media: uapi: Add controls for the THP7312 ISP

The THP7312 is an external ISP from THine. As such, it implements a
large number of parameters to control all aspects of the image
processing. Many of those controls are already standard in V4L2, but
some are fairly device-specific.

Reserve a range of 32 controls for the device. The driver will implement
4 device-specific controls to start with, define and document them. 28
additional device-specific controls should be enough for future
development.

Co-developed-by: Paul Elder <[e-mail]>
Signed-off-by: Paul Elder <[e-mail]>
Signed-off-by: Laurent Pinchart <[e-mail]>
Signed-off-by: Sakari Ailus <[e-mail]>
Signed-off-by: Hans Verkuil <[e-mail]>

Documentation/userspace-api/media/drivers/index.rst

···
 	npcm-video
 	omap3isp-uapi
 	st-vgxy61
+	thp7312
 	uvcvideo

Documentation/userspace-api/media/drivers/thp7312.rst

···
+.. SPDX-License-Identifier: GPL-2.0-only
+
+THine THP7312 ISP driver
+========================
+
+The THP7312 driver implements the following driver-specific controls:
+
+``V4L2_CID_THP7312_LOW_LIGHT_COMPENSATION``
+    Enable/Disable auto-adjustment, based on lighting conditions, of the frame
+    rate when auto-exposure is enabled.
+
+``V4L2_CID_THP7312_AUTO_FOCUS_METHOD``
+    Set method of auto-focus. Only takes effect when auto-focus is enabled.
+
+    .. flat-table::
+        :header-rows:  0
+        :stub-columns: 0
+        :widths:       1 4
+
+        * - ``0``
+          - Contrast-based auto-focus
+        * - ``1``
+          - PDAF
+        * - ``2``
+          - Hybrid of contrast-based and PDAF
+
+    Supported values for the control depend on the camera sensor module
+    connected to the THP7312. If the module doesn't have a focus lens actuator,
+    this control will not be exposed by the THP7312 driver. If the module has a
+    controllable focus lens but the sensor doesn't support PDAF, only the
+    contrast-based auto-focus value will be valid. Otherwise all values for the
+    controls will be supported.
+
+``V4L2_CID_THP7312_NOISE_REDUCTION_AUTO``
+    Enable/Disable auto noise reduction.
+
+``V4L2_CID_THP7312_NOISE_REDUCTION_ABSOLUTE``
+    Set the noise reduction strength, where 0 is the weakest and 10 is the
+    strongest.

MAINTAINERS

···
 S:	Maintained
 T:	git git://linuxtv.org/media_tree.git
 F:	Documentation/devicetree/bindings/media/i2c/thine,thp7312.yaml
+F:	Documentation/userspace-api/media/drivers/thp7312.rst
+F:	include/uapi/linux/thp7312.h
 
 THUNDERBOLT DMA TRAFFIC TEST DRIVER
 M:	Isaac Hazan <[e-mail]>

include/uapi/linux/thp7312.h

···
+/* SPDX-License-Identifier: GPL-2.0-only WITH Linux-syscall-note */
+/*
+ * THine THP7312 user space header file.
+ *
+ * Copyright (C) 2021 THine Electronics, Inc.
+ * Copyright (C) 2023 Ideas on Board Oy
+ */
+
+#ifndef __UAPI_THP7312_H_
+#define __UAPI_THP7312_H_
+
+#include <linux/v4l2-controls.h>
+
+#define V4L2_CID_THP7312_LOW_LIGHT_COMPENSATION		(V4L2_CID_USER_THP7312_BASE + 0x01)
+#define V4L2_CID_THP7312_AUTO_FOCUS_METHOD		(V4L2_CID_USER_THP7312_BASE + 0x02)
+#define V4L2_CID_THP7312_NOISE_REDUCTION_AUTO		(V4L2_CID_USER_THP7312_BASE + 0x03)
+#define V4L2_CID_THP7312_NOISE_REDUCTION_ABSOLUTE	(V4L2_CID_USER_THP7312_BASE + 0x04)
+
+#endif /* __UAPI_THP7312_H_ */

include/uapi/linux/v4l2-controls.h

···
  */
 #define V4L2_CID_USER_NPCM_BASE			(V4L2_CID_USER_BASE + 0x11b0)
 
+/*
+ * The base for THine THP7312 driver controls.
+ * We reserve 32 controls for this driver.
+ */
+#define V4L2_CID_USER_THP7312_BASE		(V4L2_CID_USER_BASE + 0x11c0)
+
 /* MPEG-class control IDs */
 /* The MPEG controls are applicable to all codec controls
  * and the 'MPEG' part of the define is historical */