Re: Firmware for Bluetooth (and wifi)

Hi,

On 01/28/2014 11:11 AM, Arend van Spriel wrote:

On 01/27/2014 11:12 AM, Tomasz Figa wrote:

quoted

quoted

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.

quoted

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.

The usual way to solve this is to have the dts file have a list of
compatibility strings going from specific to more generic, so for ie the
wifi on the cubietruck the dts file would contain:

compatible = "brcm,bcm43362", "brcm,bcm43xx-fmac";

And then the brcmfmac driver will contain .compatible = "brcm,bcm43xx-fmac"

If we then ever need to have some specific quirks in the driver the driver
can use of_device_is_compatible(dev->of_node, "brcm,bcm43362") to check for
the 43362.

Their could even be a completely separate driver for the "brcm,bcm43362",
with brcmfmac still claiming "brcm,bcm43xx-fmac", as matching is done
from left to right, so if there is a specific driver and a more generic
one the specific driver will win (assuming both are built-in / loaded
at probe time).

TL;DR: dts file should have:
  compatible = "brcm,bcm43362", "brcm,bcm43xx-fmac";
brcmfmac should have:
  .compatible = "brcm,bcm43xx-fmac",
So that we can add device specific quirks later (if necessary).

Regards,

Hans