Copyright © 2013 Andrey Smirnov <andrew.smirnov@gmail.com>
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.