Input: eeti_ts - switch to using threaded interrupt
authorDmitry Torokhov <dmitry.torokhov@gmail.com>
Mon, 20 Feb 2017 01:23:47 +0000 (17:23 -0800)
committerDmitry Torokhov <dmitry.torokhov@gmail.com>
Mon, 3 Apr 2017 23:24:34 +0000 (16:24 -0700)
Instead of having standard interrupt handler and manually firing work item
to perform I2C reads, let's switch to threaded interrupts, which were
designed specifically for this purpose.

Reviewed-by: Daniel Mack <daniel@zonque.org>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
drivers/input/touchscreen/eeti_ts.c

index fc61dbea4736ba8556d8e7c0f3de9f11eaac857c..ee6b87c606efa5738eb71e6bed374938cdff2725 100644 (file)
@@ -47,9 +47,8 @@ MODULE_PARM_DESC(flip_y, "flip y coordinate");
 struct eeti_ts {
        struct i2c_client *client;
        struct input_dev *input;
-       struct work_struct work;
-       struct mutex mutex;
        int irq_gpio, irq_active_high;
+       bool running;
 };
 
 #define EETI_TS_BITDEPTH       (11)
@@ -66,29 +65,11 @@ static inline int eeti_ts_irq_active(struct eeti_ts *eeti)
        return gpio_get_value_cansleep(eeti->irq_gpio) == eeti->irq_active_high;
 }
 
-static void eeti_ts_read(struct work_struct *work)
+static void eeti_ts_report_event(struct eeti_ts *eeti, u8 *buf)
 {
-       char buf[6];
-       unsigned int x, y, res, pressed, to = 100;
-       struct eeti_ts *eeti =
-               container_of(work, struct eeti_ts, work);
-
-       mutex_lock(&eeti->mutex);
-
-       while (eeti_ts_irq_active(eeti) && --to)
-               i2c_master_recv(eeti->client, buf, sizeof(buf));
-
-       if (!to) {
-               dev_err(&eeti->client->dev,
-                       "unable to clear IRQ - line stuck?\n");
-               goto out;
-       }
+       unsigned int res;
+       u16 x, y;
 
-       /* drop non-report packets */
-       if (!(buf[0] & 0x80))
-               goto out;
-
-       pressed = buf[0] & REPORT_BIT_PRESSED;
        res = REPORT_RES_BITS(buf[0] & (REPORT_BIT_AD0 | REPORT_BIT_AD1));
 
        x = get_unaligned_be16(&buf[1]);
@@ -109,35 +90,48 @@ static void eeti_ts_read(struct work_struct *work)
 
        input_report_abs(eeti->input, ABS_X, x);
        input_report_abs(eeti->input, ABS_Y, y);
-       input_report_key(eeti->input, BTN_TOUCH, !!pressed);
+       input_report_key(eeti->input, BTN_TOUCH, buf[0] & REPORT_BIT_PRESSED);
        input_sync(eeti->input);
-
-out:
-       mutex_unlock(&eeti->mutex);
 }
 
 static irqreturn_t eeti_ts_isr(int irq, void *dev_id)
 {
        struct eeti_ts *eeti = dev_id;
+       int len;
+       int error;
+       char buf[6];
 
-        /* postpone I2C transactions as we are atomic */
-       schedule_work(&eeti->work);
+       do {
+               len = i2c_master_recv(eeti->client, buf, sizeof(buf));
+               if (len != sizeof(buf)) {
+                       error = len < 0 ? len : -EIO;
+                       dev_err(&eeti->client->dev,
+                               "failed to read touchscreen data: %d\n",
+                               error);
+                       break;
+               }
+
+               if (buf[0] & 0x80) {
+                       /* Motion packet */
+                       eeti_ts_report_event(eeti, buf);
+               }
+       } while (eeti->running && eeti_ts_irq_active(eeti));
 
        return IRQ_HANDLED;
 }
 
 static void eeti_ts_start(struct eeti_ts *eeti)
 {
+       eeti->running = true;
+       wmb();
        enable_irq(eeti->client->irq);
-
-       /* Read the events once to arm the IRQ */
-       eeti_ts_read(&eeti->work);
 }
 
 static void eeti_ts_stop(struct eeti_ts *eeti)
 {
+       eeti->running = false;
+       wmb();
        disable_irq(eeti->client->irq);
-       cancel_work_sync(&eeti->work);
 }
 
 static int eeti_ts_open(struct input_dev *dev)
@@ -179,8 +173,6 @@ static int eeti_ts_probe(struct i2c_client *client,
                return -ENOMEM;
        }
 
-       mutex_init(&eeti->mutex);
-
        input = devm_input_allocate_device(dev);
        if (!input) {
                dev_err(dev, "Failed to allocate input device.\n");
@@ -210,18 +202,15 @@ static int eeti_ts_probe(struct i2c_client *client,
        eeti->irq_active_high = pdata->irq_active_high;
 
        irq_flags = eeti->irq_active_high ?
-               IRQF_TRIGGER_RISING : IRQF_TRIGGER_FALLING;
+               IRQF_TRIGGER_HIGH : IRQF_TRIGGER_LOW;
 
-       INIT_WORK(&eeti->work, eeti_ts_read);
        i2c_set_clientdata(client, eeti);
        input_set_drvdata(input, eeti);
 
-       error = input_register_device(input);
-       if (error)
-               return error;
-
-       error = devm_request_irq(dev, client->irq, eeti_ts_isr, irq_flags,
-                                client->name, eeti);
+       error = devm_request_threaded_irq(dev, client->irq,
+                                         NULL, eeti_ts_isr,
+                                         irq_flags | IRQF_ONESHOT,
+                                         client->name, eeti);
        if (error) {
                dev_err(dev, "Unable to request touchscreen IRQ: %d\n",
                        error);
@@ -234,6 +223,10 @@ static int eeti_ts_probe(struct i2c_client *client,
         */
        eeti_ts_stop(eeti);
 
+       error = input_register_device(input);
+       if (error)
+               return error;
+
        return 0;
 }