Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1757363AbbEVR4B (ORCPT ); Fri, 22 May 2015 13:56:01 -0400 Received: from mailapp01.imgtec.com ([195.59.15.196]:29482 "EHLO mailapp01.imgtec.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756693AbbEVRz6 (ORCPT ); Fri, 22 May 2015 13:55:58 -0400 Message-ID: <555F6CE8.1070303@imgtec.com> Date: Fri, 22 May 2015 14:52:40 -0300 From: Ezequiel Garcia User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:31.0) Gecko/20100101 Thunderbird/31.5.0 MIME-Version: 1.0 To: Andrew Bresticker CC: Linux-MIPS , "linux-kernel@vger.kernel.org" , Mike Turquette , Stephen Boyd , James Hartley , Govindraj Raja , Damien Horsley , Kevin Cernekee , James Hogan Subject: Re: [PATCH 6/9] clk: pistachio: Propagate rate changes in the MIPS PLL clock sub-tree References: <1432252663-31318-1-git-send-email-ezequiel.garcia@imgtec.com> <1432252663-31318-7-git-send-email-ezequiel.garcia@imgtec.com> In-Reply-To: Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit X-Originating-IP: [10.100.200.196] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1404 Lines: 34 On 05/22/2015 02:42 PM, Andrew Bresticker wrote: > On Thu, May 21, 2015 at 4:57 PM, Ezequiel Garcia > wrote: >> This commit passes CLK_SET_RATE_PARENT to the "mips_div", >> "mips_internal_div", and "mips_pll_mux" clocks. This flag is needed for the >> "mips" clock to propagate rate changes up to the "mips_pll" root clock. >> >> Signed-off-by: Govindraj Raja >> Signed-off-by: Ezequiel Garcia > > IIRC the clk core will prefer changing a downstream divider over > propagating the rate change up another level. So, for example, if > MIPS_PLL is initially 400Mhz and we request a MIPS rate of 200Mhz, > we'll change the first intermediate divider to /2 rather than > propagate the rate change up to MIPS_PLL. Wouldn't it be more > power-efficient to set the MIPS_PLL directly to the requested rate > rather than using external dividers to divide it down? > Indeed. Do you think we still want to be able to change the MIPS clk rate and propagate the change up to the PLL? Otherwise, I'll drop this patch and I'll drop the DIV_F and MUX_F macro patches. -- Ezequiel -- 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/