lkml.org 
[lkml]   [2023]   [Oct]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    /
    Date
    From
    SubjectRe: [PATCH v2 1/1] tty: i3c: add TTY over I3C master support
    On Tue, Oct 24, 2023 at 11:59:53AM -0400, Frank Li wrote:
    > On Tue, Oct 24, 2023 at 05:05:47PM +0200, Greg KH wrote:
    > > On Tue, Oct 24, 2023 at 10:31:51AM -0400, Frank Li wrote:
    > > > On Tue, Oct 24, 2023 at 11:30:33AM +0200, Greg KH wrote:
    > > > > On Mon, Oct 23, 2023 at 12:26:42PM -0400, Frank Li wrote:
    > > > > > On Sat, Oct 21, 2023 at 07:02:40PM +0200, Greg KH wrote:
    > > > > > > Note, your subject line needs to change.
    > > > > > >
    > > > > > > On Fri, Oct 20, 2023 at 12:00:27PM -0400, Frank Li wrote:
    > > > > > > > In typical embedded Linux systems, UART consoles require at least two pins,
    > > > > > > > TX and RX. In scenarios where I2C/I3C devices like sensors or PMICs are
    > > > > > > > present, we can save these two pins by using this driver. Pins is crucial
    > > > > > >
    > > > > > > "Pins are crucial"
    > > > > > >
    > > > > > > > resources, especially in small chip packages.
    > > > > > > >
    > > > > > > > This introduces support for using the I3C bus to transfer console tty data,
    > > > > > > > effectively replacing the need for dedicated UART pins. This not only
    > > > > > > > conserves valuable pin resources but also facilitates testing of I3C's
    > > > > > > > advanced features, including early termination, in-band interrupt (IBI)
    > > > > > > > support, and the creation of more complex data patterns. Additionally,
    > > > > > > > it aids in identifying and addressing issues within the I3C controller
    > > > > > > > driver.
    > > > > > >
    > > > > > > But where is the serial data ending up at? Not a normal uart, what is
    > > > > > > on the other end? And do line settings mean anything here?
    > > > > >
    > > > > > Currently, it use slave i3c code.
    > > > > > https://lore.kernel.org/imx/20231018215809.3477437-1-Frank.Li@nxp.com/T/#t
    > > > > >
    > > > > > idealy build an i3c->usb dongle to bride it to usb acm.
    > > > >
    > > > > So no one has built such a thing yet to determine if any of this works?
    > > >
    > > > It is easy to proof concept by I3C slave code and USB gadget ACM, then pipe
    > > > two tty (ttyACM0 and ttySI3C0 together).
    > >
    > > So you have not actually tested this? why write a driver that no one is
    > > using?
    >
    > I3c slave side tty at
    > https://lore.kernel.org/imx/20231018215809.3477437-1-Frank.Li@nxp.com/T/#t
    >
    > I just have not tested tty to USB part. This patch is major for tty -> i3c
    > master -> i3c taret -> tty now.
    >
    > As my previous said, two major purpose now.
    > 1. Save two pads.
    > 2. Test i3c master and i3c target driver. I3C target driver frame was
    > written by me and posted. It needs a driver to verify it works. In stead of
    > write a test driver (such as i2c slave, pci-endpoint), it is better to
    > write an actual function driver, such as tty. It can exchange message
    > between two boards, which connected by SDA/SCL.
    >
    > Frank
    > >
    > > > Of we also can implement a USB to I3C class standard, base on this, reuse
    > > > this tty driver at host side.
    > >
    > > Is there a USB I3C standard? I see i3c descriptors assigned by the
    > > USB-IF, but haven't dug to see if there's more than that anywhere...

    Sorry, forget answer this quesiton. Yes, it is standard class. Spec is in
    usb.org. I have not found actual usage mode yet.

    > >
    > > thanks,
    > >
    > > greg k-h

    \
     
     \ /
      Last update: 2023-10-24 18:05    [W:2.954 / U:0.020 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site