lkml.org 
[lkml]   [2016]   [Jun]   [9]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 4.2.y-ckt 144/206] Input: pwm-beeper - fix - scheduling while atomic
    Date
    4.2.8-ckt12 -stable review patch.  If anyone has any objections, please let me know.

    ---8<------------------------------------------------------------

    From: Manfred Schlaegl <manfred.schlaegl@gmx.at>

    commit f49cf3b8b4c841457244c461c66186a719e13bcc upstream.

    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>
    Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
    Signed-off-by: Kamal Mostafa <kamal@canonical.com>
    ---
    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 e82edf8..9021725 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);
    @@ -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;
    }
    --
    2.7.4
    \
     
     \ /
      Last update: 2016-06-10 00:21    [W:4.075 / U:0.036 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site