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path: root/drivers/input/touchscreen/ads7846.c
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Diffstat (limited to 'drivers/input/touchscreen/ads7846.c')
-rw-r--r--drivers/input/touchscreen/ads7846.c414
1 files changed, 335 insertions, 79 deletions
diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 46d1fec..1494175 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)
@@ -61,6 +71,7 @@ struct ts_event {
__be16 x;
__be16 y;
__be16 z1, z2;
+ int ignore;
};
struct ads7846 {
@@ -71,12 +82,23 @@ struct ads7846 {
u16 model;
u16 vref_delay_usecs;
u16 x_plate_ohms;
+ u16 pressure_max;
- u8 read_x, read_y, read_z1, read_z2;
+ u8 read_x, read_y, read_z1, read_z2, pwrdown;
+ u16 dummy; /* for the pwrdown read */
struct ts_event tc;
- struct spi_transfer xfer[8];
- struct spi_message msg;
+ struct spi_transfer xfer[10];
+ struct spi_message msg[5];
+ struct spi_message *last_msg;
+ int msg_idx;
+ int read_cnt;
+ int read_rep;
+ int last_read;
+
+ u16 debounce_max;
+ u16 debounce_tol;
+ u16 debounce_rep;
spinlock_t lock;
struct timer_list timer; /* P: lock */
@@ -84,6 +106,9 @@ struct ads7846 {
unsigned pending:1; /* P: lock */
// FIXME remove "irq_disabled"
unsigned irq_disabled:1; /* P: lock */
+ unsigned disabled:1;
+
+ int (*get_pendown_state)(void);
};
/* leave chip selected when we're done, for quicker re-select? */
@@ -125,7 +150,9 @@ struct ads7846 {
#define READ_Y (READ_12BIT_DFR(y) | ADS_PD10_ADC_ON)
#define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
#define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
-#define READ_X (READ_12BIT_DFR(x) | ADS_PD10_PDOWN) /* LAST */
+
+#define READ_X (READ_12BIT_DFR(x) | ADS_PD10_ADC_ON)
+#define PWRDOWN (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) /* LAST */
/* single-ended samples need to first power up reference voltage;
* we leave both ADC and VREF powered
@@ -152,6 +179,15 @@ struct ser_req {
struct spi_transfer xfer[6];
};
+static void ads7846_enable(struct ads7846 *ts);
+static void ads7846_disable(struct ads7846 *ts);
+
+static int device_suspended(struct device *dev)
+{
+ struct ads7846 *ts = dev_get_drvdata(dev);
+ return dev->power.power_state.event != PM_EVENT_ON || ts->disabled;
+}
+
static int ads7846_read12_ser(struct device *dev, unsigned command)
{
struct spi_device *spi = to_spi_device(dev);
@@ -164,7 +200,7 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
if (!req)
return -ENOMEM;
- INIT_LIST_HEAD(&req->msg.transfers);
+ spi_message_init(&req->msg);
/* activate reference, so it has time to settle; */
req->ref_on = REF_ON;
@@ -204,8 +240,10 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
for (i = 0; i < 6; i++)
spi_message_add_tail(&req->xfer[i], &req->msg);
+ ts->irq_disabled = 1;
disable_irq(spi->irq);
status = spi_sync(spi, &req->msg);
+ ts->irq_disabled = 0;
enable_irq(spi->irq);
if (req->msg.status)
@@ -233,6 +271,52 @@ SHOW(temp1)
SHOW(vaux)
SHOW(vbatt)
+static int is_pen_down(struct device *dev)
+{
+ struct ads7846 *ts = dev_get_drvdata(dev);
+
+ return ts->pendown;
+}
+
+static ssize_t ads7846_pen_down_show(struct device *dev,
+ struct device_attribute *attr, char *buf)
+{
+ return sprintf(buf, "%u\n", is_pen_down(dev));
+}
+
+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);
+
/*--------------------------------------------------------------------------*/
/*
@@ -264,7 +348,7 @@ static void ads7846_rx(void *ads)
if (x == MAX_12BIT)
x = 0;
- if (x && z1 && ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
+ if (likely(x && z1 && !device_suspended(&ts->spi->dev))) {
/* compute touch pressure resistance using equation #2 */
Rt = z2;
Rt -= z1;
@@ -275,6 +359,14 @@ static void ads7846_rx(void *ads)
} else
Rt = 0;
+ /* 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 */
+ if (ts->tc.ignore || Rt > ts->pressure_max) {
+ mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
+ return;
+ }
+
/* NOTE: "pendown" is inferred from pressure; we don't rely on
* being able to check nPENIRQ status, or "friendly" trigger modes
* (both-edges is much better than just-falling or low-level).
