Re: [PATCHv8 0/6] n_gsm serdev support and GNSS driver for droid4

From: Johan Hovold <johan@kernel.org>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Tony Lindgren <tony@atomide.com>, Johan Hovold <johan@kernel.org>,
	Rob Herring <robh@kernel.org>,
	Alan Cox <gnomes@lxorguk.ukuu.org.uk>,
	Lee Jones <lee.jones@linaro.org>, Jiri Slaby <jslaby@suse.cz>,
	Merlijn Wajer <merlijn@wizzup.org>, Pavel Machek <pavel@ucw.cz>,
	Peter Hurley <peter@hurleysoftware.com>,
	Sebastian Reichel <sre@kernel.org>,
	linux-serial@vger.kernel.org, devicetree@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-omap@vger.kernel.org
Subject: Re: [PATCHv8 0/6] n_gsm serdev support and GNSS driver for droid4
Date: Mon, 25 May 2020 09:44:24 +0200	[thread overview]
Message-ID: <20200525074424.GA5276@localhost> (raw)
In-Reply-To: <20200522091731.GA1203588@kroah.com>

On Fri, May 22, 2020 at 11:17:31AM +0200, Greg Kroah-Hartman wrote:
> On Tue, May 12, 2020 at 02:47:07PM -0700, Tony Lindgren wrote:
> > Hi all,
> > 
> > Here's the updated set of these patches fixed up for Johan's and
> > Pavel's earlier comments.
> > 
> > This series does the following:
> > 
> > 1. Adds functions to n_gsm.c for serdev-ngsm.c driver to use
> > 
> > 2. Adds a generic serdev-ngsm.c driver that brings up the TS 27.010
> >    TTY ports configured in devicetree with help of n_gsm.c
> > 
> > 3. Allows the use of standard Linux device drivers for dedicated
> >    TS 27.010 channels for devices like GNSS and ALSA found on some
> >    modems for example
> > 
> > 4. Adds a gnss-motmdm consumer driver for the GNSS device found on
> >    the Motorola Mapphone MDM6600 modem on devices like droid4
> > 
> > I've placed the serdev-ngsm.c under drivers/tty/serdev as it still
> > seems to make most sense with no better places available. It's no
> > longer an MFD driver as it really does not need to care what channel
> > specific consumer drivers might be configured for the generic driver.
> > Now serdev-ngsm just uses of_platform_populate() to probe whatever
> > child nodes it might find.
> > 
> > I'm not attached having the driver in drivers/tty/serdev. I just
> > don't have any better locations in mind. So using Johan's earlier
> > i2c example, the drivers/tty/serdev/serdev-ngsm.c driver is now a
> > generic protocol and bus driver, so it's getting closer to the
> > the drivers/i2c/busses analogy maybe :) Please do suggest better
> > locations other than MFD and misc if you have better ideas.
> > 
> > Now without the chardev support, the /dev/gsmtty* using apps need
> > to use "U1234AT+CFUN?" format for the packets. The advantage is
> > less kernel code, and we keep the existing /dev/gsmtty* interface.
> > 
> > If we still really need the custom chardev support, that can now
> > be added as needed with the channel specific consumer driver(s),
> > but looks like this won't be needed based on Pavel's ofono work.
> 
> Johan and Rob, any objection/review of this series?

Yeah, sorry I haven't had time to review this yet. I should be able to
look at it today.

Johan