Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751892AbaLCXEF (ORCPT ); Wed, 3 Dec 2014 18:04:05 -0500 Received: from mail-qc0-f179.google.com ([209.85.216.179]:37194 "EHLO mail-qc0-f179.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751088AbaLCXEB (ORCPT ); Wed, 3 Dec 2014 18:04:01 -0500 MIME-Version: 1.0 In-Reply-To: <20141203200307.GM7712@sirena.org.uk> References: <1417531766-29669-1-git-send-email-jay.xu@rock-chips.com> <1417591118-18695-1-git-send-email-jay.xu@rock-chips.com> <1417591118-18695-3-git-send-email-jay.xu@rock-chips.com> <20141203192024.GL7712@sirena.org.uk> <20141203200307.GM7712@sirena.org.uk> From: Sonny Rao Date: Wed, 3 Dec 2014 15:03:40 -0800 X-Google-Sender-Auth: dY8B53WuMfZe8hVVKu2P5LQjcuQ Message-ID: Subject: Re: [PATCH v2 2/2] ASoC: rockchip: i2s: add support for grabbing output clock to codec To: Mark Brown Cc: Jianqun Xu , Liam Girdwood , perex@perex.cz, tiwai@suse.de, =?UTF-8?Q?Heiko_St=C3=BCbner?= , "linux-arm-kernel@lists.infradead.org" , alsa-devel@alsa-project.org, "linux-kernel@vger.kernel.org" , "devicetree@vger.kernel.org" , linux-rockchip@lists.infradead.org Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Dec 3, 2014 at 12:03 PM, Mark Brown wrote: > On Wed, Dec 03, 2014 at 11:38:13AM -0800, Sonny Rao wrote: >> On Wed, Dec 3, 2014 at 11:20 AM, Mark Brown wrote: > >> > I would expect that the clock for the CODEC should be managed by the >> > CODEC if at all possible - that seems more logical than having the CPU >> > I2S controller request and manage it if it's a separate clock. Why add >> > this to the CPU side driver? > >> This output clock has a mux and can either be a fixed 12Mhz output or >> can be derived from the same fractional divider which drives the i2s >> block. I thought it was simpler to keep them all the same, but need >> to put ownership in the i2s in anticipation of the i2s driver setting >> it's own clock rate. > >> If you think this is an implementation detail and this output clock >> should just be owned by the codec driver, even though I'm guessing it >> will just have to be the same as i2s, then I think we can drop this >> and make sure simple card (or whatever other codec driver) claims this >> clock. > > simple-card obviously isn't a CODEC driver... Yeah, sorry. > For generality I think > the clock does need to be exposed to the CODEC driver, otherwise this > will work differently to how other systems are working and we can't > substitute in a different clock on the CODEC side so easily if it > doesn't happen to use the output from the I2S block. Ok, then I think what we will do is abandon this patch and I will send something that adds this functionality to the particular codec that I'm interested in -- max98090. I'm a little tied up at the moment so I'm not going to send that for a little while, but will come eventually. Thanks for the advice! -- 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/