Fri, 16 Mar 2012 08:28:50 -0700 от Greg KH <[email protected]>:
> You should probably take this out, along with the call below where you
> use it, as it's not needed anymore, right?
>
> > + snprintf(devname, sizeof(devname), "%s%u.%u", spi_bus_type.name,
> > + (unsigned)((dev->iobase >> 8) & 0xFF),
> > + (unsigned)(dev->iobase & 0xFF));
> > +
> > + d = bus_find_device_by_name(&spi_bus_type, NULL, devname);
> > + if (!d) {
> > + dev_err(dev->class_dev, "devices %s not found\n", devname);
> > + return -EINVAL;
> > + }
> > +
> > + priv->spi = to_spi_device(d);
>
> Is that how you register a spi device normally? I don't see any other
> SPI drivers doing this, why are you not just registering the driver with
> the bus like others do?
Because it is not an spi driver like other spi drivers are, it is based on
another common spi driver - spidev, and it is only a high level protocol driver
for ad7739 chip.
I've used platform startup code to setup platform devices.
On embedded systems chips are unlikly to be pluggable, socame to a disicion,
that it is more error safe to try to setup an ad7739 chip only for already
registered spi devices.
ad7739 device is registered from user space by issueing a command of the form:
comedi_config /dev/comedi10 ad7739 0x106
After that we can use /dev/comedi10 to work with ad7739 chip by common
functions, i.e. to get analog data from one channel with comedi_lib userspace
functions.
Comedi is a framework for common use of data acquisition purpuses from
different analog converters and digital input/outputs.
Of course, it will be more pluggable, if based spidev device will be registered
here.
I didn't find any practical needs to make it more pluggable and to register
based spidev device indeed of just searching for such a device, may be i'm
wrong.
--
Best regards,
Alexander Pazdnikov
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