@@ -296,11 +388,13 @@ static void ads7846_rx(void *ads)
if (Rt) {
input_report_abs(input_dev, ABS_X, x);
input_report_abs(input_dev, ABS_Y, y);
- input_report_abs(input_dev, ABS_PRESSURE, Rt);
sync = 1;
}
- if (sync)
+
+ if (sync) {
+ input_report_abs(input_dev, ABS_PRESSURE, Rt);
input_sync(input_dev);
+ }
#ifdef VERBOSE
if (Rt || ts->pendown)
@@ -308,80 +402,138 @@ static void ads7846_rx(void *ads)
x, y, Rt, Rt ? "" : " UP");
#endif
- /* don't retrigger while we're suspended */
spin_lock_irqsave(&ts->lock, flags);
ts->pendown = (Rt != 0);
- ts->pending = 0;
+ mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
- if (ts->spi->dev.power.power_state.event == PM_EVENT_ON) {
- if (ts->pendown)
- mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
- else if (ts->irq_disabled) {
- ts->irq_disabled = 0;
- enable_irq(ts->spi->irq);
+ spin_unlock_irqrestore(&ts->lock, flags);
+}
+
+static void ads7846_debounce(void *ads)
+{
+ struct ads7846 *ts = ads;
+ struct spi_message *m;
+ struct spi_transfer *t;
+ int val;
+ int status;
+
+ m = &ts->msg[ts->msg_idx];
+ t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
+ val = (*(u16 *)t->rx_buf) >> 3;
+ if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) {
+ /* Repeat it, if this was the first read or the read
+ * wasn't consistent enough. */
+ if (ts->read_cnt < ts->debounce_max) {
+ ts->last_read = val;
+ ts->read_cnt++;
+ } else {
+ /* Maximum number of debouncing reached and still
+ * not enough number of consistent readings. Abort
+ * the whole sample, repeat it in the next sampling
+ * period.
+ */
+ ts->tc.ignore = 1;
+ ts->read_cnt = 0;
+ /* Last message will contain ads7846_rx() as the
+ * completion function.
