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From: Sakari Ailus <sakari.ailus@linux.intel.com>
To: linux-media@vger.kernel.org
Cc: mchehab@kernel.org
Subject: [PATCH 06/24] Documentation: ccs: Add user documentation for the CCS driver
Date: Mon,  7 Dec 2020 23:15:12 +0200	[thread overview]
Message-ID: <20201207211530.21180-7-sakari.ailus@linux.intel.com> (raw)
In-Reply-To: <20201207211530.21180-1-sakari.ailus@linux.intel.com>

Add user documentation for the CCS driver. This includes e.g. sub-devices
implemented by the driver.

Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
---
 .../userspace-api/media/drivers/ccs.rst       | 59 +++++++++++++++++++
 .../userspace-api/media/drivers/index.rst     |  1 +
 MAINTAINERS                                   |  1 +
 3 files changed, 61 insertions(+)
 create mode 100644 Documentation/userspace-api/media/drivers/ccs.rst

diff --git a/Documentation/userspace-api/media/drivers/ccs.rst b/Documentation/userspace-api/media/drivers/ccs.rst
new file mode 100644
index 000000000000..9f507b0a79b5
--- /dev/null
+++ b/Documentation/userspace-api/media/drivers/ccs.rst
@@ -0,0 +1,59 @@
+.. SPDX-License-Identifier: GPL-2.0-only OR BSD-3-Clause
+
+.. include:: <isonum.txt>
+
+MIPI CCS camera sensor driver
+=============================
+
+The MIPI CCS camera sensor driver is a generic driver for `MIPI CCS
+<https://www.mipi.org/specifications/camera-command-set>`_ compliant
+camera sensors. It exposes three sub-devices representing the pixel array,
+the binner and the scaler.
+
+As the capabilities of individual devices vary, the driver exposes
+interfaces based on the capabilities that exist in hardware.
+
+Pixel Array sub-device
+----------------------
+
+The pixel array sub-device represents the camera sensor's pixel matrix, as well
+as analogue crop functionality present in many compliant devices. The analogue
+crop is configured using the ``V4L2_SEL_TGT_CROP`` on the source pad (0) of the
+entity. The size of the pixel matrix can be obtained by getting the
+``V4L2_SEL_TGT_NATIVE_SIZE`` target.
+
+Binner
+------
+
+The binner sub-device represents the binning functionality on the sensor. For
+that purpose, selection target ``V4L2_SEL_TGT_COMPOSE`` is supported on the
+sink pad (0).
+
+Additionally, if a device has no scaler or digital crop functionality, the
+source pad (1) expses another digital crop selection rectangle that can only
+crop at the end of the lines and frames.
+
+Scaler
+------
+
+The scaler sub-device represents the digital crop and scaling functionality of
+the sensor. The V4L2 selection target ``V4L2_SEL_TGT_CROP`` is used to
+configure the digital crop on the sink pad (0) when digital crop is supported.
+Scaling is configured using selection target ``V4L2_SEL_TGT_COMPOSE`` on the
+sink pad (0) as well.
+
+Additionally, if the scaler sub-device exists, its source pad (1) exposes
+another digital crop selection rectangle that can only crop at the end of the
+lines and frames.
+
+Digital and analogue crop
+-------------------------
+
+Digital crop functionality is referred to as cropping that effectively works by
+dropping some data on the floor. Analogue crop, on the other hand, means that
+the cropped information is never retrieved. In case of camera sensors, the
+analogue data is never read from the pixel matrix that are outside the
+configured selection rectangle that designates crop. The difference has an
+effect in device timing and likely also in power consumption.
+
+**Copyright** |copy| 2020 Intel Corporation
diff --git a/Documentation/userspace-api/media/drivers/index.rst b/Documentation/userspace-api/media/drivers/index.rst
index 05a82f8c0c99..1a9038f5f9fa 100644
--- a/Documentation/userspace-api/media/drivers/index.rst
+++ b/Documentation/userspace-api/media/drivers/index.rst
@@ -31,6 +31,7 @@ For more details see the file COPYING in the source distribution of Linux.
 	:maxdepth: 5
 	:numbered:
 
