* ADS7846 based touchscreen and sensor driver
*
* Copyright (c) 2005 David Brownell
+ * Copyright (c) 2006 Imre Deak <imre.deak@nokia.com>
*
* Using code from:
* - corgi_ts.c
/*
- * This code has been lightly tested on an ads7846.
+ * This code has been heavily tested on a Nokia 770, and lightly
+ * tested on an other ads7846 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 platforms' 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)
+/* this driver doesn't aim at the peak continuous sample rate */
+#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
+
struct ts_event {
/* For portability, we can't read 12 bit values using SPI (which
* would make the controller deliver them as native byteorder u16
- * with msbs zeroed). Instead, we read them as two 8-byte values,
+ * with msbs zeroed). Instead, we read them as two 8-bit values,
* which need byteswapping then range adjustment.
*/
__be16 x;
};
struct ads7846 {
- struct input_dev input;
+ struct input_dev *input;
char phys[32];
struct spi_device *spi;
u16 model;
u16 vref_delay_usecs;
u16 x_plate_ohms;
+ u16 pressure_max;
+ u8 read_x, read_y, read_z1, read_z2, pwrdown;
+ u16 dummy; /* for the pwrdown read */
struct ts_event tc;
+ u16 last_x;
+ u16 last_y;
+ u16 last_pressure;
- struct spi_transfer xfer[8];
- struct spi_message msg;
+ struct spi_transfer xfer[10];
+ struct spi_message msg[5];
+ int msg_idx;
+ int read_cnt;
+ int last_read;
+
+ u16 debounce_max;
+ u16 debounce_tol;
spinlock_t lock;
struct timer_list timer; /* P: lock */
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? */
#define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
| ADS_12_BIT | ADS_DFR)
-static const u8 read_y = READ_12BIT_DFR(y) | ADS_PD10_ADC_ON;
-static const u8 read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON;
-static const u8 read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON;
-static const u8 read_x = READ_12BIT_DFR(x) | ADS_PD10_PDOWN; /* LAST */
+#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_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
#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
| ADS_12_BIT | ADS_SER)
-static const u8 ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON;
-static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
+#define REF_ON (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
+#define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
/*--------------------------------------------------------------------------*/
*/
struct ser_req {
+ u8 ref_on;
u8 command;
+ u8 ref_off;
u16 scratch;
__be16 sample;
struct spi_message msg;
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);
struct ser_req *req = kzalloc(sizeof *req, SLAB_KERNEL);
int status;
int sample;
- int i;
+ int i;
if (!req)
return -ENOMEM;
- INIT_LIST_HEAD(&req->msg.transfers);
+ spi_message_init(&req->msg);
/* activate reference, so it has time to settle; */
- req->xfer[0].tx_buf = &ref_on;
+ req->ref_on = REF_ON;
+ req->xfer[0].tx_buf = &req->ref_on;
req->xfer[0].len = 1;
req->xfer[1].rx_buf = &req->scratch;
req->xfer[1].len = 2;
/* REVISIT: take a few more samples, and compare ... */
/* turn off reference */
- req->xfer[4].tx_buf = &ref_off;
+ req->ref_off = REF_OFF;
+ req->xfer[4].tx_buf = &req->ref_off;
req->xfer[4].len = 1;
req->xfer[5].rx_buf = &req->scratch;
req->xfer[5].len = 2;
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);
+ unsigned long flags;
+ char *endp;
+ int i;
+
+ i = simple_strtoul(buf, &endp, 10);
+ spin_lock_irqsave(&ts->lock, flags);
+
+ if (i)
+ ads7846_disable(ts);
+ else
+ ads7846_enable(ts);
+
+ spin_unlock_irqrestore(&ts->lock, flags);
+
+ return count;
+}
+
+static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
+
/*--------------------------------------------------------------------------*/
/*
static void ads7846_rx(void *ads)
{
- struct ads7846 *ts = ads;
- unsigned Rt;
- unsigned sync = 0;
- u16 x, y, z1, z2;
- unsigned long flags;
+ struct ads7846 *ts = ads;
+ struct input_dev *input_dev = ts->input;
+ unsigned Rt;
+ unsigned sync = 0;
+ u16 x, y, z1, z2;
+ unsigned long flags;
/* adjust: 12 bit samples (left aligned), built from
* two 8 bit values writen msb-first.
