]> www.pilppa.org Git - linux-2.6-omap-h63xx.git/blobdiff - drivers/input/touchscreen/ads7846.c
Merge omap-drivers
[linux-2.6-omap-h63xx.git] / drivers / input / touchscreen / ads7846.c
index 0c496d5d19597cd7702641c4867d39a994dd5320..c6164b6f476a3ecb5fde27af07ddd05c38557d01 100644 (file)
@@ -17,9 +17,8 @@
  *  it under the terms of the GNU General Public License version 2 as
  *  published by the Free Software Foundation.
  */
-#include <linux/hwmon.h>
+#include <linux/device.h>
 #include <linux/init.h>
-#include <linux/err.h>
 #include <linux/delay.h>
 #include <linux/input.h>
 #include <linux/interrupt.h>
@@ -55,8 +54,7 @@
  * files.
  */
 
-#define TS_POLL_DELAY  (1 * 1000000)   /* ns delay before the first sample */
-#define        TS_POLL_PERIOD  (5 * 1000000)   /* ns delay between samples */
+#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 */)
@@ -78,7 +76,7 @@ struct ads7846 {
        char                    phys[32];
 
        struct spi_device       *spi;
-       struct class_device     *hwmon;
+       struct attribute_group  *attr_group;
        u16                     model;
        u16                     vref_delay_usecs;
        u16                     x_plate_ohms;
@@ -101,16 +99,13 @@ struct ads7846 {
        u16                     debounce_rep;
 
        spinlock_t              lock;
-       struct hrtimer          timer;
+       struct timer_list       timer;          /* P: lock */
        unsigned                pendown:1;      /* P: lock */
        unsigned                pending:1;      /* P: lock */
 // FIXME remove "irq_disabled"
        unsigned                irq_disabled:1; /* P: lock */
        unsigned                disabled:1;
 
-       int                     (*filter)(void *data, int data_idx, int *val);
-       void                    *filter_data;
-       void                    (*filter_cleanup)(void *data);
        int                     (*get_pendown_state)(void);
 };
 
@@ -147,16 +142,15 @@ struct ads7846 {
 #define        MAX_12BIT       ((1<<12)-1)
 
 /* leave ADC powered up (disables penirq) between differential samples */
-#define        READ_12BIT_DFR(x, adc, vref) (ADS_START | ADS_A2A1A0_d_ ## x \
-       | ADS_12_BIT | ADS_DFR | \
-       (adc ? ADS_PD10_ADC_ON : 0) | (vref ? ADS_PD10_REF_ON : 0))
+#define        READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
+       | ADS_12_BIT | ADS_DFR)
 
-#define        READ_Y(vref)    (READ_12BIT_DFR(y,  1, vref))
-#define        READ_Z1(vref)   (READ_12BIT_DFR(z1, 1, vref))
-#define        READ_Z2(vref)   (READ_12BIT_DFR(z2, 1, vref))
+#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(vref)    (READ_12BIT_DFR(x,  1, vref))
-#define        PWRDOWN         (READ_12BIT_DFR(y,  0, 0))      /* 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
@@ -164,19 +158,14 @@ struct ads7846 {
 #define        READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
        | ADS_12_BIT | ADS_SER)
 
-#define        REF_ON  (READ_12BIT_DFR(x, 1, 1))
-#define        REF_OFF (READ_12BIT_DFR(y, 0, 0))
+#define        REF_ON  (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
+#define        REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
 
 /*--------------------------------------------------------------------------*/
 
 /*
  * Non-touchscreen sensors only use single-ended conversions.
- * The range is GND..vREF. The ads7843 and ads7835 must use external vREF;
- * ads7846 lets that pin be unconnected, to use internal vREF.
- *
- * FIXME make external vREF_mV be a module option, and use that as needed...
  */
-static const unsigned vREF_mV = 2500;
 
 struct ser_req {
        u8                      ref_on;
@@ -204,55 +193,50 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
        struct ser_req          *req = kzalloc(sizeof *req, GFP_KERNEL);
        int                     status;
        int                     sample;
-       int                     use_internal;
+       int                     i;
 
        if (!req)
                return -ENOMEM;
 
        spi_message_init(&req->msg);
 
