From 75cafba880ed73eeca83d2a0bec5fb202fc02741 Mon Sep 17 00:00:00 2001 From: Andy Green Date: Wed, 19 Nov 2008 17:09:37 +0000 Subject: fix-jack-debounce.patch Headphone jack detection is bouncy, it can trigger multiple interrupts on insertion or removal. This patch adds a workqueue that waits out the interrupt spew in 100ms units, and if it sees no more interrupts for 100ms only then samples and reports the jack state. I was unable to get a bounce after 20 or so tries after this. Signed-off-by: Andy Green --- drivers/input/keyboard/neo1973kbd.c | 63 ++++++++++++++++++++++++++++++++++--- 1 file changed, 59 insertions(+), 4 deletions(-) diff --git a/drivers/input/keyboard/neo1973kbd.c b/drivers/input/keyboard/neo1973kbd.c index 06fa8e049e5..6c96660f079 100644 --- a/drivers/input/keyboard/neo1973kbd.c +++ b/drivers/input/keyboard/neo1973kbd.c @@ -21,6 +21,7 @@ #include #include #include +#include #include #include @@ -28,6 +29,11 @@ struct neo1973kbd { struct input_dev *input; unsigned int suspended; + struct work_struct work; + int work_in_progress; + int hp_irq_count_in_work; + int hp_irq_count; + int jack_irq; }; static irqreturn_t neo1973kbd_aux_irq(int irq, void *dev_id) @@ -52,14 +58,61 @@ static irqreturn_t neo1973kbd_hold_irq(int irq, void *dev_id) return IRQ_HANDLED; } + +static void neo1973kbd_debounce_jack(struct work_struct *work) +{ + struct neo1973kbd *kbd = container_of(work, struct neo1973kbd, work); + + /* we wait out any multiple interrupt stuttering in 100ms lumps */ + + do { + kbd->hp_irq_count_in_work = kbd->hp_irq_count; + msleep(100); + } while (kbd->hp_irq_count != kbd->hp_irq_count_in_work); + + /* no new interrupts on jack for 100ms... ok we will report it */ + + input_report_switch(kbd->input, + SW_HEADPHONE_INSERT, + gpio_get_value(irq_to_gpio(kbd->jack_irq))); + input_sync(kbd->input); + + /* next time we get an interrupt on jack we need new work action */ + kbd->work_in_progress = 0; +} + + + static irqreturn_t neo1973kbd_headphone_irq(int irq, void *dev_id) { struct neo1973kbd *neo1973kbd_data = dev_id; - int key_pressed = gpio_get_value(irq_to_gpio(irq)); - input_report_switch(neo1973kbd_data->input, - SW_HEADPHONE_INSERT, key_pressed); - input_sync(neo1973kbd_data->input); + /* + * this interrupt is prone to bouncing and userspace doesn't like + * to have to deal with that kind of thing. So we do not accept + * that a jack interrupt is equal to a jack event. Instead we fire + * some work on the first interrupt, and it hangs about in 100ms units + * until no more interrupts come. Then it accepts the state it finds + * for jack insert and reports it once + */ + + neo1973kbd_data->hp_irq_count++; + /* + * the first interrupt we see for a while, we fire the work item + * and record the interrupt count when we did that. If more interrupts + * come in the meanwhile, we can tell by the difference in that + * stored count and hp_irq_count which increments every interrupt + */ + if (!neo1973kbd_data->work_in_progress) { + neo1973kbd_data->jack_irq = irq; + neo1973kbd_data->hp_irq_count_in_work = + neo1973kbd_data->hp_irq_count; + if (!schedule_work(&neo1973kbd_data->work)) + printk(KERN_ERR + "Unable to schedule headphone debounce\n"); + else + neo1973kbd_data->work_in_progress = 1; + } return IRQ_HANDLED; } @@ -120,6 +173,8 @@ static int neo1973kbd_probe(struct platform_device *pdev) neo1973kbd->input = input_dev; + INIT_WORK(&neo1973kbd->work, neo1973kbd_debounce_jack); + input_dev->name = "Neo1973 Buttons"; input_dev->phys = "neo1973kbd/input0"; input_dev->id.bustype = BUS_HOST; -- cgit v1.2.3