When the imx-media driver was initially merged, there was a conflict
with 8d67ae25 ("media: v4l2-ctrls: Reserve controls for MAX217X") which
was not fixed up correctly, resulting in V4L2_CID_USER_MAX217X_BASE and
V4L2_CID_USER_IMX_BASE taking on the same value. Fix by assigning imx
CID base the next available range at 0x10b0.
Signed-off-by: NSteve Longerbeam <steve_longerbeam@mentor.com>
Acked-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The vb2_queue will soon be mandatory. The videobuf2 core
will throw a verbose warning if it's not set.

The stk1160 driver is setting the queue lock, but after
the vb2_queue_init call. Avoid the warning by setting
the lock before the queue initialization.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This driver is currently specifying a video_device lock,
which means it is protecting all the ioctls (including
queue ioctls) with a single mutex.

It's therefore straightforward to implement wait_prepare
and wait_finish, by explicitly setting the vb2_queue lock.

Having these callbacks releases the queue lock while blocking,
which improves latency by allowing for example streamoff
or qbuf operations while waiting in dqbuf.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This driver is currently specifying a video_device lock,
which means it is protecting all the ioctls (including
queue ioctls) with a single mutex.

It's therefore straightforward to implement wait_prepare
and wait_finish, by explicitly setting the vb2_queue lock.

Having these callbacks releases the queue lock while blocking,
which improves latency by allowing for example streamoff
or qbuf operations while waiting in dqbuf.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Currently, this driver does not serialize its video4linux
ioctls, which is a bug, as race conditions might appear.

In addition, video_device and vb2_queue locks are now both
mandatory. Add them, and implement wait_prepare and
wait_finish.

To stay on the safe side, this commit uses a single mutex
for both locks. Better latency can be obtained by separating
these if needed.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Use the device mutex to protect the vb2_queue.
This allows to replace the ad-hoc wait_{prepare, finish}
with vb2_ops_wait_{prepare, finish}.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This driver is currently specifying a vb2_queue lock,
which means it straightforward to implement wait_prepare
and wait_finish.

Having these callbacks releases the queue lock while blocking,
which improves latency by allowing for example streamoff
or qbuf operations while waiting in dqbuf.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Use the mutex in struct mtk_mdp_ctx to protect the
capture and output  vb2_queues. This allows to replace
the ad-hoc wait_{prepare, finish} with
vb2_ops_wait_{prepare, finish}.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Currently, this driver does not serialize its video4linux
ioctls, which is a bug, as race conditions might appear.

In addition, video_device and vb2_queue locks are now both
mandatory. Add them, and implement wait_prepare and
wait_finish.

To stay on the safe side, this commit uses a single mutex
for both locks. Better latency can be obtained by separating
these if needed.
Signed-off-by: NEzequiel Garcia <ezequiel@collabora.com>
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

For m2m devices the vdev->queue lock was always taken instead of the
lock for the specific capture or output queue. Now that we pushed
the locking down into __video_do_ioctl() we can pick the correct
lock and potentially improve the performance of m2m devices.
Signed-off-by: NHans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

pd -> pad
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

imx274_write_table() is a mere wrapper (and the only user) to
imx274_regmap_util_write_table_8(). Remove this useless indirection by
merging the two functions into one.

Also get rid of the wait_ms_addr and end_addr parameters since it does
not make any sense to give them any values other than
IMX274_TABLE_WAIT_MS and IMX274_TABLE_END.
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

IMX274_DEFAULT_MODE is defined but not used. Start using it, so the
default can be more easily changed without digging into the code.
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

After restructuring struct imx274_frmfmt, the mode_index field is
still in use only for two dev_dbg() calls in imx274_s_stream(). Let's
remove it and avoid duplicated information.

Replacing the first usage requires some rather annoying but trivial
pointer math. The other one can be removed entirely since it would
print the same value anyway.
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Data about the implemented readout modes is partially stored in
imx274_formats[], the rest is scattered in several arrays. The latter
are then accessed using the mode index, e.g.:

  min_frame_len[priv->mode_index]

Consolidate all these data in imx274_formats[], and store a pointer to
the selected mode (i.e. imx274_formats[priv->mode_index]) in the main
device struct. This way code to use these data becomes more readable,
e.g.:

  priv->mode->min_frame_len

This removes lots of scaffolding code and keeps data about each mode
in a unique place.

Also remove a parameter to imx274_mode_regs() that is now unused.

While this adds the mode pointer to the device struct, it does not
remove the mode_index from it because mode_index is still used in two
dev_dbg() calls.  This will be handled in a follow-up commit.
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The current probe function calls v4l2_ctrl_handler_setup() before
initializing the format info. This triggers call paths such as:
imx274_probe -> v4l2_ctrl_handler_setup -> imx274_s_ctrl ->
imx274_set_exposure, where priv->mode_index is accessed before being
assigned.

This is wrong but does not trigger a visible bug because priv is
zero-initialized and 0 is the default value for priv->mode_index. But
this would become a crash in follow-up commits when mode_index is
replaced by a pointer that must always be valid.

