Input: ads7846 - miscellaneous fixes
- Add disable attribute to support device locking mode where
unintentional touch event shouldn't wake up the system;
- Update comments;
- Add missing spin_lock_init;
- Do device resume with the lock held;
- Do cleanup calls / free memory in the reverse order of initialization.
Signed-off-by: Imre Deak <imre.deak@nokia.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index bdec112..fec3b9b 100644
--- a/drivers/input/touchscreen/ads7846.c
+++ b/drivers/input/touchscreen/ads7846.c
@@ -2,6 +2,8 @@
* ADS7846 based touchscreen and sensor driver
*
* Copyright (c) 2005 David Brownell
+ * Copyright (c) 2006 Nokia Corporation
+ * Various changes: Imre Deak <imre.deak@nokia.com>
*
* Using code from:
* - corgi_ts.c
@@ -34,17 +36,25 @@
/*
- * This code has been lightly tested on an ads7846.
+ * This code has been tested on an ads7846 / N770 device.
* Support for ads7843 and ads7845 has only been stubbed in.
*
- * Not yet done: investigate the values reported. Are x/y/pressure
- * event values sane enough for X11? How accurate are the temperature
- * and voltage readings? (System-specific calibration should support
+ * Not yet done: How accurate are the temperature and voltage
+ * readings? (System-specific calibration should support
* accuracy of 0.3 degrees C; otherwise it's 2.0 degrees.)
*
+ * IRQ handling needs a workaround because of a shortcoming in handling
+ * edge triggered IRQs on some platforms like the OMAP1/2. These
+ * platforms don't handle the ARM lazy IRQ disabling properly, thus we
+ * have to maintain our own SW IRQ disabled status. This should be
+ * removed as soon as the affected platform's IRQ handling is fixed.
+ *
* app note sbaa036 talks in more detail about accurate sampling...
* that ought to help in situations like LCDs inducing noise (which
* can also be helped by using synch signals) and more generally.
+ * This driver tries to utilize the measures described in the app
+ * note. The strength of filtering can be set in the board-* specific
+ * files.
*/
#define TS_POLL_PERIOD msecs_to_jiffies(10)
@@ -91,6 +101,7 @@
unsigned pending:1; /* P: lock */
// FIXME remove "irq_disabled"
unsigned irq_disabled:1; /* P: lock */
+ unsigned disabled:1;
};
/* leave chip selected when we're done, for quicker re-select? */
@@ -161,6 +172,9 @@
struct spi_transfer xfer[6];
};
+static void ads7846_enable(struct ads7846 *ts);
+static void ads7846_disable(struct ads7846 *ts);
+
static int ads7846_read12_ser(struct device *dev, unsigned command)
{
struct spi_device *spi = to_spi_device(dev);
@@ -257,6 +271,37 @@
static DEVICE_ATTR(pen_down, S_IRUGO, ads7846_pen_down_show, NULL);
+static ssize_t ads7846_disable_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ struct ads7846 *ts = dev_get_drvdata(dev);
+
+ return sprintf(buf, "%u\n", ts->disabled);
+}
+
+static ssize_t ads7846_disable_store(struct device *dev,
+ struct device_attribute *attr,
+ const char *buf, size_t count)
+{
+ struct ads7846 *ts = dev_get_drvdata(dev);
+ char *endp;
+ int i;
+
+ i = simple_strtoul(buf, &endp, 10);
+ spin_lock_irq(&ts->lock);
+
+ if (i)
+ ads7846_disable(ts);
+ else
+ ads7846_enable(ts);
+
+ spin_unlock_irq(&ts->lock);
+
+ return count;
+}
+
+static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
+
/*--------------------------------------------------------------------------*/
/*
@@ -396,12 +441,9 @@
{
struct ads7846 *ts = handle;
unsigned long flags;
- int r = IRQ_HANDLED;
spin_lock_irqsave(&ts->lock, flags);
- if (ts->irq_disabled)
- r = IRQ_HANDLED;
- else {
+ if (likely(!ts->irq_disabled && !ts->disabled)) {
