On Fri, May 27, 2016 at 11:14:27AM +0200, Manfred Schlaegl wrote:
> 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.schla...@gmx.at>
Applied, thank you.
> ---
> drivers/input/misc/pwm-beeper.c | 69
> ++++++++++++++++++++++++++++-------------
> 1 file changed, 48 insertions(+), 21 deletions(-)
>
> diff --git a/drivers/input/misc/pwm-beeper.c b/drivers/input/misc/pwm-beeper.c
> index 8d71332..5f9655d 100644
> --- a/drivers/input/misc/pwm-beeper.c
> +++ b/drivers/input/misc/pwm-beeper.c
> @@ -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);
> @@ -93,6 +121,8 @@ static int pwm_beeper_probe(struct platform_device *pdev)
> */
> pwm_apply_args(beeper->pwm);
>
> + 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");
> @@ -112,6 +142,7 @@ 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);
>
> @@ -141,7 +172,6 @@ static int pwm_beeper_remove(struct platform_device *pdev)
>
> input_unregister_device(beeper->input);
>
> - pwm_disable(beeper->pwm);
> pwm_free(beeper->pwm);
>
> kfree(beeper);
> @@ -153,8 +183,7 @@ 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;
> }
> @@ -163,10 +192,8 @@ 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
>
--
Dmitry
