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From 4c83444bd41a70fe47731e589c6575da2bfc78c8 Mon Sep 17 00:00:00 2001
From: Andy Green <andy@openmoko.com>
Date: Fri, 25 Jul 2008 23:06:05 +0100
Subject: [PATCH] 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 <andy@openmoko.com>
---
drivers/input/keyboard/neo1973kbd.c | 63 ++++++++++++++++++++++++++++++++--
1 files changed, 59 insertions(+), 4 deletions(-)
diff --git a/drivers/input/keyboard/neo1973kbd.c b/drivers/input/keyboard/neo1973kbd.c
index 06fa8e0..6c96660 100644
--- a/drivers/input/keyboard/neo1973kbd.c
+++ b/drivers/input/keyboard/neo1973kbd.c
@@ -21,6 +21,7 @@
#include <linux/jiffies.h>
#include <linux/module.h>
#include <linux/slab.h>
+#include <linux/workqueue.h>
#include <asm/gpio.h>
#include <asm/mach-types.h>
@@ -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;
--
1.5.6.3
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