[PATCH 3/3] wm97xx-core: Support use as a wakeup source

[Mark Brown <broonie@opensource.wolfsonmicro.com>]

The PENDOWN signal from the WM97xx touch screen controllers can be used
to generate a wakeup event when the system is suspended. Provide a new
machine configuration option 'suspend_mode' allowing machine drivers to
enable this. If no suspend_mode is provided then the touch panel will be
powered down when the system is suspended.

Signed-off-by: Mark Brown <broonie@opensource.wolfsonmicro.com>
---
 drivers/input/touchscreen/wm97xx-core.c |   22 ++++++++++++++++++++++
 include/linux/wm97xx.h                  |    3 +++
 2 files changed, 25 insertions(+), 0 deletions(-)

diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c
index fec07c2..e1a1ca0 100644
--- a/drivers/input/touchscreen/wm97xx-core.c
+++ b/drivers/input/touchscreen/wm97xx-core.c
@@ -689,10 +689,32 @@ static int wm97xx_remove(struct device *dev)
 static int wm97xx_suspend(struct device *dev, pm_message_t state)
 {
 	struct wm97xx *wm = dev_get_drvdata(dev);
+	u16 reg;
+	int suspend_mode;
+
+	if (wm->mach_ops)
+		suspend_mode = wm->mach_ops->suspend_mode;
+	else
+		suspend_mode = 0;
 
 	if (wm->input_dev->users)
 		cancel_delayed_work_sync(&wm->ts_reader);
 
+	/* Power down the digitiser (bypassing the cache for resume) */
+	reg = wm97xx_reg_read(wm, AC97_WM97XX_DIGITISER2);
+	reg &= ~WM97XX_PRP_DET_DIG;
+	if (wm->input_dev->users && suspend_mode)
+		reg |= suspend_mode;
+	wm->ac97->bus->ops->write(wm->ac97, AC97_WM97XX_DIGITISER2, reg);
+
+	/* WM9713 has an additional power bit - turn it off if there
+	 * are no users or if suspend mode is zero. */
+	if (wm->id == WM9713_ID2 &&
+	    (!wm->input_dev->users || !suspend_mode)) {
+		reg = wm97xx_reg_read(wm, AC97_EXTENDED_MID) | 0x8000;
+		wm97xx_reg_write(wm, AC97_EXTENDED_MID, reg);
+	}
+
 	return 0;
 }
 
diff --git a/include/linux/wm97xx.h b/include/linux/wm97xx.h
index ed01c7d..2082833 100644
--- a/include/linux/wm97xx.h
+++ b/include/linux/wm97xx.h
@@ -258,6 +258,9 @@ struct wm97xx_mach_ops {
 	/* pre and post sample - can be used to minimise any analog noise */
 	void (*pre_sample) (int);  /* function to run before sampling */
 	void (*post_sample) (int);  /* function to run after sampling */
+
+	/* WM97XX_PRP value to configure while system is suspended */
+	u16 suspend_mode;
 };
 
 struct wm97xx {
-- 
1.5.5