From: Andrew Lunn <andrew@lunn.ch>
To: Johannes Berg <johannes@sipsolutions.net>
Cc: netdev@vger.kernel.org, linux-wireless@vger.kernel.org,
Alex Elder <elder@linaro.org>,
m.chetan.kumar@intel.com, Dan Williams <dcbw@redhat.com>,
Bjorn Andersson <bjorn.andersson@linaro.org>,
Johannes Berg <johannes.berg@intel.com>
Subject: Re: [RFC] wwan: add a new WWAN subsystem
Date: Tue, 25 Feb 2020 16:15:21 +0100 [thread overview]
Message-ID: <20200225151521.GA7663@lunn.ch> (raw)
In-Reply-To: <20200225105149.59963c95aa29.Id0e40565452d0d5bb9ce5cc00b8755ec96db8559@changeid>
> One issue in comining up with the notion of a "WWAN device" is that
> a typical WWAN device (especially USB ones) is not composed of just
> a single function, but may have one or multiple network functions,
> some TTYs for control, etc. These are actually not even seen by a
> single driver in Linux, but various. An additional wrinkle is that
> each of those drivers will not be aware of the others, and also be
> a driver for a generic network or TTY device (for example), so by
> itself it cannot even know it's dealing with a unified WWAN device.
>
> To still achieve a unified model, we allow each WWAN device to be
> composed of "component devices". Each component device can offer a
> certain subset of the overall functionality (which is shown in the
> struct wwan_component_device_ops). This isn't implemented right now,
> but ultimately it will allow us to have a "tentative" state, where
> a number component drivers register their component, but the full
> WWAN device is only formed if any one of them says that it indeed
> knows for sure that it's a piece of a WWAN device, or perhaps by
> some other heuristic.
Hi Johannes
Looking at it bottom up, is the WWAN device itself made up of multiple
devices? Are the TTYs separate drivers to the packet moving engines?
They have there own USB end points, and could just be standard CDC
ACM?
driver/base/component.c could be useful for bringing together these
individual devices to form the whole WWAN device. This is often used
for graphics drivers, where there can be i2c devices, display pipeline
devices, acceleration drivers etc, which each probe separately, but
need to be brought together to form a gpu driver as a whole.
Plus you need to avoid confusion by not adding another "component
framework" which means something totally different to the existing
component framework.
Andrew
next prev parent reply other threads:[~2020-02-25 15:15 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-02-25 10:00 [RFC] wwan subsystem Johannes Berg
2020-02-25 10:00 ` [RFC] wwan: add a new WWAN subsystem Johannes Berg
2020-02-25 15:15 ` Andrew Lunn [this message]
2020-02-25 15:39 ` Johannes Berg
2020-02-26 22:15 ` Dan Williams
2020-03-02 13:06 ` Johannes Berg
2020-02-25 19:00 ` David Miller
2020-02-25 19:40 ` Johannes Berg
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