From: Keke Li <keke.li@amlogic.com>
Add the file 'c3-isp.rst' that documents the c3-isp driver.
Signed-off-by: Keke Li <keke.li@amlogic.com>
---
Documentation/admin-guide/media/c3-isp.dot | 26 ++++++
Documentation/admin-guide/media/c3-isp.rst | 109 ++++++++++++++++++++++++
Documentation/admin-guide/media/v4l-drivers.rst | 1 +
MAINTAINERS | 2 +
4 files changed, 138 insertions(+)
diff --git a/Documentation/admin-guide/media/c3-isp.dot b/Documentation/admin-guide/media/c3-isp.dot
new file mode 100644
index 000000000000..42dc931ee84a
--- /dev/null
+++ b/Documentation/admin-guide/media/c3-isp.dot
@@ -0,0 +1,26 @@
+digraph board {
+ rankdir=TB
+ n00000001 [label="{{<port0> 0 | <port1> 1} | c3-isp-core\n/dev/v4l-subdev0 | {<port2> 2 | <port3> 3 | <port4> 4 | <port5> 5}}", shape=Mrecord, style=filled, fillcolor=green]
+ n00000001:port3 -> n00000008:port0
+ n00000001:port4 -> n0000000b:port0
+ n00000001:port5 -> n0000000e:port0
+ n00000001:port2 -> n00000027
+ n00000008 [label="{{<port0> 0} | c3-isp-resizer0\n/dev/v4l-subdev1 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n00000008:port1 -> n00000016 [style=bold]
+ n0000000b [label="{{<port0> 0} | c3-isp-resizer1\n/dev/v4l-subdev2 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000000b:port1 -> n0000001a [style=bold]
+ n0000000e [label="{{<port0> 0} | c3-isp-resizer2\n/dev/v4l-subdev3 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000000e:port1 -> n00000023 [style=bold]
+ n00000011 [label="{{<port0> 0} | c3-mipi-adapter\n/dev/v4l-subdev4 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n00000011:port1 -> n00000001:port0 [style=bold]
+ n00000016 [label="c3-isp-cap0\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
+ n0000001a [label="c3-isp-cap1\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
+ n0000001e [label="{{<port0> 0} | c3-mipi-csi2\n/dev/v4l-subdev5 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000001e:port1 -> n00000011:port0 [style=bold]
+ n00000023 [label="c3-isp-cap2\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
+ n00000027 [label="c3-isp-stats\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
+ n0000002b [label="c3-isp-params\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
+ n0000002b -> n00000001:port1
+ n0000003f [label="{{} | imx290 2-001a\n/dev/v4l-subdev6 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000003f:port0 -> n0000001e:port0 [style=bold]
+}
diff --git a/Documentation/admin-guide/media/c3-isp.rst b/Documentation/admin-guide/media/c3-isp.rst
new file mode 100644
index 000000000000..8adac4605a6a
--- /dev/null
+++ b/Documentation/admin-guide/media/c3-isp.rst
@@ -0,0 +1,109 @@
+.. SPDX-License-Identifier: (GPL-2.0-only OR MIT)
+
+.. include:: <isonum.txt>
+
+=================================================
+Amlogic C3 Image Signal Processing (C3ISP) driver
+=================================================
+
+Introduction
+============
+
+This file documents the Amlogic C3ISP driver located under
+drivers/media/platform/amlogic/c3/isp.
+
+The current version of the driver supports the C3ISP found on
+Amlogic C308L processor.
+
+The driver implements V4L2, Media controller and V4L2 subdev interfaces.
+Camera sensor using V4L2 subdev interface in the kernel is supported.
+
+The driver has been tested on AW419-C308L-Socket platform.
+
+Anlogic Camera hardware
+=======================
+
+The Camera hardware found on C308L processors and supported by
+the driver consists of:
+
+- 1 MIPI-CSI2 module. It handle the Physical layer of the CSI2 receivers and
+ receive MIPI data.
+ A separate camera sensor can be connected to MIPI-CSi2 module.
+- 1 MIPI-ADAPTER module. Organize MIPI data to meet ISP input requirements and
+ send MIPI data to ISP
+- 1 ISP (Image Signal Processing) module. Contain a pipeline of image processing
+ hardware blocks.
+ The ISP pipeline contains three scalers at the end.
+ The ISP also contains the DMA interface which writes the output data to memory.
+
+A high level functional view of the C3 ISP is presented below. The ISP
+takes input from the sensor.::
+
+ +---------+ +-------+
+ | Scaler |--->| WRMIF |
+ +---------+ +------------+ +--------------+ +-------+ |---------+ +-------+
+ | Sensor |--->| MIPI CSI-2 |--->| MIPI ADAPTER |--->| ISP |---|---------+ +-------+
+ +---------+ +------------+ +--------------+ +-------+ | Scaler |--->| WRMIF |
+ +---------+ +-------+
+ |---------+ +-------+
+ | Scaler |--->| WRMIF |
+ +---------+ +-------+
+
+Supported functionality
+=======================
+
+The current version of the driver supports:
+
+- Input from camera sensor via MIPI-CSI2;
+
+- Pixel output interface of ISP
+
+ - Scaling support. Configuration of the scaler module
+ for downscalling with ratio up to 8x.
