If the pwm can sleep defer actions to it using a worker. A similar approach was used in leds-pwm (c971ff185)
Trigger: 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 4.5-rc1 and 4.1. Unmodified applicable to * 4.5-rc4 * 4.4.1 (stable) * 4.3.5 (stable) * 4.1.18 (longterm) Modified applicable to * 3.18.27 (longterm) Signed-off-by: Manfred Schlaegl <manfred.schla...@gmx.at> --- drivers/input/misc/pwm-beeper.c | 62 +++++++++++++++++++++++++++++------------ 1 file changed, 44 insertions(+), 18 deletions(-) diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c index f2261ab..c160b5e 100644 --- a/drivers/input/misc/pwm-beeper.c +++ b/drivers/input/misc/pwm-beeper.c @@ -20,21 +20,42 @@ #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; + bool can_sleep; }; #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 +70,15 @@ 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); + + if (beeper->can_sleep) + schedule_work(&beeper->work); + else + __pwm_beeper_set(beeper); return 0; } @@ -87,6 +105,10 @@ static int pwm_beeper_probe(struct platform_device *pdev) goto err_free; } + beeper->can_sleep = pwm_can_sleep(beeper->pwm); + if (beeper->can_sleep) + 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"); @@ -133,6 +155,9 @@ static int pwm_beeper_remove(struct platform_device *pdev) { struct pwm_beeper *beeper = platform_get_drvdata(pdev); + if (beeper->can_sleep) + cancel_work_sync(&beeper->work); + input_unregister_device(beeper->input); pwm_disable(beeper->pwm); @@ -147,6 +172,9 @@ static int __maybe_unused pwm_beeper_suspend(struct device *dev) { struct pwm_beeper *beeper = dev_get_drvdata(dev); + if (beeper->can_sleep) + cancel_work_sync(&beeper->work); + if (beeper->period) pwm_disable(beeper->pwm); @@ -157,10 +185,8 @@ 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