Hello Mike, On 04/01/2015 03:29 AM, Michael Turquette wrote: > Quoting Javier Martinez Canillas (2015-03-31 01:59:39) >> +Tomeu who I forgot to add to the cc list. >> >> Hello Mike, >> >> Thanks a lot for your feedback. >> >> On 03/31/2015 03:40 AM, Michael Turquette wrote: >> >> >> >> I don't performance is a big issue here. I just thought that since the >> >> lookup table is already filled by the driver and the lookup function >> >> is one line, we could use that instead to get the performance benefit. >> >> >> >> But I don't mind to drop this patch and use the generic lookup function >> >> from the CCF API if that is preferred. >> > >> > Hello, >> > >> > I am not a fan of __clk_lookup and I don't like to see it used more and >> > more outside of drivers/clk/clk.c. You mentioned that performance wasn't >> > really the problem here. The real method for a driver to get a clock is >> > with clk_get(). Any reason to not use that? >> > >> >> I can certainly use clk_get() but I thought that the clk consumer API was >> not supposed to be used from within clock drivers. That's why I mentioned >> __clk_lookup() as a possibility since that is part of the provider API. > > I would like to remove __clk_lookup some day, so the fewer users now the > better. Additionally, now that we have unique struct clk pointers from > clk_get it makes a lot of sense for clk_register to stop returning > pointers to a struct clk. Hopefully we can get around to that soon. > > These two points above are enough reason for the clock provider to use > clk_get. > Got it. >> >> Below is a RFC patch that uses clk_get() [0]. That needs another patch >> which was part of a previous RFC and adds an alias for the mdma0 clock: >> >> https://lkml.org/lkml/2015/3/27/769 >> >> If you think that is the correct approach then I can post it as a patch. >> >> It would be great if you can also provide some feedback about the other >> patch in the first RFC that instead of enabling and disabling the mdma0 >> clock in driver, does it in the exynos5420 platform PM callbacks: >> >> https://lkml.org/lkml/2015/3/27/770 > > This seems like a big hack to me. > Ok, good to know. I just did because initially I thought that the clock consumer API was not allowed to be used from within clock drivers. >> >> I was asked to do it in the exynos5420 clk driver instead but maybe you >> have a different opinion on that. >> >> Best regards, >> Javier >> >> [0]: >> From c118df83da8cac65cc218ae9443622592222f5d0 Mon Sep 17 00:00:00 2001 >> From: Javier Martinez Canillas <javier.martinez@xxxxxxxxxxxxxxx> >> Date: Mon, 30 Mar 2015 17:11:40 +0200 >> Subject: [RFC] clk: exynos5420: Make sure MDMA0 clock is enabled during >> suspend >> >> Commit ae43b3289186 ("ARM: 8202/1: dmaengine: pl330: Add runtime Power >> Management support v12") added pm support for the pl330 dma driver but >> it makes the clock for the Exynos5420 MDMA0 DMA controller to be gated >> during suspend and this clock needs to remain enabled in order to make >> the system resume from a system suspend state. >> >> To make sure that the clock is enabled during suspend, enable it prior >> to entering a suspend state and disable it once the system has resumed. > > I'd like to understand the issue a bit further. Isn't the correct > solution that the clk's prepare/unprepare and enable/disable callbacks > should support the CG_STATUS requirement? > Agreed, I'll take a look to that. > Regards, > Mike > Best regards, Javier -- To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
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