+
+Driver Architecture and Design
+==============================
+
+The driver implements the V4L2 subdev interface. With the goal to model the
+hardware links between the modules and to expose a clean, logical and usable
+interface, the driver is split into V4L2 sub-devices as follows:
+
+- 1 c3-mipi-csi2 sub-device - mipi-csi2 is represented by a single sub-device.
+- 1 c3-mipi-adapter sub-device - mipi-adapter is represented by a single sub-devices.
+- 1 c3-isp-core sub-device - isp-core is represented by a single sub-devices.
+- 3 c3-isp-resizer sub-devices - isp-resizer is represented by a number of sub-devices
+ equal to the number of capture device.
+
+c3-isp-core sub-device is linked to 2 separate video device nodes and
+3 c3-isp-resizer sub-devices nodes.
+
+- 1 capture statistics video device node.
+- 1 output parameters video device node.
+- 3 c3-isp-resizer sub-device nodes.
+
+c3-isp-resizer sub-device is linked to capture video device node.
+
+- c3-isp-resizer0 is linked to c3-isp-cap0
+- c3-isp-resizer1 is linked to c3-isp-cap1
+- c3-isp-resizer2 is linked to c3-isp-cap2
+
+The media controller pipeline graph is as follows (with connected a
+IMX290 camera sensor):
+
+.. _isp_topology_graph:
+
+.. kernel-figure:: c3-isp.dot
+ :alt: c3-isp.dot
+ :align: center
+
+ Media pipeline topology
+
+Implementation
+==============
+
+Runtime configuration of the hardware via 'c3-isp-params' video device node.
+Acquiring statistics of ISP hardware via 'c3-isp-stats' video device node.
+Acquiring output image of ISP hardware via 'c3-isp-cap[0, 2]' video device node.
+
+The output size of the scaler module in the ISP is configured with
+the pixel format of 'c3-isp-cap[0, 2]' video device node.
diff --git a/Documentation/admin-guide/media/v4l-drivers.rst b/Documentation/admin-guide/media/v4l-drivers.rst
index e8761561b2fe..3bac5165b134 100644
--- a/Documentation/admin-guide/media/v4l-drivers.rst
+++ b/Documentation/admin-guide/media/v4l-drivers.rst
@@ -10,6 +10,7 @@ Video4Linux (V4L) driver-specific documentation
:maxdepth: 2
bttv
+ c3-isp
cafe_ccic
cx88
fimc
diff --git a/MAINTAINERS b/MAINTAINERS
index b2bf9c6cd194..4b06a798d30c 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1259,6 +1259,8 @@ AMLOGIC ISP DRIVER
M: Keke Li <keke.li@amlogic.com>
L: linux-media@vger.kernel.org
S: Maintained
+F: Documentation/admin-guide/media/c3-isp.dot
+F: Documentation/admin-guide/media/c3-isp.rst
F: Documentation/devicetree/bindings/media/amlogic,c3-isp.yaml
F: Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
F: drivers/media/platform/amlogic/c3/isp/
--
2.49.0Hi Keke
sorry, I missed this patch in my previous reviews.
I think you're already at v8 and there's no need to resend the whole
series. I would like to send a pull request and see this series merged
soon.
I've run the series through CI (applying a few minors to patch titles
to fix a few checkpatch warnings[1])
I can apply the below suggestions with your ack, re-run the series
through CI and send a pull request. Or, if you prefer to resend I'll
wait for a new version.
What do you prefer ?
See my comments below
On Mon, Apr 14, 2025 at 03:35:23PM +0800, Keke Li via B4 Relay wrote:
> From: Keke Li <keke.li@amlogic.com>
>
> Add the file 'c3-isp.rst' that documents the c3-isp driver.
