From: sebastian@breakpoint.cc (Sebastian Andrzej Siewior)
To: linux-arm-kernel@lists.infradead.org
Subject: [PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver
Date: Thu, 25 Oct 2012 12:23:01 +0200 [thread overview]
Message-ID: <20121025102301.GA3469@breakpoint.cc> (raw)
In-Reply-To: <5088399F.2000102@firmworks.com>
On Wed, Oct 24, 2012 at 08:55:27AM -1000, Mitch Bradley wrote:
> >> So by listing "usb-ehci" in its device ID table, a driver would
> >> essentially be saying that it can handle _all_ USB EHCI controllers.
>
>
> Actually, it means that the driver can handle at least USB EHCI
> controllers that are 100% compatible with the EHCI spec (requiring
> nothing extra). The driver might be able to handle almost-compatible
> controllers, possibly with the help of additional properties.
>
> If a DT node lists "usb-ehci" as a "fallback", it's not guaranteed that
> a given version of that driver will work, but it's worth a try in the
> event that no more-specific driver is matched.
Not sure fallback is a good term here. The of parses the compatible from left
to right. If the device specific entry is not found (in the driver) then end
up with usb-ehci. If we need a quirk later on we add the device specific entry
to the driver (which will match before usb-ehci is found) and we could use
this entry to apply the quirk. That way you can apply quirks without touch the
firmware / device tree.
Sebastian
WARNING: multiple messages have this Message-ID (diff)
From: Sebastian Andrzej Siewior <sebastian-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org>
To: Mitch Bradley <wmb-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org>
Cc: Stephen Warren <swarren-3lzwWm7+Weoh9ZMKESR00Q@public.gmane.org>,
Alan Stern
<stern-nwvwT67g6+6dFdvTe/nMLpVzexx5G7lz@public.gmane.org>,
Greg KH
<gregkh-hQyY1W1yCW8ekmWlsbkhG0B+6BGkLq7r@public.gmane.org>,
devicetree-discuss-uLR06cmDAlY/bJ5BZ2RsiQ@public.gmane.org,
USB list <linux-usb-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>,
Rob Herring <rob.herring-bsGFqQB8/DxBDgjK7y7TUQ@public.gmane.org>,
Sebastian Andrzej Siewior
<sebastian-E0PNVn5OA6ohrxcnuTQ+TQ@public.gmane.org>,
Florian Fainelli
<florian-p3rKhJxN3npAfugRpC6u6w@public.gmane.org>,
linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org
Subject: Re: [PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver
Date: Thu, 25 Oct 2012 12:23:01 +0200 [thread overview]
Message-ID: <20121025102301.GA3469@breakpoint.cc> (raw)
In-Reply-To: <5088399F.2000102-D5eQfiDGL7eakBO8gow8eQ@public.gmane.org>
On Wed, Oct 24, 2012 at 08:55:27AM -1000, Mitch Bradley wrote:
> >> So by listing "usb-ehci" in its device ID table, a driver would
> >> essentially be saying that it can handle _all_ USB EHCI controllers.
>
>
> Actually, it means that the driver can handle at least USB EHCI
> controllers that are 100% compatible with the EHCI spec (requiring
> nothing extra). The driver might be able to handle almost-compatible
> controllers, possibly with the help of additional properties.
>
> If a DT node lists "usb-ehci" as a "fallback", it's not guaranteed that
> a given version of that driver will work, but it's worth a try in the
> event that no more-specific driver is matched.
Not sure fallback is a good term here. The of parses the compatible from left
to right. If the device specific entry is not found (in the driver) then end
up with usb-ehci. If we need a quirk later on we add the device specific entry
to the driver (which will match before usb-ehci is found) and we could use
this entry to apply the quirk. That way you can apply quirks without touch the
firmware / device tree.
