.. SPDX-License-Identifier: GPL-2.0
.. include:: <isonum.txt>
The SI476x Driver
=================
Copyright |copy| 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:
.. tabularcolumns:: |p{7ex}|p{12ex}|L|
============= ============== ====================================
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:
.. tabularcolumns:: |p{7ex}|p{12ex}|L|
============= ============== ====================================
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:
.. tabularcolumns:: |p{7ex}|p{12ex}|L|
============= ============== ====================================
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:
.. tabularcolumns:: |p{7ex}|p{12ex}|p{60ex}|
============= ============== ====================================
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 for 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.