>
> Signed-off-by: Keke Li <keke.li@amlogic.com>
> ---
> Documentation/admin-guide/media/c3-isp.dot | 26 ++++++
> Documentation/admin-guide/media/c3-isp.rst | 109 ++++++++++++++++++++++++
> Documentation/admin-guide/media/v4l-drivers.rst | 1 +
> MAINTAINERS | 2 +
> 4 files changed, 138 insertions(+)
>
> diff --git a/Documentation/admin-guide/media/c3-isp.dot b/Documentation/admin-guide/media/c3-isp.dot
> new file mode 100644
> index 000000000000..42dc931ee84a
> --- /dev/null
> +++ b/Documentation/admin-guide/media/c3-isp.dot
> @@ -0,0 +1,26 @@
> +digraph board {
> + rankdir=TB
> + n00000001 [label="{{<port0> 0 | <port1> 1} | c3-isp-core\n/dev/v4l-subdev0 | {<port2> 2 | <port3> 3 | <port4> 4 | <port5> 5}}", shape=Mrecord, style=filled, fillcolor=green]
> + n00000001:port3 -> n00000008:port0
> + n00000001:port4 -> n0000000b:port0
> + n00000001:port5 -> n0000000e:port0
> + n00000001:port2 -> n00000027
> + n00000008 [label="{{<port0> 0} | c3-isp-resizer0\n/dev/v4l-subdev1 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
> + n00000008:port1 -> n00000016 [style=bold]
> + n0000000b [label="{{<port0> 0} | c3-isp-resizer1\n/dev/v4l-subdev2 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
> + n0000000b:port1 -> n0000001a [style=bold]
> + n0000000e [label="{{<port0> 0} | c3-isp-resizer2\n/dev/v4l-subdev3 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
> + n0000000e:port1 -> n00000023 [style=bold]
> + n00000011 [label="{{<port0> 0} | c3-mipi-adapter\n/dev/v4l-subdev4 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
> + n00000011:port1 -> n00000001:port0 [style=bold]
> + n00000016 [label="c3-isp-cap0\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
> + n0000001a [label="c3-isp-cap1\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
> + n0000001e [label="{{<port0> 0} | c3-mipi-csi2\n/dev/v4l-subdev5 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
> + n0000001e:port1 -> n00000011:port0 [style=bold]
> + n00000023 [label="c3-isp-cap2\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
> + n00000027 [label="c3-isp-stats\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
> + n0000002b [label="c3-isp-params\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
> + n0000002b -> n00000001:port1
> + n0000003f [label="{{} | imx290 2-001a\n/dev/v4l-subdev6 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
> + n0000003f:port0 -> n0000001e:port0 [style=bold]
> +}
> diff --git a/Documentation/admin-guide/media/c3-isp.rst b/Documentation/admin-guide/media/c3-isp.rst
> new file mode 100644
> index 000000000000..8adac4605a6a
> --- /dev/null
> +++ b/Documentation/admin-guide/media/c3-isp.rst
> @@ -0,0 +1,109 @@
> +.. SPDX-License-Identifier: (GPL-2.0-only OR MIT)
> +
> +.. include:: <isonum.txt>
> +
> +=================================================
> +Amlogic C3 Image Signal Processing (C3ISP) driver
> +=================================================
> +
> +Introduction
> +============
> +
> +This file documents the Amlogic C3ISP driver located under
> +drivers/media/platform/amlogic/c3/isp.
> +
> +The current version of the driver supports the C3ISP found on
> +Amlogic C308L processor.
> +
> +The driver implements V4L2, Media controller and V4L2 subdev interfaces.
> +Camera sensor using V4L2 subdev interface in the kernel is supported.
> +
> +The driver has been tested on AW419-C308L-Socket platform.
> +
> +Anlogic Camera hardware
s/Anlogic/Amlogic
> +=======================
> +
> +The Camera hardware found on C308L processors and supported by
> +the driver consists of:
> +
> +- 1 MIPI-CSI2 module. It handle the Physical layer of the CSI2 receivers and
> + receive MIPI data.
> + A separate camera sensor can be connected to MIPI-CSi2 module.
Do not break lines when not necessary
s/CSi2/CSI-2
> +- 1 MIPI-ADAPTER module. Organize MIPI data to meet ISP input requirements and
> + send MIPI data to ISP
> +- 1 ISP (Image Signal Processing) module. Contain a pipeline of image processing
> + hardware blocks.
> + The ISP pipeline contains three scalers at the end.
> + The ISP also contains the DMA interface which writes the output data to memory.
Ditto
> +
> +A high level functional view of the C3 ISP is presented below. The ISP
> +takes input from the sensor.::
> +
> + +---------+ +-------+
> + | Scaler |--->| WRMIF |
> + +---------+ +------------+ +--------------+ +-------+ |---------+ +-------+
> + | Sensor |--->| MIPI CSI-2 |--->| MIPI ADAPTER |--->| ISP |---|---------+ +-------+
> + +---------+ +------------+ +--------------+ +-------+ | Scaler |--->| WRMIF |
> + +---------+ +-------+
> + |---------+ +-------+
> + | Scaler |--->| WRMIF |
> + +---------+ +-------+
> +
> +Supported functionality
> +=======================
> +
> +The current version of the driver supports:
> +
> +- Input from camera sensor via MIPI-CSI2;
s/;/.
> +
> +- Pixel output interface of ISP
> +
> + - Scaling support. Configuration of the scaler module
> + for downscalling with ratio up to 8x.
To be honest I would drop this paragraph.
