Hello,
On 05/25/2011 06:13 PM, Martin Bugge (marbugge) wrote:
Hello
To be honest I became a bit disengaded after all the discussion.
What caused me a lot of problems was the request for AV link support
(which is used in SCART connectors).
Something I never plan to implement.
But after the "v4l2 Warsaw Brainstroming meeting" it was sort of approved.
It only need to be reworked to be a subdev level api.
(for that I need some help from Hans Verkuil)
But it is great that someone else also need an API for this.
I include the latest version here so you can see if you agree, and
together we will get it in.
Yes, sure.
We currently have two drivers which uses this API for CEC.
* Analog Devices adv7604
* TMS320DM8x
i want to see source code of these two drivers.From where i can get
source code of these drivers??
Thanks and Regards
Vipul Kumar Samar
At least the adv7604 is planned to be upstreamed.
Best regards
Martin Bugge
On 05/25/2011 01:52 PM, vipul kumar samar wrote:
Hello,
I am working on HDMI-CEC and planning to implement it in v4l2
framework.I came to know that a RFC is going on for the same driver.
I want to know is their any friezed version of that RFC or discussion
is still going on?? Is it included in kernel??
Thanks and Regards
Vipul Kumar Samar
--
You won't skid if you stay in a rut. -- Frank Hubbard
Author: Martin Bugge <marbu...@cisco.com>
Date: Thu, 17th of March 2011
==============================
This is a proposal for adding a Consumer Electronic Control (CEC) API to V4L2.
This document describes the changes and new ioctls needed.
Version 1.
Initial version.
Version 2.
Added support for AV.link EN 50157-2-[123].
Version 3.
Rework of mode 1.
Mode 3 is to be decided (TDB).
Minor cleanup.
Background
==========
CEC is a protocol that provides high-level control functions between various
audiovisual products.
It is an optional supplement to the High-Definition Multimedia Interface
Specification (HDMI).
In short: CEC uses pin 13 on the HDMI connector to transmit and receive small
data-packets
(maximum 16 bytes including a 1 byte header) at low data rates (~400
bits/s).
A CEC device may have any of 15 logical addresses (0 - 14).
(address 15 is broadcast and some addresses are reserved)
Physical layer is a one-wire bidirectional serial bus that uses the
industry-standard AV.link, see [3].
Due to this the proposed ioctls and events are meant to cover expansion for the
protocols in [3].
Note that AV.link mode 3 is still TBD.
References
==========
[1] High-Definition Multimedia Interface Specification version 1.3a,
Supplement 1 Consumer Electronic Control (CEC).
http://www.hdmi.org/manufacturer/specification.aspx
[2] http://www.hdmi.org/pdf/whitepaper/DesigningCECintoYourNextHDMIProduct.pdf
[3] Domestic and similar electronic equipment interconnection requirements
AV.link. EN 50157-2-[123]
Proposed solution
=================
Two new ioctls:
VIDIOC_AV_LINK_CAP (read)
VIDIOC_AV_LINK_CMD (read/write)
VIDIOC_AV_LINK_CAP:
-------------------
#define AV_LINK_CAP_MODE_CEC (1 << 0)
#define AV_LINK_CAP_MODE_1 (1 << 1)
#define AV_LINK_CAP_MODE_2 (1 << 2)
#define AV_LINK_CAP_MODE_3 (1 << 3)
Note about AV.Link Mode 3: TBD
Different manufactures might have different implementations and an option is to
have a mode per implementation.
struct vl2_av_link_cap {
__u32 capabilities;
__u32 logicaldevices;
__u32 reserved[14];
};
The capabilities field will indicate which protocols/formats this HW supports.
* AV link mode CEC:
logicaldevices: 1 -> 14, this HW supports n logical devices simultaneously.
* AV link mode 1:
logicaldevices: not used.
* AV link mode 2:
Same as AV link mode CEC.
* AV link mode 3: TBD
reserved: for future use.
VIDIOC_AV_LINK_CMD:
-------------------
The command ioctl is used both for configuration and to receive/transmit data.
