Re: Firmware for Bluetooth (and wifi)

[Arend van Spriel <arend-dY08KVG/lbpWk0Htik3J/w@public.gmane.org>]

On 01/27/2014 11:12 AM, Tomasz Figa wrote:
>> The brcmfmac driver that consumes these DT nodes will have a closer look
>> at the device obtaining the chipid during the probe and determine if it
>> can support it. So the compatible string indicates that the device needs
>> a so-called fullmac wireless driver opposed to a mac80211 aka. softmac
>> wireless driver.
> 
> The compatible string should guarantee that the chip ID register holds a
> valid value, so just "wifi-fullmac" or "brcmfmac" sounds too generic to

I am not sure I understand this requirement. Is the DT node claimed
somehow after of_find_matching_node() and unavailable to other drivers.

> me. The string must specify the family of chips with this chip ID scheme
> in a reasonably precise way. "brcm,bcm43xx-fmac" maybe? I still see a
> risk of, say, BCM43999 showing up, which would be a completely different
> chip. while having the model matching the pattern.

If a completely different chip, ie. BCM43999, shows up in a board the
device tree should not use "brcm,bcm43xx-fmac". That would be an error
in the dts file, right? All the devices listed in your bindings patch
are treated the same, ie. *compatible* on DT level and hence can have
the same compatible property.

In my opinion that is what the compatible property is about. It
identifies how a specific category of devices is accessed/configured. As
an example please see [1]. It shows one compatible string for a binding
that is used for different MPIC controllers.

Just to be clear, I like your suggestion to use "brcm,bcm43xx-fmac", but
felt you did not so added my explanation/point of view.

Regards,
Arend

[1] Documentation/devicetree/bindings/powerpc/fsl/mpic.txt