Input: ads7846 - pluggable filtering logic
Some LCDs like the LS041Y3 require a customized filtering logic for reliable readings, so make the filtering function replacable through platform specific hooks. Signed-off-by: Imre Deak <imre.deak@solidboot.com> Signed-off-by: Juha Yrjola <juha.yrjola@solidboot.com> Signed-off-by: David Brownell <dbrownell@users.sourceforge.net> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Imre Deak
Dmitry Torokhov
Родитель
78a56aab11
Коммит
da970e69ef
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@ -63,11 +63,11 @@ struct ts_event {
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/* For portability, we can't read 12 bit values using SPI (which
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* would make the controller deliver them as native byteorder u16
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* with msbs zeroed). Instead, we read them as two 8-bit values,
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* which need byteswapping then range adjustment.
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* *** WHICH NEED BYTESWAPPING *** and range adjustment.
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*/
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__be16 x;
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__be16 y;
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__be16 z1, z2;
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u16 x;
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u16 y;
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u16 z1, z2;
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int ignore;
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};
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@ -106,6 +106,9 @@ struct ads7846 {
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unsigned irq_disabled:1; /* P: lock */
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unsigned disabled:1;
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int (*filter)(void *data, int data_idx, int *val);
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void *filter_data;
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void (*filter_cleanup)(void *data);
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int (*get_pendown_state)(void);
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};
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@ -379,13 +382,13 @@ static void ads7846_rx(void *ads)
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u16 x, y, z1, z2;
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unsigned long flags;
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/* adjust: on-wire is a must-ignore bit, a BE12 value, then padding;
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* built from two 8 bit values written msb-first.
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/* ads7846_rx_val() did in-place conversion (including byteswap) from
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* on-the-wire format as part of debouncing to get stable readings.
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*/
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x = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff;
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y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff;
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z1 = (be16_to_cpu(ts->tc.z1) >> 3) & 0x0fff;
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z2 = (be16_to_cpu(ts->tc.z2) >> 3) & 0x0fff;
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x = ts->tc.x;
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y = ts->tc.y;
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z1 = ts->tc.z1;
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z2 = ts->tc.z2;
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/* range filtering */
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if (x == MAX_12BIT)
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@ -453,50 +456,85 @@ static void ads7846_rx(void *ads)
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spin_unlock_irqrestore(&ts->lock, flags);
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}
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static void ads7846_debounce(void *ads)
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static int ads7846_debounce(void *ads, int data_idx, int *val)
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{
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struct ads7846 *ts = ads;
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struct spi_message *m;
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struct spi_transfer *t;
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int val;
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int status;
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m = &ts->msg[ts->msg_idx];
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t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
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val = (be16_to_cpu(*(__be16 *)t->rx_buf) >> 3) & 0x0fff;
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if (!ts->read_cnt || (abs(ts->last_read - val) > ts->debounce_tol)) {
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if (!ts->read_cnt || (abs(ts->last_read - *val) > ts->debounce_tol)) {
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/* Start over collecting consistent readings. */
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ts->read_rep = 0;
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/* Repeat it, if this was the first read or the read
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* wasn't consistent enough. */
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if (ts->read_cnt < ts->debounce_max) {
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ts->last_read = val;
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ts->last_read = *val;
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ts->read_cnt++;
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return ADS7846_FILTER_REPEAT;
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} else {
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/* Maximum number of debouncing reached and still
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* not enough number of consistent readings. Abort
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* the whole sample, repeat it in the next sampling
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* period.
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*/
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ts->tc.ignore = 1;
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ts->read_cnt = 0;
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/* Last message will contain ads7846_rx() as the
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* completion function.
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*/
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m = ts->last_msg;
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return ADS7846_FILTER_IGNORE;
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}
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/* Start over collecting consistent readings. */
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ts->read_rep = 0;
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} else {
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if (++ts->read_rep > ts->debounce_rep) {
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/* Got a good reading for this coordinate,
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* go for the next one. */
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ts->tc.ignore = 0;
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ts->msg_idx++;
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ts->read_cnt = 0;
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ts->read_rep = 0;
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m++;
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} else
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return ADS7846_FILTER_OK;
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} else {
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/* Read more values that are consistent. */
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ts->read_cnt++;
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return ADS7846_FILTER_REPEAT;
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}
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}
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}
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static int ads7846_no_filter(void *ads, int data_idx, int *val)
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{
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return ADS7846_FILTER_OK;
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}
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static void ads7846_rx_val(void *ads)
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{
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struct ads7846 *ts = ads;
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struct spi_message *m;
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struct spi_transfer *t;
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u16 *rx_val;
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int val;
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int action;
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int status;
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m = &ts->msg[ts->msg_idx];
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t = list_entry(m->transfers.prev, struct spi_transfer, transfer_list);
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rx_val = t->rx_buf;
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/* adjust: on-wire is a must-ignore bit, a BE12 value, then padding;
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* built from two 8 bit values written msb-first.
