radio(9) - NetBSD Manual Pages

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RADIO(9)               NetBSD Kernel Developer's Manual               RADIO(9)


NAME

     radio -- interface between low- and high-level FM radio drivers


SYNOPSIS

     #include <dev/radio_if.h>

     device_t
     radio_attach_mi(const struct radio_hw_if *rhwp, void *hdlp,
         device_t dev);


DESCRIPTION

     The radio layer provides support for digitally programmable FM radio
     tuners.

     It is divided into a machine independent, high-level part responsible for
     managing device files, and low-level hardware drivers.

     The high-level radio driver attaches to the low-level driver when the
     latter calls radio_attach_mi().

     The radio_hw_if struct contains pointers to functions provided by the
     low-level driver.  The hdlp argument is a handle to a low-level driver's
     softc structure.  It is sent as the first argument to all the functions
     in radio_hw_if when the high-level driver calls them.  dev is the device
     struct for the hardware device.

     The fields of radio_hw_if are described in some more detail below.

     struct radio_hw_if {
             int     (*open)(void *, int, int, struct lwp *);
             int     (*close)(void *, int, int, struct lwp *);
             int     (*get_info)(void *, struct radio_info *);
             int     (*set_info)(void *, struct radio_info *);
             int     (*search)(void *, int);
     };

     (*open)(sc, flags, fmt, lwp)
           Called when the radio device is opened.  Optionally, if there is no
           need to call a driver's function when the device file is opened,
           NULL should be passed in this field.  Returns 0 on success, other-
           wise an error code.

     (*close)(sc, flags, fmt, lwp)
           Called when the radio device is closed.  Optionally, if there is no
           need to call a driver's function when the device file is closed,
           NULL should be passed in thie field.  Returns 0 on success, other-
           wise an error code.

     (*get_info)(sc, ri)
           Fills the radio_info struct.  This function is used to obtain the
           current state of a hardware device.  It is executed as a result of
           calling RIOCGINFO on a device file managed by the high-level
           driver.  Returns 0 on success, otherwise an error code.

     (*set_info)(sc, ri)
           Set values from the radio_info struct.  This function is used to
           modify the current state of a hardware device (enable/disable vari-
           ous modes and parameters).  It is executed as a result of calling
           RIOCSINFO on a device file managed by the high-level driver.
           Returns 0 on success, otherwise an error code.

     (*search)(sc, ri)
           Initiates automatic search for the radio station.  It is executed
           as a result of calling RIOCSSRCH on a device file managed by the
           high-level driver.  Returns 0 on success, otherwise an error code.


SEE ALSO

     radio(4)


AUTHORS

     The radio API was written by Vladimir Popov and Maxim Tsyplakov for
     OpenBSD and ported to NetBSD by Lennart Augustsson.

NetBSD 9.4_STABLE                July 9, 2018                NetBSD 9.4_STABLE