Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752448AbaAXSYZ (ORCPT ); Fri, 24 Jan 2014 13:24:25 -0500 Received: from cam-admin0.cambridge.arm.com ([217.140.96.50]:53113 "EHLO cam-admin0.cambridge.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751790AbaAXSYX (ORCPT ); Fri, 24 Jan 2014 13:24:23 -0500 Date: Fri, 24 Jan 2014 18:23:55 +0000 From: Mark Rutland To: Feng Kan Cc: "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" Subject: Re: [PATCH V4 5/5] Documentation: power: reset: Add documentation for generic SYSCON reboot driver Message-ID: <20140124182355.GF4758@e106331-lin.cambridge.arm.com> References: <1390504801-24483-1-git-send-email-fkan@apm.com> <1390504801-24483-6-git-send-email-fkan@apm.com> <20140124113920.GF814@e106331-lin.cambridge.arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jan 24, 2014 at 06:03:10PM +0000, Feng Kan wrote: > On Fri, Jan 24, 2014 at 3:39 AM, Mark Rutland wrote: > > On Thu, Jan 23, 2014 at 07:20:01PM +0000, Feng Kan wrote: > >> Add documentation for generic SYSCON reboot driver. > >> > >> Signed-off-by: Feng Kan > >> --- > >> .../bindings/power/reset/syscon-reboot.txt | 16 ++++++++++++++++ > >> 1 files changed, 16 insertions(+), 0 deletions(-) > >> create mode 100644 Documentation/devicetree/bindings/power/reset/syscon-reboot.txt > >> > >> diff --git a/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt > >> new file mode 100644 > >> index 0000000..e9eb1fe > >> --- /dev/null > >> +++ b/Documentation/devicetree/bindings/power/reset/syscon-reboot.txt > >> @@ -0,0 +1,16 @@ > >> +Generic SYSCON mapped register reset driver > > > > Bindings should describe hardware, not drivers. > > > > What precisely does this binding describe? > > > >> + > >> +Required properties: > >> +- compatible: should contain "syscon-reboot" > >> +- regmap: this is phandle to the register map node > >> +- offset: offset in the register map for the reboot register > >> +- mask: the reset value written to the reboot register > >> + > >> +Examples: > >> + > >> +reboot { > >> + compatible = "syscon-reboot"; > >> + regmap = <®mapnode>; > >> + offset = <0x0>; > >> + mask = <0x1>; > >> +}; > > > > Access size? Endianness? > FKAN: are you asking for documentation? I don't see alot of example of > support for these. If I used the enippet in the example, what endianness and access size should I expect an OS to perform? That should be documented. If this doesn't match the general case, we can add properties later to adjust the access size and/or endianness. We just need to document what the binding actually describes currently, or it's not possible to implement anything based off of the binding documentation. I should be able to read a binding document and write a dts. I shouldn't have to read the code to figure out what the binding describes. > > > > > Why can we not have a binding for the register bank this exists in, and > > have that pass on the appropriate details to a syscon-reboot driver? > > FKAN: Thats a good idea. But the hardware in this case (SCU) system > clock unit has a bunch of registers used for different functions. If syscon is > used alot in this case and we pile more attribute into it. It would get kinda > messy after a while. Huh? What's wrong with having a system clock unit binding, that the kernel can decompose as appropriate? I don't get your syscon argument. Thanks, Mark. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/