Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753478AbcKSQBg (ORCPT ); Sat, 19 Nov 2016 11:01:36 -0500 Received: from mail-wm0-f66.google.com ([74.125.82.66]:36054 "EHLO mail-wm0-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753128AbcKSQB0 (ORCPT ); Sat, 19 Nov 2016 11:01:26 -0500 From: Nicolai Stange To: Thomas Gleixner Cc: John Stultz , linux-kernel@vger.kernel.org, Nicolai Stange Subject: [RFC v8 03/28] clocksource: em_sti: split clock prepare and enable steps Date: Sat, 19 Nov 2016 17:00:30 +0100 Message-Id: <20161119160055.12491-4-nicstange@gmail.com> X-Mailer: git-send-email 2.10.2 In-Reply-To: <20161119160055.12491-1-nicstange@gmail.com> References: <20161119160055.12491-1-nicstange@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2806 Lines: 94 Currently, the em_sti driver prepares and enables the needed clock in em_sti_enable(), potentially called through its clockevent device's ->set_state_oneshot(). However, the clk_prepare() step may sleep whereas tick_program_event() and thus, ->set_state_oneshot(), can be called in atomic context. Split the clk_prepare_enable() in em_sti_enable() into two steps: - prepare the clock at device probing via clk_prepare() - and enable it in em_sti_enable() via clk_enable(). Slightly reorder resource initialization in em_sti_probe() in order to facilitate error handling. Signed-off-by: Nicolai Stange --- Notes: Compile-only tested on ARCH=arm. drivers/clocksource/em_sti.c | 25 ++++++++++++++++++------- 1 file changed, 18 insertions(+), 7 deletions(-) diff --git a/drivers/clocksource/em_sti.c b/drivers/clocksource/em_sti.c index 19bb179..46750c0 100644 --- a/drivers/clocksource/em_sti.c +++ b/drivers/clocksource/em_sti.c @@ -78,7 +78,7 @@ static int em_sti_enable(struct em_sti_priv *p) int ret; /* enable clock */ - ret = clk_prepare_enable(p->clk); + ret = clk_enable(p->clk); if (ret) { dev_err(&p->pdev->dev, "cannot enable clock\n"); return ret; @@ -107,7 +107,7 @@ static void em_sti_disable(struct em_sti_priv *p) em_sti_write(p, STI_INTENCLR, 3); /* stop clock */ - clk_disable_unprepare(p->clk); + clk_disable(p->clk); } static cycle_t em_sti_count(struct em_sti_priv *p) @@ -303,6 +303,7 @@ static int em_sti_probe(struct platform_device *pdev) struct em_sti_priv *p; struct resource *res; int irq; + int ret; p = devm_kzalloc(&pdev->dev, sizeof(*p), GFP_KERNEL); if (p == NULL) @@ -323,6 +324,13 @@ static int em_sti_probe(struct platform_device *pdev) if (IS_ERR(p->base)) return PTR_ERR(p->base); + if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt, + IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, + dev_name(&pdev->dev), p)) { + dev_err(&pdev->dev, "failed to request low IRQ\n"); + return -ENOENT; + } + /* get hold of clock */ p->clk = devm_clk_get(&pdev->dev, "sclk"); if (IS_ERR(p->clk)) { @@ -330,17 +338,20 @@ static int em_sti_probe(struct platform_device *pdev) return PTR_ERR(p->clk); } - if (devm_request_irq(&pdev->dev, irq, em_sti_interrupt, - IRQF_TIMER | IRQF_IRQPOLL | IRQF_NOBALANCING, - dev_name(&pdev->dev), p)) { - dev_err(&pdev->dev, "failed to request low IRQ\n"); - return -ENOENT; + ret = clk_prepare(p->clk); + if (ret < 0) { + dev_err(&pdev->dev, "cannot prepare clock\n"); + goto err_clk_put; } raw_spin_lock_init(&p->lock); em_sti_register_clockevent(p); em_sti_register_clocksource(p); return 0; + +err_clk_put: + clk_put(p->clk); + return ret; } static int em_sti_remove(struct platform_device *pdev) -- 2.10.2