*/
- x = be16_to_cpu(ts->tc.x) >> 4;
- y = be16_to_cpu(ts->tc.y) >> 4;
- z1 = be16_to_cpu(ts->tc.z1) >> 4;
- z2 = be16_to_cpu(ts->tc.z2) >> 4;
+ x = ts->tc.x >> 3;
+ y = ts->tc.y >> 3;
+ z1 = ts->tc.z1 >> 3;
+ z2 = ts->tc.z2 >> 3;
/* range filtering */
if (x == MAX_12BIT)
} else
Rt = 0;
+ if (Rt > ts->pressure_max) {
+ if (ts->last_pressure) {
+ x = ts->last_x;
+ y = ts->last_y;
+ }
+ Rt = ts->pressure_max;
+ }
+
+ ts->last_x = x;
+ ts->last_y = y;
+ ts->last_pressure = Rt;
+
/* 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).
* won't notice that, even if nPENIRQ never fires ...
*/
if (!ts->pendown && Rt != 0) {
- input_report_key(&ts->input, BTN_TOUCH, 1);
+ input_report_key(input_dev, BTN_TOUCH, 1);
sync = 1;
} else if (ts->pendown && Rt == 0) {
- input_report_key(&ts->input, BTN_TOUCH, 0);
+ input_report_key(input_dev, BTN_TOUCH, 0);
sync = 1;
}
if (Rt) {
- input_report_abs(&ts->input, ABS_X, x);
- input_report_abs(&ts->input, ABS_Y, y);
- input_report_abs(&ts->input, ABS_PRESSURE, 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)
- input_sync(&ts->input);
+ input_sync(input_dev);
#ifdef VERBOSE
if (Rt || ts->pendown)
spin_unlock_irqrestore(&ts->lock, flags);
}
+static void ads7846_debounce(void *ads)
+{
+ struct ads7846 *ts = ads;
+ struct spi_message *m;
+ struct spi_transfer *t;
+ u16 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 &&
+ ts->read_cnt < ts->debounce_max)) {
+ /* Repeat it, if this was the first read or the read wasn't
+ * consistent enough */
+ ts->read_cnt++;
+ ts->last_read = val;
+ } else {
+ /* Go for the next read */
+ ts->msg_idx++;
+ ts->read_cnt = 0;
+ m++;
+ }
+ 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;
+
+ ts->msg_idx = 0;
+ status = spi_async(ts->spi, &ts->msg[0]);
+ if (status)
+ dev_err(&ts->spi->dev, "spi_async --> %d\n", status);
+}
+
+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->irq_disabled && !ts->disabled)) {
if (!ts->irq_disabled) {
ts->irq_disabled = 1;
+ /* The following has at the moment no effect whatsoever
+ * on OMAP, that's why we maintain the disabled
+ * state ourselves */
disable_irq(ts->spi->irq);
}
- status = spi_async(ts->spi, &ts->msg);
- if (status)
- dev_err(&ts->spi->dev, "spi_async --> %d\n",
- status);
+ if (!ts->pending) {
+ ts->pending = 1;
+ mod_timer(&ts->timer, jiffies);
+ }
}
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;
-
- 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) {
disable_irq(ts->spi->irq);
}
} else {
+ unsigned long flags;
+
/* polling; force a final SPI completion;
* that will clean things up neatly
*/
while (ts->pendown || ts->pending) {
spin_unlock_irqrestore(&ts->lock, flags);
- udelay(10);
+ msleep(1);
spin_lock_irqsave(&ts->lock, flags);
}
}
* leave it that way after every request
*/
+ 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);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ts->lock, flags);
+
+ spi->dev.power.power_state = message;
+ ads7846_disable(ts);
+
spin_unlock_irqrestore(&ts->lock, flags);
+
return 0;
+
}
static int ads7846_resume(struct spi_device *spi)
{
struct ads7846 *ts = dev_get_drvdata(&spi->dev);
+ unsigned long flags;
+
+ spin_lock_irqsave(&ts->lock, flags);
- ts->irq_disabled = 0;
- enable_irq(ts->spi->irq);
spi->dev.power.power_state = PMSG_ON;
+ ads7846_enable(ts);
+
+ spin_unlock_irqrestore(&ts->lock, flags);
+
return 0;
}
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 i;
+ int err;
if (!spi->irq) {
dev_dbg(&spi->dev, "no IRQ?\n");
}
/* don't exceed max specified sample rate */
- if (spi->max_speed_hz > (125000 * 16)) {
+ if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
- (spi->max_speed_hz/16)/1000);
+ (spi->max_speed_hz/SAMPLE_BITS)/1000);
return -EINVAL;
}
* to discard the four garbage LSBs.