+ */
+ m = ts->last_msg;
}
+ /* Start over collecting consistent readings. */
+ ts->read_rep = 0;
+ } else {
+ if (++ts->read_rep > ts->debounce_rep) {
+ /* Got a good reading for this coordinate,
+ * go for the next one. */
+ ts->tc.ignore = 0;
+ ts->msg_idx++;
+ ts->read_cnt = 0;
+ ts->read_rep = 0;
+ m++;
+ } else
+ /* Read more values that are consistent. */
+ ts->read_cnt++;
}
-
- spin_unlock_irqrestore(&ts->lock, flags);
+ status = spi_async(ts->spi, m);
+ if (status)
+ dev_err(&ts->spi->dev, "spi_async --> %d\n",
+ status);
}
static void ads7846_timer(unsigned long handle)
{
struct ads7846 *ts = (void *)handle;
int status = 0;
- unsigned long flags;
+
+ spin_lock_irq(&ts->lock);
+
+ if (unlikely(ts->msg_idx && !ts->pendown)) {
+ /* measurment cycle ended */
+ if (!device_suspended(&ts->spi->dev)) {
+ ts->irq_disabled = 0;
+ enable_irq(ts->spi->irq);
+ }
+ ts->pending = 0;
+ ts->msg_idx = 0;
+ } else {
+ /* pen is still down, continue with the measurement */
+ ts->msg_idx = 0;
+ status = spi_async(ts->spi, &ts->msg[0]);
+ if (status)
+ dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
+ }
+
+ spin_unlock_irq(&ts->lock);
+}
+
+static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
+{
+ struct ads7846 *ts = handle;
+ unsigned long flags;
spin_lock_irqsave(&ts->lock, flags);
- if (!ts->pending) {
- ts->pending = 1;
+ if (likely(ts->get_pendown_state())) {
if (!ts->irq_disabled) {
+ /* REVISIT irq logic for many ARM chips has cloned a
+ * bug wherein disabling an irq in its handler won't
+ * work;(it's disabled lazily, and too late to work.
+ * until all their irq logic is fixed, we must shadow
+ * that state here.
+ */
ts->irq_disabled = 1;
disable_irq(ts->spi->irq);
+ ts->pending = 1;
+ mod_timer(&ts->timer, jiffies);
}
- status = spi_async(ts->spi, &ts->msg);
- if (status)
- dev_err(&ts->spi->dev, "spi_async --> %d\n",
- status);
}
spin_unlock_irqrestore(&ts->lock, flags);
-}
-static irqreturn_t ads7846_irq(int irq, void *handle, struct pt_regs *regs)
-{
- ads7846_timer((unsigned long) handle);
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;
+ if (ts->disabled)
+ return;
- spin_lock_irqsave(&ts->lock, flags);
-
- spi->dev.power.power_state = message;
+ ts->disabled = 1;
/* are we waiting for IRQ, or polling? */
- if (!ts->pendown) {
- if (!ts->irq_disabled) {
- ts->irq_disabled = 1;
- disable_irq(ts->spi->irq);
- }
+ if (!ts->pending) {
+ ts->irq_disabled = 1;
+ disable_irq(ts->spi->irq);
} else {
- /* polling; force a final SPI completion;
- * that will clean things up neatly
+ /* the timer will run at least once more, and
+ * leave everything in a clean state, IRQ disabled
*/
- if (!ts->pending)
- mod_timer(&ts->timer, jiffies);
-
- while (ts->pendown || ts->pending) {
- spin_unlock_irqrestore(&ts->lock, flags);
- udelay(10);
- spin_lock_irqsave(&ts->lock, flags);
+ while (ts->pending) {
+ spin_unlock_irq(&ts->lock);
+ msleep(1);
+ spin_lock_irq(&ts->lock);
}
}
@@ -389,17 +541,45 @@ ads7846_suspend(struct spi_device *spi, pm_message_t message)
* leave it that way after every request
*/
- spin_unlock_irqrestore(&ts->lock, flags);
+}
+
+/* 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;
}
@@ -408,6 +588,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
struct ads7846 *ts;
struct input_dev *input_dev;
struct ads7846_platform_data *pdata = spi->dev.platform_data;
+ struct spi_message *m;
struct spi_transfer *x;
int err;
@@ -428,6 +609,11 @@ static int __devinit ads7846_probe(struct spi_device *spi)
return -EINVAL;
}
+ if (pdata->get_pendown_state == NULL) {
+ dev_dbg(&spi->dev, "no get_pendown_state function?\n");
+ return -EINVAL;
+ }
+
/* We'd set the wordsize to 12 bits ... except that some controllers
* will then treat the 8 bit command words as 12 bits (and drop the
* four MSBs of the 12 bit result). Result: inputs must be shifted
@@ -451,9 +637,21 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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;
+ ts->pressure_max = pdata->pressure_max ? : ~0;
+ if (pdata->debounce_max) {
+ ts->debounce_max = pdata->debounce_max;
+ ts->debounce_tol = pdata->debounce_tol;
+ ts->debounce_rep = pdata->debounce_rep;
+ if (ts->debounce_rep > ts->debounce_max + 1)
+ ts->debounce_rep = ts->debounce_max - 1;
+ } else
+ ts->debounce_tol = ~0;
+ ts->get_pendown_state = pdata->get_pendown_state;
snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
@@ -477,60 +675,100 @@ static int __devinit ads7846_probe(struct spi_device *spi)
/* set up the transfers to read touchscreen state; this assumes we
* use formula #2 for pressure, not #3.
