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- Documentation
- video4linux
- si476x.txt
SI476x Driver Readme
------------------------------------------------
Copyright (C) 2013 Andrey Smirnov <andrew.smirnov@gmail.com>
TODO for the driver
------------------------------
- According to the SiLabs' datasheet it is possible to update the
firmware of the radio chip in the run-time, thus bringing it to the
most recent version. Unfortunately I couldn't find any mentioning of
the said firmware update for the old chips that I tested the driver
against, so for chips like that the driver only exposes the old
functionality.
Parameters exposed over debugfs
-------------------------------
SI476x allow user to get multiple characteristics that can be very
useful for EoL testing/RF performance estimation, parameters that have
very little to do with V4L2 subsystem. Such parameters are exposed via
debugfs and can be accessed via regular file I/O operations.
The drivers exposes following files:
* /sys/kernel/debug/<device-name>/acf
This file contains ACF(Automatically Controlled Features) status
information. The contents of the file is binary data of the
following layout:
Offset | Name | Description
====================================================================
0x00 | blend_int | Flag, set when stereo separation has
| | crossed below the blend threshold
--------------------------------------------------------------------
0x01 | hblend_int | Flag, set when HiBlend cutoff
| | frequency is lower than threshold
--------------------------------------------------------------------
0x02 | hicut_int | Flag, set when HiCut cutoff
| | frequency is lower than threshold
--------------------------------------------------------------------
0x03 | chbw_int | Flag, set when channel filter
| | bandwidth is less than threshold
--------------------------------------------------------------------
0x04 | softmute_int | Flag indicating that softmute
| | attenuation has increased above
| | softmute threshold
--------------------------------------------------------------------
0x05 | smute | 0 - Audio is not soft muted
| | 1 - Audio is soft muted
--------------------------------------------------------------------
0x06 | smattn | Soft mute attenuation level in dB
--------------------------------------------------------------------
0x07 | chbw | Channel filter bandwidth in kHz
--------------------------------------------------------------------
0x08 | hicut | HiCut cutoff frequency in units of
| | 100Hz
--------------------------------------------------------------------
0x09 | hiblend | HiBlend cutoff frequency in units
| | of 100 Hz
--------------------------------------------------------------------
0x10 | pilot | 0 - Stereo pilot is not present
| | 1 - Stereo pilot is present
--------------------------------------------------------------------
0x11 | stblend | Stereo blend in %
--------------------------------------------------------------------
* /sys/kernel/debug/<device-name>/rds_blckcnt
This file contains statistics about RDS receptions. It's binary data
has the following layout:
Offset | Name | Description
====================================================================
0x00 | expected | Number of expected RDS blocks
--------------------------------------------------------------------
0x02 | received | Number of received RDS blocks
--------------------------------------------------------------------
0x04 | uncorrectable | Number of uncorrectable RDS blocks
--------------------------------------------------------------------
* /sys/kernel/debug/<device-name>/agc
This file contains information about parameters pertaining to
AGC(Automatic Gain Control)
The layout is:
Offset | Name | Description
====================================================================
0x00 | mxhi | 0 - FM Mixer PD high threshold is
| | not tripped
| | 1 - FM Mixer PD high threshold is
| | tripped
--------------------------------------------------------------------
0x01 | mxlo | ditto for FM Mixer PD low
--------------------------------------------------------------------
0x02 | lnahi | ditto for FM LNA PD high
--------------------------------------------------------------------
0x03 | lnalo | ditto for FM LNA PD low
--------------------------------------------------------------------
0x04 | fmagc1 | FMAGC1 attenuator resistance
| | (see datasheet for more detail)
--------------------------------------------------------------------
0x05 | fmagc2 | ditto for FMAGC2
--------------------------------------------------------------------
0x06 | pgagain | PGA gain in dB
--------------------------------------------------------------------
0x07 | fmwblang | FM/WB LNA Gain in dB
--------------------------------------------------------------------
* /sys/kernel/debug/<device-name>/rsq
This file contains information about parameters pertaining to
RSQ(Received Signal Quality)
The layout is:
Offset | Name | Description
====================================================================
0x00 | multhint | 0 - multipath value has not crossed
| | the Multipath high threshold
| | 1 - multipath value has crossed
| | the Multipath high threshold
--------------------------------------------------------------------
0x01 | multlint | ditto for Multipath low threshold
--------------------------------------------------------------------
0x02 | snrhint | 0 - received signal's SNR has not
| | crossed high threshold
| | 1 - received signal's SNR has
| | crossed high threshold
--------------------------------------------------------------------
0x03 | snrlint | ditto for low threshold
--------------------------------------------------------------------
0x04 | rssihint | ditto for RSSI high threshold
--------------------------------------------------------------------
0x05 | rssilint | ditto for RSSI low threshold
--------------------------------------------------------------------
0x06 | bltf | Flag indicating if seek command
| | reached/wrapped seek band limit
--------------------------------------------------------------------
0x07 | snr_ready | Indicates that SNR metrics is ready
--------------------------------------------------------------------
0x08 | rssiready | ditto for RSSI metrics
--------------------------------------------------------------------
0x09 | injside | 0 - Low-side injection is being used
| | 1 - High-side injection is used
--------------------------------------------------------------------
0x10 | afcrl | Flag indicating if AFC rails
--------------------------------------------------------------------
0x11 | valid | Flag indicating if channel is valid
--------------------------------------------------------------------
0x12 | readfreq | Current tuned frequency
--------------------------------------------------------------------
0x14 | freqoff | Signed frequency offset in units of
| | 2ppm
--------------------------------------------------------------------
0x15 | rssi | Signed value of RSSI in dBuV
--------------------------------------------------------------------
0x16 | snr | Signed RF SNR in dB
--------------------------------------------------------------------
0x17 | issi | Signed Image Strength Signal
| | indicator
--------------------------------------------------------------------
0x18 | lassi | Signed Low side adjacent Channel
| | Strength indicator
--------------------------------------------------------------------
0x19 | hassi | ditto fpr High side
--------------------------------------------------------------------
0x20 | mult | Multipath indicator
--------------------------------------------------------------------
0x21 | dev | Frequency deviation
--------------------------------------------------------------------
0x24 | assi | Adjacent channel SSI
--------------------------------------------------------------------
0x25 | usn | Ultrasonic noise indicator
--------------------------------------------------------------------
0x26 | pilotdev | Pilot deviation in units of 100 Hz
--------------------------------------------------------------------
0x27 | rdsdev | ditto for RDS
--------------------------------------------------------------------
0x28 | assidev | ditto for ASSI
--------------------------------------------------------------------
0x29 | strongdev | Frequency deviation
--------------------------------------------------------------------
0x30 | rdspi | RDS PI code
--------------------------------------------------------------------
* /sys/kernel/debug/<device-name>/rsq_primary
This file contains information about parameters pertaining to
RSQ(Received Signal Quality) for primary tuner only. Layout is as
the one above.