On Sat, Jul 25, 2009 at 03:17:05PM +0200, Valentin Eduardo (Nokia-D/Helsinki)
wrote:
> On Sat, Jul 25, 2009 at 03:25:25PM +0200, ext Hans Verkuil wrote:
> > On Friday 24 July 2009 18:37:28 Eduardo Valentin wrote:
> > > This patch adds a document file for si4713 device driver.
> > > It describes the driver interfaces and organization.
> > >
> > > Signed-off-by: Eduardo Valentin <[email protected]>
> > > ---
> > > linux/Documentation/video4linux/si4713.txt | 175
> > > ++++++++++++++++++++++++++++
> > > 1 files changed, 175 insertions(+), 0 deletions(-)
> > > create mode 100644 linux/Documentation/video4linux/si4713.txt
> > >
> > > diff --git a/linux/Documentation/video4linux/si4713.txt
> > > b/linux/Documentation/video4linux/si4713.txt
> > > new file mode 100644
> > > index 0000000..3843af5
> > > --- /dev/null
> > > +++ b/linux/Documentation/video4linux/si4713.txt
> > > @@ -0,0 +1,175 @@
> > > +Driver for I2C radios for the Silicon Labs Si4713 FM Radio Transmitters
> > > +
> > > +Copyright (c) 2009 Nokia Corporation
> > > +Contact: Eduardo Valentin <[email protected]>
> > > +
> > > +
> > > +Information about the Device
> > > +============================
> > > +This chip is a Silicon Labs product. It is a I2C device, currently on
> > > 0×63 address.
> > > +Basically, it has transmission and signal noise level measurement
> > > features.
> > > +
> > > +The Si4713 integrates transmit functions for FM broadcast stereo
> > > transmission.
> > > +The chip also allows integrated receive power scanning to identify low
> > > signal
> > > +power FM channels.
> > > +
> > > +The chip is programmed using commands and responses. There are also
> > > several
> > > +properties which can change the behavior of this chip.
> > > +
> > > +Users must comply with local regulations on radio frequency (RF)
> > > transmission.
> > > +
> > > +Device driver description
> > > +=========================
> > > +There are two modules to handle this device. One is a I2C device driver
> > > +and the other is a platform driver.
> > > +
> > > +The I2C device driver exports a v4l2-subdev interface to the kernel.
> > > +All properties can also be accessed by v4l2 extended controls interface,
> > > by
> > > +using the v4l2-subdev calls (g_ext_ctrls, s_ext_ctrls).
> > > +
> > > +The platform device driver exports a v4l2 radio device interface to user
> > > land.
> > > +So, it uses the I2C device driver as a sub device in order to send the
> > > user
> > > +commands to the actual device. Basically it is a wrapper to the I2C
> > > device driver.
> > > +
> > > +Applications can use v4l2 radio API to specify frequency of operation,
> > > mute state,
> > > +etc. But mostly of its properties will be present in the extended
> > > controls.
> > > +
> > > +When the v4l2 mute property is set to 1 (true), the driver will turn the
> > > chip off.
> > > +
> > > +Properties description
> > > +======================
> > > +
> > > +The properties can be accessed using v4l2 extended controls.
> > > +Here is an output from v4l2-ctl util:
> > > +
> > > +# v4l2-ctl -d /dev/radio0 --all -l
> > > +Driver Info:
> > > + Driver name : radio-si4713
> > > + Card type : Silicon Labs Si4713 Modulator
> > > + Bus info :
> > > + Driver version: 0
> > > + Capabilities : 0x00080800
> > > + RDS Output
> > > + Modulator
> > > +Audio output: 0 (FM Modulator Audio Out)
> > > +Frequency: 1545600 (96.600000 MHz)
> > > +Video Standard = 0x00000000
> > > +Modulator:
> > > + Name : FM Modulator
> > > + Capabilities : 62.5 Hz stereo rds
> > > + Frequency range : 76.0 MHz - 108.0 MHz
> > > + Available subchannels: mono rds
> > > +
> > > +User Controls
> > > +
> > > + mute (bool) : default=1 value=0
> > > +
> > > +FM Radio Modulator Controls
> > > +
> > > + rds_program_id (int) : min=0 max=65535 step=1
> > > default=0 value=0
> > > + rds_program_type (int) : min=0 max=31 step=1 default=0
> > > value=0
> > > + rds_ps_name (str) : value='Si4713 ' len=1024
> > > +' len=1024 rds_radio_text (str) : value='Si4713
> >
> > This doesn't look right. I think this output is from an old v4l2-ctl
> > version.
> > I'd like to see this output anyway using the latest v4l2-ctl version as I
> > haven't been able to test it myself.
>
> Yeah. My bad, forgot to update here. This is the output from the older
> version.
I've just checked that now v4l2-ctl does not report rds subchannel for
txsubchannel.
Just to confirm this is something which is missing right?
In that case, I can include this minor addition also in v11.
>
> >
> > Based on this output it also looks as if the rds_radio_text string has a \r
> > at the end. If so, is it supposed to be there?
>
> Yeah, the \r it is required for Radio Text.