Fix the bug before it shows up by initializing struct members early.
Signed-off-by: NLuca Ceresoli <luca@lucaceresoli.net>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Add a v4l2 sub-device driver for the ak7375 lens voice coil.
This is a voice coil module using the i2c bus to control the
focus position.

ak7375 can write multiple bytes of data at a time. If more
data is received instead of the stop condition after receiving
one byte of data, the address inside the chip is automatically
incremented and the data is written into the next address.

The ak7375 can control the position with 12 bits value and
consists of two 8 bit registers show as below:
register 0x00(AK7375_REG_POSITION):
    +---+---+---+---+---+---+---+---+
    |D11|D10|D09|D08|D07|D06|D05|D04|
    +---+---+---+---+---+---+---+---+
register 0x01:
    +---+---+---+---+---+---+---+---+
    |D03|D02|D01|D00|---|---|---|---|
    +---+---+---+---+---+---+---+---+

This driver support :
    - set ak7375 to standby mode once suspend and
      turn it back to active if resume
    - set the position via V4L2_CID_FOCUS_ABSOLUTE ctrl

[Sakari Ailus: Rename val as ret in probe, drop redundant error message]
Signed-off-by: NTianshu Qiu <tian.shu.qiu@intel.com>
Signed-off-by: NBingbu Cao <bingbu.cao@intel.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Add device tree bindings for AKM ak7375 voice coil lens
driver. This chip is used to drive a lens in a camera module.
Signed-off-by: NTianshu Qiu <tian.shu.qiu@intel.com>
Signed-off-by: NBingbu Cao <bingbu.cao@intel.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Driver must reject frame interval enumeration of unsupported resolution.
This was detected by v4l2-compliance format ioctl test:
v4l2-compliance Format ioctls:
    info: found 2 frameintervals for pixel format 4745504a and size 176x144
  fail: v4l2-test-formats.cpp(123):
                           found frame intervals for invalid size 177x144
    test VIDIOC_ENUM_FMT/FRAMESIZES/FRAMEINTERVALS: FAIL
Signed-off-by: NHugues Fruchet <hugues.fruchet@st.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This sparse warning is emitted by using v4l2_find_nearest_size in some
cases. Fix it in the framework.

>> drivers/media/i2c/ov5640.c:1394:14: sparse: incorrect type in assignment
+(different base types) @@    expected struct ov5640_mode_info const *mode @@
+got ststruct ov5640_mode_info const *mode @@
   drivers/media/i2c/ov5640.c:1394:14:    expected struct ov5640_mode_info const
+*mode
   drivers/media/i2c/ov5640.c:1394:14:    got struct ov5640_mode_info const ( *<
+noident> )[9]
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

According to ov5640 datasheet xvclk is allowed to be between 6 and 54 MHz.
I run a successful test with 27 MHz.
Signed-off-by: NPhilipp Puschmann <pp@emlix.com>
Reviewed-by: NFabio Estevam <fabio.estevam@nxp.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The banding filter ON/OFF is controlled via bit 5 of COM8 register.  It
is attempted to be enabled in ov772x_set_params() by the following line.

	ret = ov772x_mask_set(client, COM8, BNDF_ON_OFF, 1);

But this unexpectedly results disabling the banding filter, because the
mask and set bits are exclusive.

On the other hand, ov772x_s_ctrl() correctly sets the bit by:

	ret = ov772x_mask_set(client, COM8, BNDF_ON_OFF, BNDF_ON_OFF);

The same fix was already applied to non-soc_camera version of ov772x
driver in the commit commit a024ee14 ("media: ov772x: correct setting
of banding filter")

Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

When the subdevice doesn't provide s_power core ops callback, the
v4l2_subdev_call for s_power returns -ENOIOCTLCMD.  If the subdevice
doesn't have the special handling for its power saving mode, the s_power
isn't required.  So -ENOIOCTLCMD from the v4l2_subdev_call should be
ignored.

Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Acked-by: NSylwester Nawrocki <sylvester.nawrocki@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The struct clk_init_data init variable is declared in the isp_xclk_init()
function so is an automatic variable allocated in the stack. But it's not
explicitly zero-initialized, so some init fields are left uninitialized.

This causes the data structure to have undefined values that may confuse
the common clock framework when the clock is registered.

For example, the uninitialized .flags field could have the CLK_IS_CRITICAL
bit set, causing the framework to wrongly prepare the clk on registration.
This leads to the isp_xclk_prepare() callback being called, which in turn
calls to the omap3isp_get() function that increments the isp dev refcount.

Since this omap3isp_get() call is unexpected, this leads to an unbalanced
omap3isp_get() call that prevents the requested IRQ to be later enabled,
due the refcount not being 0 when the correct omap3isp_get() call happens.

Fixes: 9b28ee3c ("[media] omap3isp: Use the common clock framework")
Signed-off-by: NJavier Martinez Canillas <javierm@redhat.com>
Reviewed-by: NSebastian Reichel <sebastian.reichel@collabora.co.uk>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

DW9807 is a 10 bit DAC from Dongwoon, designed for linear
control of voice coil motor.

