From: Guenter Roeck <linux@roeck-us.net>
To: Peter Chen <peter.chen@nxp.com>,
Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Peter Chen <hzpeterchen@gmail.com>,
Greg KH <gregkh@linuxfoundation.org>,
Felipe Balbi <felipe.balbi@linux.intel.com>,
Oliver Neukum <oneukum@suse.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-usb@vger.kernel.org" <linux-usb@vger.kernel.org>,
Roger Quadros <rogerq@ti.com>, Jun Li <jun.li@nxp.com>
Subject: Re: [PATCH v17 2/3] usb: USB Type-C connector class
Date: Wed, 8 Mar 2017 06:44:47 -0800 [thread overview]
Message-ID: <055d6289-c728-30bb-279e-65e08be5e538@roeck-us.net> (raw)
In-Reply-To: <HE1PR04MB145053A5B07D66602ADEAB928B2E0@HE1PR04MB1450.eurprd04.prod.outlook.com>
On 03/07/2017 10:50 PM, Peter Chen wrote:
>
>>>> You mean type-C trigger an ACPI event, and this ACPI event can notify
>>>> related USB controller driver doing role switch?
>>>
>>> No (firmware programs the dual-role hw/registers), but never mind.
>>> That could be the case.
>>>
>>>> If it is correct, there is a notifier between type-C and USB
>>>> controller driver, how to define this notifier for non-ACPI platform?
>>>
>>> Once there is a platform with Type-C like that, the problem needs to
>>> be solved. However..
>>>
>>>>> I'm not commenting on Roger's dual role patch series, but I don't
>>>>> really think it should be mixed with Type-C. USB Type-C and USB
>>>>> Power Delivery define their own ways of handling the roles, and they
>>>>> are not limited to the data role only. Things like OTG for example
>>>>> will, and actually can not be supported. With Type-C we will have
>>>>> competing state machines compared to OTG. The dual-role framework
>>>>> may be useful on systems that provide more traditional connectors,
>>>>> which possibly have the ID-pin like micro-AB, and possibly also
>>>>> support OTG. It can also be something that exist in parallel with the Type-C
>> class, but there just can not be any dependencies between the two.
>>>>>
>>>>
>>>> Yes, there are two independent things. But if the kernel doesn't have
>>>> a notifier between type-C message sender (type-c class) and message
>>>> receiver (like USB controller driver for role switch or other drivers
>>>> for alternate mode message), we had to find some ways at userspace.
>>>
>>> ..what ever the solution is, it really can't rely on user space.
>>>
>>
>> ... and, at least for our application, using extcon for the necessary notifications works
>> just fine.
>>
>
> I see, that means you have a hardware signal to notify role switch.
>
In our case the Type-C protocol manager (including alternate mode handling)
is implemented in an EC. The EC signals the extcon-cros_ec driver, which
in turn signals the phy driver as well as the DP driver. The Type-C class
is orthogonal; extcon-cros_ec will also register with the Type-C class code
once that is upstream.
As mentioned earlier, using extcon for signaling was the most convenient means
for us to pass events around. I am more than open to change it to a bus,
if that can be made to work - we'd have to keep in mind though that this code
already works without Type-C infrastructure and is for the most part already
upstream (the rk3399 code it ties into is upstream, and extcon-cros_ec has been
submitted as https://patchwork.kernel.org/patch/9583045/).
As for to how to handle alternate mode if the Type-C protocol manager
(TCPM) is implemented in the kernel - I have not yet implemented it yet,
but my thinking goes along the line described by Heikki in his last e-mail.
Note that we also have a kernel driver for FUSB302 which ties into my tcpm
driver. I'll have to check if that is public yet and if I or someone
else can publish it if there is interest.
