1 files changed, 335 insertions, 79 deletions

diff --git a/drivers/input/touchscreen/ads7846.c b/drivers/input/touchscreen/ads7846.c
index 46d1fec2cfd8..1494175ac6fe 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");