-       /* FIXME boards with ads7846 might use external vref instead ... */
-       use_internal = (ts->model == 7846);
-
-       /* maybe turn on internal vREF, and let it settle */
-       if (use_internal) {
-               req->ref_on = REF_ON;
-               req->xfer[0].tx_buf = &req->ref_on;
-               req->xfer[0].len = 1;
-               spi_message_add_tail(&req->xfer[0], &req->msg);
-
-               req->xfer[1].rx_buf = &req->scratch;
-               req->xfer[1].len = 2;
-
-               /* for 1uF, settle for 800 usec; no cap, 100 usec.  */
-               req->xfer[1].delay_usecs = ts->vref_delay_usecs;
-               spi_message_add_tail(&req->xfer[1], &req->msg);
-       }
+       /* activate reference, so it has time to settle; */
+       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;
+
+       /*
+        * for external VREF, 0 usec (and assume it's always on);
+        * for 1uF, use 800 usec;
+        * no cap, 100 usec.
+        */
+       req->xfer[1].delay_usecs = ts->vref_delay_usecs;
 
        /* take sample */
        req->command = (u8) command;
        req->xfer[2].tx_buf = &req->command;
        req->xfer[2].len = 1;
-       spi_message_add_tail(&req->xfer[2], &req->msg);
-
        req->xfer[3].rx_buf = &req->sample;
        req->xfer[3].len = 2;
-       spi_message_add_tail(&req->xfer[3], &req->msg);
 
        /* REVISIT:  take a few more samples, and compare ... */
 
-       /* maybe off internal vREF */
-       if (use_internal) {
-               req->ref_off = REF_OFF;
-               req->xfer[4].tx_buf = &req->ref_off;
-               req->xfer[4].len = 1;
-               spi_message_add_tail(&req->xfer[4], &req->msg);
-
-               req->xfer[5].rx_buf = &req->scratch;
-               req->xfer[5].len = 2;
-               CS_CHANGE(req->xfer[5]);
-               spi_message_add_tail(&req->xfer[5], &req->msg);
-       }
+       /* turn off reference */
+       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;
+
+       CS_CHANGE(req->xfer[5]);
+
+       /* group all the transfers together, so we can't interfere with
+        * reading touchscreen state; disable penirq while sampling
+        */
+       for (i = 0; i < 6; i++)
+               spi_message_add_tail(&req->xfer[i], &req->msg);
 
        ts->irq_disabled = 1;
        disable_irq(spi->irq);
@@ -272,60 +256,21 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
        return status ? status : sample;
 }
 
-#define SHOW(name,var,adjust) static ssize_t \
+#define SHOW(name) static ssize_t \
 name ## _show(struct device *dev, struct device_attribute *attr, char *buf) \
 { \
-       struct ads7846 *ts = dev_get_drvdata(dev); \
        ssize_t v = ads7846_read12_ser(dev, \
-                       READ_12BIT_SER(var) | ADS_PD10_ALL_ON); \
+                       READ_12BIT_SER(name) | ADS_PD10_ALL_ON); \
        if (v < 0) \
                return v; \
-       return sprintf(buf, "%u\n", adjust(ts, v)); \
+       return sprintf(buf, "%u\n", (unsigned) v); \
 } \
 static DEVICE_ATTR(name, S_IRUGO, name ## _show, NULL);
 
-
-/* Sysfs conventions report temperatures in millidegrees Celcius.
- * We could use the low-accuracy two-sample scheme, but can't do the high
- * accuracy scheme without calibration data.  For now we won't try either;
- * userspace sees raw sensor values, and must scale appropriately.
- */
-static inline unsigned null_adjust(struct ads7846 *ts, ssize_t v)
-{
-       return v;
-}
-
-SHOW(temp0, temp0, null_adjust)                // temp1_input
-SHOW(temp1, temp1, null_adjust)                // temp2_input
-
-
-/* sysfs conventions report voltages in millivolts.  We can convert voltages
- * if we know vREF.  userspace may need to scale vAUX to match the board's
- * external resistors; we assume that vBATT only uses the internal ones.
- */
-static inline unsigned vaux_adjust(struct ads7846 *ts, ssize_t v)
-{
-       unsigned retval = v;
-
-       /* external resistors may scale vAUX into 0..vREF */
-       retval *= vREF_mV;
-       retval = retval >> 12;
-       return retval;
-}
-
-static inline unsigned vbatt_adjust(struct ads7846 *ts, ssize_t v)
-{
-       unsigned retval = vaux_adjust(ts, v);
-
-       /* ads7846 has a resistor ladder to scale this signal down */
-       if (ts->model == 7846)
-               retval *= 4;
-       return retval;
-}
-
-SHOW(in0_input, vaux, vaux_adjust)
-SHOW(in1_input, vbatt, vbatt_adjust)
-
+SHOW(temp0)
+SHOW(temp1)
+SHOW(vaux)
+SHOW(vbatt)
 
