Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753461AbaKHBHI (ORCPT ); Fri, 7 Nov 2014 20:07:08 -0500 Received: from mail-ie0-f173.google.com ([209.85.223.173]:51186 "EHLO mail-ie0-f173.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753422AbaKHBHG (ORCPT ); Fri, 7 Nov 2014 20:07:06 -0500 From: Doug Anderson To: Mike Turquette Cc: Heiko Stuebner , Dmitry Torokhov , linux-arm-kernel@lists.infradead.org, linux-rockchip@lists.infradead.org, Russell King - ARM Linux , Doug Anderson , linux-kernel@vger.kernel.org Subject: [PATCH v2] clk: Propagate prepare and enable when reparenting orphans Date: Fri, 7 Nov 2014 17:06:58 -0800 Message-Id: <1415408818-28028-1-git-send-email-dianders@chromium.org> X-Mailer: git-send-email 2.1.0.rc2.206.gedb03e5 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- Changes in v2: - Only do the work for orphans, not for other users of __clk_reparent(). drivers/clk/clk.c | 20 ++++++++++++++++++-- 1 file changed, 18 insertions(+), 2 deletions(-) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 4896ae9..0f04b7c 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -1652,6 +1652,22 @@ void __clk_reparent(struct clk *clk, struct clk *new_parent) __clk_recalc_rates(clk, POST_RATE_CHANGE); } +static void __clk_reparent_orphan(struct clk *clk, struct clk *new_parent) +{ + __clk_reparent(clk, new_parent); + + if (clk->prepare_count) { + unsigned long flags; + + __clk_prepare(new_parent); + + flags = clk_enable_lock(); + if (clk->enable_count) + __clk_enable(new_parent); + clk_enable_unlock(flags); + } +} + /** * clk_set_parent - switch the parent of a mux clk * @clk: the mux clk whose input we are switching @@ -1953,13 +1969,13 @@ int __clk_init(struct device *dev, struct clk *clk) if (orphan->num_parents && orphan->ops->get_parent) { i = orphan->ops->get_parent(orphan->hw); if (!strcmp(clk->name, orphan->parent_names[i])) - __clk_reparent(orphan, clk); + __clk_reparent_orphan(orphan, clk); continue; } for (i = 0; i < orphan->num_parents; i++) if (!strcmp(clk->name, orphan->parent_names[i])) { - __clk_reparent(orphan, clk); + __clk_reparent_orphan(orphan, clk); break; } } -- 2.1.0.rc2.206.gedb03e5 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/