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Subject: Re: [PATCH v1 0/3] Add virtual serial null modem emulation driver
To:     Rishi Gupta <gupt21@gmail.com>, gregkh@linuxfoundation.org,
        robh+dt@kernel.org
Cc:     jslaby@suse.com, linux-serial@vger.kernel.org,
        linux-kernel@vger.kernel.org
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From:   "H. Peter Anvin" <hpa@zytor.com>
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Date:   Mon, 6 Jan 2020 12:23:55 -0800
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On 2020-01-05 23:21, Rishi Gupta wrote:
> The driver named ttyvs creates virtual tty/serial device which emulates
> behaviour of a real serial port device. Serial port events like parity,
> frame, overflow errors, ring indications, break assertions, flow controls
> are also emulated.
> 
> It supports both device-tree and non device-tree platforms. And works in
> both built-in and loadable driver methods.
> 
> Use cases
> ~~~~~~~~~~~~~~~~~
> This driver saves time to market and have following use cases including
> but not limited to; automated testing, GPS and other data simulation, data
> injection for corner case testing, scaleability testing, data sniffing,
> robotics emulator/simulator, application development when hardware,
> firmware and driver is still not available, identifying hardware issues
> from software bugs quickly during development, development cost reduction
> across team, product demo where data from hardware needs to be sent to the
> GUI application, data forwarding, serial port redirection etc.
> 
> Basic idea
> ~~~~~~~~~~~~~~~~~
> 
> This driver implements a virtual multi-port serial card in such a
> way that the virtual card can have 0 to N number of virtual serial
> ports (tty devices). The devices created in this card are used in
> exactly the same way as the real tty devices using standard termios
> and Linux/Posix APIs.

OK, I believe I have asked this before, at least when this has come up in
other contexts: any reason not to do this by adding the missing elements to
the pty interface? For fixed-name nodes, the legacy PTY interface is basically
what you need.

It would probably have other benefits, as well.

	-hpa