 static int is_pen_down(struct device *dev)
 {
@@ -373,40 +318,49 @@ static ssize_t ads7846_disable_store(struct device *dev,
 
 static DEVICE_ATTR(disable, 0664, ads7846_disable_show, ads7846_disable_store);
 
-/*--------------------------------------------------------------------------*/
+static struct attribute *ads7846_attributes[] = {
+       &dev_attr_temp0.attr,
+       &dev_attr_temp1.attr,
+       &dev_attr_vbatt.attr,
+       &dev_attr_vaux.attr,
+       &dev_attr_pen_down.attr,
+       &dev_attr_disable.attr,
+       NULL,
+};
 
-static void ads7846_report_pen_state(struct ads7846 *ts, int down)
-{
-       struct input_dev        *input_dev = ts->input;
+static struct attribute_group ads7846_attr_group = {
+       .attrs = ads7846_attributes,
+};
 
-       input_report_key(input_dev, BTN_TOUCH, down);
-       if (!down)
-               input_report_abs(input_dev, ABS_PRESSURE, 0);
-#ifdef VERBOSE
-       pr_debug("%s: %s\n", ts->spi->dev.bus_id, down ? "DOWN" : "UP");
-#endif
-}
+/*
+ * ads7843/7845 don't have temperature sensors, and
+ * use the other sensors a bit differently too
+ */
 
-static void ads7846_report_pen_position(struct ads7846 *ts, int x, int y,
-                                       int pressure)
-{
-       struct input_dev        *input_dev = ts->input;
+static struct attribute *ads7843_attributes[] = {
+       &dev_attr_vbatt.attr,
+       &dev_attr_vaux.attr,
+       &dev_attr_pen_down.attr,
+       &dev_attr_disable.attr,
+       NULL,
+};
 
-       input_report_abs(input_dev, ABS_X, x);
-       input_report_abs(input_dev, ABS_Y, y);
-       input_report_abs(input_dev, ABS_PRESSURE, pressure);
+static struct attribute_group ads7843_attr_group = {
+       .attrs = ads7843_attributes,
+};
 
-#ifdef VERBOSE
-       pr_debug("%s: %d/%d/%d\n", ts->spi->dev.bus_id, x, y, pressure);
-#endif
-}
+static struct attribute *ads7845_attributes[] = {
+       &dev_attr_vaux.attr,
+       &dev_attr_pen_down.attr,
+       &dev_attr_disable.attr,
+       NULL,
+};
 
-static void ads7846_sync_events(struct ads7846 *ts)
-{
-       struct input_dev        *input_dev = ts->input;
+static struct attribute_group ads7845_attr_group = {
+       .attrs = ads7845_attributes,
+};
 
-       input_sync(input_dev);
-}
+/*--------------------------------------------------------------------------*/
 
 /*
  * PENIRQ only kicks the timer.  The timer only reissues the SPI transfer,
@@ -419,22 +373,25 @@ static void ads7846_sync_events(struct ads7846 *ts)
 static void ads7846_rx(void *ads)
 {
        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:  on-wire is a must-ignore bit, a BE12 value, then padding;
         * built from two 8 bit values written msb-first.
         */
-       x = ts->tc.x;
-       y = ts->tc.y;
-       z1 = ts->tc.z1;
-       z2 = ts->tc.z2;
+       x = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff;
+       y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff;
+       z1 = (be16_to_cpu(ts->tc.z1) >> 3) & 0x0fff;
+       z2 = (be16_to_cpu(ts->tc.z2) >> 3) & 0x0fff;
 
        /* range filtering */
        if (x == MAX_12BIT)
                x = 0;
 
