From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tomasz Figa Subject: Re: [PATCH] ARM: dts: Remove mau_pd node for Exynos5420 Date: Thu, 24 Apr 2014 12:06:59 +0200 Message-ID: <5358E243.7010004@samsung.com> References: <1398145155-4615-1-git-send-email-tushar.behera@linaro.org> <03b001cf5edc$ae42e770$0ac8b650$@samsung.com> <5358D46F.2050303@linaro.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mailout1.w1.samsung.com ([210.118.77.11]:44299 "EHLO mailout1.w1.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754218AbaDXKHI (ORCPT ); Thu, 24 Apr 2014 06:07:08 -0400 Received: from eucpsbgm1.samsung.com (unknown [203.254.199.244]) by mailout1.w1.samsung.com (Oracle Communications Messaging Server 7u4-24.01(7.0.4.24.0) 64bit (built Nov 17 2011)) with ESMTP id <0N4J002Z15FSH720@mailout1.w1.samsung.com> for linux-samsung-soc@vger.kernel.org; Thu, 24 Apr 2014 11:07:04 +0100 (BST) In-reply-to: <5358D46F.2050303@linaro.org> Sender: linux-samsung-soc-owner@vger.kernel.org List-Id: linux-samsung-soc@vger.kernel.org To: Tushar Behera , Kukjin Kim , 'Alim Akhtar' Cc: linux-samsung-soc@vger.kernel.org, jhbird.choi@samsung.com On 24.04.2014 11:07, Tushar Behera wrote: > On 04/23/2014 03:43 PM, Kukjin Kim wrote: >> Tushar Behera wrote: >>> >>> On 22 April 2014 13:08, Alim Akhtar wrote: >>>> Hi Tushar >>>> >>>> On Tue, Apr 22, 2014 at 11:09 AM, Tushar Behera >>>> wrote: >>>>> MAU powerdomain provides clocks for Audio sub-system block. This block >>>>> comprises of the I2S audio controller, audio DMA blocks and Audio >>>>> sub-system clock registers. >>>>> >>>>> Right now, there is no way to hook up power-domains with clock >>> providers. >>>>> During late boot when this power-domain gets disabled, we get following >>>>> external abort. >> >> + Jonghwan Choi >> >> Well, this is not a perfect solution to support MAU power domain, it's true it is a problem right now though. >> >> In other words, this is just temporal fix for the problem. >> >> How about accessing clock stuff for audio sub-system with handling MAU power domain via generic IO power domain? >> > > + Tomasz Figa > > Existing power domain driver exynos4_pm_init_power_domain is registered > with an arch_initcall whereas the clk-exynos-audss driver is registered > with core_initcall. Hence even if add mau_pd node to clk-exynos-audss > node, the binding with power-domain doesn't happen. I'd say core_initcall is way too early for clk-exynos-audss driver. It should be at most subsys_initcall. As far as I can see, all users of clocks provided by this driver (i.e. i2s) are probed at device_initcall level anyway. > > Alternately, if Tomasz's patches are applied [1], power-domain binding > is successful. But because of the init order, clk-exynos-audss defers > probe resulting in a kernel crash. Forcing clk-exynos-audss to register > through arch_initcall() fixes this issue, but I am not sure if that is okay. If the driver crashes on deferred probe, then it's a bug and it should be fixed. Best regards, Tomasz