From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from mail.kapsi.fi ([217.30.184.167]:49869 "EHLO mail.kapsi.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751502AbaAORZb (ORCPT ); Wed, 15 Jan 2014 12:25:31 -0500 Message-ID: <52D6C488.5090207@iki.fi> Date: Wed, 15 Jan 2014 19:25:28 +0200 From: Antti Palosaari MIME-Version: 1.0 To: Hans Verkuil CC: linux-media@vger.kernel.org, Mauro Carvalho Chehab Subject: Re: [PATCH RFC v6 07/12] v4l: add device capability flag for SDR receiver References: <1388289844-2766-1-git-send-email-crope@iki.fi> <1388289844-2766-8-git-send-email-crope@iki.fi> <52C94C51.2010005@xs4all.nl> <52D49691.4000405@iki.fi> In-Reply-To: <52D49691.4000405@iki.fi> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-media-owner@vger.kernel.org List-ID: On 14.01.2014 03:44, Antti Palosaari wrote: > On 05.01.2014 14:13, Hans Verkuil wrote: >> On 12/29/2013 05:03 AM, Antti Palosaari wrote: >>> VIDIOC_QUERYCAP IOCTL is used to query device capabilities. Add new >>> capability flag to inform given device supports SDR capture. >>> >>> Cc: Hans Verkuil >>> Signed-off-by: Antti Palosaari >>> Acked-by: Hans Verkuil >>> --- >>> include/uapi/linux/videodev2.h | 2 ++ >>> 1 file changed, 2 insertions(+) >>> >>> diff --git a/include/uapi/linux/videodev2.h >>> b/include/uapi/linux/videodev2.h >>> index c50e449..f596b7b 100644 >>> --- a/include/uapi/linux/videodev2.h >>> +++ b/include/uapi/linux/videodev2.h >>> @@ -267,6 +267,8 @@ struct v4l2_capability { >>> #define V4L2_CAP_RADIO 0x00040000 /* is a radio device */ >>> #define V4L2_CAP_MODULATOR 0x00080000 /* has a modulator */ >>> >>> +#define V4L2_CAP_SDR_CAPTURE 0x00100000 /* Is a SDR capture >>> device */ >>> + >>> #define V4L2_CAP_READWRITE 0x01000000 /* read/write >>> systemcalls */ >>> #define V4L2_CAP_ASYNCIO 0x02000000 /* async I/O */ >>> #define V4L2_CAP_STREAMING 0x04000000 /* streaming >>> I/O ioctls */ >>> >> >> This new capability needs to be documented in DocBook as well >> (vidioc-querycap.xml). > > It is already. There is following related flags: V4L2_CAP_TUNER V4L2_CAP_RADIO V4L2_CAP_MODULATOR V4L2_CAP_SDR_CAPTURE V4L2_CAP_TUNER flag is overlapping with all these and is redundant at least currently. Lets take a example as a radio device. There is V4L2_CAP_RADIO flag to say it is radio and then there is flag V4L2_CAP_TUNER which means signal is coming from antenna? So there could be radio device without V4L2_CAP_TUNER flag, for example radio over IP, right? Due to that I started thinking relation of V4L2_CAP_SDR_CAPTURE and V4L2_CAP_TUNER and V4L2_CAP_RADIO flags. ADC is pretty much mandatory element of SDR receiver (and DAC SDR transmitter). Whilst ADC is mandatory, RF tuner is not. So should I map V4L2_CAP_TUNER to indicate there is RF tuner? regards Antti -- http://palosaari.fi/