media: i2c: adv748: Fix kerneldoc

The field is gone, remove the documentation.

Signed-off-by: Ricardo Ribalda <ribalda@chromium.org>
Reviewed-by: Randy Dunlap <rdunlap@infradead.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: adv748x: Remove dead function declaration

There is no implementation of adv748x_register_subdevs(), remove the
declaration in the header file.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Wolfram Sang <wsa+renesas@sang-engineering.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>

media: mc-entity: Rename media_entity_remote_pad() to media_pad_remote_pad_first()

The media_entity_remote_pad() is misnamed, as it operates on a pad and
not an entity. Rename it to media_pad_remote_pad_first() to clarify its
behaviour.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@kernel.org>

media: media/i2c: fix kerneldoc issues for media i2c headers

This fixes these kernel-doc warnings:

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI1A' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI1B' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI1C' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI2A' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI2B' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI2C' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI3A' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI3B' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI3C' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_CVBS_VI4A' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI2A_VI1A' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI2B_VI1B' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI2C_VI1C' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI2A_VI3A' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI2B_VI3B' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI2C_VI3C' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI4A_VI1A' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI4A_VI1B' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI4A_VI1C' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI4A_VI3A' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI4A_VI3B' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_SVIDEO_VI4A_VI3C' not described in enum 'tvp514x_input'

include/media/i2c/tvp514x.h:70: warning: Enum value 'INPUT_INVALID' not described in enum 'tvp514x_input'
include/media/i2c/tvp514x.h:82: warning: Enum value 'OUTPUT_10BIT_422_EMBEDDED_SYNC' not described in enum 'tvp514x_output'
include/media/i2c/tvp514x.h:82: warning: Enum value 'OUTPUT_20BIT_422_SEPERATE_SYNC' not described in enum 'tvp514x_output'
include/media/i2c/tvp514x.h:82: warning: Enum value 'OUTPUT_10BIT_422_SEPERATE_SYNC' not described in enum 'tvp514x_output'
include/media/i2c/tvp514x.h:82: warning: Enum value 'OUTPUT_INVALID' not described in enum 'tvp514x_output'
include/media/i2c/adv7343.h:38: warning: cannot understand function prototype: 'struct adv7343_power_mode '
include/media/i2c/s5k4ecgx.h:31: warning: expecting prototype for struct ss5k4ecgx_platform_data. Prototype was for struct
s5k4ecgx_platform_data instead
include/media/i2c/mt9t112.h:21: warning: cannot understand function prototype: 'struct mt9t112_platform_data '
include/media/i2c/noon010pc30.h:13: warning: Cannot understand * @clk_rate: the clock frequency in Hz
include/media/i2c/s5k6aa.h:45: warning: Function parameter or member 'bus_type' not described in 's5k6aa_platform_data'
include/media/i2c/tw9910.h:19: warning: cannot understand function prototype: 'enum tw9910_mpout_pin '
include/media/i2c/tw9910.h:36: warning: cannot understand function prototype: 'struct tw9910_video_info '
include/media/i2c/ov772x.h:53: warning: cannot understand function prototype: 'struct ov772x_camera_info '
include/media/i2c/s5c73m3.h:53: warning: Function parameter or member 'bus_type' not described in 's5c73m3_platform_data'
drivers/media/i2c/ccs/ccs-quirk.h:50: warning: Function parameter or member 'post_streamoff' not described in 'ccs_quirk'
drivers/media/i2c/ccs/ccs-quirk.h:50: warning: Function parameter or member 'flags' not described in 'ccs_quirk'
drivers/media/i2c/ccs/ccs-data.h:144: warning: expecting prototype for struct ccs_pdaf_pix_loc_block_desc. Prototype was for struct
ccs_pdaf_pix_loc_pixel_desc instead
drivers/media/i2c/tvp514x_regs.h:272: warning: Function parameter or member 'token' not described in 'tvp514x_reg'
drivers/media/i2c/tvp514x_regs.h:272: warning: Function parameter or member 'reg' not described in 'tvp514x_reg'
drivers/media/i2c/tvp514x_regs.h:272: warning: Function parameter or member 'val' not described in 'tvp514x_reg'
drivers/media/i2c/m5mols/m5mols.h:69: warning: Function parameter or member 'brightness' not described in 'm5mols_exif'
drivers/media/i2c/m5mols/m5mols.h:147: error: Cannot parse struct or union!
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN0' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN1' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN2' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN3' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN4' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN5' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN6' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_AIN7' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_HDMI' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_TTL' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_TXA' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_TXB' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:65: warning: Enum value 'ADV748X_PORT_MAX' not described in enum 'adv748x_ports'
drivers/media/i2c/adv748x/adv748x.h:199: warning: Function parameter or member 'i2c_clients' not described in 'adv748x_state'
drivers/media/i2c/adv748x/adv748x.h:199: warning: Function parameter or member 'regmap' not described in 'adv748x_state'

Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: adv748x: csi2: Set virtual channel when device is reset

It's not enough to set the CSI-2 virtual channel for TXA and TXB during
probe: it also needs to be set when the device is reset. Move the virtual
channel selection to adv748x_reset() that is called during probe and
when the device needs to be reset.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: adv748x: afe: Select input port when device is reset

It's not enough to select the AFE input port during probe: it also needs
to be set when the device is reset. Move the port selection to
adv748x_reset() that is called during probe and when the device needs to
be reset.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: i2c: adv748x: Adjust TXA data lanes number

When outputting SD-Core output through the TXA MIPI CSI-2 interface,
the number of enabled data lanes should be reduced in order to guarantee
that the two video formats produced by the SD-Core (480i and 576i)
generate a MIPI CSI-2 link clock frequency compatible with the MIPI D-PHY
specifications.

Limit the number of enabled data lanes to 2, which is guaranteed to
support 480i and 576i formats.

Cache the number of enabled data lanes to be able to report it through
the new get_mbus_config operation.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: i2c: adv748x: Fix unsafe macros

Enclose multiple macro parameters in parentheses in order to
make such macros safer and fix the Clang warning below:

drivers/media/i2c/adv748x/adv748x-afe.c:452:12: warning: operator '?:'
has lower precedence than '|'; '|' will be evaluated first
[-Wbitwise-conditional-parentheses]

ret = sdp_clrset(state, ADV748X_SDP_FRP, ADV748X_SDP_FRP_MASK, enable
? ctrl->val - 1 : 0);

Fixes: 3e89586a64df ("media: i2c: adv748x: add adv748x driver")
Reported-by: Dmitry Vyukov <dvyukov@google.com>
Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+huawei@kernel.org>

media: i2c: adv748x: Remove PAGE_WAIT

The ADV748X_PAGE_WAIT is a fake page to insert arbitrary delays in the
register tables.

Its only usage was removed, so we can remove the handling and simplify
the code.

Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: i2c: adv748x: Convert SW reset routine to function

The ADV748x is currently reset by writting a small table of registers to
the device.

The table lacks documentation and contains magic values to perform the
actions, including using a fake register address to introduce a delay
loop.

Remove the table, and convert to code, documenting the purpose of the
specific writes along the way.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: adv748x: Implement TX link_setup callback

When the adv748x driver is informed about a link being created from HDMI or
AFE to a CSI-2 TX output, the 'link_setup()' callback is invoked. Make
sure to implement proper routing management at link setup time, to route
the selected video stream to the desired TX output.

Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: adv748x: Store the TX sink in HDMI/AFE

Both the AFE and HDMI s_stream routines (adv748x_afe_s_stream() and
adv748x_hdmi_s_stream()) have to enable the CSI-2 TX they are streaming video
data to.

With the introduction of dynamic routing between HDMI and AFE entities to
TXA, the video stream sink needs to be set at run time, and not statically
selected as the s_stream functions are currently doing.

To fix this, store a reference to the active CSI-2 TX sink for both HDMI and
AFE sources, and operate on it when starting/stopping the stream.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: adv748x: Store the source subdevice in TX

The power_up_tx() procedure needs to set a few registers conditionally to
the selected video source, but it currently checks for the provided tx to
be either TXA or TXB.

With the introduction of dynamic routing between HDMI and AFE entities to
TXA, checking which TX the function is operating on is not meaningful anymore.