-       if (likely(x && z1)) {
+       if (likely(x && z1 && !device_suspended(&ts->spi->dev))) {
                /* compute touch pressure resistance using equation #2 */
                Rt = z2;
                Rt -= z1;
@@ -449,108 +406,97 @@ static void ads7846_rx(void *ads)
        * the maximum. Don't report it to user space, repeat at least
        * once more the measurement */
        if (ts->tc.ignore || Rt > ts->pressure_max) {
-#ifdef VERBOSE
-               pr_debug("%s: ignored %d pressure %d\n",
-                       ts->spi->dev.bus_id, ts->tc.ignore, Rt);
-#endif
-               hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD),
-                             HRTIMER_REL);
+               mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
                return;
        }
 
-       /* NOTE: We can't rely on the pressure to determine the pen down
-        * state. The pressure value can fluctuate for quite a while
-        * after lifting the pen and in some cases may not even settle at
-        * the expected value. The only safe way to check for the pen up
-        * condition is in the timer by reading the pen IRQ state.
+       /* 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).
+        *
+        * REVISIT:  some boards may require reading nPENIRQ; it's
+        * needed on 7843.  and 7845 reads pressure differently...
+        *
+        * REVISIT:  the touchscreen might not be connected; this code
+        * won't notice that, even if nPENIRQ never fires ...
         */
+       if (!ts->pendown && Rt != 0) {
+               input_report_key(input_dev, BTN_TOUCH, 1);
+               sync = 1;
+       } else if (ts->pendown && Rt == 0) {
+               input_report_key(input_dev, BTN_TOUCH, 0);
+               sync = 1;
+       }
+
        if (Rt) {
-               if (!ts->pendown) {
-                       ads7846_report_pen_state(ts, 1);
-                       ts->pendown = 1;
-               }
-               ads7846_report_pen_position(ts, x, y, Rt);
-               ads7846_sync_events(ts);
+               input_report_abs(input_dev, ABS_X, x);
+               input_report_abs(input_dev, ABS_Y, y);
+               sync = 1;
+       }
+
+       if (sync) {
+               input_report_abs(input_dev, ABS_PRESSURE, Rt);
+               input_sync(input_dev);
        }
 
-       hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_PERIOD), HRTIMER_REL);
+#ifdef VERBOSE
+       if (Rt || ts->pendown)
+               pr_debug("%s: %d/%d/%d%s\n", ts->spi->dev.bus_id,
+                       x, y, Rt, Rt ? "" : " UP");
+#endif
+
+       spin_lock_irqsave(&ts->lock, flags);
+
+       ts->pendown = (Rt != 0);
+       mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
+
+       spin_unlock_irqrestore(&ts->lock, flags);
 }
 
-static int ads7846_debounce(void *ads, int data_idx, int *val)
+static void ads7846_debounce(void *ads)
 {
        struct ads7846          *ts = ads;
+       struct spi_message      *m;
+       struct spi_transfer     *t;
+       int                     val;
+       int                     status;
 
-       if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
-               /* Start over collecting consistent readings. */
-               ts->read_rep = 0;
+       m = &ts->msg[ts->msg_idx];
+       t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
+       val = (be16_to_cpu(*(__be16 *)t->rx_buf) >> 3) & 0x0fff;
+       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->last_read = val;
                        ts->read_cnt++;
-                       return ADS7846_FILTER_REPEAT;
                } 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;
-                       return ADS7846_FILTER_IGNORE;
+                       /* 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;
-                       return ADS7846_FILTER_OK;
-               } else {
+                       m++;
+               } else
                        /* Read more values that are consistent. */
                        ts->read_cnt++;
-                       return ADS7846_FILTER_REPEAT;
-               }
-       }
-}
-
-static int ads7846_no_filter(void *ads, int data_idx, int *val)
-{
-       return ADS7846_FILTER_OK;
-}
-
-static void ads7846_rx_val(void *ads)
-{
-       struct ads7846 *ts = ads;
-       struct spi_message *m;
-       struct spi_transfer *t;
-       u16 *rx_val;
-       int val;
-       int action;
-       int status;
-
-       m = &ts->msg[ts->msg_idx];
-       t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
-       rx_val = (u16 *)t->rx_buf;
-       val = be16_to_cpu(*rx_val) >> 3;
-
-       action = ts->filter(ts->filter_data, ts->msg_idx, &val);
-       switch (action) {
-       case ADS7846_FILTER_REPEAT:
-               break;
-       case ADS7846_FILTER_IGNORE:
-               ts->tc.ignore = 1;
-               /* Last message will contain ads7846_rx() as the
-                * completion function.
-                */
-               m = ts->last_msg;
-               break;
-       case ADS7846_FILTER_OK:
-               *rx_val = val;
-               ts->tc.ignore = 0;
-               m = &ts->msg[++ts->msg_idx];
-               break;
-       default:
-               BUG();
        }
        status = spi_async(ts->spi, m);
        if (status)
@@ -558,27 +504,21 @@ static void ads7846_rx_val(void *ads)
                                status);
 }
 
