lis3: add power management functions

This enabled power management functions for the SPI transport layer of the
lis3 devices.  The device's suspend mode is only entered in case no wakeup
threshold has been given.  In this case, the device is supposed to wake up
the system and must thus not be put to deep sleep.

[randy.dunlap@oracle.com: fix lis3-spi for CONFIG_PM=n]
Signed-off-by: Daniel Mack <daniel@caiaq.de>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Eric Piel <eric.piel@tremplin-utc.net>
Signed-off-by: Randy Dunlap <randy.dunlap@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/hwmon/lis3lv02d_spi.c

@@ -87,13 +87,41 @@ static int __devexit lis302dl_spi_remove(struct spi_device *spi)
 	return 0;
 }
 
+#ifdef CONFIG_PM
+static int lis3lv02d_spi_suspend(struct spi_device *spi, pm_message_t mesg)
+{
+	struct lis3lv02d *lis3 = spi_get_drvdata(spi);
+
+	if (!lis3->pdata->wakeup_flags)
+		lis3lv02d_poweroff(&lis3_dev);
+
+	return 0;
+}
+
+static int lis3lv02d_spi_resume(struct spi_device *spi)
+{
+	struct lis3lv02d *lis3 = spi_get_drvdata(spi);
+
+	if (!lis3->pdata->wakeup_flags)
+		lis3lv02d_poweron(lis3);
+
+	return 0;
+}
+
+#else
+#define lis3lv02d_spi_suspend	NULL
+#define lis3lv02d_spi_resume	NULL
+#endif
+
 static struct spi_driver lis302dl_spi_driver = {
 	.driver	 = {
 		.name   = DRV_NAME,
 		.owner  = THIS_MODULE,
 	},
 	.probe	= lis302dl_spi_probe,
 	.remove	= __devexit_p(lis302dl_spi_remove),
+	.suspend = lis3lv02d_spi_suspend,
+	.resume  = lis3lv02d_spi_resume,
 };
 
 static int __init lis302dl_init(void)