Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67;
Date:   Tue, 28 May 2019 11:54:02 +0200
From:   Pali =?utf-8?B?Um9ow6Fy?= <pali.rohar@gmail.com>
To:     Jean Delvare <jdelvare@suse.de>
Cc:     Wolfram Sang <wsa@the-dreams.de>,
        Andy Shevchenko <andy.shevchenko@gmail.com>,
        =?utf-8?B?TWljaGHFgiBLxJlwaWXFhA==?= <kernel@kempniu.pl>,
        Steven Honeyman <stevenhoneyman@gmail.com>,
        Valdis Kletnieks <Valdis.Kletnieks@vt.edu>,
        Jochen Eisinger <jochen@penguin-breeder.org>,
        Gabriele Mazzotta <gabriele.mzt@gmail.com>,
        Andy Lutomirski <luto@kernel.org>,
        Mario Limonciello <Mario_Limonciello@dell.com>,
        Alex Hung <alex.hung@canonical.com>,
        Takashi Iwai <tiwai@suse.de>,
        linux-i2c <linux-i2c@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Platform Driver <platform-driver-x86@vger.kernel.org>
Subject: Re: [PATCH v2] i2c: i801: Register optional lis3lv02d i2c device on
 Dell machines
Message-ID: <20190528095402.hlnqfon6jk452one@pali>
References: <CAHp75Vf=-RQvCtS684Q5+X=YKmZXgP_1kr0to8BGZX0jQAsuZw@mail.gmail.com>
 <20180212153012.vffvjmz26ifyxbj5@pali>
 <CAHp75VfF+qwCXcr3yuayE-Z+UG9wuMOKfGzLhdyPk79daEi9gQ@mail.gmail.com>
 <20180213150004.5d2v7y7wwuure4io@pali>
 <CAHp75VfxgbFiDxyrqyMRE8s85L1_EzkVvrA1NGYA5_su=5oGVQ@mail.gmail.com>
 <20180213165023.xmzovx7fd3gdljxw@pali>
 <20180226203255.lnnzipipjz5l2itz@ninjato>
 <20190528111953.0e5415f4@endymion>
 <20190528094132.ytsittb5hcgthoy2@pali>
 <1559037015.6521.3.camel@suse.de>
MIME-Version: 1.0
Content-Type: text/plain; charset=utf-8
Content-Disposition: inline
Content-Transfer-Encoding: 8bit
In-Reply-To: <1559037015.6521.3.camel@suse.de>
User-Agent: NeoMutt/20170113 (1.7.2)
Sender: linux-kernel-owner@vger.kernel.org
Precedence: bulk

On Tuesday 28 May 2019 11:50:15 Jean Delvare wrote:
> On Tue, 2019-05-28 at 11:41 +0200, Pali Rohár wrote:
> > This is not a problem. lis3lv02d provides two things:
> > 
> > 1) 3 axes accelerometer
> > 2) optional interrupt and signal it to userspace via misc device
> > 
> > dell-smo8800 does not call any parts of lis2lv02d module. It just
> > provides for userspace same misc device API as lis3lv02d.
> > 
> > As lis3lv02d has misc device optional, registered i2c device from
> > i2c-i801 does not enable it.
> > 
> > So technically it is one device, but their functionality divided into
> > two modules. One which reports accelerometer axes and one which signals
> > disk fall interrupt. These two modules and functionalities does not have
> > to interact, so it is safe to have them separated.
> 
> OK, thanks for the explanation. But assuming that we now instantiate
> the lis2lv02d device from i2c-i801 for exactly all the same machines,
> can't we just *enable* the freefall misc device feature of lis2lv02d
> and kill the dell-smo8800 driver completely? Seems more simple to
> maintain going forward.

I though about it and I already wrote that is it not practical. For ACPI
drivers there is easy way to get that interrupt number from ACPI tables.
From i2c-i801 PCI driver it is hard to get interrupt number for
particular ACPI device...

That is way I preferred simple solution: ACPI driver for ACPI device and
i2c driver for i2c device.

-- 
Pali Rohár
pali.rohar@gmail.com