-static int ads7846_timer(struct hrtimer *handle)
+static void ads7846_timer(unsigned long handle)
 {
-       struct ads7846  *ts = container_of(handle, struct ads7846, timer);
+       struct ads7846  *ts = (void *)handle;
        int             status = 0;
 
        spin_lock_irq(&ts->lock);
 
-       if (unlikely(!ts->get_pendown_state() ||
-                    device_suspended(&ts->spi->dev))) {
-               if (ts->pendown) {
-                       ads7846_report_pen_state(ts, 0);
-                       ads7846_sync_events(ts);
-                       ts->pendown = 0;
-               }
-
-               /* measurment cycle ended */
+       if (unlikely(ts->msg_idx && !ts->pendown)) {
+               /* measurement 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;
@@ -588,7 +528,6 @@ static int ads7846_timer(struct hrtimer *handle)
        }
 
        spin_unlock_irq(&ts->lock);
-       return HRTIMER_NORESTART;
 }
 
 static irqreturn_t ads7846_irq(int irq, void *handle)
@@ -599,17 +538,15 @@ static irqreturn_t ads7846_irq(int irq, void *handle)
        spin_lock_irqsave(&ts->lock, flags);
        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.
+                       /* The ARM do_simple_IRQ() dispatcher doesn't act
+                        * like the other dispatchers:  it will report IRQs
+                        * even after they've been disabled.  We work around
+                        * that here.  (The "generic irq" framework may help...)
                         */
                        ts->irq_disabled = 1;
                        disable_irq(ts->spi->irq);
                        ts->pending = 1;
-                       hrtimer_start(&ts->timer, ktime_set(0, TS_POLL_DELAY),
-                                       HRTIMER_REL);
+                       mod_timer(&ts->timer, jiffies);
                }
        }
        spin_unlock_irqrestore(&ts->lock, flags);
@@ -692,11 +629,9 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 {
        struct ads7846                  *ts;
        struct input_dev                *input_dev;
-       struct class_device             *hwmon = ERR_PTR(-ENOMEM);
        struct ads7846_platform_data    *pdata = spi->dev.platform_data;
        struct spi_message              *m;
        struct spi_transfer             *x;
-       int                             vref;
        int                             err;
 
        if (!spi->irq) {
@@ -716,38 +651,36 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                return -EINVAL;
        }
 
+       /* REVISIT when the irq can be triggered active-low, or if for some
+        * reason the touchscreen isn't hooked up, we don't need to access
+        * the pendown state.
+        */
        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
-        * to discard the four garbage LSBs.  (Also, not all controllers can
-        * support 12 bit words.)
+       /* We'd set TX wordsize 8 bits and RX wordsize to 13 bits ... except
+        * that even if the hardware can do that, the SPI controller driver
+        * may not.  So we stick to very-portable 8 bit words, both RX and TX.
         */
+       spi->bits_per_word = 8;
 
        ts = kzalloc(sizeof(struct ads7846), GFP_KERNEL);
        input_dev = input_allocate_device();
-       hwmon = hwmon_device_register(&spi->dev);
-       if (!ts || !input_dev || IS_ERR(hwmon)) {
+       if (!ts || !input_dev) {
                err = -ENOMEM;
                goto err_free_mem;
        }
 
        dev_set_drvdata(&spi->dev, ts);
        spi->dev.power.power_state = PMSG_ON;
-       spi->mode = SPI_MODE_1;
-       err = spi_setup(spi);
-       if (err < 0)
-               goto err_free_mem;
 
        ts->spi = spi;
        ts->input = input_dev;
-       ts->hwmon = hwmon;
 
