Input: wm831x-ts - fix races with IRQ management

[pandora-kernel.git] / drivers / input / touchscreen / wm831x-ts.c

diff --git a/drivers/input/touchscreen/wm831x-ts.c b/drivers/input/touchscreen/wm831x-ts.c
index 6ae054f..b937301 100644 (file)
--- a/drivers/input/touchscreen/wm831x-ts.c
+++ b/drivers/input/touchscreen/wm831x-ts.c
@@ -68,8 +68,23 @@ struct wm831x_ts {
        unsigned int pd_irq;
        bool pressure;
        bool pen_down;
+       struct work_struct pd_data_work;
 };
 
+static void wm831x_pd_data_work(struct work_struct *work)
+{
+       struct wm831x_ts *wm831x_ts =
+               container_of(work, struct wm831x_ts, pd_data_work);
+
+       if (wm831x_ts->pen_down) {
+               enable_irq(wm831x_ts->data_irq);
+               dev_dbg(wm831x_ts->wm831x->dev, "IRQ PD->DATA done\n");
+       } else {
+               enable_irq(wm831x_ts->pd_irq);
+               dev_dbg(wm831x_ts->wm831x->dev, "IRQ DATA->PD done\n");
+       }
+}
+
 static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data)
 {
        struct wm831x_ts *wm831x_ts = irq_data;
@@ -110,6 +125,9 @@ static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data)
        }
 
        if (!wm831x_ts->pen_down) {
+               /* Switch from data to pen down */
+               dev_dbg(wm831x->dev, "IRQ DATA->PD\n");
+
                disable_irq_nosync(wm831x_ts->data_irq);
 
                /* Don't need data any more */
@@ -128,6 +146,8 @@ static irqreturn_t wm831x_ts_data_irq(int irq, void *irq_data)
                                         ABS_PRESSURE, 0);
 
                input_report_key(wm831x_ts->input_dev, BTN_TOUCH, 0);
+
+               schedule_work(&wm831x_ts->pd_data_work);
        }
 
        input_sync(wm831x_ts->input_dev);
@@ -141,6 +161,11 @@ static irqreturn_t wm831x_ts_pen_down_irq(int irq, void *irq_data)
        struct wm831x *wm831x = wm831x_ts->wm831x;
        int ena = 0;
 
+       if (wm831x_ts->pen_down)
+               return IRQ_HANDLED;
+
+       disable_irq_nosync(wm831x_ts->pd_irq);
+
        /* Start collecting data */
        if (wm831x_ts->pressure)
                ena |= WM831X_TCH_Z_ENA;
@@ -156,7 +181,10 @@ static irqreturn_t wm831x_ts_pen_down_irq(int irq, void *irq_data)
                        WM831X_TCHPD_EINT, WM831X_TCHPD_EINT);
 
        wm831x_ts->pen_down = true;
-       enable_irq(wm831x_ts->data_irq);
+
+       /* Switch from pen down to data */
+       dev_dbg(wm831x->dev, "IRQ PD->DATA\n");
+       schedule_work(&wm831x_ts->pd_data_work);
 
        return IRQ_HANDLED;
 }
@@ -182,13 +210,28 @@ static void wm831x_ts_input_close(struct input_dev *idev)
        struct wm831x_ts *wm831x_ts = input_get_drvdata(idev);
        struct wm831x *wm831x = wm831x_ts->wm831x;
 
+       /* Shut the controller down, disabling all other functionality too */
        wm831x_set_bits(wm831x, WM831X_TOUCH_CONTROL_1,
-                       WM831X_TCH_ENA | WM831X_TCH_CVT_ENA |
-                       WM831X_TCH_X_ENA | WM831X_TCH_Y_ENA |
-                       WM831X_TCH_Z_ENA, 0);
+                       WM831X_TCH_ENA | WM831X_TCH_X_ENA |
+                       WM831X_TCH_Y_ENA | WM831X_TCH_Z_ENA, 0);
 
-       if (wm831x_ts->pen_down)
+       /* Make sure any pending IRQs are done, the above will prevent
+        * new ones firing.
+        */
+       synchronize_irq(wm831x_ts->data_irq);
+       synchronize_irq(wm831x_ts->pd_irq);
+
+       /* Make sure the IRQ completion work is quiesced */
+       flush_work_sync(&wm831x_ts->pd_data_work);
+
+       /* If we ended up with the pen down then make sure we revert back
+        * to pen detection state for the next time we start up.
+        */
+       if (wm831x_ts->pen_down) {
                disable_irq(wm831x_ts->data_irq);
+               enable_irq(wm831x_ts->pd_irq);
+               wm831x_ts->pen_down = false;
+       }
 }
 
 static __devinit int wm831x_ts_probe(struct platform_device *pdev)
@@ -212,6 +255,7 @@ static __devinit int wm831x_ts_probe(struct platform_device *pdev)
 
        wm831x_ts->wm831x = wm831x;
        wm831x_ts->input_dev = input_dev;
+       INIT_WORK(&wm831x_ts->pd_data_work, wm831x_pd_data_work);
 
        /*
         * If we have a direct IRQ use it, otherwise use the interrupt