*/
- if (!(ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL)))
- return -ENOMEM;
+ ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
+ input_dev = input_allocate_device();
+ if (!ts || !input_dev) {
+ err = -ENOMEM;
+ goto err_free_mem;
+ }
dev_set_drvdata(&spi->dev, ts);
+ spi->dev.power.power_state = PMSG_ON;
ts->spi = spi;
- spi->dev.power.power_state = PMSG_ON;
+ ts->input = input_dev;
init_timer(&ts->timer);
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;
+ ts->debounce_max = pdata->debounce_max ? : 1;
+ ts->debounce_tol = pdata->debounce_tol ? : 10;
- init_input_dev(&ts->input);
+ snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
- ts->input.dev = &spi->dev;
- ts->input.name = "ADS784x Touchscreen";
- snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id);
- ts->input.phys = ts->phys;
+ input_dev->name = "ADS784x Touchscreen";
+ input_dev->phys = ts->phys;
+ input_dev->cdev.dev = &spi->dev;
- ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
- ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
- input_set_abs_params(&ts->input, ABS_X,
+ input_dev->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
+ input_dev->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
+ input_set_abs_params(input_dev, ABS_X,
pdata->x_min ? : 0,
pdata->x_max ? : MAX_12BIT,
0, 0);
- input_set_abs_params(&ts->input, ABS_Y,
+ input_set_abs_params(input_dev, ABS_Y,
pdata->y_min ? : 0,
pdata->y_max ? : MAX_12BIT,
0, 0);
- input_set_abs_params(&ts->input, ABS_PRESSURE,
+ input_set_abs_params(input_dev, ABS_PRESSURE,
pdata->pressure_min, pdata->pressure_max, 0, 0);
- input_register_device(&ts->input);
-
/* set up the transfers to read touchscreen state; this assumes we
* use formula #2 for pressure, not #3.
*/
+ m = &ts->msg[0];
x = ts->xfer;
+ spi_message_init(m);
+
/* y- still on; turn on only y+ (and ADC) */
- x->tx_buf = &read_y;
+ ts->read_y = READ_Y;
+ x->tx_buf = &ts->read_y;
x->len = 1;
+ spi_message_add_tail(x, m);
+
x++;
x->rx_buf = &ts->tc.y;
x->len = 2;
+ 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) {
- x->tx_buf = &read_z1;
+ 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, m);
+
x++;
x->rx_buf = &ts->tc.z1;
x->len = 2;
- x++;
+ spi_message_add_tail(x, m);
+
+ m->complete = ads7846_debounce;
+ m->context = ts;
- x->tx_buf = &read_z2;
+ 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, m);
+
x++;
x->rx_buf = &ts->tc.z2;
x->len = 2;
- x++;
+ spi_message_add_tail(x, m);
+
+ m->complete = ads7846_debounce;
+ m->context = ts;
}
- /* turn y- off, x+ on, then leave in lowpower */
- x->tx_buf = &read_x;
+ /* power down */
+ m++;
+ spi_message_init(m);
+
+ x++;
+ ts->pwrdown = PWRDOWN;
+ x->tx_buf = &ts->pwrdown;
x->len = 1;
+ spi_message_add_tail(x, m);
+
x++;
- x->rx_buf = &ts->tc.x;
+ x->rx_buf = &ts->dummy;
x->len = 2;
- x++;
-
- CS_CHANGE(x[-1]);
+ CS_CHANGE(*x);
+ spi_message_add_tail(x, m);
- for (i = 0; i < x - ts->xfer; i++)
- spi_message_add_tail(&ts->xfer[i], &ts->msg);
- ts->msg.complete = ads7846_rx;
- ts->msg.context = ts;
+ m->complete = ads7846_rx;
+ m->context = ts;
if (request_irq(spi->irq, ads7846_irq,
SA_SAMPLE_RANDOM | SA_TRIGGER_FALLING,
spi->dev.bus_id, ts)) {
dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
- input_unregister_device(&ts->input);
- kfree(ts);
- return -EBUSY;
+ err = -EBUSY;
+ goto err_free_mem;
}
dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
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_remove_attr;
+
return 0;
+
+ 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);
+ kfree(ts);
+ return err;
}
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);
+ if (ts->irq_disabled)
+ enable_irq(ts->spi->irq);
+
kfree(ts);
dev_dbg(&spi->dev, "unregistered touchscreen\n");
projects / linux-2.6-omap-h63xx.git / blobdiff