From: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
Convert the dm355evm keys driver to use IRQ threading instead of
a private workqueue. IRQ threads were added to Linux after this
driver was written, and in this case fit what the driver needs.
(Although the non-shared thread costs more runtime memory.)
Signed-off-by: David Brownell <dbrownell@xxxxxxxxxxxxxxxxxxxxx>
---
drivers/input/misc/dm355evm_keys.c | 42 ++++++++++++++++-------------------
1 file changed, 20 insertions(+), 22 deletions(-)
--- a/drivers/input/misc/dm355evm_keys.c
+++ b/drivers/input/misc/dm355evm_keys.c
@@ -23,30 +23,16 @@
* pressed, or its autorepeat kicks in, an event is sent. This driver
* read those events from the small (32 event) queue and reports them.
*
- * Because we communicate with the MSP430 using I2C, and all I2C calls
- * in Linux sleep, we need to cons up a kind of threaded IRQ handler
- * using a work_struct. The IRQ is active low, but we use it through
- * the GPIO controller so we can trigger on falling edges.
- *
* Note that physically there can only be one of these devices.
*
* This driver was tested with firmware revision A4.
*/
struct dm355evm_keys {
- struct work_struct work;
struct input_dev *input;
struct device *dev;
int irq;
};
-static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
-{
- struct dm355evm_keys *keys = _keys;
-
- schedule_work(&keys->work);
- return IRQ_HANDLED;
-}
-
/* These initial keycodes can be remapped by dm355evm_setkeycode(). */
static struct {
u16 event;
@@ -110,13 +96,12 @@ static struct {
{ 0x3169, KEY_PAUSE, },
};
-static void dm355evm_keys_work(struct work_struct *work)
+/* runs in an IRQ thread -- can (and will!) sleep */
+static irqreturn_t dm355evm_keys_irq(int irq, void *_keys)
{
- struct dm355evm_keys *keys;
+ struct dm355evm_keys *keys = _keys;
int status;
- keys = container_of(work, struct dm355evm_keys, work);
-
/* For simplicity we ignore INPUT_COUNT and just read
* events until we get the "queue empty" indicator.
* Reading INPUT_LOW decrements the count.
@@ -183,6 +168,19 @@ static void dm355evm_keys_work(struct wo
input_report_key(keys->input, keycode, 0);
input_sync(keys->input);
}
+ return IRQ_HANDLED;
+}
+
+/*
+ * Because we communicate with the MSP430 using I2C, and all I2C calls
+ * in Linux sleep, we use a threaded IRQ handler. The IRQ itself is
+ * active low, but we go through the GPIO controller so we can trigger
+ * on falling edges and not worry about enabling/disabling the IRQ in
+ * the keypress handling path.
+ */
+static irqreturn_t dm355evm_keys_hardirq(int irq, void *_keys)
+{
+ return IRQ_WAKE_THREAD;
}
static int dm355evm_setkeycode(struct input_dev *dev, int index, int keycode)
@@ -233,7 +231,6 @@ static int __devinit dm355evm_keys_probe
keys->dev = &pdev->dev;
keys->input = input;
- INIT_WORK(&keys->work, dm355evm_keys_work);
/* set up "threaded IRQ handler" */
status = platform_get_irq(pdev, 0);
@@ -260,9 +257,10 @@ static int __devinit dm355evm_keys_probe
/* REVISIT: flush the event queue? */
- status = request_irq(keys->irq, dm355evm_keys_irq,
- IRQF_TRIGGER_FALLING,
- dev_name(&pdev->dev), keys);
+ status = request_threaded_irq(keys->irq,
+ dm355evm_keys_hardirq, dm355evm_keys_irq,
+ IRQF_TRIGGER_FALLING,
+ dev_name(&pdev->dev), keys);
if (status < 0)
goto fail1;
--
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