This driver creates a V4L2 subdevice and
provides control to set the desired focus.
Signed-off-by: NAlan Chiang <alanx.chiang@intel.com>
Signed-off-by: NAndy Yeh <andy.yeh@intel.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Reviewed-by: NTomasz Figa <tfiga@chromium.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Dongwoon DW9807 is a voice coil lens driver.
Signed-off-by: NAlan Chiang <alanx.chiang@intel.com>
Signed-off-by: NAndy Yeh <andy.yeh@intel.com>
Reviewed-by: NRob Herring <robh@kernel.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This patch adds Bingbu as additional maintainer, and both Tian Shu and Jian Xu
as reviewers for IPU3 CIO2 driver.
Signed-off-by: NYong Zhi <yong.zhi@intel.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The final version of the COMPILE_TEST patch for this driver missed
one warning about suspend/resume functions that can now appear
on platforms that don't always set CONFIG_PM:

drivers/media/platform/omap3isp/isp.c:1008:13: error: 'isp_resume_modules' defined but not used [-Werror=unused-function]
 static void isp_resume_modules(struct isp_device *isp)
             ^~~~~~~~~~~~~~~~~~
drivers/media/platform/omap3isp/isp.c:974:12: error: 'isp_suspend_modules' defined but not used [-Werror=unused-function]
 static int isp_suspend_modules(struct isp_device *isp)

This marks the respective functions as __maybe_unused as an easy
workaround.

Fixes: 24313113 ("media: omap3isp: Allow it to build with COMPILE_TEST")
Signed-off-by: NArnd Bergmann <arnd@arndb.de>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Set the V4L2_SUBDEV_FL_HAS_DEVNODE flag for the subdevice so that the
subdevice device node is created.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The ov772x driver is going to offer a V4L2 sub-device interface, so
changing the output data format and the frame interval on this sub-device
can be made anytime.  However, these requests are preferred to fail while
the video stream on the device is active.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The set_fmt() in subdev pad ops, the s_ctrl() for subdev control handler,
and the s_frame_interval() in subdev video ops could be called when the
device is under power saving mode.  These callbacks for ov772x driver
cause updating H/W registers that will fail under power saving mode.

This avoids it by not apply any changes to H/W if the device is not powered
up.  Instead the changes will be restored right after power-up.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The ov772x driver provides three V4L2 controls and the current value of
each control is saved as a variable in the private data structure.

We don't need to keep track of the current value by ourself, if we use
v4l2_ctrl returned from v4l2_ctrl_new_std() instead.

This is a preparatory change to avoid accessing registers under power
saving mode.  This simplifies s_ctrl() by making it just return without
saving the current control value in private area when it is called under
power saving mode.

Cc: Jacopo Mondi <jacopo+renesas@jmondi.org>
Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This splits the s_frame_interval() in subdev video ops into selecting the
frame interval and setting up the registers.

This is a preparatory change to avoid accessing registers under power
saving mode.

Cc: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Depending on the v4l2 driver, calling s_power() could be nested.  So the
actual transitions between power saving mode and normal operation mode
should only happen at the first power on and the last power off.

This adds an s_power() nesting counter and updates the power state if the
counter is modified from 0 to != 0 or from != 0 to 0.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The ov772x driver currently only supports legacy platform data probe.
This change enables device tree probing.

Note that the platform data probe can select auto or manual edge control
mode, but the device tree probling can only select auto edge control mode
for now.

[Sakari Ailus: Remove direct OF dependencies from device ID table]

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Currently the ov772x driver obtains a clock with a specific consumer ID.
As there's a single clock for this driver, we could omit clock-names
property in device tree by passing NULL as a consumer ID to clk_get().

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Suggested-by: NLaurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The ov772x driver uses "rstb-gpios" and "pwdn-gpios" for reset and
powerdown pins.  However, using generic names for these gpios is
preferred.  ("reset-gpios" and "powerdown-gpios" respectively)

There is only one mainline user for these gpios, so rename to generic
names.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

Create a source pad and set the media controller type to the sensor.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

This change adds checks for register read errors and returns correct
error code.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Reviewed-by: NJacopo Mondi <jacopo@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>

The ov772x driver only works when the i2c controller have
I2C_FUNC_PROTOCOL_MANGLING.  However, many i2c controller drivers don't
support it.

The reason that the ov772x requires I2C_FUNC_PROTOCOL_MANGLING is that
it doesn't support repeated starts.

This changes the reading ov772x register method so that it doesn't
require I2C_FUNC_PROTOCOL_MANGLING by calling two separated i2c messages.

Cc: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Cc: Hans Verkuil <hans.verkuil@cisco.com>
Cc: Wolfram Sang <wsa@the-dreams.de>
Reviewed-by: NJacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: NAkinobu Mita <akinobu.mita@gmail.com>
Signed-off-by: NSakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: NMauro Carvalho Chehab <mchehab+samsung@kernel.org>