From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753223AbbDBMod (ORCPT ); Thu, 2 Apr 2015 08:44:33 -0400 Received: from mail-yh0-f44.google.com ([209.85.213.44]:36715 "EHLO mail-yh0-f44.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750876AbbDBMoa (ORCPT ); Thu, 2 Apr 2015 08:44:30 -0400 MIME-Version: 1.0 In-Reply-To: <551D362B.90901@collabora.co.uk> References: <1427961979-29477-1-git-send-email-k.kozlowski@samsung.com> <551D362B.90901@collabora.co.uk> Date: Thu, 2 Apr 2015 14:44:29 +0200 X-Google-Sender-Auth: ycEauswKjTqcNe9n_5-o_HOl1Uo Message-ID: Subject: Re: [PATCH 1/2] ARM: EXYNOS: Get current parent clock for power domain on/off From: Krzysztof Kozlowski To: Javier Martinez Canillas Cc: Krzysztof Kozlowski , Kukjin Kim , devicetree@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-samsung-soc@vger.kernel.org, linux-kernel@vger.kernel.org, Marek Szyprowski Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 2015-04-02 14:29 GMT+02:00 Javier Martinez Canillas : > Hello Krzysztof, > > On 04/02/2015 10:06 AM, Krzysztof Kozlowski wrote: >> Using a fixed (by DTS) parent for clocks when turning on the power domain >> may introduce issues in other drivers. For example when such driver >> changes the parent during runtime and expects that he is the only place >> of such change. >> >> Do not rely entirely on DTS providing the fixed parent for such clocks. >> Instead if "pclkN" clock name is missing, grab a current parent of clock >> with clk_get_parent(). >> >> Signed-off-by: Krzysztof Kozlowski >> --- >> Documentation/devicetree/bindings/arm/exynos/power_domain.txt | 8 +++++--- >> arch/arm/mach-exynos/pm_domains.c | 9 ++++++--- >> 2 files changed, 11 insertions(+), 6 deletions(-) >> >> diff --git a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >> index 5da38c5ed476..0fc1312f6fd5 100644 >> --- a/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >> +++ b/Documentation/devicetree/bindings/arm/exynos/power_domain.txt >> @@ -19,9 +19,11 @@ Optional Properties: >> domains. >> - clock-names: The following clocks can be specified: >> - oscclk: Oscillator clock. >> - - pclkN, clkN: Pairs of parent of input clock and input clock to the >> - devices in this power domain. Maximum of 4 pairs (N = 0 to 3) >> - are supported currently. >> + - pclkN, clkN: Input clocks (clkN) to the devices in this power domain. >> + Optionally with parrents (pclkN). If such parent is provided >> + it will be used for reparenting the given clock when domain >> + is turned on. Otherwise the parent before power down will be >> + used. Maximum of 4 pairs (N = 0 to 3) are supported currently. >> - asbN: Clocks required by asynchronous bridges (ASB) present in >> the power domain. These clock should be enabled during power >> domain on/off operations. >> diff --git a/arch/arm/mach-exynos/pm_domains.c b/arch/arm/mach-exynos/pm_domains.c >> index cbe56b35aea0..c55bcf52a6ad 100644 >> --- a/arch/arm/mach-exynos/pm_domains.c >> +++ b/arch/arm/mach-exynos/pm_domains.c >> @@ -37,6 +37,7 @@ struct exynos_pm_domain { >> struct clk *oscclk; >> struct clk *clk[MAX_CLK_PER_DOMAIN]; >> struct clk *pclk[MAX_CLK_PER_DOMAIN]; >> + unsigned int pclk_dynamic:MAX_CLK_PER_DOMAIN; >> struct clk *asb_clk[MAX_CLK_PER_DOMAIN]; >> }; >> >> @@ -62,6 +63,9 @@ static int exynos_pd_power(struct generic_pm_domain *domain, bool power_on) >> for (i = 0; i < MAX_CLK_PER_DOMAIN; i++) { >> if (IS_ERR(pd->clk[i])) >> break; >> + /* If parent was not set in DT, save current parent */ >> + if (pd->pclk_dynamic & (1 << i)) > > Small nit: I personally think that using the BIT(i) macro for shifting bits > is more readable but I guess is a matter of personal taste. Right, it seems I always forget about BIT macro. I'll respin with BIT() and your review/tested tags. Thanks for feedback and testing! Best regards, Krzysztof