Guenter
next prev parent reply other threads:[~2017-03-08 14:45 UTC|newest]
Thread overview: 64+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-02-21 14:24 [PATCH v17 0/3] USB Type-C Connector class Heikki Krogerus
2017-02-21 14:24 ` [PATCH v17 1/3] lib/string: add sysfs_match_string helper Heikki Krogerus
2017-02-21 14:24 ` [PATCH v17 2/3] usb: USB Type-C connector class Heikki Krogerus
2017-03-02 15:22 ` Mats Karrman
2017-03-03 3:13 ` Guenter Roeck
2017-03-03 7:29 ` Mats Karrman
2017-03-03 9:48 ` Enric Balletbo Serra
2017-03-03 12:59 ` Heikki Krogerus
2017-03-03 14:49 ` Guenter Roeck
2017-03-03 19:27 ` Mats Karrman
2017-03-06 9:37 ` Oliver Neukum
2017-03-06 13:14 ` Heikki Krogerus
2017-03-07 22:30 ` Mats Karrman
2017-03-08 1:38 ` Guenter Roeck
2017-04-08 23:09 ` USB Type-C Port Manager API concern Mats Karrman
2017-04-09 15:16 ` Guenter Roeck
2017-04-09 21:05 ` Mats Karrman
2017-04-14 2:57 ` Guenter Roeck
2017-04-14 8:30 ` Mats Karrman
2017-03-08 13:58 ` [PATCH v17 2/3] usb: USB Type-C connector class Heikki Krogerus
2017-03-10 22:22 ` Mats Karrman
2017-03-10 23:41 ` Guenter Roeck
2017-04-18 18:52 ` Badhri Jagan Sridharan
2017-04-19 11:23 ` Heikki Krogerus
2017-04-19 14:45 ` Badhri Jagan Sridharan
2017-04-19 15:14 ` Guenter Roeck
2017-04-19 17:22 ` Badhri Jagan Sridharan
2017-04-19 19:29 ` Guenter Roeck
2017-04-20 12:24 ` Heikki Krogerus
2017-04-20 19:46 ` Badhri Jagan Sridharan
2017-04-21 12:12 ` Heikki Krogerus
2017-04-21 13:14 ` Guenter Roeck
2017-04-21 14:27 ` Rajaram R
2017-04-21 16:43 ` Guenter Roeck
2017-04-22 9:23 ` Rajaram R
2017-04-24 17:50 ` Badhri Jagan Sridharan
2017-04-25 8:26 ` Rajaram R
2017-04-25 14:10 ` Guenter Roeck
2017-04-27 6:20 ` Rajaram R
2017-04-27 18:10 ` Guenter Roeck
2017-04-28 10:52 ` Heikki Krogerus
2017-04-20 11:55 ` Heikki Krogerus
2017-03-03 14:41 ` Guenter Roeck
2017-03-03 3:35 ` Peter Chen
2017-03-03 4:29 ` Guenter Roeck
2017-03-03 4:52 ` Peter Chen
2017-03-03 14:36 ` Guenter Roeck
2017-03-06 1:24 ` Peter Chen
2017-03-03 14:31 ` Heikki Krogerus
2017-03-06 1:15 ` Peter Chen
2017-03-06 13:16 ` Heikki Krogerus
2017-03-07 1:36 ` Peter Chen
2017-03-07 8:57 ` Heikki Krogerus
2017-03-08 1:53 ` Guenter Roeck
2017-03-08 6:50 ` Peter Chen
2017-03-08 14:44 ` Guenter Roeck [this message]
2017-03-09 2:00 ` Peter Chen
2017-02-21 14:24 ` [PATCH v17 3/3] usb: typec: add driver for Intel Whiskey Cove PMIC USB Type-C PHY Heikki Krogerus
2017-02-21 15:42 ` [PATCH v17 0/3] USB Type-C Connector class Felipe Balbi
2017-03-21 11:14 ` Heikki Krogerus
2017-03-21 10:23 ` Greg KH
2017-03-21 10:37 ` Heikki Krogerus
2017-03-22 21:15 ` Mats Karrman
2017-03-23 8:16 ` Heikki Krogerus
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