if (!ts->irq_disabled) {
/* REVISIT irq logic for many ARM chips has cloned a
* bug wherein disabling an irq in its handler won't
@@ -419,20 +461,17 @@
}
}
spin_unlock_irqrestore(&ts->lock, flags);
- return r;
+
+ return IRQ_HANDLED;
}
/*--------------------------------------------------------------------------*/
-static int
-ads7846_suspend(struct spi_device *spi, pm_message_t message)
+/* Must be called with ts->lock held */
+static void ads7846_disable(struct ads7846 *ts)
{
- struct ads7846 *ts = dev_get_drvdata(&spi->dev);
- unsigned long flags;
-
- spin_lock_irqsave(&ts->lock, flags);
-
- spi->dev.power.power_state = message;
+ if (ts->disabled)
+ return;
/* are we waiting for IRQ, or polling? */
if (!ts->pendown) {
@@ -448,9 +487,9 @@
mod_timer(&ts->timer, jiffies);
while (ts->pendown || ts->pending) {
- spin_unlock_irqrestore(&ts->lock, flags);
+ spin_unlock_irq(&ts->lock);
msleep(1);
- spin_lock_irqsave(&ts->lock, flags);
+ spin_lock_irq(&ts->lock);
}
}
@@ -458,17 +497,46 @@
* leave it that way after every request
*/
- spin_unlock_irqrestore(&ts->lock, flags);
+ ts->disabled = 1;
+}
+
+/* Must be called with ts->lock held */
+static void ads7846_enable(struct ads7846 *ts)
+{
+ if (!ts->disabled)
+ return;
+
+ ts->disabled = 0;
+ ts->irq_disabled = 0;
+ enable_irq(ts->spi->irq);
+}
+
+static int ads7846_suspend(struct spi_device *spi, pm_message_t message)
+{
+ struct ads7846 *ts = dev_get_drvdata(&spi->dev);
+
+ spin_lock_irq(&ts->lock);
+
+ spi->dev.power.power_state = message;
+ ads7846_disable(ts);
+
+ spin_unlock_irq(&ts->lock);
+
return 0;
+
}
static int ads7846_resume(struct spi_device *spi)
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
- ts->irq_disabled = 0;
- enable_irq(ts->spi->irq);
+ spin_lock_irq(&ts->lock);
+
spi->dev.power.power_state = PMSG_ON;
+ ads7846_enable(ts);
+
+ spin_unlock_irq(&ts->lock);
+
return 0;
}
@@ -521,6 +589,8 @@
ts->timer.data = (unsigned long) ts;
ts->timer.function = ads7846_timer;
+ spin_lock_init(&ts->lock);
+
ts->model = pdata->model ? : 7846;
ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
@@ -671,13 +741,25 @@
device_create_file(&spi->dev, &dev_attr_pen_down);
+ device_create_file(&spi->dev, &dev_attr_disable);
+
err = input_register_device(input_dev);
if (err)
- goto err_free_irq;
+ goto err_remove_attr;
return 0;
- err_free_irq:
+ err_remove_attr:
+ device_remove_file(&spi->dev, &dev_attr_disable);
+ device_remove_file(&spi->dev, &dev_attr_pen_down);
+ if (ts->model == 7846) {
+ device_remove_file(&spi->dev, &dev_attr_temp1);
+ device_remove_file(&spi->dev, &dev_attr_temp0);
+ }
+ if (ts->model != 7845)
+ device_remove_file(&spi->dev, &dev_attr_vbatt);
+ device_remove_file(&spi->dev, &dev_attr_vaux);
+
free_irq(spi->irq, ts);
err_free_mem:
input_free_device(input_dev);
@@ -689,22 +771,24 @@
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
+ input_unregister_device(ts->input);
+
ads7846_suspend(spi, PMSG_SUSPEND);
- free_irq(ts->spi->irq, ts);
- if (ts->irq_disabled)
- enable_irq(ts->spi->irq);
+ device_remove_file(&spi->dev, &dev_attr_disable);
device_remove_file(&spi->dev, &dev_attr_pen_down);
-
if (ts->model == 7846) {
- device_remove_file(&spi->dev, &dev_attr_temp0);
device_remove_file(&spi->dev, &dev_attr_temp1);
+ device_remove_file(&spi->dev, &dev_attr_temp0);
}
if (ts->model != 7845)
device_remove_file(&spi->dev, &dev_attr_vbatt);
device_remove_file(&spi->dev, &dev_attr_vaux);
- input_unregister_device(ts->input);
+ free_irq(ts->spi->irq, ts);
+ if (ts->irq_disabled)
+ enable_irq(ts->spi->irq);
+
kfree(ts);
dev_dbg(&spi->dev, "unregistered touchscreen\n");