linux/Documentation/userspace-api
Niklas Söderlund b562e72bdb media: rppx1: Add framework to support Dreamchip RPPX1 ISP
Add a framework driver for Dreamchip RPPX1 ISP. The driver aims to
provide a framework for other V4L2 based drivers to drive the RPPX1
functionality. The reason for this split is that the RPPX1 IP itself do
not provide any DMA engines to drive data to/from the device, instead it
depends on other IP blocks to implement these features.

While the peripherals around the RPPX1 ISP used in different designs and
by different vendors are different the RPPX1 core itself is the same.
For this reason the framework solution to be able to split the Dreamchip
RPPX1 driver from vendors usage of it have been picked in hope to reduce
duplication of the common parts.

The design is to try and keep the surface of this framework as small as
possible. The intention of this change is to be able to fill all needs
of this.

  * Two functions to create and destroy a RPPX1 instance, rppx1_create()
    and rppx1_destory(). These are intended to be called in the users
    probe and remove code paths.

  * Two functions to start and stop the RPPX1 processing, rppx1_start()
    and rppx1_stop(). These are intended to be called in the users
    stream on and stream off code paths.

  * One function to ask the RPPX1 to process parameters buffer prepared
    by user space, rppx1_params(). The intention is to call this
    function when the parameter buffer is queued to the V4L2 driver and
    the result stored by the driver until the time it needs to be
    written to the RPPX1. It's the users responsibility to write it
    either using MMIO or other means.

  * One function to fill in a statistic buffer based on the current
    status of the RPPX1, rppx1_stats_fill_isr(). The intention is that
    the user call's this in its interrupt handler when it knows the
    RPPX1 is done processing a frame.

  * One function to ack and retrieve the interrupts generated by the
    RPPX1, rppx1_interrupt(). The intention is to call this function
    when the users interrupt handler detects the RPPX1 have raised and
    interrupt. There is no need for the user to understand, or act, on
    the actual RPPX1 interrupt, but it can if it wants too.

The initial support in the framework is limited and do not implement any
ISP processing algorithms other then configuring the RPPX1 to process
any Bayer (8-, 10, or 12-bit) image and produce either a RGB or YUYV
output. It do however probe all function blocks of the RPPX1 and provide
an interface to interact with both parameter and statistic bufferers.
The user of the framework will not change as algorithms for the
different function blocks of the ISP are being added.

Signed-off-by: Niklas Söderlund <niklas.soderlund+renesas@ragnatech.se>
Co-developed-by: Jai Luthra <jai.luthra+renesas@ideasonboard.com>
Signed-off-by: Jai Luthra <jai.luthra+renesas@ideasonboard.com>
Co-developed-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
Signed-off-by: Jacopo Mondi <jacopo.mondi+renesas@ideasonboard.com>
Reviewed-by: Jacopo Mondi <jacopo.mondi@ideasonboard.com>
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
2026-07-30 20:51:35 +03:00
..
accelerators Documentation: ocxl.rst: Update consortium site 2025-03-12 16:26:45 -06:00
ebpf
fwctl fwctl/bnxt_fwctl: Add documentation entries 2026-03-31 13:33:55 -03:00
gpio Documentation: use a source-read extension for the index link boilerplate 2026-01-23 11:59:34 -07:00
ioctl Char/Misc/IIO/FPGA/GPIB/etc driver updates for 7.2-rc1 2026-06-22 12:20:21 -07:00
media media: rppx1: Add framework to support Dreamchip RPPX1 ISP 2026-07-30 20:51:35 +03:00
netlink docs: netlink: Correct buffer sizing info 2026-05-15 15:52:18 -07:00
check_exec.rst security: Add EXEC_RESTRICT_FILE and EXEC_DENY_INTERACTIVE securebits 2024-12-18 17:00:29 -08:00
dcdbas.rst Documentation: move driver-api/dcdbas to userspace-api/ 2024-01-03 14:17:40 -07:00
dma-buf-alloc-exchange.rst
dma-buf-heaps.rst dma-buf: heaps: system: document system_cc_shared heap 2026-04-10 14:20:01 +02:00
ELF.rst
futex2.rst
index.rst Scheduler changes for v7.0: 2026-02-10 12:50:10 -08:00
iommufd.rst iommufd: Fix spelling errors in iommufd.rst 2025-08-18 11:15:06 -03:00
isapnp.rst Documentation: move driver-api/isapnp to userspace-api/ 2024-01-03 14:17:39 -07:00
landlock.rst landlock: Add API support and docs for the quiet flags 2026-06-14 20:17:19 +02:00
liveupdate.rst liveupdate: document current compatibility status 2026-06-01 09:19:38 +03:00
lsm.rst LSM: Create lsm_list_modules system call 2023-11-12 22:54:42 -05:00
mfd_noexec.rst mm/memfd: add documentation for MFD_NOEXEC_SEAL MFD_EXEC 2024-06-15 10:43:07 -07:00
mseal.rst LoongArch: Enable ARCH_SUPPORTS_MSEAL_SYSTEM_MAPPINGS 2025-05-30 21:45:42 +08:00
no_new_privs.rst
ntsync.rst docs: ntsync: Add documentation for the ntsync uAPI. 2025-01-08 13:18:12 +01:00
perf_ring_buffer.rst coresight: docs: Remove target sink from examples 2025-03-11 14:55:57 +00:00
rseq.rst rseq: Reenable performance optimizations conditionally 2026-05-06 17:40:27 +02:00
seccomp_filter.rst
spec_ctrl.rst Documentation/x86: Fix PR_SET_SPECULATION_CTRL error codes 2025-12-29 16:27:45 +01:00
sysfs-platform_profile.rst docs: Fix typos, improve grammar in Userspace API 2025-06-09 15:13:33 -06:00
tee.rst Documentation: Destage TEE subsystem documentation 2023-12-08 15:45:10 -07:00
unshare.rst
vduse.rst Documentation: Add documentation for VDUSE Address Space IDs 2026-01-28 15:32:18 -05:00