> +
> +Driver Architecture and Design
> +==============================
> +
> +The driver implements the V4L2 subdev interface. With the goal to model the
The driver also implements the V4L2 video capture interface and the
Media Controller interface.
To be honest, I would drop this first phrase.
> +hardware links between the modules and to expose a clean, logical and usable
> +interface, the driver is split into V4L2 sub-devices as follows:
s/is split into/registers the following/
s/as follows//
> +
> +- 1 c3-mipi-csi2 sub-device - mipi-csi2 is represented by a single sub-device.
> +- 1 c3-mipi-adapter sub-device - mipi-adapter is represented by a single sub-devices.
> +- 1 c3-isp-core sub-device - isp-core is represented by a single sub-devices.
> +- 3 c3-isp-resizer sub-devices - isp-resizer is represented by a number of sub-devices
> + equal to the number of capture device.
> +
> +c3-isp-core sub-device is linked to 2 separate video device nodes and
> +3 c3-isp-resizer sub-devices nodes.
> +
> +- 1 capture statistics video device node.
> +- 1 output parameters video device node.
> +- 3 c3-isp-resizer sub-device nodes.
> +
> +c3-isp-resizer sub-device is linked to capture video device node.
> +
> +- c3-isp-resizer0 is linked to c3-isp-cap0
> +- c3-isp-resizer1 is linked to c3-isp-cap1
> +- c3-isp-resizer2 is linked to c3-isp-cap2
> +
> +The media controller pipeline graph is as follows (with connected a
> +IMX290 camera sensor):
> +
> +.. _isp_topology_graph:
> +
> +.. kernel-figure:: c3-isp.dot
> + :alt: c3-isp.dot
> + :align: center
> +
> + Media pipeline topology
> +
> +Implementation
> +==============
> +
> +Runtime configuration of the hardware via 'c3-isp-params' video device node.
> +Acquiring statistics of ISP hardware via 'c3-isp-stats' video device node.
> +Acquiring output image of ISP hardware via 'c3-isp-cap[0, 2]' video device node.
> +
> +The output size of the scaler module in the ISP is configured with
> +the pixel format of 'c3-isp-cap[0, 2]' video device node.
The output size.. configured with the pixel format ?
I would say:
The final picture size and format is configured using the V4L2 video
capture interface on the 'c3-isp-cap[0, 2]' video device nodes.
I would also mention the ISP is supported in libcamera (or better, on
its way to be supported by libcamera).
I can send an update to this patch for your review. Is this ok ?
I'll check with maintainers on how to then moved forward and collect
this series.
For reference, the branch where I applied minor fixups to pass
media-ci style checks and with this last patch updated is available
here
https://gitlab.freedesktop.org/linux-media/users/jmondi/-/pipelines/1406119
> diff --git a/Documentation/admin-guide/media/v4l-drivers.rst b/Documentation/admin-guide/media/v4l-drivers.rst
> index e8761561b2fe..3bac5165b134 100644
> --- a/Documentation/admin-guide/media/v4l-drivers.rst
> +++ b/Documentation/admin-guide/media/v4l-drivers.rst
> @@ -10,6 +10,7 @@ Video4Linux (V4L) driver-specific documentation
> :maxdepth: 2
>
> bttv
> + c3-isp
> cafe_ccic
> cx88
> fimc
> diff --git a/MAINTAINERS b/MAINTAINERS
> index b2bf9c6cd194..4b06a798d30c 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1259,6 +1259,8 @@ AMLOGIC ISP DRIVER
> M: Keke Li <keke.li@amlogic.com>
> L: linux-media@vger.kernel.org
> S: Maintained
> +F: Documentation/admin-guide/media/c3-isp.dot
> +F: Documentation/admin-guide/media/c3-isp.rst
> F: Documentation/devicetree/bindings/media/amlogic,c3-isp.yaml
> F: Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
> F: drivers/media/platform/amlogic/c3/isp/
>
> --
> 2.49.0
>
>
>
Hi Jacopo
Thanks for your reply.
On 2025/4/15 22:55, Jacopo Mondi wrote:
> [ EXTERNAL EMAIL ]
>
> Hi Keke
> sorry, I missed this patch in my previous reviews.
>
> I think you're already at v8 and there's no need to resend the whole
> series. I would like to send a pull request and see this series merged
> soon.
>
> I've run the series through CI (applying a few minors to patch titles
> to fix a few checkpatch warnings[1])
>
> I can apply the below suggestions with your ack, re-run the series
> through CI and send a pull request. Or, if you prefer to resend I'll
> wait for a new version.
>
> What do you prefer ?
I will send a new version.
> See my comments below
>
> On Mon, Apr 14, 2025 at 03:35:23PM +0800, Keke Li via B4 Relay wrote:
>> From: Keke Li <keke.li@amlogic.com>
>>
>> Add the file 'c3-isp.rst' that documents the c3-isp driver.
