Input: tsc2007 - convert to threaded IRQ

Instead of using hard IRQ and workqueue solution switch to using threaded
interrupt handler to simplify the code and locking rules.

Tested-by: Thierry Reding <thierry.reding@avionic-design.de>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>

1 files changed, 66 insertions, 84 deletions

diff --git a/drivers/input/touchscreen/tsc2007.c b/drivers/input/touchscreen/tsc2007.c
index fadc11545b1e..e3aaf50ee8d3 100644
--- a/drivers/input/touchscreen/tsc2007.c
+++ b/drivers/input/touchscreen/tsc2007.c
@@ -66,7 +66,6 @@ struct ts_event {
 struct tsc2007 {
         struct input_dev        *input;
         char                    phys[32];
-        struct delayed_work     work;
 
         struct i2c_client       *client;
 
@@ -76,9 +75,11 @@ struct tsc2007 {
         unsigned long           poll_delay;
         unsigned long           poll_period;
 
-        bool                    pendown;
         int                     irq;
 
+        wait_queue_head_t       wait;
+        bool                    stopped;
+
         int                     (*get_pendown_state)(void);
         void                    (*clear_penirq)(void);
 };
@@ -141,25 +142,8 @@ static u32 tsc2007_calculate_pressure(struct tsc2007 *tsc, struct ts_event *tc)
         return rt;
 }
 
-static void tsc2007_send_up_event(struct tsc2007 *tsc)
-{
-        struct input_dev *input = tsc->input;
-
-        dev_dbg(&tsc->client->dev, "UP\n");
-
-        input_report_key(input, BTN_TOUCH, 0);
-        input_report_abs(input, ABS_PRESSURE, 0);
-        input_sync(input);
-}
-
-static void tsc2007_work(struct work_struct *work)
+static bool tsc2007_is_pen_down(struct tsc2007 *ts)
 {
-        struct tsc2007 *ts =
-                container_of(to_delayed_work(work), struct tsc2007, work);
-        bool debounced = false;
-        struct ts_event tc;
-        u32 rt;
-
         /*
          * NOTE: We can't rely on the pressure to determine the pen down
          * state, even though this controller has a pressure sensor.
@@ -170,79 +154,82 @@ static void tsc2007_work(struct work_struct *work)
          * The only safe way to check for the pen up condition is in the
          * work function by reading the pen signal state (it's a GPIO
          * and IRQ). Unfortunately such callback is not always available,
-         * in that case we have rely on the pressure anyway.
+         * in that case we assume that the pen is down and expect caller
+         * to fall back on the pressure reading.
          */
-        if (ts->get_pendown_state) {
-                if (unlikely(!ts->get_pendown_state())) {
-                        tsc2007_send_up_event(ts);
-                        ts->pendown = false;
-                        goto out;
-                }
 
-                dev_dbg(&ts->client->dev, "pen is still down\n");
-        }
+        if (!ts->get_pendown_state)
+                return true;
 
-        tsc2007_read_values(ts, &tc);
+        return ts->get_pendown_state();
+}
 
-        rt = tsc2007_calculate_pressure(ts, &tc);
-        if (rt > ts->max_rt) {
-                /*
-                 * Sample found inconsistent by debouncing or pressure is
-                 * beyond the maximum. Don't report it to user space,
-                 * repeat at least once more the measurement.
-                 */
-                dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
-                debounced = true;
-                goto out;
+static irqreturn_t tsc2007_soft_irq(int irq, void *handle)
+{
+        struct tsc2007 *ts = handle;
+        struct input_dev *input = ts->input;
+        struct ts_event tc;
+        u32 rt;
 
-        }
+        while (!ts->stopped && tsc2007_is_pen_down(ts)) {
+
+                /* pen is down, continue with the measurement */
+                tsc2007_read_values(ts, &tc);
 
-        if (rt) {
-                struct input_dev *input = ts->input;
+                rt = tsc2007_calculate_pressure(ts, &tc);
 
-                if (!ts->pendown) {
-                        dev_dbg(&ts->client->dev, "DOWN\n");
+                if (rt == 0 && !ts->get_pendown_state) {
+                        /*
+                         * If pressure reported is 0 and we don't have
+                         * callback to check pendown state, we have to
+                         * assume that pen was lifted up.
+                         */
+                        break;
+                }
+
+                if (rt <= ts->max_rt) {
+                        dev_dbg(&ts->client->dev,
+                                "DOWN point(%4d,%4d), pressure (%4u)\n",
+                                tc.x, tc.y, rt);
 