>
>
> >
> > Regards,
> >
> > Hans
> >
> > > + audio_limiter_feature_enabled (bool) : default=1 value=1
> > > + audio_limiter_release_time (int) : min=250 max=102390 step=50
> > > default=5010 value=5010 flags=slider
> > > + audio_limiter_deviation (int) : min=0 max=90000 step=10
> > > default=66250 value=1020 flags=slider
> > > +audio_compression_feature_enabl (bool) : default=1 value=1
> > > + audio_compression_gain (int) : min=0 max=20 step=1 default=15
> > > value=15 flags=slider
> > > + audio_compression_threshold (int) : min=-40 max=0 step=1
> > > default=-40 value=-40 flags=slider
> > > + audio_compression_attack_time (int) : min=0 max=5000 step=500
> > > default=0 value=0 flags=slider
> > > + audio_compression_release_time (int) : min=100000 max=1000000
> > > step=100000 default=1000000 value=1000000 flags=slider
> > > + pilot_tone_feature_enabled (bool) : default=1 value=1
> > > + pilot_tone_deviation (int) : min=0 max=90000 step=10
> > > default=6750 value=6750 flags=slider
> > > + pilot_tone_frequency (int) : min=0 max=19000 step=1
> > > default=19000 value=19000 flags=slider
> > > + pre_emphasis_settings (menu) : min=0 max=2 default=1 value=1
> > > + tune_power_level (int) : min=0 max=120 step=1 default=88
> > > value=120 flags=slider
> > > + tune_antenna_capacitor (int) : min=0 max=191 step=1 default=0
> > > value=112 flags=slider
> > > +
> > > +Here is a summary of them:
> > > +
> > > +* Pilot is an audible tone sent by the device.
> > > +
> > > +pilot_frequency - Configures the frequency of the stereo pilot tone.
> > > +pilot_deviation - Configures pilot tone frequency deviation level.
> > > +pilot_enabled - Enables or disables the pilot tone feature.
> > > +
> > > +* The si4713 device is capable of applying audio compression to the
> > > transmitted signal.
> > > +
> > > +acomp_enabled - Enables or disables the audio dynamic range control
> > > feature.
> > > +acomp_gain - Sets the gain for audio dynamic range control.
> > > +acomp_threshold - Sets the threshold level for audio dynamic range
> > > control.
> > > +acomp_attack_time - Sets the attack time for audio dynamic range control.
> > > +acomp_release_time - Sets the release time for audio dynamic range
> > > control.
> > > +
> > > +* Limiter setups audio deviation limiter feature. Once a over deviation
> > > occurs,
> > > +it is possible to adjust the front-end gain of the audio input and always
> > > +prevent over deviation.
> > > +
> > > +limiter_enabled - Enables or disables the limiter feature.
> > > +limiter_deviation - Configures audio frequency deviation level.
> > > +limiter_release_time - Sets the limiter release time.
> > > +
> > > +* Tuning power
> > > +
> > > +power_level - Sets the output power level for signal transmission.
> > > +antenna_capacitor - This selects the value of antenna tuning capacitor
> > > manually
> > > +or automatically if set to zero.
> > > +
> > > +* RDS related
> > > +
> > > +rds_ps_name - Sets the RDS ps name field for transmission.
> > > +rds_radio_text - Sets the RDS radio text for transmission.
> > > +rds_pi - Sets the RDS PI field for transmission.
> > > +rds_pty - Sets the RDS PTY field for transmission.
> > > +
> > > +* Region related
> > > +
> > > +preemphasis - sets the preemphasis to be applied for transmission.
> > > +
> > > +RNL
> > > +===
> > > +
> > > +This device also has an interface to measure received noise level. To do
> > > that, you should
> > > +ioctl the device node. Here is an code of example:
> > > +
> > > +int main (int argc, char *argv[])
> > > +{
> > > + struct si4713_rnl rnl;
> > > + int fd = open("/dev/radio0", O_RDWR);
> > > + int rval;
> > > +
> > > + if (argc < 2)
> > > + return -EINVAL;
> > > +
> > > + if (fd < 0)
> > > + return fd;
> > > +
> > > + sscanf(argv[1], "%d", &rnl.frequency);
> > > +
> > > + rval = ioctl(fd, SI4713_IOC_MEASURE_RNL, &rnl);
> > > + if (rval < 0)
> > > + return rval;
> > > +
> > > + printf("received noise level: %d\n", rnl.rnl);
> > > +
> > > + close(fd);
> > > +}
> > > +
> > > +The struct si4713_rnl and SI4713_IOC_MEASURE_RNL are defined under
> > > +include/media/si4713.h.
> > > +
> > > +Stereo/Mono and RDS subchannels
> > > +===============================
> > > +
> > > +The device can also be configured using the available sub channels for
> > > +transmission. To do that use S/G_MODULATOR ioctl and configure
> > > txsubchans properly.
> > > +Refer to v4l2-spec for proper use of this ioctl.
> > > +
> > > +Testing
> > > +=======
> > > +Testing is usually done with v4l2-ctl utility for managing FM tuner
> > > cards.
> > > +The tool can be found in v4l-dvb repository under v4l2-apps/util
> > > directory.
> > > +
> > > +Example for setting rds ps name:
> > > +# v4l2-ctl -d /dev/radio0 --set-ctrl=rds_ps_name="Dummy"
> > > +
> >
> >
> >
> > --
> > Hans Verkuil - video4linux developer - sponsored by TANDBERG Telecom
>
> --
> Eduardo Valentin
--
Eduardo Valentin
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