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Input: pwm-beeper - fix - scheduling while atomic

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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: Manfred Schlaegl <manfred.schlaegl@gmx.at>
Cc: stable@vger.kernel.org
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Manfred Schlaegl 2016-05-27 16:36:36 -07:00 committed by Dmitry Torokhov
parent 6f49a398b2
commit f49cf3b8b4
1 changed files with 48 additions and 21 deletions
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69
drivers/input/misc/pwm-beeper.c
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@ -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;
@ -49,22 +68,31 @@ 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;
}
static void pwm_beeper_stop(struct pwm_beeper *beeper)
{
cancel_work_sync(&beeper->work);
if (beeper->period)
pwm_disable(beeper->pwm);
}
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)
{
unsigned long pwm_id = (unsigned long)dev_get_platdata(&pdev->dev);
@ -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;
}