Re: [Letux-kernel] [PATCH RFC] bluetooth: add uart h4 devices via serdev/devicetree

Sebastian Reichel
2018-11-12T22:27:33Z

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Hi,

On Mon, Nov 12, 2018 at 10:19:02PM +0100, H. Nikolaus Schaller wrote:
> > Am 12.11.2018 um 21:59 schrieb Andreas Kemnade <andreas@kemnade.info>:
> > On Sun, 11 Nov 2018 03:46:48 +0100
> > Sebastian Reichel <sebastian.reichel@collabora.com> wrote:
> >> On Sun, Nov 11, 2018 at 12:20:34AM +0100, Andreas Kemnade wrote:
> >>> This is a first try to be able to use h4 devices specified in
> >>> the devicetree, so you do not need to call hciattach and
> >>> it can be automatically probed.
> >>>
> >>> Of course, proper devicetree bindings documentation is
> >>> missing. And also you would extend that by regulator/
> >>> enable gpio settings.
> >>>
> >>> But before proceeding further it should be checked if the
> >>> general way of doing things is right.
> >>>
> >>> Signed-off-by: Andreas Kemnade <andreas@kemnade.info>
> >>> ---
> >>
> >> Patch looks good to me, just one note
> >>
> > I found one thing myself:
> > Shouldn't we have a generic compatible string like "generic-h4".
> > ehci-platform.c has for example:
> > { .compatible = "generic-ehci", },
>
> There might be differences in h4 compatible devices (e.g. default
> baud rate) so that I would not bet there a "generic-h4" suffices
> in the long run.

My suggestion is to use this in DT:

compatible = "wi2wi,w2cbw003-bluetooth", "<something generic>";

The driver can start with supporting just the generic compatible
string. If somebody finds some incompatible differences, the driver
can add a custom handler for the wi2wi chip without breaking DT
ABI.

-- Sebastian

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