Driver for MaxLinear/Exar USB (UART) Serial Adapters - Greg Kroah-Hartman

From: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To: Patong Yang <patong.mxl@gmail.com>
Cc: linux-usb@vger.kernel.org, johan@kernel.org, pyang@maxlinear.com
Subject: Driver for MaxLinear/Exar USB (UART) Serial Adapters
Date: Thu, 26 Jul 2018 12:57:36 +0200	[thread overview]
Message-ID: <20180726105736.GA28080@kroah.com> (raw)

On Tue, Jul 24, 2018 at 03:36:36PM -0700, Patong Yang wrote:
> The original driver/patch was submitted on April 4, 2018.  This is the
> second version based on the feedback received on the original patch.
> 
> v2: Removed custom IOCTLs, as suggested by Greg KH
>     Using standard Linux GPIO APIs, as suggested by Greg KH
>     Removed file reads/writes as suggested by Greg KH
> 
> Signed-off-by: Patong Yang <patong.mxl@gmail.com>
> ---
>  drivers/usb/serial/xrusb_serial.c | 2380 +++++++++++++++++++++++++++++
>  drivers/usb/serial/xrusb_serial.h |  234 +++

Why do you need a .h file for a single driver?  Please just put it all
into one file.

But there is a bigger problem here:

> +	xrusb_tty_driver = alloc_tty_driver(XRUSB_TTY_MINORS);
> +	if (!xrusb_tty_driver)
> +		return -ENOMEM;

Why are you not using the usb serial core here?  You need to do that,
not try to provide your own custom tty driver.  That way userspace
programs will "just work" with your new device, no changes needed as
your major/minor number and device name would be custom only for your
device, which is not acceptable.

By doing that, your code will also be much smaller, always a good
benefit as well.

thanks,

greg k-h
---
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html