From: swarren@wwwdotorg•org (Stephen Warren)
To: linux-arm-kernel@lists•infradead.org
Subject: [PATCH v1 1/9] of: Add NVIDIA Tegra XUSB mailbox binding
Date: Wed, 25 Jun 2014 17:00:03 -0600 [thread overview]
Message-ID: <53AB5473.3050204@wwwdotorg.org> (raw)
In-Reply-To: <CAL1qeaFPjq9nqA2GDZZW+=DZsddWCkUjJcnRsfPkBWj8gmFsiw@mail.gmail.com>
On 06/25/2014 04:37 PM, Andrew Bresticker wrote:
> On Wed, Jun 25, 2014 at 2:42 PM, Stephen Warren <swarren@wwwdotorg•org> wrote:
>> On 06/18/2014 12:16 AM, Andrew Bresticker wrote:
>>> Add device-tree bindings for the Tegra XUSB mailbox which will be used
>>> for communication between the Tegra XHCI controller and the host.
>>
>> Sorry for the slow review.
>>
>>> diff --git a/Documentation/devicetree/bindings/mailbox/nvidia,tegra124-xusb-mbox.txt b/Documentation/devicetree/bindings/mailbox/nvidia,tegra124-xusb-mbox.txt
>>
>>> +NVIDIA Tegra XUSB mailbox
>>> +=========================
>>> +
>>> +The Tegra XUSB mailbox is used by the Tegra XHCI controller's firmware to
>>> +communicate with the host.
>>
>> Isn't the mailbox an internal implementation detail of the XUSB controller.
>>
>> In other words, I'd naively think that there isn't a standalone generic
>> mailbox that can be used by anything, but we just happen to want to use
>> for XUSB. Rather, there's an XUSB controller, and part of the interface
>> to that controller is a mailbox.
>
> Yes, the mailbox isn't an actual piece of hardware but rather the
> interface through which the XUSB host and AP communicate.
>
>> As such, I don't think we want a standalone mailbox node in DT. Rather,
>> we should add the required reg and interrupt values into the XUSB DT node.
>>
>> The driver for that XUSB HW module can either:
>>
>> a) Register as both a mailbox driver and an EHCI driver.
>>
>> b) Spawn a child device to instantiate the mailbox driver.
>>
>> Perhaps (b) could be assisted by using the MFD framework?
>
> So in the RFC series I did something like (a) where the XUSB host
> handled the mailbox interrupt with both the PHY and host could
> registering notifiers to handle the messages. It was suggested by
> Arnd though that I make a separate mailbox driver. Instead of having
> a both a host and mailbox node, I could have a single XUSB host node
> and have the mailbox driver bind to that - thoughts?
Yes, that sounds like what I meant by (b) above. I don't think you can
actually have 2 drivers bind to the same DT node though, so it'd have to
work something like:
* XUSB host node causes a platform device to be instantiated
* XUSB host driver probe()s against that
* XUSB host driver's probe() creates a platform device for the mailbox
* XUSB mailbox driver probe()s against that.
Or, perhaps go completely MFD, and have 2 child devices (XUSB host and
XUSB mailbox) instantiated by the MFD parent, which is what is in the DT.
next prev parent reply other threads:[~2014-06-25 23:00 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-06-18 6:16 [PATCH v1 0/9] Tegra XHCI support Andrew Bresticker
2014-06-18 6:16 ` [PATCH v1 1/9] of: Add NVIDIA Tegra XUSB mailbox binding Andrew Bresticker
2014-06-25 21:42 ` Stephen Warren
2014-06-25 22:37 ` Andrew Bresticker
2014-06-25 23:00 ` Stephen Warren [this message]
2014-06-18 6:16 ` [PATCH v1 2/9] mailbox: Add NVIDIA Tegra XUSB mailbox driver Andrew Bresticker
2014-06-25 22:02 ` Stephen Warren
2014-06-25 23:07 ` Andrew Bresticker
2014-06-18 6:16 ` [PATCH v1 3/9] of: Update Tegra XUSB pad controller binding for USB Andrew Bresticker
2014-06-25 21:46 ` Stephen Warren
2014-06-25 22:25 ` Andrew Bresticker
2014-06-26 20:00 ` Stephen Warren
2014-06-18 6:16 ` [PATCH v1 4/9] pinctrl: tegra-xusb: Add USB PHY support Andrew Bresticker
2014-06-25 22:12 ` Stephen Warren
2014-06-25 23:30 ` Andrew Bresticker
2014-06-26 18:08 ` Stephen Warren
2014-06-27 21:22 ` Andrew Bresticker
2014-06-27 15:00 ` Felipe Balbi
2014-06-27 16:05 ` Stephen Warren
2014-06-18 6:16 ` [PATCH v1 5/9] of: Add NVIDIA Tegra XHCI controller binding Andrew Bresticker
2014-06-25 21:52 ` Stephen Warren
2014-06-25 23:01 ` Andrew Bresticker
2014-06-25 23:13 ` Stephen Warren
2014-06-25 21:54 ` Stephen Warren
2014-06-25 23:02 ` Andrew Bresticker
2014-06-25 23:14 ` Stephen Warren
2014-06-18 6:16 ` [PATCH v1 6/9] usb: xhci: Add NVIDIA Tegra XHCI host-controller driver Andrew Bresticker
2014-06-20 16:58 ` Julius Werner
2014-07-08 21:52 ` Andrew Bresticker
2014-07-09 14:08 ` Alan Stern
2014-07-10 10:40 ` Arnd Bergmann
2014-06-25 22:37 ` Stephen Warren
2014-06-26 0:06 ` Andrew Bresticker
2014-06-26 18:07 ` Stephen Warren
2014-06-27 21:19 ` Andrew Bresticker
2014-06-27 22:01 ` Stephen Warren
2014-06-18 6:16 ` [PATCH v1 7/9] ARM: tegra: Add Tegra124 XUSB mailbox and XHCI controller Andrew Bresticker
2014-06-18 6:16 ` [PATCH v1 8/9] ARM: tegra: jetson-tk1: Add XHCI support Andrew Bresticker
2014-06-18 6:16 ` [PATCH v1 9/9] ARM: tegra: venice2: " Andrew Bresticker
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