>>
>> Signed-off-by: Keke Li <keke.li@amlogic.com>
>> ---
>> Documentation/admin-guide/media/c3-isp.dot | 26 ++++++
>> Documentation/admin-guide/media/c3-isp.rst | 109 ++++++++++++++++++++++++
>> Documentation/admin-guide/media/v4l-drivers.rst | 1 +
>> MAINTAINERS | 2 +
>> 4 files changed, 138 insertions(+)
>>
>> diff --git a/Documentation/admin-guide/media/c3-isp.dot b/Documentation/admin-guide/media/c3-isp.dot
>> new file mode 100644
>> index 000000000000..42dc931ee84a
>> --- /dev/null
>> +++ b/Documentation/admin-guide/media/c3-isp.dot
>> @@ -0,0 +1,26 @@
>> +digraph board {
>> + rankdir=TB
>> + n00000001 [label="{{<port0> 0 | <port1> 1} | c3-isp-core\n/dev/v4l-subdev0 | {<port2> 2 | <port3> 3 | <port4> 4 | <port5> 5}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n00000001:port3 -> n00000008:port0
>> + n00000001:port4 -> n0000000b:port0
>> + n00000001:port5 -> n0000000e:port0
>> + n00000001:port2 -> n00000027
>> + n00000008 [label="{{<port0> 0} | c3-isp-resizer0\n/dev/v4l-subdev1 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n00000008:port1 -> n00000016 [style=bold]
>> + n0000000b [label="{{<port0> 0} | c3-isp-resizer1\n/dev/v4l-subdev2 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n0000000b:port1 -> n0000001a [style=bold]
>> + n0000000e [label="{{<port0> 0} | c3-isp-resizer2\n/dev/v4l-subdev3 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n0000000e:port1 -> n00000023 [style=bold]
>> + n00000011 [label="{{<port0> 0} | c3-mipi-adapter\n/dev/v4l-subdev4 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n00000011:port1 -> n00000001:port0 [style=bold]
>> + n00000016 [label="c3-isp-cap0\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
>> + n0000001a [label="c3-isp-cap1\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
>> + n0000001e [label="{{<port0> 0} | c3-mipi-csi2\n/dev/v4l-subdev5 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n0000001e:port1 -> n00000011:port0 [style=bold]
>> + n00000023 [label="c3-isp-cap2\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
>> + n00000027 [label="c3-isp-stats\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
>> + n0000002b [label="c3-isp-params\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
>> + n0000002b -> n00000001:port1
>> + n0000003f [label="{{} | imx290 2-001a\n/dev/v4l-subdev6 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
>> + n0000003f:port0 -> n0000001e:port0 [style=bold]
>> +}
>> diff --git a/Documentation/admin-guide/media/c3-isp.rst b/Documentation/admin-guide/media/c3-isp.rst
>> new file mode 100644
>> index 000000000000..8adac4605a6a
>> --- /dev/null
>> +++ b/Documentation/admin-guide/media/c3-isp.rst
>> @@ -0,0 +1,109 @@
>> +.. SPDX-License-Identifier: (GPL-2.0-only OR MIT)
>> +
>> +.. include:: <isonum.txt>
>> +
>> +=================================================
>> +Amlogic C3 Image Signal Processing (C3ISP) driver
>> +=================================================
>> +
>> +Introduction
>> +============
>> +
>> +This file documents the Amlogic C3ISP driver located under
>> +drivers/media/platform/amlogic/c3/isp.
>> +
>> +The current version of the driver supports the C3ISP found on
>> +Amlogic C308L processor.
>> +
>> +The driver implements V4L2, Media controller and V4L2 subdev interfaces.
>> +Camera sensor using V4L2 subdev interface in the kernel is supported.
>> +
>> +The driver has been tested on AW419-C308L-Socket platform.
>> +
>> +Anlogic Camera hardware
> s/Anlogic/Amlogic
Will use "Amlogic".
>> +=======================
>> +
>> +The Camera hardware found on C308L processors and supported by
>> +the driver consists of:
>> +
>> +- 1 MIPI-CSI2 module. It handle the Physical layer of the CSI2 receivers and
>> + receive MIPI data.
>> + A separate camera sensor can be connected to MIPI-CSi2 module.
> Do not break lines when not necessary
OK.
>
> s/CSi2/CSI-2
Will use "CSI-2".
>> +- 1 MIPI-ADAPTER module. Organize MIPI data to meet ISP input requirements and
>> + send MIPI data to ISP
>> +- 1 ISP (Image Signal Processing) module. Contain a pipeline of image processing
>> + hardware blocks.
>> + The ISP pipeline contains three scalers at the end.
>> + The ISP also contains the DMA interface which writes the output data to memory.
> Ditto
OK.
