plan to send a few other similar patches for other CSI receiver drivers,
and if the current patchset needs to wait for those before it can be merged,
that's fine for me.

The reason I decided to post the camss patch first is the patch [3] by
Vladimir Lypak. The third patch in this series is the Vladimir's patch
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().

[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



^ permalink raw reply	[flat|nested] 9+ messages in thread

end of thread, other threads:[~2021-02-18 18:58 UTC | newest]

Thread overview: 9+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-02-17 22:11 [PATCH v2 0/3] media: qcom: camss: V4L2_CID_PIXEL_RATE/LINK_FREQ fixes Andrey Konovalov
2021-02-17 22:11 ` [PATCH v2 1/3] v4l: common: v4l2_get_link_freq: add printing a warning Andrey Konovalov
2021-02-18  7:55   ` Jacopo Mondi
2021-02-18 17:14     ` Andrey Konovalov
2021-02-17 22:11 ` [PATCH v2 2/3] media: camss: use v4l2_get_link_freq() to calculate the relevant clocks Andrey Konovalov
2021-02-18  8:07   ` Jacopo Mondi
2021-02-18  9:45     ` Andrey Konovalov
2021-02-17 22:11 ` [PATCH v2 3/3] media: qcom: camss: Fix overflows in clock rate calculations Andrey Konovalov
2021-02-18  8:15   ` Jacopo Mondi

This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).