.. SPDX-License-Identifier: GPL-2.0
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.. include:: <isonum.txt>
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The SI476x Driver
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=================
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Copyright |copy| 2013 Andrey Smirnov <andrew.smirnov@gmail.com>
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TODO for the driver
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-------------------
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- According to the SiLabs' datasheet it is possible to update the
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firmware of the radio chip in the run-time, thus bringing it to the
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most recent version. Unfortunately I couldn't find any mentioning of
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the said firmware update for the old chips that I tested the driver
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against, so for chips like that the driver only exposes the old
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functionality.
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Parameters exposed over debugfs
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-------------------------------
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SI476x allow user to get multiple characteristics that can be very
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useful for EoL testing/RF performance estimation, parameters that have
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very little to do with V4L2 subsystem. Such parameters are exposed via
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debugfs and can be accessed via regular file I/O operations.
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The drivers exposes following files:
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* /sys/kernel/debug/<device-name>/acf
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This file contains ACF(Automatically Controlled Features) status
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information. The contents of the file is binary data of the
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following layout:
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.. tabularcolumns:: |p{7ex}|p{12ex}|L|
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============= ============== ====================================
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Offset Name Description
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============= ============== ====================================
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0x00 blend_int Flag, set when stereo separation has
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crossed below the blend threshold
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0x01 hblend_int Flag, set when HiBlend cutoff
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frequency is lower than threshold
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0x02 hicut_int Flag, set when HiCut cutoff
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frequency is lower than threshold
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0x03 chbw_int Flag, set when channel filter
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bandwidth is less than threshold
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0x04 softmute_int Flag indicating that softmute
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attenuation has increased above
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softmute threshold
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0x05 smute 0 - Audio is not soft muted
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1 - Audio is soft muted
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0x06 smattn Soft mute attenuation level in dB
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0x07 chbw Channel filter bandwidth in kHz
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0x08 hicut HiCut cutoff frequency in units of
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100Hz
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0x09 hiblend HiBlend cutoff frequency in units
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of 100 Hz
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0x10 pilot 0 - Stereo pilot is not present
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1 - Stereo pilot is present
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0x11 stblend Stereo blend in %
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============= ============== ====================================
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* /sys/kernel/debug/<device-name>/rds_blckcnt
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This file contains statistics about RDS receptions. It's binary data
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has the following layout:
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.. tabularcolumns:: |p{7ex}|p{12ex}|L|
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============= ============== ====================================
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Offset Name Description
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============= ============== ====================================
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0x00 expected Number of expected RDS blocks
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0x02 received Number of received RDS blocks
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0x04 uncorrectable Number of uncorrectable RDS blocks
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============= ============== ====================================
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* /sys/kernel/debug/<device-name>/agc
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This file contains information about parameters pertaining to
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AGC(Automatic Gain Control)
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The layout is:
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.. tabularcolumns:: |p{7ex}|p{12ex}|L|
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============= ============== ====================================
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Offset Name Description
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============= ============== ====================================
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0x00 mxhi 0 - FM Mixer PD high threshold is
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not tripped
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1 - FM Mixer PD high threshold is
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tripped
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0x01 mxlo ditto for FM Mixer PD low
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0x02 lnahi ditto for FM LNA PD high
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0x03 lnalo ditto for FM LNA PD low
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0x04 fmagc1 FMAGC1 attenuator resistance
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(see datasheet for more detail)
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0x05 fmagc2 ditto for FMAGC2
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0x06 pgagain PGA gain in dB
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0x07 fmwblang FM/WB LNA Gain in dB
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============= ============== ====================================
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* /sys/kernel/debug/<device-name>/rsq
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This file contains information about parameters pertaining to
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RSQ(Received Signal Quality)
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The layout is:
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.. tabularcolumns:: |p{7ex}|p{12ex}|p{60ex}|
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============= ============== ====================================
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Offset Name Description
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============= ============== ====================================
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0x00 multhint 0 - multipath value has not crossed
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the Multipath high threshold
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1 - multipath value has crossed
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the Multipath high threshold
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0x01 multlint ditto for Multipath low threshold
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0x02 snrhint 0 - received signal's SNR has not
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crossed high threshold
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1 - received signal's SNR has
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crossed high threshold
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0x03 snrlint ditto for low threshold
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0x04 rssihint ditto for RSSI high threshold
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0x05 rssilint ditto for RSSI low threshold
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0x06 bltf Flag indicating if seek command
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reached/wrapped seek band limit
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0x07 snr_ready Indicates that SNR metrics is ready
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0x08 rssiready ditto for RSSI metrics
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0x09 injside 0 - Low-side injection is being used
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1 - High-side injection is used
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0x10 afcrl Flag indicating if AFC rails
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0x11 valid Flag indicating if channel is valid
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0x12 readfreq Current tuned frequency
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0x14 freqoff Signed frequency offset in units of
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2ppm
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0x15 rssi Signed value of RSSI in dBuV
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0x16 snr Signed RF SNR in dB
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0x17 issi Signed Image Strength Signal
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indicator
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0x18 lassi Signed Low side adjacent Channel
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Strength indicator
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0x19 hassi ditto fpr High side
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0x20 mult Multipath indicator
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0x21 dev Frequency deviation
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0x24 assi Adjacent channel SSI
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0x25 usn Ultrasonic noise indicator
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0x26 pilotdev Pilot deviation in units of 100 Hz
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0x27 rdsdev ditto for RDS
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0x28 assidev ditto for ASSI
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0x29 strongdev Frequency deviation
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0x30 rdspi RDS PI code
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============= ============== ====================================
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* /sys/kernel/debug/<device-name>/rsq_primary
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This file contains information about parameters pertaining to
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RSQ(Received Signal Quality) for primary tuner only. Layout is as
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the one above.
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