>> +
>> +A high level functional view of the C3 ISP is presented below. The ISP
>> +takes input from the sensor.::
>> +
>> + +---------+ +-------+
>> + | Scaler |--->| WRMIF |
>> + +---------+ +------------+ +--------------+ +-------+ |---------+ +-------+
>> + | Sensor |--->| MIPI CSI-2 |--->| MIPI ADAPTER |--->| ISP |---|---------+ +-------+
>> + +---------+ +------------+ +--------------+ +-------+ | Scaler |--->| WRMIF |
>> + +---------+ +-------+
>> + |---------+ +-------+
>> + | Scaler |--->| WRMIF |
>> + +---------+ +-------+
>> +
>> +Supported functionality
>> +=======================
>> +
>> +The current version of the driver supports:
>> +
>> +- Input from camera sensor via MIPI-CSI2;
> s/;/.
>
Will use "."
>> +
>> +- Pixel output interface of ISP
>> +
>> + - Scaling support. Configuration of the scaler module
>> + for downscalling with ratio up to 8x.
> To be honest I would drop this paragraph.
>
Will drop this paragraph.
>> +
>> +Driver Architecture and Design
>> +==============================
>> +
>> +The driver implements the V4L2 subdev interface. With the goal to model the
> The driver also implements the V4L2 video capture interface and the
> Media Controller interface.
>
> To be honest, I would drop this first phrase.
>
>
Will drop the first phrase.
>> +hardware links between the modules and to expose a clean, logical and usable
>> +interface, the driver is split into V4L2 sub-devices as follows:
> s/is split into/registers the following/
Will use "registers the following".
> s/as follows//
>
Will remove "as follows".
>> +
>> +- 1 c3-mipi-csi2 sub-device - mipi-csi2 is represented by a single sub-device.
>> +- 1 c3-mipi-adapter sub-device - mipi-adapter is represented by a single sub-devices.
>> +- 1 c3-isp-core sub-device - isp-core is represented by a single sub-devices.
>> +- 3 c3-isp-resizer sub-devices - isp-resizer is represented by a number of sub-devices
>> + equal to the number of capture device.
>> +
>> +c3-isp-core sub-device is linked to 2 separate video device nodes and
>> +3 c3-isp-resizer sub-devices nodes.
>> +
>> +- 1 capture statistics video device node.
>> +- 1 output parameters video device node.
>> +- 3 c3-isp-resizer sub-device nodes.
>> +
>> +c3-isp-resizer sub-device is linked to capture video device node.
>> +
>> +- c3-isp-resizer0 is linked to c3-isp-cap0
>> +- c3-isp-resizer1 is linked to c3-isp-cap1
>> +- c3-isp-resizer2 is linked to c3-isp-cap2
>> +
>> +The media controller pipeline graph is as follows (with connected a
>> +IMX290 camera sensor):
>> +
>> +.. _isp_topology_graph:
>> +
>> +.. kernel-figure:: c3-isp.dot
>> + :alt: c3-isp.dot
>> + :align: center
>> +
>> + Media pipeline topology
>> +
>> +Implementation
>> +==============
>> +
>> +Runtime configuration of the hardware via 'c3-isp-params' video device node.
>> +Acquiring statistics of ISP hardware via 'c3-isp-stats' video device node.
>> +Acquiring output image of ISP hardware via 'c3-isp-cap[0, 2]' video device node.
>> +
>> +The output size of the scaler module in the ISP is configured with
>> +the pixel format of 'c3-isp-cap[0, 2]' video device node.
> The output size.. configured with the pixel format ?
>
> I would say:
>
> The final picture size and format is configured using the V4L2 video
> capture interface on the 'c3-isp-cap[0, 2]' video device nodes.
OK.
> I would also mention the ISP is supported in libcamera (or better, on
> its way to be supported by libcamera).
>
> I can send an update to this patch for your review. Is this ok ?
OK, thanks.
> I'll check with maintainers on how to then moved forward and collect
> this series.
>
> For reference, the branch where I applied minor fixups to pass
> media-ci style checks and with this last patch updated is available
> here
> https://gitlab.freedesktop.org/linux-media/users/jmondi/-/pipelines/1406119
>
Will refer to your update for this patch.
