Instead of manually create and handler kernel thread switch to threaded
IRQ and let kernel IRQ core manage thread for us.
Signed-off-by: Dmitry Torokhov <redacted>
---
drivers/input/touchscreen/ucb1400_ts.c | 235 +++++++++++++++-----------------
include/linux/ucb1400.h | 6 +-
2 files changed, 115 insertions(+), 126 deletions(-)
diff --git a/drivers/input/touchscreen/ucb1400_ts.c b/drivers/input/touchscreen/ucb1400_ts.c
index 5c6b7b3..1862633 100644
--- a/drivers/input/touchscreen/ucb1400_ts.c
+++ b/drivers/input/touchscreen/ucb1400_ts.c
#include <linux/module.h>
#include <linux/init.h>
-#include <linux/completion.h>
#include <linux/delay.h>
+#include <linux/sched.h>
+#include <linux/wait.h>
#include <linux/input.h>
#include <linux/device.h>
#include <linux/interrupt.h>
-#include <linux/suspend.h>
-#include <linux/kthread.h>
-#include <linux/freezer.h>
#include <linux/ucb1400.h>
+#define UCB1400_TS_POLL_PERIOD 10 /* ms */
+
static int adcsync;
static int ts_delay = 55; /* us */
static int ts_delay_pressure; /* us */
/* Switch to interrupt mode. */
-static void ucb1400_ts_mode_int(struct snd_ac97 *ac97)
+static void ucb1400_ts_mode_int(struct ucb1400_ts *ucb)
{
- ucb1400_reg_write(ac97, UCB_TS_CR,
+ ucb1400_reg_write(ucb->ac97, UCB_TS_CR,
UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
UCB_TS_CR_MODE_INT);@@ -53,7 +53,9 @@ static unsigned int ucb1400_ts_read_pressure(struct ucb1400_ts *ucb)
UCB_TS_CR_TSMX_POW | UCB_TS_CR_TSPX_POW |
UCB_TS_CR_TSMY_GND | UCB_TS_CR_TSPY_GND |
UCB_TS_CR_MODE_PRES | UCB_TS_CR_BIAS_ENA);
+
udelay(ts_delay_pressure);
+
return ucb1400_adc_read(ucb->ac97, UCB_ADC_INP_TSPY, adcsync);
}
@@ -127,26 +129,26 @@ static unsigned int ucb1400_ts_read_yres(struct ucb1400_ts *ucb)
return ucb1400_adc_read(ucb->ac97, 0, adcsync);
}
-static int ucb1400_ts_pen_up(struct snd_ac97 *ac97)
+static int ucb1400_ts_pen_up(struct ucb1400_ts *ucb)
{
- unsigned short val = ucb1400_reg_read(ac97, UCB_TS_CR);
+ unsigned short val = ucb1400_reg_read(ucb->ac97, UCB_TS_CR);
return val & (UCB_TS_CR_TSPX_LOW | UCB_TS_CR_TSMX_LOW);
}
-static void ucb1400_ts_irq_enable(struct snd_ac97 *ac97)
+static void ucb1400_ts_irq_enable(struct ucb1400_ts *ucb)
{
- ucb1400_reg_write(ac97, UCB_IE_CLEAR, UCB_IE_TSPX);
- ucb1400_reg_write(ac97, UCB_IE_CLEAR, 0);
- ucb1400_reg_write(ac97, UCB_IE_FAL, UCB_IE_TSPX);
+ ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, UCB_IE_TSPX);
+ ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
+ ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, UCB_IE_TSPX);
}
-static void ucb1400_ts_irq_disable(struct snd_ac97 *ac97)
+static void ucb1400_ts_irq_disable(struct ucb1400_ts *ucb)
{
- ucb1400_reg_write(ac97, UCB_IE_FAL, 0);
+ ucb1400_reg_write(ucb->ac97, UCB_IE_FAL, 0);
}
-static void ucb1400_ts_evt_add(struct input_dev *idev, u16 pressure, u16 x, u16 y)
+static void ucb1400_ts_report_event(struct input_dev *idev, u16 pressure, u16 x, u16 y)
{
input_report_abs(idev, ABS_X, x);
input_report_abs(idev, ABS_Y, y);@@ -162,7 +164,7 @@ static void ucb1400_ts_event_release(struct input_dev *idev)
input_sync(idev);
}
-static void ucb1400_handle_pending_irq(struct ucb1400_ts *ucb)
+static void ucb1400_clear_pending_irq(struct ucb1400_ts *ucb)
{
unsigned int isr;
@@ -171,32 +173,34 @@ static void ucb1400_handle_pending_irq(struct ucb1400_ts *ucb)
ucb1400_reg_write(ucb->ac97, UCB_IE_CLEAR, 0);
if (isr & UCB_IE_TSPX)
- ucb1400_ts_irq_disable(ucb->ac97);
+ ucb1400_ts_irq_disable(ucb);
else
- dev_dbg(&ucb->ts_idev->dev, "ucb1400: unexpected IE_STATUS = %#x\n", isr);
- enable_irq(ucb->irq);
+ dev_dbg(&ucb->ts_idev->dev,
+ "ucb1400: unexpected IE_STATUS = %#x\n", isr);
}
-static int ucb1400_ts_thread(void *_ucb)
+/*
+ * A restriction with interrupts exists when using the ucb1400, as
+ * the codec read/write routines may sleep while waiting for codec
+ * access completion and uses semaphores for access control to the
+ * AC97 bus. Therefore the driver is forced to use threaded interrupt
+ * handler.
