From mboxrd@z Thu Jan 1 00:00:00 1970 From: Alexandre Belloni Subject: Re: [PATCH] pwm: mxs: set pwm_chip can_sleep flag Date: Tue, 8 Apr 2014 16:24:26 +0200 Message-ID: <20140408142425.GB8861@piout.net> References: <1396956597-26159-1-git-send-email-shawn.guo@freescale.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Received: from top.free-electrons.com ([176.31.233.9]:52645 "EHLO mail.free-electrons.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1756634AbaDHOY3 (ORCPT ); Tue, 8 Apr 2014 10:24:29 -0400 Content-Disposition: inline In-Reply-To: <1396956597-26159-1-git-send-email-shawn.guo@freescale.com> Sender: linux-pwm-owner@vger.kernel.org List-Id: linux-pwm@vger.kernel.org To: Shawn Guo Cc: linux-pwm@vger.kernel.org, Thierry Reding , Stefan Wahren , linux-arm-kernel@lists.infradead.org On 08/04/2014 at 19:29:57 +0800, Shawn Guo wrote : > The .config() calls clk_get_rate() which might sleep, so we need to set > pwm_chip can_sleep flag. Otherwise, we see the following warning when > using pwm driven heartbeat led. > > WARNING: CPU: 0 PID: 0 at kernel/locking/mutex.c:856 mutex_trylock+0x184/0x1a4() > DEBUG_LOCKS_WARN_ON(in_interrupt()) > Modules linked in: > CPU: 0 PID: 0 Comm: swapper Not tainted 3.14.0-rc5 #18 > [] (unwind_backtrace) from [] (show_stack+0x10/0x14) > [] (show_stack) from [] (warn_slowpath_common+0x6c/0x8c) > [] (warn_slowpath_common) from [] (warn_slowpath_fmt+0x30/0x40) > [] (warn_slowpath_fmt) from [] (mutex_trylock+0x184/0x1a4) > [] (mutex_trylock) from [] (clk_prepare_lock+0xc/0xec) > [] (clk_prepare_lock) from [] (clk_get_rate+0xc/0x68) > [] (clk_get_rate) from [] (mxs_pwm_config+0x20/0x198) > [] (mxs_pwm_config) from [] (pwm_config+0x60/0x70) > [] (pwm_config) from [] (__led_pwm_set+0x1c/0x3c) > [] (__led_pwm_set) from [] (led_heartbeat_function+0x70/0x110) > [] (led_heartbeat_function) from [] (call_timer_fn+0x7c/0x164) > [] (call_timer_fn) from [] (run_timer_softirq+0x1f0/0x260) > [] (run_timer_softirq) from [] (__do_softirq+0xc4/0x2f0) > [] (__do_softirq) from [] (irq_exit+0xa4/0x10c) > [] (irq_exit) from [] (handle_IRQ+0x34/0x84) > [] (handle_IRQ) from [] (__irq_svc+0x44/0x54) > [] (__irq_svc) from [] (arch_cpu_idle+0x40/0x48) > [] (arch_cpu_idle) from [] (cpu_startup_entry+0x70/0x198) > [] (cpu_startup_entry) from [] (start_kernel+0x2a8/0x2f8) > > Reported-by: Stefan Wahren > Signed-off-by: Shawn Guo Acked-by: Alexandre Belloni > --- > drivers/pwm/pwm-mxs.c | 1 + > 1 file changed, 1 insertion(+) > > diff --git a/drivers/pwm/pwm-mxs.c b/drivers/pwm/pwm-mxs.c > index 9475bc7..4f1bb4e 100644 > --- a/drivers/pwm/pwm-mxs.c > +++ b/drivers/pwm/pwm-mxs.c > @@ -147,6 +147,7 @@ static int mxs_pwm_probe(struct platform_device *pdev) > mxs->chip.dev = &pdev->dev; > mxs->chip.ops = &mxs_pwm_ops; > mxs->chip.base = -1; > + mxs->chip.can_sleep = true; > ret = of_property_read_u32(np, "fsl,pwm-number", &mxs->chip.npwm); > if (ret < 0) { > dev_err(&pdev->dev, "failed to get pwm number: %d\n", ret); > -- > 1.8.3.2 > > -- Alexandre Belloni, Free Electrons Embedded Linux, Kernel and Android engineering http://free-electrons.com