Input: wm97xx-core - support use as a wakeup source

The WM97xx touch screen controllers can be used to generate a wakeup
event when the system is suspended. Provide a new core API call
wm97xx_set_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>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 39 insertions, 0 deletions

diff --git a/drivers/input/touchscreen/wm97xx-core.c b/drivers/input/touchscreen/wm97xx-core.c
index fec07c28281a..e9c7ea46b6e3 100644
--- a/drivers/input/touchscreen/wm97xx-core.c
+++ b/drivers/input/touchscreen/wm97xx-core.c
@@ -262,6 +262,23 @@ void wm97xx_config_gpio(struct wm97xx *wm, u32 gpio, enum wm97xx_gpio_dir dir,
 EXPORT_SYMBOL_GPL(wm97xx_config_gpio);
 
 /*
+ * Configure the WM97XX_PRP value to use while system is suspended.
+ * If a value other than 0 is set then WM97xx pen detection will be
+ * left enabled in the configured mode while the system is in suspend,
+ * the device has users and suspend has not been disabled via the
+ * wakeup sysfs entries.
+ *
+ * @wm:   WM97xx device to configure
+ * @mode: WM97XX_PRP value to configure while suspended
+ */
+void wm97xx_set_suspend_mode(struct wm97xx *wm, u16 mode)
+{
+	wm->suspend_mode = mode;
+	device_init_wakeup(&wm->input_dev->dev, mode != 0);
+}
+EXPORT_SYMBOL_GPL(wm97xx_set_suspend_mode);
+
+/*
  * Handle a pen down interrupt.
  */
 static void wm97xx_pen_irq_worker(struct work_struct *work)
@@ -689,10 +706,32 @@ 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 (device_may_wakeup(&wm->input_dev->dev))
+		suspend_mode = wm->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)
+		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;
 }