2 files changed, 109 insertions, 0 deletions

diff --git a/Documentation/hwmon/hpfall.c b/Documentation/hwmon/hpfall.c
new file mode 100644
index 000000000000..bbea1ccfd46a
--- /dev/null
+++ b/Documentation/hwmon/hpfall.c
@@ -0,0 +1,101 @@
+/* Disk protection for HP machines.
+ *
+ * Copyright 2008 Eric Piel
+ * Copyright 2009 Pavel Machek <pavel@suse.cz>
+ *
+ * GPLv2.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <sys/types.h>
+#include <string.h>
+#include <stdint.h>
+#include <errno.h>
+#include <signal.h>
+
+void write_int(char *path, int i)
+{
+        char buf[1024];
+        int fd = open(path, O_RDWR);
+        if (fd < 0) {
+                perror("open");
+                exit(1);
+        }
+        sprintf(buf, "%d", i);
+        if (write(fd, buf, strlen(buf)) != strlen(buf)) {
+                perror("write");
+                exit(1);
+        }
+        close(fd);
+}
+
+void set_led(int on)
+{
+        write_int("/sys/class/leds/hp::hddprotect/brightness", on);
+}
+
+void protect(int seconds)
+{
+        write_int("/sys/block/sda/device/unload_heads", seconds*1000);
+}
+
+int on_ac(void)
+{
+//      /sys/class/power_supply/AC0/online
+}
+
+int lid_open(void)
+{
+//      /proc/acpi/button/lid/LID/state
+}
+
+void ignore_me(void)
+{
+        protect(0);
+        set_led(0);
+
+}
+
+int main(int argc, char* argv[])
+{
+       int fd, ret;
+
+       fd = open("/dev/freefall", O_RDONLY);
+       if (fd < 0) {
+               perror("open");
+               return EXIT_FAILURE;
+       }
+
+        signal(SIGALRM, ignore_me);
+
+       for (;;) {
+               unsigned char count;
+
+               ret = read(fd, &count, sizeof(count));
+               alarm(0);
+               if ((ret == -1) && (errno == EINTR)) {
+                       /* Alarm expired, time to unpark the heads */
+                       continue;
+               }
+
+               if (ret != sizeof(count)) {
+                       perror("read");
+                       break;
+               }
+
+               protect(21);
+               set_led(1);
+               if (1 || on_ac() || lid_open()) {
+                       alarm(2);
+               } else {
+                       alarm(20);
+               }
+       }
+
+       close(fd);
+       return EXIT_SUCCESS;
+}
diff --git a/Documentation/hwmon/lis3lv02d b/Documentation/hwmon/lis3lv02d
index 0fcfc4a7ccdc..287f8c902656 100644
--- a/Documentation/hwmon/lis3lv02d
+++ b/Documentation/hwmon/lis3lv02d
@@ -33,6 +33,14 @@ rate - reports the sampling rate of the accelerometer device in HZ
 This driver also provides an absolute input class device, allowing
 the laptop to act as a pinball machine-esque joystick.
 
+Another feature of the driver is misc device called "freefall" that
+acts similar to /dev/rtc and reacts on free-fall interrupts received
+from the device. It supports blocking operations, poll/select and
+fasync operation modes. You must read 1 bytes from the device.  The
+result is number of free-fall interrupts since the last successful
+read (or 255 if number of interrupts would not fit).
+
+
 Axes orientation
 ----------------