From mboxrd@z Thu Jan 1 00:00:00 1970 From: Santosh Shilimkar Subject: Re: [Patch v3 0/5] Introduce keystone reset driver Date: Tue, 20 May 2014 09:49:17 -0400 Message-ID: <537B5D5D.8030106@ti.com> References: <1400495155-11136-1-git-send-email-ivan.khoronzhuk@ti.com> <5095812.b6DgWAxYzH@wuerfel> <537B5598.8070603@ti.com> <5272855.vIyLIadgKe@wuerfel> Mime-Version: 1.0 Content-Type: text/plain; charset="ISO-8859-1" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <5272855.vIyLIadgKe@wuerfel> Sender: linux-doc-owner@vger.kernel.org To: Arnd Bergmann , Ivan Khoronzhuk Cc: dbaryshkov@gmail.com, dwmw2@infradead.org, ijc+devicetree@hellion.org.uk, robh+dt@kernel.org, pawel.moll@arm.com, mark.rutland@arm.com, galak@codeaurora.org, grant.likely@linaro.org, rdunlap@infradead.org, linux@arm.linux.org.uk, grygorii.strashko@ti.com, olof@lixom.net, w-kwok2@ti.com, sboyd@codeaurora.org, devicetree@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org, linux-arm-kernel@lists.infradead.org List-Id: devicetree@vger.kernel.org On Tuesday 20 May 2014 09:44 AM, Arnd Bergmann wrote: > On Tuesday 20 May 2014 16:16:08 Ivan Khoronzhuk wrote: >> Thank for the reply >> >> The reset driver uses two ranges: >> - RSTYPE, RSTCTRL,RSTCFG, RSISO (Reset Main PLL Controller) >> - RESETMUX8-10 registers >> >> The content of these register ranges are completely used by the reset >> driver. >> Currently no one on the SoC can access them instead of the reset driver. >> Also we don't use syscon/regmap at all - so adding this will be some >> overhead. >> >> As I posted previously: >> "...configuring Reset multiplexer & PLL. And it tunes not only watchdog >> usage..." >> >> Yes, it tunes not only watchdog usage and uses part of registers from >> PLL controller, >> but all it works with are connected with reset functionality. These >> ranges are used only >> by reset driver and their purpose is reset functionality. >> >> Maybe in the future some soft can use ranges in question for own tasks, >> but it should be >> done via reset driver. So as I see there is no reasons to use regmap for >> reset driver. > > You should not look at these registers in isolation, they are part of > some register area that has other functions as well and that you should > at least represent correctly in DT. > > When I see something like > > + reg = <0x23100e4 0x10>, > + <0x2620328 0x10>; > > I am certain that there are other things between 0x2310000 and 0x23100e3, and > probably after 0x23100f4 as well. There must be some data sheet that > gives this register range a proper name, so put that into DT rather than > making up some arbitrary stuff that happens to match how today's kernel > driver needs it. > Even though there are no other users, I think you have a valid point about DT representing the hardware layout in the correct form. Regards, Santosh