+	ccs
 	cx2341x-uapi
 	imx-uapi
 	max2175
diff --git a/MAINTAINERS b/MAINTAINERS
index e97d4d9d741e..ab0bf9b8dd72 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11644,6 +11644,7 @@ L:	linux-media@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/media/i2c/mipi-ccs.yaml
 F:	Documentation/driver-api/media/drivers/ccs/
+F:	Documentation/userspace-api/media/drivers/ccs.rst
 F:	drivers/media/i2c/ccs-pll.c
 F:	drivers/media/i2c/ccs-pll.h
 F:	drivers/media/i2c/ccs/
-- 
2.29.2


  parent reply	other threads:[~2020-12-07 21:25 UTC|newest]

Thread overview: 29+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-12-07 21:15 [PATCH 00/24] Additional CCS feature support Sakari Ailus
2020-12-07 21:15 ` [PATCH 01/24] ccs: Add digital gain support Sakari Ailus
2020-12-07 21:15 ` [PATCH 02/24] ccs: Add support for old-style SMIA digital gain Sakari Ailus
2020-12-07 21:15 ` [PATCH 03/24] ccs: Remove analogue gain field Sakari Ailus
2020-12-07 21:15 ` [PATCH 04/24] ccs: Only add analogue gain control if the device supports it Sakari Ailus
2020-12-07 21:15 ` [PATCH 05/24] v4l: uapi: Add user control base for CCS controls Sakari Ailus
2020-12-07 21:15 ` Sakari Ailus [this message]
2020-12-07 21:15 ` [PATCH 07/24] v4l: uapi: ccs: Add controls for analogue gain constants Sakari Ailus
2020-12-09 17:00   ` kernel test robot
2020-12-11 11:39   ` [PATCH v1.1 " Sakari Ailus
2020-12-07 21:15 ` [PATCH 08/24] ccs: Add support for analogue gain coefficient controls Sakari Ailus
2020-12-07 21:15 ` [PATCH 09/24] v4l: uapi: ccs: Add controls for CCS alternative analogue gain Sakari Ailus
2020-12-07 21:15 ` [PATCH 10/24] ccs: Add support for alternate analogue global gain Sakari Ailus
2020-12-07 21:15 ` [PATCH 11/24] ccs: Add debug prints for MSR registers Sakari Ailus
2020-12-07 21:15 ` [PATCH 12/24] v4l: uapi: ccs: Add CCS controls for shading correction Sakari Ailus
2020-12-07 21:15 ` [PATCH 13/24] ccs: Add shading correction and luminance correction level controls Sakari Ailus
2020-12-07 21:15 ` [PATCH 14/24] ccs: Get the endpoint by port rather than any next endpoint Sakari Ailus
2020-12-07 21:15 ` [PATCH 15/24] ccs: Don't change the I²C address just for software reset Sakari Ailus
2020-12-07 21:15 ` [PATCH 16/24] ccs: Only do software reset if we have no hardware reset Sakari Ailus
2020-12-07 21:15 ` [PATCH 17/24] ccs: Wait until software reset is done Sakari Ailus
2021-01-12 16:49   ` Mauro Carvalho Chehab
2021-01-12 17:12     ` Sakari Ailus
2020-12-07 21:15 ` [PATCH 18/24] ccs: Hardware requires a delay after starting the clock of lifting reset Sakari Ailus
2020-12-07 21:15 ` [PATCH 19/24] ccs: Add a sanity check for external clock frequency Sakari Ailus
2020-12-07 21:15 ` [PATCH 20/24] ccs: Support and default to auto PHY control Sakari Ailus
2020-12-07 21:15 ` [PATCH 21/24] Documentation: Include CCS PLL calculator to CCS driver documentation Sakari Ailus
2020-12-07 21:15 ` [PATCH 22/24] ccs-pll: Switch from standard integer types to kernel ones Sakari Ailus
2020-12-07 21:15 ` [PATCH 23/24] ccs: " Sakari Ailus
2020-12-07 21:15 ` [PATCH 24/24] Revert "media: ccs-pll: Fix MODULE_LICENSE" Sakari Ailus

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