From mboxrd@z Thu Jan  1 00:00:00 1970
From: Flora Fu <flora.fu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
Subject: Re: [PATCH v3 1/8] soc: mediatek: Add PMIC wrapper for MT8135 and
 MT6397 SoC
Date: Tue, 9 Dec 2014 10:15:37 +0800
Message-ID: <1418091337.5663.9.camel@mtksdaap41>
References: <1417752479-4749-1-git-send-email-flora.fu@mediatek.com>
	 <1417752479-4749-2-git-send-email-flora.fu@mediatek.com>
	 <2751641.o51TuZRl88@wuerfel>
Mime-Version: 1.0
Content-Type: text/plain; charset="UTF-8"
Content-Transfer-Encoding: 7bit
Return-path: <devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org>
In-Reply-To: <2751641.o51TuZRl88@wuerfel>
Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
To: Arnd Bergmann <arnd-r2nGTMty4D4@public.gmane.org>, Matthias Brugger <matthias.bgg-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>
Cc: linux-arm-kernel-IAPFreCvJWM7uuMidbF8XUB+6BGkLq7r@public.gmane.org, Rob Herring <robh+dt-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, Samuel Ortiz <sameo-VuQAYsv1563Yd54FQh9/CA@public.gmane.org>, Lee Jones <lee.jones-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Liam Girdwood <lgirdwood-Re5JQEeQqe8AvxtiuMwx3w@public.gmane.org>, Mark Brown <broonie-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>, arm-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org, Mark Rutland <mark.rutland-5wv7dgnIgG8@public.gmane.org>, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Russell King <linux-lFZ/pmaqli7XmaaqVzeoHQ@public.gmane.org>, srv_heupstream-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org, Pawel Moll <pawel.moll-5wv7dgnIgG8@public.gmane.org>, Ian Campbell <ijc+devicetree-KcIKpvwj1kUDXYZnReoRVg@public.gmane.org>, linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, HenryC Chen <henryc.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>, Menghui Lin <menghui.lin-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>, Olof Johansson <olof-nZhT3qVonbNeoWH0uzbU5w@public.gmane.org>, Sascha Hauer <kernel-bIcnvbaLZ9MEGnE8C9+IrQ@public.gmane.org>, Kumar Gala <galak-sgV2jX0FEOL9JmXXK+q4OQ@public.gmane.org>, Grant Likely <grant.likely-QSEj5FYQhm4dnm+yROfE0A@public.gmane.org>, Yingjoe Chen <yingjoe.chen-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>, Eddie Huang <eddie.huang-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>, Dongdong Cheng <dongdong.cheng-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
List-Id: devicetree@vger.kernel.org

Hi, Arnd,

On Fri, 2014-12-05 at 11:13 +0100, Arnd Bergmann wrote:
> On Friday 05 December 2014 12:07:52 Flora Fu wrote:
> > Add PMIC wrapper of MT8135 to access MT6397 MFD.
> > 
> > Signed-off-by: Flora Fu <flora.fu-NuS5LvNUpcJWk0Htik3J/w@public.gmane.org>
> > 
> 
> Please explain what a PMIC wrapper is and why you need one for MT8135.
> I don't understand the purpose of this code at all. Is this just another
> way of accessing the MT6397 when not using i2c or spi like other
> PMIC drivers do?
> 

Yes, MT8135 uses a proprietary hardware to communicate with MT6397. 
The hardware is called PMIC Wrapper or PWRAP.
Since it is not standard i2c or spi protocols, a soc related software
driver is implemented to handle access protocols in AP side.

+-----------------+           +---------------+
|                 |           |               |
| Mediatek AP SoC |           |               |
| (ex. MT8135)    |           |    MT6397     |
|                 |           |               |
|      +--------+ | (SPI bus) | +--------+    |
|      |        | |-----------| |        |    |
|      |  PMIC  | |-----------| |  PMIC  |    |
|      | Wrapper| |-----------| | Wrapper|    |
|      |        | |-----------| |        |    |
|      +--------+ |           | +--------+    |
|                 |           |               |
+-----------------+           +---------------+

Thanks,
Flora


--
To unsubscribe from this list: send the line "unsubscribe devicetree" in
the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html