From: Puma Hsu <pumahsu@google.com>
To: Heikki Krogerus <heikki.krogerus@linux.intel.com>
Cc: Guenter Roeck <linux@roeck-us.net>,
Greg KH <gregkh@linuxfoundation.org>,
Badhri Jagan Sridharan <badhri@google.com>,
Kyle Tso <kyletso@google.com>,
Albert Wang <albertccwang@google.com>,
Chien Kun Niu <rickyniu@google.com>,
linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH V2] usb: typec: Add sysfs node to show connector orientation
Date: Fri, 25 Oct 2019 14:46:54 +0800 [thread overview]
Message-ID: <CAGCq0LZcZUD6jUhcnRTQqtoO2MzCuv8hUndkv5Ekcq=sX7oT4w@mail.gmail.com> (raw)
In-Reply-To: <20191024120346.GC15396@kuha.fi.intel.com>
Hi Heikki,
Sure, I will check about this.
Thanks for advising me.
Thanks in advance.
Puma Hsu
On Thu, Oct 24, 2019 at 8:06 PM Heikki Krogerus
<heikki.krogerus@linux.intel.com> wrote:
>
> Hi,
>
> On Thu, Oct 24, 2019 at 05:02:18PM +0800, Puma Hsu wrote:
> > Yes, generally this might be purely informational or be a dynamically
> > debuggable
> > mechanism for end user as I mentioned in previous discussion
> > thread(https://lkml.org/lkml/2019/10/22/198).
> > Could I know if it is not suitable that we expose a file for
> > informational usage?
> >
> > If everyone agreed above, about the definition of “unknown” and the condition
> > “don’t know the orientation”, what about adding additional return value?
> > 1. For original “unknown”, it is a generic unknown state which can
> > indicate no
> > matter connector is disconnected, cannot specify which cc side
> > is configured(such as Ra-Ra),
> > or even driver can not know the orientation.
> > 2. New additional value “unavailable”, it can be used to
> > specifically explicate that
> > driver can not know the orientation.
> > Take UCSI as example, it can use generic “unknown” or “unavailable” if
> > it wants.
> > But if it exposes “unavailable”, then application in user space can
> > know that this attribute is not useful.
> >
> > I summarize the proposal definition below:
> > - unknown (generic unknown. driver don’t or can’t know the polarity,
> > e.g. disconnected, both cc1 and cc2 are the same, )
> > - normal (configured in cc1 side)
> > - reversed (configured in cc2 side)
> > - unavailable (not support the polarity detection)
>
> Now the attribute would be supplying two types of information:
>
> 1) Does the driver know the orientation
> 2) The current orientation
>
> Let's not do that! If you really need this, then just implement the
> ".is_visible" callback with it. You just need to add a flag to the
> struct typec_capability that tells does the driver know the
> orientation or not. Something like:
>
> unsigned int orientation_aware:1;
>
> We already "hide" the identity information if the underlying driver
> is unable to supply it. By making this attribute optional as well (by
> hiding it when it's not known), the style of exposing the information
> is kept the same throughout the class.
>
> thanks,
>
> --
> heikki
prev parent reply other threads:[~2019-10-25 6:47 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-22 8:59 [PATCH V2] usb: typec: Add sysfs node to show connector orientation Puma Hsu
2019-10-22 17:27 ` Greg KH
2019-10-23 3:26 ` Puma Hsu
2019-10-23 8:32 ` Heikki Krogerus
2019-10-23 13:44 ` Guenter Roeck
2019-10-23 13:53 ` Puma Hsu
2019-10-23 14:29 ` Heikki Krogerus
2019-10-23 15:01 ` Guenter Roeck
2019-10-23 15:57 ` Heikki Krogerus
2019-10-24 9:02 ` Puma Hsu
2019-10-24 12:06 ` Heikki Krogerus
2019-10-25 6:46 ` Puma Hsu [this message]
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