+ */
+static irqreturn_t ucb1400_irq(int irqnr, void *devid)
{
- struct ucb1400_ts *ucb = _ucb;
- struct task_struct *tsk = current;
- int valid = 0;
- struct sched_param param = { .sched_priority = 1 };
+ struct ucb1400_ts *ucb = devid;
+ unsigned int x, y, p;
+ bool penup;
- sched_setscheduler(tsk, SCHED_FIFO, ¶m);
+ if (unlikely(irqnr != ucb->irq))
+ return IRQ_NONE;
- set_freezable();
- while (!kthread_should_stop()) {
- unsigned int x, y, p;
- long timeout;
+ ucb1400_clear_pending_irq(ucb);
- ucb->ts_restart = 0;
+ /* Start with a small delay before checking pendown state */
+ msleep(UCB1400_TS_POLL_PERIOD);
- if (ucb->irq_pending) {
- ucb->irq_pending = 0;
- ucb1400_handle_pending_irq(ucb);
- }
+ while (!ucb->stopped && !(penup = ucb1400_ts_pen_up(ucb))) {
ucb1400_adc_enable(ucb->ac97);
x = ucb1400_ts_read_xpos(ucb);@@ -204,91 +208,62 @@ static int ucb1400_ts_thread(void *_ucb)
p = ucb1400_ts_read_pressure(ucb);
ucb1400_adc_disable(ucb->ac97);
- /* Switch back to interrupt mode. */
- ucb1400_ts_mode_int(ucb->ac97);
-
- msleep(10);
-
- if (ucb1400_ts_pen_up(ucb->ac97)) {
- ucb1400_ts_irq_enable(ucb->ac97);
-
- /*
- * If we spat out a valid sample set last time,
- * spit out a "pen off" sample here.
- */
- if (valid) {
- ucb1400_ts_event_release(ucb->ts_idev);
- valid = 0;
- }
-
- timeout = MAX_SCHEDULE_TIMEOUT;
- } else {
- valid = 1;
- ucb1400_ts_evt_add(ucb->ts_idev, p, x, y);
- timeout = msecs_to_jiffies(10);
- }
+ ucb1400_ts_report_event(ucb->ts_idev, p, x, y);
- wait_event_freezable_timeout(ucb->ts_wait,
- ucb->irq_pending || ucb->ts_restart ||
- kthread_should_stop(), timeout);
+ wait_event_timeout(ucb->ts_wait, ucb->stopped,
+ msecs_to_jiffies(UCB1400_TS_POLL_PERIOD));
}
- /* Send the "pen off" if we are stopping with the pen still active */
- if (valid)
- ucb1400_ts_event_release(ucb->ts_idev);
+ ucb1400_ts_event_release(ucb->ts_idev);
- ucb->ts_task = NULL;
- return 0;
+ if (!ucb->stopped) {
+ /* Switch back to interrupt mode. */
+ ucb1400_ts_mode_int(ucb);
+ ucb1400_ts_irq_enable(ucb);
+ }
+
+ return IRQ_HANDLED;
}
-/*
- * A restriction with interrupts exists when using the ucb1400, as
- * the codec read/write routines may sleep while waiting for codec
- * access completion and uses semaphores for access control to the
- * AC97 bus. A complete codec read cycle could take anywhere from
- * 60 to 100uSec so we *definitely* don't want to spin inside the
- * interrupt handler waiting for codec access. So, we handle the
- * interrupt by scheduling a RT kernel thread to run in process
- * context instead of interrupt context.