Sebastian
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next prev parent reply other threads:[~2012-10-25 10:23 UTC|newest]
Thread overview: 85+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-20 22:10 [PATCH v2 0/2] Update ehci-platform driver to support devicetree Tony Prisk
2012-10-20 22:10 ` Tony Prisk
2012-10-20 22:10 ` [PATCH v2 1/2] USB: Update EHCI-platform driver to devicetree Tony Prisk
2012-10-20 22:10 ` Tony Prisk
2012-10-21 2:02 ` Alan Stern
2012-10-21 2:02 ` Alan Stern
[not found] ` <1350771032-11527-2-git-send-email-linux-ci5G2KO2hbZ+pU9mqzGVBQ@public.gmane.org>
2012-10-22 14:51 ` Alan Stern
2012-10-20 22:10 ` [PATCH v2 2/2] USB: doc: Binding document for ehci-platform driver Tony Prisk
2012-10-20 22:10 ` Tony Prisk
2012-10-21 17:34 ` Florian Fainelli
2012-10-21 17:34 ` Florian Fainelli
2012-10-22 16:07 ` Stephen Warren
2012-10-22 16:07 ` Stephen Warren
2012-10-22 17:34 ` Alan Stern
2012-10-22 17:34 ` Alan Stern
2012-10-22 17:48 ` Stephen Warren
2012-10-22 17:48 ` Stephen Warren
2012-10-22 19:00 ` Alan Stern
2012-10-22 19:00 ` Alan Stern
2012-10-22 22:10 ` Stephen Warren
2012-10-22 22:10 ` Stephen Warren
2012-10-23 14:10 ` Alan Stern
2012-10-23 14:10 ` Alan Stern
2012-10-23 16:15 ` Stephen Warren
2012-10-23 16:15 ` Stephen Warren
2012-10-23 17:59 ` Alan Stern
2012-10-23 17:59 ` Alan Stern
2012-10-23 18:47 ` Stephen Warren
2012-10-23 18:47 ` Stephen Warren
2012-10-23 19:33 ` Alan Stern
2012-10-23 19:33 ` Alan Stern
2012-10-23 20:06 ` Rob Herring
2012-10-23 20:06 ` Rob Herring
2012-10-24 14:57 ` Alan Stern
2012-10-24 14:57 ` Alan Stern
2012-10-24 15:26 ` Sebastian Andrzej Siewior
2012-10-24 15:26 ` Sebastian Andrzej Siewior
2012-10-24 16:16 ` Stephen Warren
2012-10-24 16:16 ` Stephen Warren
2012-10-24 16:36 ` Florian Fainelli
2012-10-24 16:36 ` Florian Fainelli
2012-10-24 16:38 ` Alan Stern
2012-10-24 16:38 ` Alan Stern
2012-10-24 16:44 ` Florian Fainelli
2012-10-24 16:44 ` Florian Fainelli
2012-10-24 18:04 ` Alan Stern
2012-10-24 18:04 ` Alan Stern
2012-10-24 18:18 ` Florian Fainelli
2012-10-24 18:18 ` Florian Fainelli
2012-10-24 16:45 ` Stephen Warren
2012-10-24 16:45 ` Stephen Warren
2012-10-24 17:46 ` Alan Stern
2012-10-24 17:46 ` Alan Stern
2012-10-24 18:09 ` Stephen Warren
2012-10-24 18:09 ` Stephen Warren
2012-10-24 18:55 ` Mitch Bradley
2012-10-24 18:55 ` Mitch Bradley
2012-10-24 19:30 ` Alan Stern
2012-10-24 19:30 ` Alan Stern
2012-10-25 10:23 ` Sebastian Andrzej Siewior [this message]
2012-10-25 10:23 ` Sebastian Andrzej Siewior
2012-10-25 14:36 ` Alan Stern
2012-10-25 14:36 ` Alan Stern
2012-10-26 8:02 ` Sebastian Andrzej Siewior
2012-10-26 8:02 ` Sebastian Andrzej Siewior
2012-10-26 14:54 ` Alan Stern
2012-10-26 14:54 ` Alan Stern
2012-10-25 15:53 ` Stephen Warren
2012-10-25 15:53 ` Stephen Warren
2012-10-24 19:41 ` Alan Stern
2012-10-24 19:41 ` Alan Stern
2012-10-24 16:44 ` Alan Stern
2012-10-24 16:44 ` Alan Stern
2012-10-24 16:48 ` Stephen Warren
2012-10-24 16:48 ` Stephen Warren
2012-10-24 17:42 ` Rob Herring
2012-10-24 17:42 ` Rob Herring
2012-10-24 17:57 ` Alan Stern
2012-10-24 17:57 ` Alan Stern
2012-10-24 16:28 ` Stephen Warren
2012-10-24 16:28 ` Stephen Warren
2012-10-24 16:54 ` Alan Stern
2012-10-24 16:54 ` Alan Stern
2012-10-24 17:37 ` Florian Fainelli
2012-10-24 17:37 ` Florian Fainelli
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