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Message-ID: <574412BC.1070406@gmx.at> Date: Tue, 24 May 2016 10:37:16 +0200 From: Manfred Schlaegl <manfred.schlaegl@....at> To: Dmitry Torokhov <dmitry.torokhov@...il.com> Cc: Thierry Reding <thierry.reding@...il.com>, Manfred Schlaegl <manfred.schlaegl@...zinger.com>, Luis de Bethencourt <luis@...ethencourt.com>, Olivier Sobrie <olivier@...rie.be>, linux-input@...r.kernel.org, linux-kernel@...r.kernel.org, Greg Kroah-Hartman <gregkh@...uxfoundation.org> Subject: Re: [PATCH] Input: pwm-beeper - fix: scheduling while atomic Pwm config may sleep so defer it using a worker. On a Freescale i.MX53 based board we ran into "BUG: scheduling while atomic" because input_inject_event locks interrupts, but imx_pwm_config_v2 sleeps. Tested on Freescale i.MX53 SoC with 4.6.0 and 4.1.24. Signed-off-by: Manfred Schlaegl <manfred.schlaegl@....at> --- drivers/input/misc/pwm-beeper.c | 54 +++++++++++++++++++++++++++-------------- 1 file changed, 36 insertions(+), 18 deletions(-) diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c index f2261ab..014495d3 100644 --- a/drivers/input/misc/pwm-beeper.c +++ b/drivers/input/misc/pwm-beeper.c @@ -20,21 +20,41 @@ #include <linux/platform_device.h> #include <linux/pwm.h> #include <linux/slab.h> +#include <linux/workqueue.h> struct pwm_beeper { struct input_dev *input; struct pwm_device *pwm; + struct work_struct work; unsigned long period; }; #define HZ_TO_NANOSECONDS(x) (1000000000UL/(x)) +static void __pwm_beeper_set(struct pwm_beeper *beeper) +{ + unsigned long period = beeper->period; + + pwm_config(beeper->pwm, period / 2, period); + + if (period == 0) + pwm_disable(beeper->pwm); + else + pwm_enable(beeper->pwm); +} + +static void pwm_beeper_work(struct work_struct *work) +{ + struct pwm_beeper *beeper = + container_of(work, struct pwm_beeper, work); + + __pwm_beeper_set(beeper); +} + static int pwm_beeper_event(struct input_dev *input, unsigned int type, unsigned int code, int value) { - int ret = 0; struct pwm_beeper *beeper = input_get_drvdata(input); - unsigned long period; if (type != EV_SND || value < 0) return -EINVAL; @@ -49,18 +69,12 @@ static int pwm_beeper_event(struct input_dev *input, return -EINVAL; } - if (value == 0) { - pwm_disable(beeper->pwm); - } else { - period = HZ_TO_NANOSECONDS(value); - ret = pwm_config(beeper->pwm, period / 2, period); - if (ret) - return ret; - ret = pwm_enable(beeper->pwm); - if (ret) - return ret; - beeper->period = period; - } + if (value == 0) + beeper->period = 0; + else + beeper->period = HZ_TO_NANOSECONDS(value); + + schedule_work(&beeper->work); return 0; } @@ -87,6 +101,8 @@ static int pwm_beeper_probe(struct platform_device *pdev) goto err_free; } + INIT_WORK(&beeper->work, pwm_beeper_work); + beeper->input = input_allocate_device(); if (!beeper->input) { dev_err(&pdev->dev, "Failed to allocate input device\n"); @@ -135,6 +151,8 @@ static int pwm_beeper_remove(struct platform_device *pdev) input_unregister_device(beeper->input); + cancel_work_sync(&beeper->work); + pwm_disable(beeper->pwm); pwm_free(beeper->pwm); @@ -147,6 +165,8 @@ static int __maybe_unused pwm_beeper_suspend(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); + cancel_work_sync(&beeper->work); + if (beeper->period) pwm_disable(beeper->pwm); @@ -157,10 +177,8 @@ static int __maybe_unused pwm_beeper_resume(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); - if (beeper->period) { - pwm_config(beeper->pwm, beeper->period / 2, beeper->period); - pwm_enable(beeper->pwm); - } + if (beeper->period) + __pwm_beeper_set(beeper); return 0; } -- 2.1.4
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