/* mode 1 */
struct avl_mode1_conf {
__u32 enable;
__u32 upstream_arb_mask;
__u32 downstream_arb_mask;
};
struct avl_mode1 {
__u32 ctrl_signal_frame;
__u32 tx_frame_arb;
__u32 tx_status;
};
/* mode 2, CEC and possible mode 3 */
struct avl_conf {
__u32 enable;
__u32 index;
__u32 addr;
};
struct avl {
__u32 len;
__u8 msg[16];
__u32 tx_status;
};
struct v4l2_av_link_cmd {
__u32 command;
__u32 mode;
__u32 reserved[2];
union {
struct avl_mode1_conf avlm1_conf;
struct avl_mode1 avlm1;
struct avl_conf conf;
struct avl avl;
__u32 raw[12];
};
};
/* command */
#define V4L2_AV_LINK_CMD_CONF (1)
#define V4L2_AV_LINK_CMD_TX (2)
#define V4L2_AV_LINK_CMD_RX (3)
/* mode */
#define AV_LINK_CMD_MODE_CEC (1)
#define AV_LINK_CMD_MODE_1 (2)
#define AV_LINK_CMD_MODE_2 (3)
#define AV_LINK_CMD_MODE_3 (4)
/* Tx status */
#define V4L2_AV_LINK_STAT_TX_OK (0)
#define V4L2_AV_LINK_STAT_TX_ARB_LOST (1)
#define V4L2_AV_LINK_STAT_TX_RETRY_TIMEOUT (2)
#define V4L2_AV_LINK_STAT_TX_BROADCAST_REJECT (3)
Not every tx status is applicable for all modes, see table 1.
|-------------------------------------------------------|
| Av link Mode | CEC | 1 | 2 | 3 |
|-------------------------------------------------------|
| Status | | | | |
|-------------------------------------------------------|
| TX_OK | a | a* | a | a** |
|-------------------------------------------------------|
| TX_ARB_LOST | a | a | a | a** |
|-------------------------------------------------------|
| TX_RETRY_TIMEOUT | a | n/a | a | a** |
|-------------------------------------------------------|
| TX_BROADCAST_REJECT | a | n/a | a | a** |
|-------------------------------------------------------|
Table 1: tx status versus mode.
a: applicable
n/a: not applicable
*: TX_OK for mode 1 only imply transmit complete, no ack bit
**: mode 3 is TBD
Configuration command:
----------------------
* AV link mode CEC:
Must be done for each logical device address which is to be
enabled on this HW. Maximum number of logical devices
is found with the capability ioctl.
conf:
index: 0 -> number_of_logical_devices-1
enable: true/false
addr: logical address
* AV link mode 1:
In mode 1 the message frame length is fixed to 20 bits (excluding the
START and ESC bit).
Some of these bits (Qty 1 - 6) and /PAS and /DES can be arbitrated by
the receiver to signal modes and supported formats/standards.
conf:
enable: true/false
upstream_arb_mask:
downstream_arb_mask:
A "0" in a bit position will pull down that bit during reveive,
if that bit is allowed to be arbitrated.
|--------------------------------------------------------------------|
| Bits: | 31 - 21 | 19 | 18 | 17 | 16 | 15 -> 0 |
|--------------------------------------------------------------------|
| head bits: | x | DIR | /PAS | /NAS | /DES | Qty-1 -> Qty-16 |
|--------------------------------------------------------------------|
Table 2: Mode 1 Control signal frame (x: not used)
* AV link mode 2:
Same as AV link mode CEC.
* AV link mode 3: TBD
Tx/Rx command:
--------------
* AV link mode CEC:
len: length of message in bytes (data + header).
msg: the raw message received/transmitted.
tx_status: tx status in blocking mode.
* AV link mode 1:
Frame received/transmitted:
ctrl_signal_frame: See Table 2.
In blocking mode only:
tx_frame_arb: The resulting frame as transmitted. Will indicate which
bits was arbitrated during transmit, see Table 2.
tx_status: tx status, see Table 1.
* AV link mode 2:
len: length of message in bytes (data + command block).
msg: the raw message received/transmitted (without the start sequence).
tx_status: tx status in blocking mode.
* AV link mode 3: TBD.
len: length of message in bits, maximum 100 bits.
msg: the raw message received/transmitted. (without the start sequence).
tx_status: tx status in blocking mode.
Events
------
In the case of non-blocking mode the driver will issue the following events:
V4L2_EVENT_AV_LINK_TX
V4L2_EVENT_AV_LINK_RX
V4L2_EVENT_AV_LINK_TX
-----------------
* transmit is complete with the following status:
Add an additional struct to the struct v4l2_event
struct v4l2_event_av_link_tx {
__u32 status;
__u32 tx_mode1_frame_arb;
};
* The status field is the same as in blocking mode described above.
* The tx_mode1_frame_arb apply only to mode 1.
V4L2_EVENT_AV_LINK_RX
-----------------
* received a complete message
Use the VIDIOC_AV_LINK_CMD to read the message.
Comments ?
Martin Bugge
--
Martin Bugge - Tandberg (now a part of Cisco)
--
