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Date: Fri, 3 Apr 2015 10:35:56 +0200 From: Krzysztof Kozlowski <k.kozlowski@...sung.com> To: Andrzej Hajda <a.hajda@...sung.com> Cc: Krzysztof Kozlowski <k.kozlowski@...sung.com>, Javier Martinez Canillas <javier.martinez@...labora.co.uk>, Kukjin Kim <kgene@...nel.org>, devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org, linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org, Marek Szyprowski <m.szyprowski@...sung.com> Subject: Re: [PATCH 1/2] ARM: EXYNOS: Get current parent clock for power domain on/off 2015-04-03 10:12 GMT+02:00 Andrzej Hajda <a.hajda@...sung.com>: > On 04/02/2015 02:44 PM, Krzysztof Kozlowski wrote: >> 2015-04-02 14:29 GMT+02:00 Javier Martinez Canillas >> <javier.martinez@...labora.co.uk>: >>> 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(). > > Hi Krzysztof, > > I wonder if it wouldn't be better to drop entirely pclks. Power domains > should save/restore its previous state, setting fixed parents on domain > resume can fool drivers as you described earlier. I wanted to preserve full backward compatibility (including behaviour compatibility). However I can't find valid reason to switch to some fixed clock after powering up domain so if there are not objections I will drop pclk entirely. Thanks! Krzysztof -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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