From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751779AbcBKVTu (ORCPT ); Thu, 11 Feb 2016 16:19:50 -0500 Received: from mail-pf0-f177.google.com ([209.85.192.177]:34615 "EHLO mail-pf0-f177.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751707AbcBKVTs (ORCPT ); Thu, 11 Feb 2016 16:19:48 -0500 From: Michael Turquette To: linux-clk@vger.kernel.org Cc: lee.jones@linaro.org, sboyd@codeaurora.org, maxime.ripard@free-electrons.com, maxime.coquelin@st.com, geert@linux-m68k.org, heiko@sntech.de, andre.przywara@arm.com, rklein@nvidia.com, linux-kernel@vger.kernel.org, Michael Turquette Subject: [PATCH v42 5/6] clk: clk_put WARNs if user has not disabled clk Date: Thu, 11 Feb 2016 13:19:13 -0800 Message-Id: <1455225554-13267-6-git-send-email-mturquette@baylibre.com> X-Mailer: git-send-email 2.1.4 In-Reply-To: <1455225554-13267-1-git-send-email-mturquette@baylibre.com> References: <1455225554-13267-1-git-send-email-mturquette@baylibre.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>From the clk_put kerneldoc in include/linux/clk.h: """ Note: drivers must ensure that all clk_enable calls made on this clock source are balanced by clk_disable calls prior to calling this function. """ The common clock framework implementation of the clk.h api has per-user reference counts for calls to clk_prepare and clk_disable. As such it can enforce the requirement to properly call clk_disable and clk_unprepare before calling clk_put. Because this requirement is probably violated in many places, this patch starts with a simple warning. Once offending code has been fixed this check could additionally release the reference counts automatically. Signed-off-by: Michael Turquette --- Changed in v2ish: * s/WARN_ON/WARN_ON_ONCE/ to reduce noise for pm-clocks drivers/clk/clk.c | 8 ++++++++ 1 file changed, 8 insertions(+) diff --git a/drivers/clk/clk.c b/drivers/clk/clk.c index 01183e3..d81f970 100644 --- a/drivers/clk/clk.c +++ b/drivers/clk/clk.c @@ -2824,6 +2824,14 @@ void __clk_put(struct clk *clk) clk->max_rate < clk->core->req_rate) clk_core_set_rate_nolock(clk->core, clk->core->req_rate); + /* + * before calling clk_put, all calls to clk_prepare and clk_enable from + * a given user must be balanced with calls to clk_disable and + * clk_unprepare by that same user + */ + WARN_ON_ONCE(clk->prepare_count); + WARN_ON_ONCE(clk->enable_count); + owner = clk->core->owner; kref_put(&clk->core->ref, __clk_release); -- 2.1.4