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/
/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/
/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/
/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/
/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 | Singed 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 | Adjascent 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/
/rsq_primary
This file contains information about parameters pertaining to
RSQ(Received Signal Quality) for primary tuner only. Layout is as
the one above.
