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Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface

From Heikki Krogerus <heikki.krogerus@linux.intel.com>
Newsgroups linux.kernel
Subject Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface
Date 2016-02-10 11:40 +0100
Message-ID <r0AlI-YK-5@gated-at.bofh.it> (permalink)
References <r0jXz-76q-5@gated-at.bofh.it> <r0jXB-76q-39@gated-at.bofh.it> <r0lcZ-7On-1@gated-at.bofh.it>
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On Tue, Feb 09, 2016 at 10:21:55AM -0800, Greg KH wrote:
> On Tue, Feb 09, 2016 at 07:01:22PM +0200, Heikki Krogerus wrote:
> > USB Type-C Connector System Software Interface (UCSI) is a
> > specification that defines registers and data structures
> > used to interface with the USB Type-C connectors on a system.
> > 
> > The specification is public and available at:
> > http://www.intel.com/content/www/us/en/io/universal-serial-bus/usb-type-c-ucsi-spec.html
> > 
> 
> What does this driver / code actually do?  Why is it needed?  What
> interface to the rest of the kernel / userspace does it provide?

I will fix this describe these things in the commit message. I'll just
but some UCSI background in case somebody is interested. So UCSI is in
practice a standard for USB Type-C controllers..

UCSI is the control interface for USB Type-C connectors (regardless
was USB PD supported or not) in MS Windows, so most likely all new HW
platforms designed to work also with Windows that are equipped with
USB Type-C will have UCSI device for controlling the USB Type-C ports.
In some cases the hardware for Type-C will be just a PHY like fusb30x
on these platforms (it's cheaper then USB PD or complete USB Type-C
controller), but in those cases the PHY is probable attached to an EC
or is completely controlled by system FW like BIOS together with any
USB PD communication in cases where USB PD is supported, and is in any
case not visible to the OS. Instead UCSI device is exposed to the OS
to give it means to apply its policies to the USB Type-C port.

> Why would we care about this?

I'll try to explain why it's important to export the control of USB
Type-C ports to the user space in my answer to your comments to the
first patch of this series, the one introducing the class.

But surely everybody agrees that decision about the policies regarding
USB Type-C ports, like which data role to use, do we charge or are we
letting the other end charge, etc., belongs to the user? If you plug
your phone to your desktop, I would imagine that you want to see the
phone primarily as the USB device and the desktop as host, and to
achieve the device role, you don't want to be forced to unplug/replug
your phone from the desktop until you achieve device role, right?

> You need to describe this a lot better than you did...

Sure thing. I'm sorry about the poor description. I send these out too
hastily.


Thanks,

-- 
heikki

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[PATCH 0/3] usb: USB Type-C Class and driver for UCSI Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-09 18:10 +0100
  [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-09 18:10 +0100
    Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Greg KH <gregkh@linuxfoundation.org> - 2016-02-09 19:30 +0100
      Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-10 11:40 +0100
        Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Greg KH <gregkh@linuxfoundation.org> - 2016-02-10 18:30 +0100
          Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-11 15:10 +0100
            Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-15 16:40 +0100
              Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-16 10:30 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-16 14:50 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-17 09:00 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-17 10:10 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Felipe Balbi <balbif@gmail.com> - 2016-02-17 11:40 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-17 11:40 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-17 12:20 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Felipe Balbi <balbi@kernel.org> - 2016-02-17 14:40 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-17 15:30 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Peter Chen <hzpeterchen@gmail.com> - 2016-02-18 10:20 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-18 11:50 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Rajaram R <rajaram.officemail@gmail.com> - 2016-02-18 11:40 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-18 11:50 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Rajaram R <rajaram.officemail@gmail.com> - 2016-02-18 12:10 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Felipe Balbi <balbi@kernel.org> - 2016-02-17 14:40 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-17 15:00 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Felipe Balbi <balbif@gmail.com> - 2016-02-18 08:10 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-18 11:30 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Felipe Balbi <balbif@gmail.com> - 2016-02-18 11:40 +0100
                Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-18 11:50 +0100
        Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Peter Chen <hzpeterchen@gmail.com> - 2016-02-18 10:40 +0100
          Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-18 10:50 +0100
    Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-10 12:30 +0100
      Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-10 13:10 +0100
    Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-02-10 13:00 +0100
      Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-10 14:30 +0100
        Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-02-10 15:10 +0100
          Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Bjørn Mork <bjorn@mork.no> - 2016-02-10 16:20 +0100
            Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-02-11 09:30 +0100
              Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Bjørn Mork <bjorn@mork.no> - 2016-02-11 10:10 +0100
      Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-10 15:20 +0100
        Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-02-10 15:30 +0100
          Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.de> - 2016-02-10 16:20 +0100
            Fwd: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software Interface Andy Shevchenko <andy.shevchenko@gmail.com> - 2016-02-11 09:20 +0100
              Re: Fwd: [PATCH 2/3] usb: type-c: USB Type-C Connector System  Software Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-11 15:20 +0100
    Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Oliver Neukum <oneukum@suse.com> - 2016-02-10 14:10 +0100
      Re: [PATCH 2/3] usb: type-c: USB Type-C Connector System Software  Interface Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-11 15:10 +0100
  [PATCH 3/3] usb: type-c: UCSI ACPI driver Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-09 18:10 +0100
    Re: [PATCH 3/3] usb: type-c: UCSI ACPI driver Greg KH <gregkh@linuxfoundation.org> - 2016-02-09 19:30 +0100
      Re: [PATCH 3/3] usb: type-c: UCSI ACPI driver Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-10 11:30 +0100
  Re: [PATCH 0/3] usb: USB Type-C Class and driver for UCSI Oliver Neukum <oneukum@suse.com> - 2016-02-17 20:00 +0100
    Re: [PATCH 0/3] usb: USB Type-C Class and driver for UCSI Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-18 10:30 +0100
  Re: [PATCH 0/3] usb: USB Type-C Class and driver for UCSI Rajaram R <rajaram.officemail@gmail.com> - 2016-02-17 20:40 +0100
    Re: [PATCH 0/3] usb: USB Type-C Class and driver for UCSI Heikki Krogerus <heikki.krogerus@linux.intel.com> - 2016-02-18 12:10 +0100
      Re: [PATCH 0/3] usb: USB Type-C Class and driver for UCSI Oliver Neukum <oneukum@suse.com> - 2016-02-18 12:20 +0100

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