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Diffstat (limited to 'Documentation/media/v4l-drivers/si476x.rst')
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diff --git a/Documentation/media/v4l-drivers/si476x.rst b/Documentation/media/v4l-drivers/si476x.rst new file mode 100644 index 000000000000..d5c07bb7524d --- /dev/null +++ b/Documentation/media/v4l-drivers/si476x.rst @@ -0,0 +1,150 @@ +.. 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: + + ============= ============== ==================================== + 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. |