From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 51BCEC4167B for ; Mon, 13 Nov 2023 11:08:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230131AbjKMLIB (ORCPT ); Mon, 13 Nov 2023 06:08:01 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38892 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S230115AbjKMLH5 (ORCPT ); Mon, 13 Nov 2023 06:07:57 -0500 Received: from perceval.ideasonboard.com (perceval.ideasonboard.com [213.167.242.64]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id E27B91718; Mon, 13 Nov 2023 03:07:48 -0800 (PST) Received: from pendragon.ideasonboard.com (213-243-189-158.bb.dnainternet.fi [213.243.189.158]) by perceval.ideasonboard.com (Postfix) with ESMTPSA id 62A6410A; Mon, 13 Nov 2023 12:07:22 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=ideasonboard.com; s=mail; t=1699873642; bh=44XxDMZ8vV3iZkNBqPO1GmXv2iPnvXqCnW7IKgatAEc=; h=Date:From:To:Cc:Subject:References:In-Reply-To:From; b=f+g1zMT5sVTdL0UYHZw8lTioKQ71fT9LaG2nS3f3ftw+VxQsWnosT0cx4CH7bkU5P t6WCi04avRTLwUJlSuFwVJd0E19oqlEMdXAn04A0DWKwoxOEqBlpzVHNVcbQWmC2Ln LpMRv49vUCqPnEE/A1p/tjFWpQQZwmyTuD8YpoNc= Date: Mon, 13 Nov 2023 13:07:54 +0200 From: Laurent Pinchart To: Hans Verkuil Cc: Shengjiu Wang , sakari.ailus@iki.fi, tfiga@chromium.org, m.szyprowski@samsung.com, mchehab@kernel.org, linux-media@vger.kernel.org, linux-kernel@vger.kernel.org, shengjiu.wang@gmail.com, Xiubo.Lee@gmail.com, festevam@gmail.com, nicoleotsuka@gmail.com, lgirdwood@gmail.com, broonie@kernel.org, perex@perex.cz, tiwai@suse.com, alsa-devel@alsa-project.org, linuxppc-dev@lists.ozlabs.org Subject: Re: [PATCH v9 10/15] media: uapi: Add V4L2_CTRL_TYPE_FIXED_POINT Message-ID: <20231113110754.GB24338@pendragon.ideasonboard.com> References: <1699595289-25773-1-git-send-email-shengjiu.wang@nxp.com> <1699595289-25773-11-git-send-email-shengjiu.wang@nxp.com> <4cd6b593-2376-4cbc-a7c8-d3eb36a2f7a0@xs4all.nl> <20231113104238.GA13981@pendragon.ideasonboard.com> <6a3e7eb9-505c-4cfb-8a86-a8947a2e44d5@xs4all.nl> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <6a3e7eb9-505c-4cfb-8a86-a8947a2e44d5@xs4all.nl> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Nov 13, 2023 at 11:56:49AM +0100, Hans Verkuil wrote: > On 13/11/2023 11:42, Laurent Pinchart wrote: > > On Mon, Nov 13, 2023 at 11:29:09AM +0100, Hans Verkuil wrote: > >> Hi Shengjiu, > >> > >> On 10/11/2023 06:48, Shengjiu Wang wrote: > >>> Fixed point controls are used by the user to configure > >>> a fixed point value in 64bits, which Q31.32 format. > >>> > >>> Signed-off-by: Shengjiu Wang > >> > >> This patch adds a new control type. This is something that also needs to be > >> tested by v4l2-compliance, and for that we need to add support for this to > >> one of the media test-drivers. The best place for that is the vivid driver, > >> since that has already a bunch of test controls for other control types. > >> > >> See e.g. VIVID_CID_INTEGER64 in vivid-ctrls.c. > >> > >> Can you add a patch adding a fixed point test control to vivid? > > > > I don't think V4L2_CTRL_TYPE_FIXED_POINT is a good idea. This seems to > > relate more to units than control types. We have lots of fixed-point > > values in controls already, using the 32-bit and 64-bit integer control > > types. They use various locations for the decimal point, depending on > > the control. If we want to make this more explicit to users, we should > > work on adding unit support to the V4L2 controls. > > "Fixed Point" is not a unit, it's a type. 