*/
- INIT_LIST_HEAD(&ts->msg.transfers);
+ m = &ts->msg[0];
x = ts->xfer;
+ spi_message_init(m);
+
/* y- still on; turn on only y+ (and ADC) */
ts->read_y = READ_Y;
x->tx_buf = &ts->read_y;
x->len = 1;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
x++;
x->rx_buf = &ts->tc.y;
x->len = 2;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
+
+ m->complete = ads7846_debounce;
+ m->context = ts;
+
+ m++;
+ spi_message_init(m);
+
+ /* turn y- off, x+ on, then leave in lowpower */
+ x++;
+ ts->read_x = READ_X;
+ x->tx_buf = &ts->read_x;
+ x->len = 1;
+ spi_message_add_tail(x, m);
+
+ x++;
+ x->rx_buf = &ts->tc.x;
+ x->len = 2;
+ spi_message_add_tail(x, m);
+
+ m->complete = ads7846_debounce;
+ m->context = ts;
/* turn y+ off, x- on; we'll use formula #2 */
if (ts->model == 7846) {
+ m++;
+ spi_message_init(m);
+
x++;
ts->read_z1 = READ_Z1;
x->tx_buf = &ts->read_z1;
x->len = 1;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
x++;
x->rx_buf = &ts->tc.z1;
x->len = 2;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
+
+ m->complete = ads7846_debounce;
+ m->context = ts;
+
+ m++;
+ spi_message_init(m);
x++;
ts->read_z2 = READ_Z2;
x->tx_buf = &ts->read_z2;
x->len = 1;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
x++;
x->rx_buf = &ts->tc.z2;
x->len = 2;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
+
+ m->complete = ads7846_debounce;
+ m->context = ts;
}
- /* turn y- off, x+ on, then leave in lowpower */
+ /* power down */
+ m++;
+ spi_message_init(m);
+
x++;
- ts->read_x = READ_X;
- x->tx_buf = &ts->read_x;
+ ts->pwrdown = PWRDOWN;
+ x->tx_buf = &ts->pwrdown;
x->len = 1;
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
x++;
- x->rx_buf = &ts->tc.x;
+ x->rx_buf = &ts->dummy;
x->len = 2;
CS_CHANGE(*x);
- spi_message_add_tail(x, &ts->msg);
+ spi_message_add_tail(x, m);
- ts->msg.complete = ads7846_rx;
- ts->msg.context = ts;
+ m->complete = ads7846_rx;
+ m->context = ts;
+
+ ts->last_msg = m;
if (request_irq(spi->irq, ads7846_irq,
SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
@@ -559,13 +797,27 @@ static int __devinit ads7846_probe(struct spi_device *spi)
device_create_file(&spi->dev, &dev_attr_vbatt);
device_create_file(&spi->dev, &dev_attr_vaux);
+ 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);
@@ -577,20 +829,24 @@ static int __devexit ads7846_remove(struct spi_device *spi)
{
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);
+ /* suspend left the IRQ disabled */
+ enable_irq(ts->spi->irq);
+
kfree(ts);
dev_dbg(&spi->dev, "unregistered touchscreen\n");
generated by cgit v0.10.2 at 2024-11-13 08:56:44 (GMT)