From mboxrd@z Thu Jan 1 00:00:00 1970 From: sboyd@codeaurora.org (Stephen Boyd) Date: Fri, 10 Apr 2015 17:59:08 -0700 Subject: [PATCH 1/4] clk: Propagate prepare and enable when reparenting orphans In-Reply-To: <1427988853-9549-2-git-send-email-heiko@sntech.de> References: <1427988853-9549-1-git-send-email-heiko@sntech.de> <1427988853-9549-2-git-send-email-heiko@sntech.de> Message-ID: <552871DC.2020400@codeaurora.org> To: linux-arm-kernel@lists.infradead.org List-Id: linux-arm-kernel.lists.infradead.org On 04/02/15 08:34, Heiko Stuebner wrote: > From: Doug Anderson > > With the existing code, if you find a parent for an orhpan that has > already been prepared / enabled, you won't enable the parent. That > can cause later problems since the clock tree isn't in a consistent > state. Fix by propagating the prepare and enable. > > NOTE: this does bring up the question about whether the enable of the > orphan actually made sense. If the orphan's parent wasn't enabled by > default (by the bootloader or the default state of the hardware) then > the original enable of the orphan probably didn't do what the caller > though it would. Some users of the orphan might have preferred an > EPROBE_DEFER be returned until we had a full path to a root clock. > This patch doesn't address those concerns and really just syncs up the > state. > > Tested on rk3288-evb-rk808 by temporarily considering "sclk_tsadc" as > a critical clock (to simulate a driver enabling it at bootup). > > Before: > > clock enable_cnt prepare_cnt rate accuracy phase > ---------------------------------------------------------------------------------------- > xin32k 0 0 32768 0 0 > sclk_hdmi_cec 0 0 32768 0 0 > sclk_otg_adp 0 0 32768 0 0 > sclk_tsadc 1 1 993 0 0 > > After: > > clock enable_cnt prepare_cnt rate accuracy phase > ---------------------------------------------------------------------------------------- > xin32k 1 1 32768 0 0 > sclk_hdmi_cec 0 0 32768 0 0 > sclk_otg_adp 0 0 32768 0 0 > sclk_tsadc 1 1 993 0 0 > > Note that xin32k on rk808 is a clock that cannot be disabled in > hardware (it's an always on clock), so really all we needed to do was > to sync up the state. > > Signed-off-by: Doug Anderson > > Adapted to recent clk->clk_core changes and move orphan handling to > a separate function as the main clk_core_reparent function is already > also used in other contexts. > Signed-off-by: Heiko Stuebner > --- Sorry I don't get this patch at all. We shouldn't be handing out clocks to consumers if the clock is an orphan. We also have a problem syncing enable state in the framework with what is there in hardware when we boot up. These aren't the same problem but they're related. Let's not conflate the two. -- Qualcomm Innovation Center, Inc. is a member of Code Aurora Forum, a Linux Foundation Collaborative Project