'Db', 'Hz' etc. are units. It's not a unit, but I think it's related to units. My point is that, without units support, I don't see why we need a formal definition of fixed-point types, and why this series couldn't just use VIVID_CID_INTEGER64. Drivers already interpret VIVID_CID_INTEGER64 values as they see fit. > A quick "git grep -i "fixed point" Documentation/userspace-api/media/' > only shows a single driver specific control (dw100.rst). > > I'm not aware of other controls in mainline that use fixed point. The analog gain control for sensors for instance. > Note that V4L2_CTRL_TYPE_FIXED_POINT is a Q31.32 format. By setting > min/max/step you can easily map that to just about any QN.M format where > N <= 31 and M <= 32. > > In the case of dw100 it is a bit different in that it is quite specialized > and it had to fit in 16 bits. > > >>> --- > >>> .../userspace-api/media/v4l/vidioc-g-ext-ctrls.rst | 13 +++++++------ > >>> .../userspace-api/media/v4l/vidioc-queryctrl.rst | 9 ++++++++- > >>> .../userspace-api/media/videodev2.h.rst.exceptions | 1 + > >>> drivers/media/v4l2-core/v4l2-ctrls-api.c | 5 ++++- > >>> drivers/media/v4l2-core/v4l2-ctrls-core.c | 2 ++ > >>> include/uapi/linux/videodev2.h | 1 + > >>> 6 files changed, 23 insertions(+), 8 deletions(-) > >>> > >>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst > >>> index e8475f9fd2cf..e7e5d78dc11e 100644 > >>> --- a/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst > >>> +++ b/Documentation/userspace-api/media/v4l/vidioc-g-ext-ctrls.rst > >>> @@ -162,13 +162,13 @@ still cause this situation. > >>> * - __s32 > >>> - ``value`` > >>> - New value or current value. Valid if this control is not of type > >>> - ``V4L2_CTRL_TYPE_INTEGER64`` and ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is > >>> - not set. > >>> + ``V4L2_CTRL_TYPE_INTEGER64``, ``V4L2_CTRL_TYPE_FIXED_POINT`` and > >>> + ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is not set. > >>> * - __s64 > >>> - ``value64`` > >>> - New value or current value. Valid if this control is of type > >>> - ``V4L2_CTRL_TYPE_INTEGER64`` and ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is > >>> - not set. > >>> + ``V4L2_CTRL_TYPE_INTEGER64``, ``V4L2_CTRL_TYPE_FIXED_POINT`` and > >>> + ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is not set. > >>> * - char * > >>> - ``string`` > >>> - A pointer to a string. Valid if this control is of type > >>> @@ -193,8 +193,9 @@ still cause this situation. > >>> * - __s64 * > >>> - ``p_s64`` > >>> - A pointer to a matrix control of signed 64-bit values. Valid if > >>> - this control is of type ``V4L2_CTRL_TYPE_INTEGER64`` and > >>> - ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` is set. > >>> + this control is of type ``V4L2_CTRL_TYPE_INTEGER64``, > >>> + ``V4L2_CTRL_TYPE_FIXED_POINT`` and ``V4L2_CTRL_FLAG_HAS_PAYLOAD`` > >>> + is set. > >>> * - struct :c:type:`v4l2_area` * > >>> - ``p_area`` > >>> - A pointer to a struct :c:type:`v4l2_area`. Valid if this control is > >>> diff --git a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst > >>> index 4d38acafe8e1..f3995ec57044 100644 > >>> --- a/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst > >>> +++ b/Documentation/userspace-api/media/v4l/vidioc-queryctrl.rst > >>> @@ -235,7 +235,8 @@ See also the examples in :ref:`control`. > >>> - ``default_value`` > >>> - The default value of a ``V4L2_CTRL_TYPE_INTEGER``, ``_INTEGER64``, > >>> ``_BOOLEAN``, ``_BITMASK``, ``_MENU``, ``_INTEGER_MENU``, ``_U8`` > >>> - or ``_U16`` control. Not valid for other types of controls. > >>> + ``_FIXED_POINT`` or ``_U16`` control. Not valid for other types of > >>> + controls. > >>> > >>> .. note:: > >>> > >>> @@ -549,6 +550,12 @@ See also the examples in :ref:`control`. > >>> - n/a > >>> - A struct :c:type:`v4l2_ctrl_av1_film_grain`, containing AV1 Film Grain > >>> parameters for stateless video decoders. > >>> + * - ``V4L2_CTRL_TYPE_FIXED_POINT`` > >>> + - any > >>> + - any > >>> + - any > >>> + - A 64-bit integer valued control, containing parameter which is > >>> + Q31.32 format. > >>> > >>> .. raw:: latex > >>> > >>> diff --git a/Documentation/userspace-api/media/videodev2.h.rst.exceptions b/Documentation/userspace-api/media/videodev2.h.rst.exceptions > >>> index e61152bb80d1..2faa5a2015eb 100644 > >>> --- a/Documentation/userspace-api/media/videodev2.h.rst.exceptions > >>> +++ b/Documentation/userspace-api/media/videodev2.h.rst.exceptions > >>> @@ -167,6 +167,7 @@ replace symbol V4L2_CTRL_TYPE_AV1_SEQUENCE :c:type:`v4l2_ctrl_type` > >>> replace symbol V4L2_CTRL_TYPE_AV1_TILE_GROUP_ENTRY :c:type:`v4l2_ctrl_type` > >>> replace symbol V4L2_CTRL_TYPE_AV1_FRAME :c:type:`v4l2_ctrl_type` > >>> replace symbol V4L2_CTRL_TYPE_AV1_FILM_GRAIN :c:type:`v4l2_ctrl_type` > >>> +replace symbol V4L2_CTRL_TYPE_FIXED_POINT :c:type:`v4l2_ctrl_type` > >>> > >>> # V4L2 capability defines > >>> replace define V4L2_CAP_VIDEO_CAPTURE device-capabilities > >>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-api.c b/drivers/media/v4l2-core/v4l2-ctrls-api.c > >>> index 002ea6588edf..e6a0fb8d6791 100644 > >>> --- a/drivers/media/v4l2-core/v4l2-ctrls-api.c > >>> +++ b/drivers/media/v4l2-core/v4l2-ctrls-api.c > >>> @@ -57,6 +57,7 @@ static int ptr_to_user(struct v4l2_ext_control *c, > >>> return copy_to_user(c->string, ptr.p_char, len + 1) ? > >>> -EFAULT : 0; > >>> case V4L2_CTRL_TYPE_INTEGER64: > >>> + case V4L2_CTRL_TYPE_FIXED_POINT: > >>> c->value64 = *ptr.p_s64; > >>> break; > >>> default: > >>> @@ -132,6 +133,7 @@ static int user_to_new(struct v4l2_ext_control *c, struct v4l2_ctrl *ctrl) > >>> > >>> switch (ctrl->type) { > >>> case V4L2_CTRL_TYPE_INTEGER64: > >>> + case V4L2_CTRL_TYPE_FIXED_POINT: > >>> *ctrl->p_new.p_s64 = c->value64; > >>> break; > >>> case V4L2_CTRL_TYPE_STRING: > >>> @@ -540,7 +542,8 @@ static int validate_ctrls(struct v4l2_ext_controls *cs, > >>> */ > >>> if (ctrl->is_ptr) > >>> continue; > >>> - if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64) > >>> + if (ctrl->type == V4L2_CTRL_TYPE_INTEGER64 || > >>> + ctrl->type == V4L2_CTRL_TYPE_FIXED_POINT) > >>> p_new.p_s64 = &cs->controls[i].value64; > >>> else > >>> p_new.p_s32 = &cs->controls[i].value; > >>> diff --git a/drivers/media/v4l2-core/v4l2-ctrls-core.c b/drivers/media/v4l2-core/v4l2-ctrls-core.c > >>> index a662fb60f73f..9d50df0d9874 100644 > >>> --- a/drivers/media/v4l2-core/v4l2-ctrls-core.c > >>> +++ b/drivers/media/v4l2-core/v4l2-ctrls-core.c > >>> @@ -1187,6 +1187,7 @@ static int std_validate_elem(const struct v4l2_ctrl *ctrl, u32 idx, > >>> case V4L2_CTRL_TYPE_INTEGER: > >>> return ROUND_TO_RANGE(ptr.p_s32[idx], u32, ctrl); > >>> case V4L2_CTRL_TYPE_INTEGER64: > >>> + case V4L2_CTRL_TYPE_FIXED_POINT: > >>> /* > >>> * We can't use the ROUND_TO_RANGE define here due to > >>> * the u64 divide that needs special care. > >>> @@ -1779,6 +1780,7 @@ static struct v4l2_ctrl *v4l2_ctrl_new(struct v4l2_ctrl_handler *hdl, > >>> /* Prefill elem_size for all types handled by std_type_ops */ > >>> switch ((u32)type) { > >>> case V4L2_CTRL_TYPE_INTEGER64: > >>> + case V4L2_CTRL_TYPE_FIXED_POINT: > >>> elem_size = sizeof(s64); > >>> break; > >>> case V4L2_CTRL_TYPE_STRING: > >>> diff --git a/include/uapi/linux/videodev2.h b/include/uapi/linux/videodev2.h > >>> index cf8c44595a1d..9482ac66a675 100644 > >>> --- a/include/uapi/linux/videodev2.h > >>> +++ b/include/uapi/linux/videodev2.h > >>> @@ -1903,6 +1903,7 @@ enum v4l2_ctrl_type { > >>> V4L2_CTRL_TYPE_STRING = 7, > >>> V4L2_CTRL_TYPE_BITMASK = 8, > >>> V4L2_CTRL_TYPE_INTEGER_MENU = 9, > >>> + V4L2_CTRL_TYPE_FIXED_POINT = 10, > >>> > >>> /* Compound types are >= 0x0100 */ > >>> V4L2_CTRL_COMPOUND_TYPES = 0x0100, -- Regards, Laurent Pinchart