- */
-static irqreturn_t ucb1400_hard_irq(int irqnr, void *devid)
+static void ucb1400_ts_stop(struct ucb1400_ts *ucb)
{
- struct ucb1400_ts *ucb = devid;
+ /* Signal IRQ thread to stop polling and disable the handler. */
+ ucb->stopped = true;
+ mb();
+ wake_up(&ucb->ts_wait);
+ disable_irq(ucb->irq);
- if (irqnr == ucb->irq) {
- disable_irq_nosync(ucb->irq);
- ucb->irq_pending = 1;
- wake_up(&ucb->ts_wait);
- return IRQ_HANDLED;
- }
- return IRQ_NONE;
+ ucb1400_ts_irq_disable(ucb);
+ ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0);
+}
+
+/* Must be called with ts->lock held */
+static void ucb1400_ts_start(struct ucb1400_ts *ucb)
+{
+ /* Tell IRQ thread that it may poll the device. */
+ ucb->stopped = false;
+ mb();
+
+ ucb1400_ts_mode_int(ucb);
+ ucb1400_ts_irq_enable(ucb);
+
+ enable_irq(ucb->irq);
}
static int ucb1400_ts_open(struct input_dev *idev)
{
struct ucb1400_ts *ucb = input_get_drvdata(idev);
- int ret = 0;
-
- BUG_ON(ucb->ts_task);
- ucb->ts_task = kthread_run(ucb1400_ts_thread, ucb, "UCB1400_ts");
- if (IS_ERR(ucb->ts_task)) {
- ret = PTR_ERR(ucb->ts_task);
- ucb->ts_task = NULL;
- }
+ ucb1400_ts_start(ucb);
- return ret;
+ return 0;
}
static void ucb1400_ts_close(struct input_dev *idev)
{
struct ucb1400_ts *ucb = input_get_drvdata(idev);
- if (ucb->ts_task)
- kthread_stop(ucb->ts_task);
-
- ucb1400_ts_irq_disable(ucb->ac97);
- ucb1400_reg_write(ucb->ac97, UCB_TS_CR, 0);
+ ucb1400_ts_stop(ucb);
}
#ifndef NO_IRQ@@ -342,11 +317,11 @@ static int __devinit ucb1400_ts_detect_irq(struct ucb1400_ts *ucb)
return 0;
}
-static int __devinit ucb1400_ts_probe(struct platform_device *dev)
+static int __devinit ucb1400_ts_probe(struct platform_device *pdev)
{
+ struct ucb1400_ts *ucb = pdev->dev.platform_data;
int error, x_res, y_res;
u16 fcsr;
- struct ucb1400_ts *ucb = dev->dev.platform_data;
ucb->ts_idev = input_allocate_device();
if (!ucb->ts_idev) {@@ -362,21 +337,13 @@ static int __devinit ucb1400_ts_probe(struct platform_device *dev)
goto err_free_devs;
}
}
+ printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq);
init_waitqueue_head(&ucb->ts_wait);
- error = request_irq(ucb->irq, ucb1400_hard_irq, IRQF_TRIGGER_RISING,
- "UCB1400", ucb);
- if (error) {
- printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n",
- ucb->irq, error);
- goto err_free_devs;
- }
- printk(KERN_DEBUG "UCB1400: found IRQ %d\n", ucb->irq);
-
input_set_drvdata(ucb->ts_idev, ucb);
- ucb->ts_idev->dev.parent = &dev->dev;
+ ucb->ts_idev->dev.parent = &pdev->dev;
ucb->ts_idev->name = "UCB1400 touchscreen interface";
ucb->ts_idev->id.vendor = ucb1400_reg_read(ucb->ac97,
AC97_VENDOR_ID1);@@ -404,6 +371,17 @@ static int __devinit ucb1400_ts_probe(struct platform_device *dev)
input_set_abs_params(ucb->ts_idev, ABS_Y, 0, y_res, 0, 0);
input_set_abs_params(ucb->ts_idev, ABS_PRESSURE, 0, 0, 0, 0);
+ ucb1400_ts_stop(ucb);
+
+ error = request_threaded_irq(ucb->irq, NULL, ucb1400_irq,
+ IRQF_TRIGGER_RISING | IRQF_ONESHOT,
+ "UCB1400", ucb);
+ if (error) {
+ printk(KERN_ERR "ucb1400: unable to grab irq%d: %d\n",
+ ucb->irq, error);
+ goto err_free_devs;
+ }
+
error = input_register_device(ucb->ts_idev);
if (error)
goto err_free_irq; return error;
}
-static int __devexit ucb1400_ts_remove(struct platform_device *dev)
+static int __devexit ucb1400_ts_remove(struct platform_device *pdev)
{
- struct ucb1400_ts *ucb = dev->dev.platform_data;
+ struct ucb1400_ts *ucb = pdev->dev.platform_data;
free_irq(ucb->irq, ucb);
input_unregister_device(ucb->ts_idev);@@ -429,24 +407,37 @@ static int __devexit ucb1400_ts_remove(struct platform_device *dev)
}
#ifdef CONFIG_PM_SLEEP
+static int ucb1400_ts_suspend(struct device *dev)
+{
+ struct ucb1400_ts *ucb = dev->platform_data;
+ struct input_dev *idev = ucb->ts_idev;
+
+ mutex_lock(&idev->mutex);
+
+ if (idev->users)
+ ucb1400_ts_start(ucb);
+
+ mutex_unlock(&idev->mutex);
+ return 0;
+}
+
static int ucb1400_ts_resume(struct device *dev)
{
struct ucb1400_ts *ucb = dev->platform_data;
+ struct input_dev *idev = ucb->ts_idev;
- if (ucb->ts_task) {
- /*
- * Restart the TS thread to ensure the
- * TS interrupt mode is set up again
- * after sleep.
- */
- ucb->ts_restart = 1;
- wake_up(&ucb->ts_wait);
- }
+ mutex_lock(&idev->mutex);
+
+ if (idev->users)
+ ucb1400_ts_stop(ucb);
+
+ mutex_unlock(&idev->mutex);
return 0;
}
#endif