>> diff --git a/Documentation/admin-guide/media/v4l-drivers.rst b/Documentation/admin-guide/media/v4l-drivers.rst
>> index e8761561b2fe..3bac5165b134 100644
>> --- a/Documentation/admin-guide/media/v4l-drivers.rst
>> +++ b/Documentation/admin-guide/media/v4l-drivers.rst
>> @@ -10,6 +10,7 @@ Video4Linux (V4L) driver-specific documentation
>> :maxdepth: 2
>>
>> bttv
>> + c3-isp
>> cafe_ccic
>> cx88
>> fimc
>> diff --git a/MAINTAINERS b/MAINTAINERS
>> index b2bf9c6cd194..4b06a798d30c 100644
>> --- a/MAINTAINERS
>> +++ b/MAINTAINERS
>> @@ -1259,6 +1259,8 @@ AMLOGIC ISP DRIVER
>> M: Keke Li <keke.li@amlogic.com>
>> L: linux-media@vger.kernel.org
>> S: Maintained
>> +F: Documentation/admin-guide/media/c3-isp.dot
>> +F: Documentation/admin-guide/media/c3-isp.rst
>> F: Documentation/devicetree/bindings/media/amlogic,c3-isp.yaml
>> F: Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
>> F: drivers/media/platform/amlogic/c3/isp/
>>
>> --
>> 2.49.0
>>
>>
>>
From: Keke Li <keke.li@amlogic.com>
Add the file 'c3-isp.rst' that documents the c3-isp driver.
Signed-off-by: Keke Li <keke.li@amlogic.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
---
Documentation/admin-guide/media/c3-isp.dot | 26 +++++
Documentation/admin-guide/media/c3-isp.rst | 101 ++++++++++++++++++
.../admin-guide/media/v4l-drivers.rst | 1 +
MAINTAINERS | 2 +
4 files changed, 130 insertions(+)
create mode 100644 Documentation/admin-guide/media/c3-isp.dot
create mode 100644 Documentation/admin-guide/media/c3-isp.rst
diff --git a/Documentation/admin-guide/media/c3-isp.dot b/Documentation/admin-guide/media/c3-isp.dot
new file mode 100644
index 000000000000..42dc931ee84a
--- /dev/null
+++ b/Documentation/admin-guide/media/c3-isp.dot
@@ -0,0 +1,26 @@
+digraph board {
+ rankdir=TB
+ n00000001 [label="{{<port0> 0 | <port1> 1} | c3-isp-core\n/dev/v4l-subdev0 | {<port2> 2 | <port3> 3 | <port4> 4 | <port5> 5}}", shape=Mrecord, style=filled, fillcolor=green]
+ n00000001:port3 -> n00000008:port0
+ n00000001:port4 -> n0000000b:port0
+ n00000001:port5 -> n0000000e:port0
+ n00000001:port2 -> n00000027
+ n00000008 [label="{{<port0> 0} | c3-isp-resizer0\n/dev/v4l-subdev1 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n00000008:port1 -> n00000016 [style=bold]
+ n0000000b [label="{{<port0> 0} | c3-isp-resizer1\n/dev/v4l-subdev2 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000000b:port1 -> n0000001a [style=bold]
+ n0000000e [label="{{<port0> 0} | c3-isp-resizer2\n/dev/v4l-subdev3 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000000e:port1 -> n00000023 [style=bold]
+ n00000011 [label="{{<port0> 0} | c3-mipi-adapter\n/dev/v4l-subdev4 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n00000011:port1 -> n00000001:port0 [style=bold]
+ n00000016 [label="c3-isp-cap0\n/dev/video0", shape=box, style=filled, fillcolor=yellow]
+ n0000001a [label="c3-isp-cap1\n/dev/video1", shape=box, style=filled, fillcolor=yellow]
+ n0000001e [label="{{<port0> 0} | c3-mipi-csi2\n/dev/v4l-subdev5 | {<port1> 1}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000001e:port1 -> n00000011:port0 [style=bold]
+ n00000023 [label="c3-isp-cap2\n/dev/video2", shape=box, style=filled, fillcolor=yellow]
+ n00000027 [label="c3-isp-stats\n/dev/video3", shape=box, style=filled, fillcolor=yellow]
+ n0000002b [label="c3-isp-params\n/dev/video4", shape=box, style=filled, fillcolor=yellow]
+ n0000002b -> n00000001:port1
+ n0000003f [label="{{} | imx290 2-001a\n/dev/v4l-subdev6 | {<port0> 0}}", shape=Mrecord, style=filled, fillcolor=green]
+ n0000003f:port0 -> n0000001e:port0 [style=bold]
+}
diff --git a/Documentation/admin-guide/media/c3-isp.rst b/Documentation/admin-guide/media/c3-isp.rst
new file mode 100644
index 000000000000..bc5e2f836e8d
--- /dev/null
+++ b/Documentation/admin-guide/media/c3-isp.rst
@@ -0,0 +1,101 @@
+.. SPDX-License-Identifier: (GPL-2.0-only OR MIT)
+
+.. include:: <isonum.txt>
+
+=================================================
+Amlogic C3 Image Signal Processing (C3ISP) driver
+=================================================
+
+Introduction
+============
+
+This file documents the Amlogic C3ISP driver located under
+drivers/media/platform/amlogic/c3/isp.
+
+The current version of the driver supports the C3ISP found on
+Amlogic C308L processor.
+
+The driver implements V4L2, Media controller and V4L2 subdev interfaces.
