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List:       freebsd-hackers
Subject:    Re: Bus Driver probe and attach device
From:       Yuka Muromachi <yuka.muromachi () gmail ! com>
Date:       2005-07-22 7:59:04
Message-ID: c5c2798005072200596b85444b () mail ! gmail ! com
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It mean I have 2 way to do it? (please view the code below)

CodecPresent = az_rw(sc, AZX_REG_STATESTS);
for (idx=0; idx<AZX_MAX_CODECS; idx++)
{
    if ((CodecPresent >> idx) & 0x0001)
    {
        // alloc codec info
        // fill codec info
        device_t codec_dev = device_add_child(azbus_dev, NULL, -1);
        device_set_ivars(codec_dev, codec);

        // I can probe and attach new device self here.
        device_probe_and_attach(codec_dev);
    }
}

// Or, I can probe and attach all new child here
bus_generic_attach(azbus_dev);


05/07/22 $B$K(B takawata@jp.freebsd.org<takawata@jp.freebsd.org> \
$B$5$s$O=q$-$^$7$?(B:
> In message <c5c2798005072123385249195e@mail.gmail.com>, $B<<D.M%9a(B wrote:
> > Hi:
> > 
> > I'm trying to written Azalia (HD Audio) driver for freebsd now.
> > 
> > The HDA controller is a standard controller, which can take max> >15 codecs. I'm \
> > planning made it be a bus driver (azalia bus). 
> > I tried to read the PCI, USB and Firewire driver code be sample.
> > It looks:
> > 
> > 1. Detect codec which already connected to azalia controller.
> > 2. call device_add_child(azbus_dev, NULL, -1); to create a child
> > device, which attach to azalia bus driver.
> > 3. allocate memory to put codec info (e.g. device id, vendor id, 
> > revision..etc), and call device_set_ivars(codec_dev, codec_info);
> > save the codec_info ptr into device's ivars.
> > 4. Continue 1 ~ 3, untin all available codecs be added.
> > 
> > After all codecs be added, I call the device_probe_and_attach(azbus_dev);,
> > but there is no thing happend. 
> 
> Because it trys to attach azbus driver itself, not try to attach its child.
> 
> > Then I try to call bus_generic_attach(azbus_dev);, the codecs driver probe
> > function be called.
> 
> > Is this correct (use bus_generic_attach()), and I'm interested the detail.
> 
> Correct. It calls device_probe_and_attach() for all child you already
> add.
> 
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