                         input_report_key(input, BTN_TOUCH, 1);
-                        ts->pendown = true;
+                        input_report_abs(input, ABS_X, tc.x);
+                        input_report_abs(input, ABS_Y, tc.y);
+                        input_report_abs(input, ABS_PRESSURE, rt);
+
+                        input_sync(input);
+
+                } else {
+                        /*
+                         * Sample found inconsistent by debouncing or pressure is
+                         * beyond the maximum. Don't report it to user space,
+                         * repeat at least once more the measurement.
+                         */
+                        dev_dbg(&ts->client->dev, "ignored pressure %d\n", rt);
                 }
 
-                input_report_abs(input, ABS_X, tc.x);
-                input_report_abs(input, ABS_Y, tc.y);
-                input_report_abs(input, ABS_PRESSURE, rt);
+                wait_event_timeout(ts->wait, ts->stopped,
+                                   msecs_to_jiffies(ts->poll_period));
+        }
 
-                input_sync(input);
+        dev_dbg(&ts->client->dev, "UP\n");
 
-                dev_dbg(&ts->client->dev, "point(%4d,%4d), pressure (%4u)\n",
-                        tc.x, tc.y, rt);
+        input_report_key(input, BTN_TOUCH, 0);
+        input_report_abs(input, ABS_PRESSURE, 0);
+        input_sync(input);
 
-        } else if (!ts->get_pendown_state && ts->pendown) {
-                /*
-                 * We don't have callback to check pendown state, so we
-                 * have to assume that since pressure reported is 0 the
-                 * pen was lifted up.
-                 */
-                tsc2007_send_up_event(ts);
-                ts->pendown = false;
-        }
+        if (ts->clear_penirq)
+                ts->clear_penirq();
 
- out:
-        if (ts->pendown || debounced)
-                schedule_delayed_work(&ts->work,
-                                      msecs_to_jiffies(ts->poll_period));
-        else
-                enable_irq(ts->irq);
+        return IRQ_HANDLED;
 }
 
-static irqreturn_t tsc2007_irq(int irq, void *handle)
+static irqreturn_t tsc2007_hard_irq(int irq, void *handle)
 {
         struct tsc2007 *ts = handle;
 
-        if (!ts->get_pendown_state || likely(ts->get_pendown_state())) {
-                disable_irq_nosync(ts->irq);
-                schedule_delayed_work(&ts->work,
-                                      msecs_to_jiffies(ts->poll_delay));
-        }
+        if (!ts->get_pendown_state || likely(ts->get_pendown_state()))
+                return IRQ_WAKE_THREAD;
 
         if (ts->clear_penirq)
                 ts->clear_penirq();
@@ -252,15 +239,10 @@ static irqreturn_t tsc2007_irq(int irq, void *handle)
 
 static void tsc2007_free_irq(struct tsc2007 *ts)
 {
+        ts->stopped = true;
+        mb();
+        wake_up(&ts->wait);
         free_irq(ts->irq, ts);
-        if (cancel_delayed_work_sync(&ts->work)) {
-                /*
-                 * Work was pending, therefore we need to enable
-                 * IRQ here to balance the disable_irq() done in the
-                 * interrupt handler.
-                 */
-                enable_irq(ts->irq);
-        }
 }
 
 static int __devinit tsc2007_probe(struct i2c_client *client,
@@ -290,7 +272,7 @@ static int __devinit tsc2007_probe(struct i2c_client *client,
         ts->client = client;
         ts->irq = client->irq;
         ts->input = input_dev;
-        INIT_DELAYED_WORK(&ts->work, tsc2007_work);
+        init_waitqueue_head(&ts->wait);
 
         ts->model             = pdata->model;
         ts->x_plate_ohms      = pdata->x_plate_ohms;
@@ -318,8 +300,8 @@ static int __devinit tsc2007_probe(struct i2c_client *client,
         if (pdata->init_platform_hw)
                 pdata->init_platform_hw();
 
-        err = request_irq(ts->irq, tsc2007_irq, 0,
-                        client->dev.driver->name, ts);
+        err = request_threaded_irq(ts->irq, tsc2007_hard_irq, tsc2007_soft_irq,
+                                   IRQF_ONESHOT, client->dev.driver->name, ts);
         if (err < 0) {
                 dev_err(&client->dev, "irq %d busy?\n", ts->irq);
                 goto err_free_mem;