-       hrtimer_init(&ts->timer, CLOCK_MONOTONIC, HRTIMER_REL);
+       init_timer(&ts->timer);
+       ts->timer.data = (unsigned long) ts;
        ts->timer.function = ads7846_timer;
 
        spin_lock_init(&ts->lock);
@@ -756,25 +689,14 @@ static int __devinit ads7846_probe(struct spi_device *spi)
        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->filter != NULL) {
-               if (pdata->filter_init != NULL) {
-                       err = pdata->filter_init(pdata, &ts->filter_data);
-                       if (err < 0)
-                               goto err_free_mem;
-               }
-               ts->filter = pdata->filter;
-               ts->filter_cleanup = pdata->filter_cleanup;
-       } else if (pdata->debounce_max) {
+       if (pdata->debounce_max) {
                ts->debounce_max = pdata->debounce_max;
-               if (ts->debounce_max < 2)
-                       ts->debounce_max = 2;
                ts->debounce_tol = pdata->debounce_tol;
                ts->debounce_rep = pdata->debounce_rep;
-               ts->filter = ads7846_debounce;
-               ts->filter_data = ts;
+               if (ts->debounce_rep > ts->debounce_max + 1)
+                       ts->debounce_rep = ts->debounce_max - 1;
        } else
-               ts->filter = ads7846_no_filter;
+               ts->debounce_tol = ~0;
        ts->get_pendown_state = pdata->get_pendown_state;
 
        snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
@@ -796,8 +718,6 @@ static int __devinit ads7846_probe(struct spi_device *spi)
        input_set_abs_params(input_dev, ABS_PRESSURE,
                        pdata->pressure_min, pdata->pressure_max, 0, 0);
 
-       vref = pdata->keep_vref_on;
-
        /* set up the transfers to read touchscreen state; this assumes we
         * use formula #2 for pressure, not #3.
         */
@@ -807,7 +727,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
        spi_message_init(m);
 
        /* y- still on; turn on only y+ (and ADC) */
-       ts->read_y = READ_Y(vref);
+       ts->read_y = READ_Y;
        x->tx_buf = &ts->read_y;
        x->len = 1;
        spi_message_add_tail(x, m);
@@ -817,7 +737,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
        x->len = 2;
        spi_message_add_tail(x, m);
 
-       m->complete = ads7846_rx_val;
+       m->complete = ads7846_debounce;
        m->context = ts;
 
        m++;
@@ -825,7 +745,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 
        /* turn y- off, x+ on, then leave in lowpower */
        x++;
-       ts->read_x = READ_X(vref);
+       ts->read_x = READ_X;
        x->tx_buf = &ts->read_x;
        x->len = 1;
        spi_message_add_tail(x, m);
@@ -835,7 +755,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
        x->len = 2;
        spi_message_add_tail(x, m);
 
-       m->complete = ads7846_rx_val;
+       m->complete = ads7846_debounce;
        m->context = ts;
 
        /* turn y+ off, x- on; we'll use formula #2 */
@@ -844,7 +764,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                spi_message_init(m);
 
                x++;
-               ts->read_z1 = READ_Z1(vref);
+               ts->read_z1 = READ_Z1;
                x->tx_buf = &ts->read_z1;
                x->len = 1;
                spi_message_add_tail(x, m);
@@ -854,14 +774,14 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                x->len = 2;
                spi_message_add_tail(x, m);
 
-               m->complete = ads7846_rx_val;
+               m->complete = ads7846_debounce;
                m->context = ts;
 
                m++;
                spi_message_init(m);
 
                x++;
-               ts->read_z2 = READ_Z2(vref);
+               ts->read_z2 = READ_Z2;
                x->tx_buf = &ts->read_z2;
                x->len = 1;
                spi_message_add_tail(x, m);
@@ -871,7 +791,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
                x->len = 2;
                spi_message_add_tail(x, m);
 
-               m->complete = ads7846_rx_val;
+               m->complete = ads7846_debounce;
                m->context = ts;
        }
 
@@ -896,81 +816,47 @@ static int __devinit ads7846_probe(struct spi_device *spi)
 
        ts->last_msg = m;
 
-       if (request_irq(spi->irq, ads7846_irq,
-                       IRQF_SAMPLE_RANDOM | IRQF_TRIGGER_FALLING,
-                       spi->dev.bus_id, ts)) {
+       if (request_irq(spi->irq, ads7846_irq, IRQF_TRIGGER_FALLING,
+                       spi->dev.driver->name, ts)) {
                dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
                err = -EBUSY;
-               goto err_cleanup_filter;
+               goto err_free_mem;
        }
 
