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Commit f49cf3b8 authored by Manfred Schlaegl's avatar Manfred Schlaegl Committed by Dmitry Torokhov
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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.

Signed-off-by: default avatarManfred Schlaegl <manfred.schlaegl@gmx.at>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarDmitry Torokhov <dmitry.torokhov@gmail.com>
parent 6f49a398

drivers/input/misc/pwm-beeper.c

+48 −21
Original line number Diff line number Diff line
@@ -20,21 +20,40 @@ 
#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;



	if (period) {

		pwm_config(beeper->pwm, period / 2, period);

		pwm_enable(beeper->pwm);

	} else

		pwm_disable(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;
@@ -49,20 +68,29 @@ static int pwm_beeper_event(struct input_dev *input, 
		return -EINVAL;

	}



	if (value == 0) {

	if (value == 0)

		beeper->period = 0;

	else

		beeper->period = HZ_TO_NANOSECONDS(value);



	schedule_work(&beeper->work);



	return 0;

}



static void pwm_beeper_stop(struct pwm_beeper *beeper)

{

	cancel_work_sync(&beeper->work);



	if (beeper->period)

		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;

}



	return 0;

static void pwm_beeper_close(struct input_dev *input)

{

	struct pwm_beeper *beeper = input_get_drvdata(input);



	pwm_beeper_stop(beeper);

}



static int pwm_beeper_probe(struct platform_device *pdev)
@@ -87,6 +115,8 @@ 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");
@@ -106,6 +136,7 @@ static int pwm_beeper_probe(struct platform_device *pdev) 
	beeper->input->sndbit[0] = BIT(SND_TONE) | BIT(SND_BELL);



	beeper->input->event = pwm_beeper_event;

	beeper->input->close = pwm_beeper_close;



	input_set_drvdata(beeper->input, beeper);
@@ -135,7 +166,6 @@ static int pwm_beeper_remove(struct platform_device *pdev) 


	input_unregister_device(beeper->input);



	pwm_disable(beeper->pwm);

	pwm_free(beeper->pwm);



	kfree(beeper);
@@ -147,8 +177,7 @@ static int __maybe_unused pwm_beeper_suspend(struct device *dev) 
{

	struct pwm_beeper *beeper = dev_get_drvdata(dev);



	if (beeper->period)

		pwm_disable(beeper->pwm);

	pwm_beeper_stop(beeper);



	return 0;

}
@@ -157,10 +186,8 @@ 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;

}