Re: [RFC PATCH 05/06] input/rmi4: F01 - device control

From: Dmitry Torokhov <dmitry.torokhov@gmail.com>
To: Christopher Heiny <cheiny@synaptics.com>
Cc: Linus Walleij <linus.walleij@stericsson.com>,
	Jean Delvare <khali@linux-fr.org>,
	Linux Kernel <linux-kernel@vger.kernel.org>,
	Linux Input <linux-input@vger.kernel.org>,
	Allie Xiong <axiong@synaptics.com>, Vivian Ly <vly@synaptics.com>,
	Daniel Rosenberg <daniel.rosenberg@synaptics.com>,
	Alexandra Chin <alexandra.chin@tw.synaptics.com>,
	Joerie de Gram <j.de.gram@gmail.com>,
	Wolfram Sang <w.sang@pengutronix.de>,
	Mathieu Poirier <mathieu.poirier@linaro.org>,
	Naveen Kumar Gaddipati <naveen.gaddipati@stericsson.com>
Subject: Re: [RFC PATCH 05/06] input/rmi4: F01 - device control
Date: Tue, 27 Nov 2012 01:29:13 -0800	[thread overview]
Message-ID: <20121127092913.GC25658@core.coreip.homeip.net> (raw)
In-Reply-To: <50B3EDBF.3030209@synaptics.com>

On Mon, Nov 26, 2012 at 02:31:27PM -0800, Christopher Heiny wrote:
> On 11/26/2012 01:40 AM, Dmitry Torokhov wrote:
> >Hi Christopher,
> >
> >On Fri, Nov 16, 2012 at 07:58:53PM -0800, Christopher Heiny wrote:
> >>RMI Function 01 implements basic device control and power management
> >>behaviors for the RMI4 sensor.
> >>
> >>rmi_f01.h exports definitions that we expect to be used by other functionality
> >>in the future (such as firmware reflash).
> >
> >Please see my comments below.
> 
> Hi Dmitry,
> 
> Thanks for the feedback and the patch.  I've got just one question,
> included below, with a bunch of snipping).
> 
> 				Chris
> 
> >
> >>
> >>
> >>Signed-off-by: Christopher Heiny <cheiny@synaptics.com>
> >>
> >>Cc: Dmitry Torokhov <dmitry.torokhov@gmail.com>
> >>Cc: Linus Walleij <linus.walleij@stericsson.com>
> >>Cc: Naveen Kumar Gaddipati <naveen.gaddipati@stericsson.com>
> >>Cc: Joeri de Gram <j.de.gram@gmail.com>
> >>
> >>
> >>---
> >>
> >>  drivers/input/rmi4/rmi_f01.c | 1348 ++++++++++++++++++++++++++++++++++++++++++
> >>  drivers/input/rmi4/rmi_f01.h |  160 +++++
> >>  2 files changed, 1508 insertions(+), 0 deletions(-)
> >>
> >>diff --git a/drivers/input/rmi4/rmi_f01.c b/drivers/input/rmi4/rmi_f01.c
> >>new file mode 100644
> >>index 0000000..038266c
> >>--- /dev/null
> >>+++ b/drivers/input/rmi4/rmi_f01.c
> >>@@ -0,0 +1,1348 @@
> >>+/*
> >>+ * Copyright (c) 2011-2012 Synaptics Incorporated
> >>+ * Copyright (c) 2011 Unixphere
> >>+ *
> >>+ * This program is free software; you can redistribute it and/or modify
> >>+ * it under the terms of the GNU General Public License as published by
> >>+ * the Free Software Foundation; either version 2 of the License, or
> >>+ * (at your option) any later version.
> 
> [snip]
> 
> >>+/**
> >>+ * @reset - set this bit to force a firmware reset of the sensor.
> >>+ */
> >>+struct f01_device_commands {
> >>+	bool reset:1;
> >>+	u8 reserved:7;
> >
> >When specifying bitwise fields please use u8, u16, etc only.
> 
> Um, OK.  Previously patch feedback suggested to use bool instead of
> u8 for single bit fields (see here:
> http://www.spinics.net/lists/linux-input/msg22198.html).  So I'm a
> little confused.  It's no big deal to change it back, but I'd like
> confirmation that it is really what we should do.

I believe that it is better to specify exact bitness of the base type of
the bitfield so you do not surprised by the alignment.

Thanks.

-- 
Dmitry