-       dev_info(&spi->dev, "touchscreen + hwmon, irq %d\n", spi->irq);
+       dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
 
-       /* take a first sample, leaving nPENIRQ active and vREF off; avoid
+       /* take a first sample, leaving nPENIRQ active; avoid
         * the touchscreen, in case it's not connected.
         */
        (void) ads7846_read12_ser(&spi->dev,
                          READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
 
-       /* ads7843/7845 don't have temperature sensors, and
-        * use the other ADC lines a bit differently too
-        */
-       if (ts->model == 7846) {
-               err = device_create_file(&spi->dev, &dev_attr_temp0);
-               if (err)
-                       goto err_remove_attr7;
-               err = device_create_file(&spi->dev, &dev_attr_temp1);
-               if (err)
-                       goto err_remove_attr6;
-       }
-       /* in1 == vBAT (7846), or a non-scaled ADC input */
-       if (ts->model != 7845) {
-               err = device_create_file(&spi->dev, &dev_attr_in1_input);
-               if (err)
-                       goto err_remove_attr5;
+       switch (ts->model) {
+       case 7846:
+               ts->attr_group = &ads7846_attr_group;
+               break;
+       case 7845:
+               ts->attr_group = &ads7845_attr_group;
+               break;
+       default:
+               ts->attr_group = &ads7843_attr_group;
+               break;
        }
-       /* in0 == a non-scaled ADC input */
-       err = device_create_file(&spi->dev, &dev_attr_in0_input);
-       if (err)
-               goto err_remove_attr4;
-
-       /* non-hwmon device attributes */
-       err = device_create_file(&spi->dev, &dev_attr_pen_down);
-       if (err)
-               goto err_remove_attr3;
-       err = device_create_file(&spi->dev, &dev_attr_disable);
+       err = sysfs_create_group(&spi->dev.kobj, ts->attr_group);
        if (err)
-               goto err_remove_attr2;
+               goto err_free_irq;
 
        err = input_register_device(input_dev);
        if (err)
-               goto err_remove_attr1;
+               goto err_remove_attr_group;
 
        return 0;
 
- err_remove_attr1:
-       device_remove_file(&spi->dev, &dev_attr_disable);
- err_remove_attr2:
-       device_remove_file(&spi->dev, &dev_attr_pen_down);
- err_remove_attr3:
-       device_remove_file(&spi->dev, &dev_attr_in0_input);
- err_remove_attr4:
-       if (ts->model != 7845)
-               device_remove_file(&spi->dev, &dev_attr_in1_input);
- err_remove_attr5:
-       if (ts->model == 7846) {
-               device_remove_file(&spi->dev, &dev_attr_temp1);
- err_remove_attr6:
-               device_remove_file(&spi->dev, &dev_attr_temp0);
-       }
- err_remove_attr7:
+ err_remove_attr_group:
+       sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
+ err_free_irq:
        free_irq(spi->irq, ts);
- err_cleanup_filter:
-       if (ts->filter_cleanup)
-               ts->filter_cleanup(ts->filter_data);
  err_free_mem:
-       if (!IS_ERR(hwmon))
-               hwmon_device_unregister(hwmon);
        input_free_device(input_dev);
        kfree(ts);
        return err;
@@ -980,28 +866,16 @@ static int __devexit ads7846_remove(struct spi_device *spi)
 {
        struct ads7846          *ts = dev_get_drvdata(&spi->dev);
 
-       hwmon_device_unregister(ts->hwmon);
        input_unregister_device(ts->input);
 
        ads7846_suspend(spi, PMSG_SUSPEND);
 
-       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_in1_input);
-       device_remove_file(&spi->dev, &dev_attr_in0_input);
+       sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
 
        free_irq(ts->spi->irq, ts);
        /* suspend left the IRQ disabled */
        enable_irq(ts->spi->irq);
 
-       if (ts->filter_cleanup != NULL)
-               ts->filter_cleanup(ts->filter_data);
-
        kfree(ts);
 
        dev_dbg(&spi->dev, "unregistered touchscreen\n");
@@ -1049,7 +923,7 @@ static int __init ads7846_init(void)
 
        return spi_register_driver(&ads7846_driver);
 }
-device_initcall(ads7846_init);
+module_init(ads7846_init);
 
 static void __exit ads7846_exit(void)
 {