media: nuvoton: Convert to platform remove callback returning void

The .remove() callback for a platform driver returns an int which makes
many driver authors wrongly assume it's possible to do error handling by
returning an error code. However the value returned is ignored (apart
from emitting a warning) and this typically results in resource leaks.

To improve here there is a quest to make the remove callback return
void. In the first step of this quest all drivers are converted to
.remove_new(), which already returns void. Eventually after all drivers
are converted, .remove_new() will be renamed to .remove().

Trivially convert this driver from always returning zero in the remove
callback to the void returning variant.

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@pengutronix.de>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: videobuf2: core: Rename min_buffers_needed field in vb2_queue

Rename min_buffers_needed into min_queued_buffers and update
the documentation about it.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
[hverkuil: Drop the change where min_queued_buffers + 1 buffers would be]
[hverkuil: allocated. Now this patch only renames this field instead of making]
[hverkuil: a functional change as well.]
[hverkuil: Renamed 3 remaining min_buffers_needed occurrences.]

media: nuvoton: npcm-video: Fix sleeping in atomic context

Change to use mutex instead of spinlock for buffer list lock to fix
sleeping in atomic context warnings reported by the Smatch tool.

Fixes: 70721089985c ("media: nuvoton: Add driver for NPCM video capture and encoding engine")
Reported-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Marvin Lin <milkfafa@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: nuvoton: Stop direct calls to queue num_buffers field

Use vb2_get_num_buffers() to avoid using queue num_buffers field directly.
This allows us to change how the number of buffers is computed in the
future.

Signed-off-by: Benjamin Gaignard <benjamin.gaignard@collabora.com>
Reviewed-by: Andrzej Pietrasiewicz <andrzej.p@collabora.com>
CC: Joseph Liu <kwliu@nuvoton.com>
CC: Marvin Lin <kflin@nuvoton.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: nuvoton: npcm-video: Fix IS_ERR() vs NULL bug

The of_parse_phandle() function returns NULL on error. It never returns
error pointers. Update the check accordingly.

Fixes: 70721089985c ("media: nuvoton: Add driver for NPCM video capture and encoding engine")
Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: nuvoton: Add driver for NPCM video capture and encoding engine

Add driver for Video Capture/Differentiation Engine (VCD) and Encoding
Compression Engine (ECE) present on Nuvoton NPCM SoCs. As described in
the datasheet NPCM750D_DS_Rev_1.0, the VCD can capture frames from
digital video input and compare two frames in memory, and then the ECE
can compress the frame data into HEXTILE format. This driver implements
V4L2 interfaces and provides user controls to support KVM feature, also
tested with VNC Viewer ver.6.22.826 and openbmc/obmc-ikvm.

Signed-off-by: Marvin Lin <milkfafa@gmail.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>