From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752200AbcHHPxZ (ORCPT ); Mon, 8 Aug 2016 11:53:25 -0400 Received: from mail-wm0-f45.google.com ([74.125.82.45]:35424 "EHLO mail-wm0-f45.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752125AbcHHPxX (ORCPT ); Mon, 8 Aug 2016 11:53:23 -0400 Subject: Re: [PATCH] clk: Hi6220: enable stub clock driver for ARCH_HISI To: Amit Kucheria , Leo Yan References: <1470627463-20570-1-git-send-email-leo.yan@linaro.org> <20160808064241.GA30622@leoy-linaro> Cc: Michael Turquette , Stephen Boyd , Jiancheng Xue , Philipp Zabel , Rob Herring , linux-clk@vger.kernel.org, LKML , Dietmar Eggemann , Guodong Xu From: Daniel Thompson Message-ID: <5d98a054-c057-81eb-9ee7-789353a093e5@linaro.org> Date: Mon, 8 Aug 2016 16:53:19 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101 Thunderbird/45.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 08/08/16 15:42, Amit Kucheria wrote: > On Mon, Aug 8, 2016 at 12:12 PM, Leo Yan wrote: >> Hi Amit, >> >> On Mon, Aug 08, 2016 at 11:23:31AM +0530, Amit Kucheria wrote: >>> On Mon, Aug 8, 2016 at 9:07 AM, Leo Yan wrote: >>>> In current kernel config 'CONFIG_STUB_CLK_HI6220' is disabled by >>>> default, as result stub clock driver has not been registered and >>>> CPUFreq driver cannot work. >>> >>> I have a related patch that has been pending for a while: >>> https://lkml.org/lkml/2016/6/20/375 but it was tied only to the >>> thermal driver. >> >> I also have concern this patch may duplicate with yours. >> >>> Is the stub mandatory for the architecture? Will other SoCs in the >>> family will use the same stub? >> >> I don't think stub driver is mandartory for archtitecture and it's >> only used by Hi6220 on Hikey. AFAIK, currently stub driver is only used >> by CPU frequency change. >> >> The logic is: >> Thermal cooling device driver >> `-> CPUFreq DT driver >> `-> Stub clock driver >> >> ARM is working on Hikey for EAS profiling, so usually the use case is >> to enable CPUFreq driver and stub clock driver. Sometimes it only >> need enable this driver without thermal driver; so this is why we >> cannot rely on thermal driver to enable stub clock driver. >> >> I'm open-minded if you have better idea to enable it. >> >>>> This patch is to enable stub clock driver in config for ARCH_HISI. >>>> >>>> Reported-by: Dietmar Eggemann >>>> Signed-off-by: Leo Yan >>>> --- >>>> drivers/clk/hisilicon/Kconfig | 1 + >>>> 1 file changed, 1 insertion(+) >>>> >>>> diff --git a/drivers/clk/hisilicon/Kconfig b/drivers/clk/hisilicon/Kconfig >>>> index 3f537a0..9e0a95e 100644 >>>> --- a/drivers/clk/hisilicon/Kconfig >>>> +++ b/drivers/clk/hisilicon/Kconfig >>>> @@ -23,5 +23,6 @@ config RESET_HISI >>>> config STUB_CLK_HI6220 >>>> bool "Hi6220 Stub Clock Driver" >>>> depends on COMMON_CLK_HI6220 && MAILBOX >>>> + default ARCH_HISI > > Instead of forcing this up on the entire arch, why not restrict it to > just the cpufreq driver? ARM_HISI_ACPU_CPUFREQ? I'm struggling to understand the concern here. default doesn't force this option on anything, it just sets the default. Personally I might prefer 'default y' because it is simpler and involves less thinking. However the other drivers in this directory use 'default ARCH_HISI' (i.e. they do not default on for a COMPILE_TEST) so copying their approach is quite reasonable. Daniel.