To fix this, store the subdevice of the source providing video data to the
CSI-2 TX in the 'struct adv748x_csi2' representing the TX and check on it.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: adv748x: Add is_txb()

Add small is_txb() macro to the existing is_txa() and use it where
appropriate.

Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: i2c: adv748x: store number of CSI-2 lanes described in device tree

The adv748x CSI-2 transmitters TXA and TXB can use different number of
lanes to transmit data. In order to be able to configure the device
correctly this information need to be parsed from device tree and stored
in each TX private data structure.

TXA supports 1, 2 and 4 lanes while TXB supports 1 lane.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Tested-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Hans Verkuil <hverkuil-cisco@xs4all.nl>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: i2c: adv748x: Register only enabled inputs

The adv748x assumes input endpoints are always enabled, and registers
a subdevice for each of them when the corresponding output subdevice
is registered.

Fix this by conditionally registering the input subdevice only if it is
actually described in device tree.

Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: i2c: adv748x: Handle TX[A|B] power management

As the driver is now allowed to probe with a single output endpoint,
power management routines shall now take into account the case a CSI-2 TX
is not enabled.

Unify the adv748x_tx_power() routine to handle transparently TXA and TXB,
and enable the CSI-2 outputs conditionally.

Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: i2c: adv748x: Support probing a single output

Currently the adv748x driver will fail to probe unless both of its
output endpoints (TXA and TXB) are connected.

Make the driver support probing provided that there is at least one
input, and one output connected and protect the clean-up function from
accessing un-initialized fields.

Following patches will fix other uses of un-initialized TXs in the driver,
such as power management functions.

Tested-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo+renesas@jmondi.org>
Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: adv748x: convert to SPDX identifiers

As original license mentioned, it is GPL-2.0+ in SPDX.
Then, MODULE_LICENSE() should be "GPL" instead of "GPL v2".
See ${LINUX}/include/linux/module.h

"GPL" [GNU Public License v2 or later]
"GPL v2" [GNU Public License v2]

Signed-off-by: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Reviewed-by: Simon Horman <horms+renesas@verge.net.au>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

media: i2c: adv748x: Add support for i2c_new_secondary_device

The ADV748x has twelve 256-byte maps that can be accessed via the main
I2C ports. Each map has it own I2C address and acts as a standard slave
device on the I2C bus.

Allow a device tree node to override the default addresses so that
address conflicts with other devices on the same bus may be resolved at
the board description level.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

media: i2c: adv748x: Add missing CBUS page

The ADV748x has 12 pages mapped onto I2C addresses.

In the existing implementation only 11 are mapped correctly in the page
enumerations, which causes an off-by-one fault on pages above the
infoframe definition due to a missing 'CBUS' page.

This causes the address for the CEC, SDP, TXA, and TXB to be incorrectly
programmed during the iterations in adv748x_initialise_clients().

Until now this has gone un-noticed due to the fact that following the
creation of the clients - the device is reset and the addresses are
reprogrammed in manually by the call to "adv748x_write_regs(state,
adv748x_set_slave_address);"

As part of moving to dynamic i2c address allocations repair this by
providing the missing CBUS page definition.

Signed-off-by: Kieran Bingham <kieran.bingham@ideasonboard.com>
Reviewed-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

media: i2c: adv748x: Store the pixel rate ctrl on CSI objects

The current implementation has to search the list of controls for the
pixel rate control, each time it is set. This can be optimised easily
by storing the ctrl pointer in the CSI/TX object, and referencing that
directly.

While at it, fix up a missing blank line also highlighted in review
comments.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Tested-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Acked-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

media: i2c: adv748x: add adv748x driver

Provide support for the ADV7481 and ADV7482.

The driver is modelled with 4 subdevices to allow simultaneous streaming
from the AFE (Analog front end) and HDMI inputs though two CSI TX
entities.

The HDMI entity is linked to the TXA CSI bus, whilst the AFE is linked
to the TXB CSI bus.

The driver is based on a prototype by Koji Matsuoka in the Renesas BSP,
and an earlier rework by Niklas Söderlund.

Signed-off-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>