hp accelerometer: add freefall detection

This adds freefall handling to hp_accel driver.  According to HP, it
should just work, without us having to set the chip up by hand.

hpfall.c is example .c program that parks the disk when accelerometer
detects free fall.  It should work; for now, it uses fixed 20seconds
protection period.

Signed-off-by: Pavel Machek <pavel@suse.cz>
Cc: Thomas Renninger <trenn@suse.de>
Cc: Éric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/hwmon/lis3lv02d.h b/drivers/hwmon/lis3lv02d.h
index 223f1c0763bb..2e7597c42d80 100644
--- a/drivers/hwmon/lis3lv02d.h
+++ b/drivers/hwmon/lis3lv02d.h
@@ -170,6 +170,11 @@ struct acpi_lis3lv02d {
         unsigned char           is_on;     /* whether the device is on or off */
         unsigned char           usage;     /* usage counter */
         struct axis_conversion  ac;        /* hw -> logical axis */
+
+        u32                     irq;       /* IRQ number */
+        struct fasync_struct    *async_queue; /* queue for the misc device */
+        wait_queue_head_t       misc_wait; /* Wait queue for the misc device */
+        unsigned long           misc_opened; /* bit0: whether the device is open */
 };
 
 int lis3lv02d_init_device(struct acpi_lis3lv02d *dev);