Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756079Ab3DOVd4 (ORCPT ); Mon, 15 Apr 2013 17:33:56 -0400 Received: from wolverine01.qualcomm.com ([199.106.114.254]:17716 "EHLO wolverine01.qualcomm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755321Ab3DOVdi (ORCPT ); Mon, 15 Apr 2013 17:33:38 -0400 X-IronPort-AV: E=Sophos;i="4.87,479,1363158000"; d="scan'208";a="38538874" Message-ID: <516C7231.6060305@codeaurora.org> Date: Mon, 15 Apr 2013 14:33:37 -0700 From: Stephen Boyd User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:17.0) Gecko/20130328 Thunderbird/17.0.5 MIME-Version: 1.0 To: Rob Herring CC: "linux-arm-kernel@lists.infradead.org" , linux-arm-msm , "devicetree-discuss@lists.ozlabs.org" , "linux-kernel@vger.kernel.org" Subject: Re: [PATCHv2 1/4] Documentation: Add memory mapped ARM architected timer binding References: <1365812863-5367-1-git-send-email-sboyd@codeaurora.org> <1365812863-5367-2-git-send-email-sboyd@codeaurora.org> <516C6F12.5020208@gmail.com> In-Reply-To: <516C6F12.5020208@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2140 Lines: 57 On 04/15/13 14:20, Rob Herring wrote: > On Fri, Apr 12, 2013 at 7:27 PM, Stephen Boyd wrote: >> @@ -26,3 +30,52 @@ Example: >> <1 10 0xf08>; >> clock-frequency = <100000000>; >> }; >> + >> +** Memory mapped timer node properties >> + >> +- compatible : Should at least contain "arm,armv7-timer-mem". > Everything about this timer is architecturally defined? If not, let's > use a more specific name. I'm not sure I'm following you, but everything described here is part of the ARM definition. What would be a more specific name? > >> + >> +- clock-frequency : The frequency of the main counter, in Hz. Optional. >> + >> +- reg : The control frame base address. >> + >> +Note that #address-cells, #size-cells, and ranges shall be present to ensure >> +the CPU can address a frame's registers. >> + >> +Frame: >> + >> +- frame-number: 0 to 7. > I'd really like to get rid of the frame numbers and sub-nodes. Is the > frame number significant to software? We need the frame number to read and write registers in the control frame (the first base in the parent node). We currently use it to determine if a frame has support for the virtual timer by reading the CNTTIDR (a register with 4 bits per frame describing capabilities). If we wanted to control access to the second view of a frame we would also need to configure the CNTPL0ACRn register that pertains to the frame we're controlling. Without a frame number we wouldn't know which register to write. > >> +- interrupts : Interrupt list for physical and virtual timers in that order. >> + The virtual timer interrupt is optional. > Is that optional per frame? Yes the virtual and physical timer interrupt is per-frame and the virtual interrupt is optional. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, hosted by The Linux Foundation -- 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/