target/linux/s3c24xx/patches-2.6.24/1123-fix-jack-debounce.patch.patch

   1 From 9a5d2d81c0bf5c8fe2ac58d267033876904ed925 Mon Sep 17 00:00:00 2001
   2 From: Andy Green <andy@openmoko.com>
   3 Date: Sun, 13 Apr 2008 07:25:57 +0100
   4 Subject: [PATCH] fix-jack-debounce.patch
   5
   6 Headphone jack detection is bouncy, it can trigger multiple interrupts
   7 on insertion or removal.  This patch adds a workqueue that waits out the
   8 interrupt spew in 100ms units, and if it sees no more interrupts for 100ms
   9 only then samples and reports the jack state.  I was unable to get a bounce
  10 after 20 or so tries after this.
  11
  12 Signed-off-by: Andy Green <andy@openmoko.com>
  13 ---
  14  drivers/input/keyboard/neo1973kbd.c |   63 ++++++++++++++++++++++++++++++++--
  15  1 files changed, 59 insertions(+), 4 deletions(-)
  16
  17 diff --git a/drivers/input/keyboard/neo1973kbd.c b/drivers/input/keyboard/neo1973kbd.c
  18 index 06fa8e0..6c96660 100644
  19 --- a/drivers/input/keyboard/neo1973kbd.c
  20 +++ b/drivers/input/keyboard/neo1973kbd.c
  21 @@ -21,6 +21,7 @@
  22  #include <linux/jiffies.h>
  23  #include <linux/module.h>
  24  #include <linux/slab.h>
  25 +#include <linux/workqueue.h>
  26
  27  #include <asm/gpio.h>
  28  #include <asm/mach-types.h>
  29 @@ -28,6 +29,11 @@
  30  struct neo1973kbd {
  31         struct input_dev *input;
  32         unsigned int suspended;
  33 +       struct work_struct work;
  34 +       int work_in_progress;
  35 +       int hp_irq_count_in_work;
  36 +       int hp_irq_count;
  37 +       int jack_irq;
  38  };
  39
  40  static irqreturn_t neo1973kbd_aux_irq(int irq, void *dev_id)
  41 @@ -52,14 +58,61 @@ static irqreturn_t neo1973kbd_hold_irq(int irq, void *dev_id)
  42         return IRQ_HANDLED;
  43  }
  44
  45 +
  46 +static void neo1973kbd_debounce_jack(struct work_struct *work)
  47 +{
  48 +       struct neo1973kbd *kbd = container_of(work, struct neo1973kbd, work);
  49 +
  50 +       /* we wait out any multiple interrupt stuttering in 100ms lumps */
  51 +
  52 +       do {
  53 +               kbd->hp_irq_count_in_work = kbd->hp_irq_count;
  54 +               msleep(100);
  55 +       } while (kbd->hp_irq_count != kbd->hp_irq_count_in_work);
  56 +
  57 +       /* no new interrupts on jack for 100ms... ok we will report it */
  58 +
  59 +       input_report_switch(kbd->input,
  60 +                           SW_HEADPHONE_INSERT,
  61 +                           gpio_get_value(irq_to_gpio(kbd->jack_irq)));
  62 +       input_sync(kbd->input);
  63 +
  64 +       /* next time we get an interrupt on jack we need new work action */
  65 +       kbd->work_in_progress = 0;
  66 +}
  67 +
  68 +
  69 +
  70  static irqreturn_t neo1973kbd_headphone_irq(int irq, void *dev_id)
  71  {
  72         struct neo1973kbd *neo1973kbd_data = dev_id;
  73
  74 -       int key_pressed = gpio_get_value(irq_to_gpio(irq));
  75 -       input_report_switch(neo1973kbd_data->input,
  76 -                           SW_HEADPHONE_INSERT, key_pressed);
  77 -       input_sync(neo1973kbd_data->input);
  78 +       /*
  79 +        * this interrupt is prone to bouncing and userspace doesn't like
  80 +        * to have to deal with that kind of thing.  So we do not accept
  81 +        * that a jack interrupt is equal to a jack event.  Instead we fire
  82 +        * some work on the first interrupt, and it hangs about in 100ms units
  83 +        * until no more interrupts come.  Then it accepts the state it finds
  84 +        * for jack insert and reports it once
  85 +        */
  86 +
  87 +       neo1973kbd_data->hp_irq_count++;
  88 +       /*
  89 +        * the first interrupt we see for a while, we fire the work item
  90 +        * and record the interrupt count when we did that.  If more interrupts
  91 +        * come in the meanwhile, we can tell by the difference in that
  92 +        * stored count and hp_irq_count which increments every interrupt
  93 +        */
  94 +       if (!neo1973kbd_data->work_in_progress) {
  95 +               neo1973kbd_data->jack_irq = irq;
  96 +               neo1973kbd_data->hp_irq_count_in_work =
  97 +                                               neo1973kbd_data->hp_irq_count;
  98 +               if (!schedule_work(&neo1973kbd_data->work))
  99 +                       printk(KERN_ERR
 100 +                               "Unable to schedule headphone debounce\n");
 101 +               else
 102 +                       neo1973kbd_data->work_in_progress = 1;
 103 +       }
 104
 105         return IRQ_HANDLED;
 106  }
 107 @@ -120,6 +173,8 @@ static int neo1973kbd_probe(struct platform_device *pdev)
 108
 109         neo1973kbd->input = input_dev;
 110
 111 +       INIT_WORK(&neo1973kbd->work, neo1973kbd_debounce_jack);
 112 +
 113         input_dev->name = "Neo1973 Buttons";
 114         input_dev->phys = "neo1973kbd/input0";
 115         input_dev->id.bustype = BUS_HOST;
 116 --
 117 1.5.6.5
 118