+Camera sensor using V4L2 subdev interface in the kernel is supported.
+
+The driver has been tested on AW419-C308L-Socket platform.
+
+Amlogic C3 ISP
+==============
+
+The Camera hardware found on C308L processors and supported by
+the driver consists of:
+
+- 1 MIPI-CSI-2 module: handles the physical layer of the MIPI CSI-2 receiver and
+ receive data from the connected camera sensor.
+- 1 MIPI-ADAPTER module: organize MIPI data to meet ISP input requirements and
+ send MIPI data to ISP.
+- 1 ISP (Image Signal Processing) module: contain a pipeline of image processing
+ hardware blocks. The ISP pipeline contains three resizers at the end each of
+ them connected to a DMA interface which writes the output data to memory.
+
+An high level functional view of the C3 ISP is presented below.::
+
+ +----------+ +-------+
+ | Resizer |--->| WRMIF |
+ +---------+ +------------+ +--------------+ +-------+ |----------+ +-------+
+ | Sensor |--->| MIPI CSI-2 |--->| MIPI ADAPTER |--->| ISP |---|----------+ +-------+
+ +---------+ +------------+ +--------------+ +-------+ | Resizer |--->| WRMIF |
+ +----------+ +-------+
+ |----------+ +-------+
+ | Resizer |--->| WRMIF |
+ +----------+ +-------+
+
+Driver architecture and design
+==============================
+
+With the goal to model the hardware links between the modules and to expose a
+clean, logical and usable interface, the driver is split into the
+following V4L2 sub-devices:
+
+- 1 `c3-mipi-csi2` sub-device - the MIPI CSI-2 receiver
+- 1 `c3-mipi-adapter` sub-device - the MIPI adapter
+- 1 `c3-isp-core` sub-device - the ISP core
+- 3 `c3-isp-resizer` sub-devices - the ISP resizers
+
+The `c3-isp-core` sub-device is linked to 2 video device nodes for statistics
+capture and parameters programming:
+
+- the `c3-isp-stats` capture video device node for statistics capture
+- the `c3-isp-params` output video device for parameters programming
+
+Each `c3-isp-resizer` sub-device is linked to a capture video device node where
+frames are captured from:
+
+- `c3-isp-resizer0` is linked to the `c3-isp-cap0` capture video device
+- `c3-isp-resizer1` is linked to the `c3-isp-cap1` capture video device
+- `c3-isp-resizer2` is linked to the `c3-isp-cap2` capture video device
+
+The media controller pipeline graph is as follows (with connected a
+IMX290 camera sensor):
+
+.. _isp_topology_graph:
+
+.. kernel-figure:: c3-isp.dot
+ :alt: c3-isp.dot
+ :align: center
+
+ Media pipeline topology
+
+Implementation
+==============
+
+Runtime configuration of the ISP hardware is performed on the `c3-isp-params`
+video device node using the :ref:`V4L2_META_FMT_C3ISP_PARAMS
+<v4l2-meta-fmt-c3isp-params>` as data format. The buffer structure is defined by
+:c:type:`c3_isp_params_cfg`.
+
+Statistics are captured from the `c3-isp-stats` video device node using the
+:ref:`V4L2_META_FMT_C3ISP_STATS <v4l2-meta-fmt-c3isp-stats>` data format.
+
+The final picture size and format is configured using the V4L2 video
+capture interface on the `c3-isp-cap[0, 2]` video device nodes.
+
+The Amlogic C3 ISP is supported by `libcamera <https://libcamera.org>`_ with a
+dedicated pipeline handler and algorithms that perform run-time image correction
+and enhancement.
diff --git a/Documentation/admin-guide/media/v4l-drivers.rst b/Documentation/admin-guide/media/v4l-drivers.rst
index e8761561b2fe..3bac5165b134 100644
--- a/Documentation/admin-guide/media/v4l-drivers.rst
+++ b/Documentation/admin-guide/media/v4l-drivers.rst
@@ -10,6 +10,7 @@ Video4Linux (V4L) driver-specific documentation
:maxdepth: 2
bttv
+ c3-isp
cafe_ccic
cx88
fimc
diff --git a/MAINTAINERS b/MAINTAINERS
index d165b806aa8f..0b83cc99b429 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -1257,6 +1257,8 @@ AMLOGIC ISP DRIVER
M: Keke Li <keke.li@amlogic.com>
L: linux-media@vger.kernel.org
S: Maintained
+F: Documentation/admin-guide/media/c3-isp.dot
+F: Documentation/admin-guide/media/c3-isp.rst
F: Documentation/devicetree/bindings/media/amlogic,c3-isp.yaml
F: Documentation/userspace-api/media/v4l/metafmt-c3-isp.rst
F: drivers/media/platform/amlogic/c3/isp/
--
2.48.1© 2016 - 2025 Red Hat, Inc.