Re: WIP Droid 4 voice calls, GNSS & PM with a TS 27.010 serdev driver

From: Pavel Machek <pavel@ucw.cz>
To: Tony Lindgren <tony@atomide.com>
Cc: linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org, linux-omap@vger.kernel.org,
	Jarkko Nikula <jarkko.nikula@bitmer.com>,
	Johan Hovold <johan@kernel.org>,
	Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>,
	Marcel Partap <mpartap@gmx.net>,
	Merlijn Wajer <merlijn@wizzup.org>,
	Michael Scott <hashcode0f@gmail.com>, NeKit <nekit1000@gmail.com>,
	omerlle@gmail.com, Sebastian Reichel <sre@kernel.org>,
	Peter Ujfalusi <peter.ujfalusi@ti.com>,
	Rob Herring <robh@kernel.org>
Subject: Re: WIP Droid 4 voice calls, GNSS & PM with a TS 27.010 serdev driver
Date: Tue, 18 Dec 2018 13:46:16 +0100	[thread overview]
Message-ID: <20181218124616.GA10758@amd> (raw)
In-Reply-To: <20181217004450.GW6707@atomide.com>

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Hi!

> So the little elves have been slowly working to get voice calls
> working on droid 4 with the mainline kernel. And just in time for the
> upcoming holidays, it might be possible to call friends and relatives.
> 
> I've pushed out an experimental branch containing serdev ts 27.010
> UART multiplexing support. That contains a serdev core driver for the
> mdm6600 modem (that also now idles the modem for PM), support for Alsa
> ASoC voice codec and mixer, and a GNSS driver for the GPS.

Thanks for doing the work.

I'm quite busy these days, but...

# commit	 64cf2bf6b7614da35028a11974acb5a445dcc535 (patch)
# n_gsm: Use const unsigned char * and size_t
# We can use const unsigned char * and size_t. This makes things
# a bit easier for adding serdev support.
# 
# Note that gsm_control_modem() gsm_control_rls() read the data
# for tty control characters and then call gsm_control_reply()
# that allocates a new reply and copies the data.
# 
# REVISIT: Check size_t usage vs int
# 
# Signed-off-by: Tony Lindgren <tony@atomide.com>

Dunno, I see that you might want const there, but u8 -> unsigned char
seems like a step in wrong direction.

# commit	   cd16272060d8100ef0388349cf88f42a1dc667fc (patch)
# tty: n_gsm: Add support for serdev

Is it worth putting those in separate file? n_gsm_serdev.c?

# commit	    0c1bc81ba976bcd480d6e3c3009a28589f8427c0 (patch)
# mfd: motmdm: Add Motorola TS 27.010 serdev driver for devices like droid4

Oh, that is a lot of fun. Especially state machine for parsing modem
responses. I wonder how well it is going to work when modem is
accessed over USB... 

motmdm_read_state(... size_t len)

I applied it over my tree (I still need patches for display,
right?). I'm getting

/data/fast/l/k/drivers/mfd/motorola-mdm.c:1132:3: error: initializer
element is not constant
/data/fast/l/k/drivers/mfd/motorola-mdm.c:1132:3: error: (near
initialization for 'motmdm_driver.driver.name')
/data/fast/l/k/scripts/Makefile.build:291: recipe for target
'drivers/mfd/motorola-mdm.o' failed

Oh and that mdelay(3000) is going to hurt... especially because
console is initialized very late or d4.

I did a quick test in my config... and it did not break my old setup
-- voice calls still work when set up over USB and with manual mixer
setup. That was good surprise.

Thanks,
									Pavel

diff --git a/drivers/mfd/motorola-mdm.c b/drivers/mfd/motorola-mdm.c
index eea754d..2b7c324 100644
--- a/drivers/mfd/motorola-mdm.c
+++ b/drivers/mfd/motorola-mdm.c
@@ -1129,7 +1129,7 @@ static void motmdm_remove(struct serdev_device *serdev)
 
 static struct serdev_device_driver motmdm_driver = {
 	.driver = {
-		.name = motmdm_driver_name,
+		.name = "motmdm",
 		.of_match_table = of_match_ptr(motmdm_id_table),
 		.pm = &motmdm_pm_ops,
 	},


-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html

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