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*/
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val = be16_to_cpu(*rx_val) >> 3;
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action = ts->filter(ts->filter_data, ts->msg_idx, &val);
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switch (action) {
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case ADS7846_FILTER_REPEAT:
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break;
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case ADS7846_FILTER_IGNORE:
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ts->tc.ignore = 1;
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/* Last message will contain ads7846_rx() as the
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* completion function.
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*/
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m = ts->last_msg;
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break;
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case ADS7846_FILTER_OK:
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*rx_val = val;
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ts->tc.ignore = 0;
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m = &ts->msg[++ts->msg_idx];
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break;
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default:
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BUG();
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}
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status = spi_async(ts->spi, m);
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if (status)
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@ -689,14 +727,25 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
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ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;
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ts->pressure_max = pdata->pressure_max ? : ~0;
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if (pdata->debounce_max) {
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if (pdata->filter != NULL) {
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if (pdata->filter_init != NULL) {
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err = pdata->filter_init(pdata, &ts->filter_data);
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if (err < 0)
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goto err_free_mem;
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}
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ts->filter = pdata->filter;
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ts->filter_cleanup = pdata->filter_cleanup;
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} else if (pdata->debounce_max) {
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ts->debounce_max = pdata->debounce_max;
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if (ts->debounce_max < 2)
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ts->debounce_max = 2;
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ts->debounce_tol = pdata->debounce_tol;
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ts->debounce_rep = pdata->debounce_rep;
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if (ts->debounce_rep > ts->debounce_max + 1)
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ts->debounce_rep = ts->debounce_max - 1;
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ts->filter = ads7846_debounce;
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ts->filter_data = ts;
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} else
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ts->debounce_tol = ~0;
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ts->filter = ads7846_no_filter;
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ts->get_pendown_state = pdata->get_pendown_state;
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snprintf(ts->phys, sizeof(ts->phys), "%s/input0", spi->dev.bus_id);
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@ -737,7 +786,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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x->len = 2;
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spi_message_add_tail(x, m);
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m->complete = ads7846_debounce;
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m->complete = ads7846_rx_val;
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m->context = ts;
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m++;
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@ -755,7 +804,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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x->len = 2;
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spi_message_add_tail(x, m);
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m->complete = ads7846_debounce;
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m->complete = ads7846_rx_val;
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m->context = ts;
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/* turn y+ off, x- on; we'll use formula #2 */
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@ -774,7 +823,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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x->len = 2;
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spi_message_add_tail(x, m);
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m->complete = ads7846_debounce;
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m->complete = ads7846_rx_val;
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m->context = ts;
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m++;
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@ -791,7 +840,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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x->len = 2;
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spi_message_add_tail(x, m);
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m->complete = ads7846_debounce;
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m->complete = ads7846_rx_val;
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m->context = ts;
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}
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@ -820,7 +869,7 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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spi->dev.driver->name, ts)) {
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dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
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err = -EBUSY;
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goto err_free_mem;
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goto err_cleanup_filter;
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}
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dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);
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@ -856,6 +905,9 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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sysfs_remove_group(&spi->dev.kobj, ts->attr_group);
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err_free_irq:
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free_irq(spi->irq, ts);
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err_cleanup_filter:
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if (ts->filter_cleanup)
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ts->filter_cleanup(ts->filter_data);
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err_free_mem:
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input_free_device(input_dev);
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kfree(ts);
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@ -876,6 +928,9 @@ static int __devexit ads7846_remove(struct spi_device *spi)
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/* suspend left the IRQ disabled */
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enable_irq(ts->spi->irq);
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if (ts->filter_cleanup)
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ts->filter_cleanup(ts->filter_data);
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kfree(ts);
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dev_dbg(&spi->dev, "unregistered touchscreen\n");
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@ -5,6 +5,12 @@
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*
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* It's OK if the min/max values are zero.
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*/
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enum ads7846_filter {
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ADS7846_FILTER_OK,
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ADS7846_FILTER_REPEAT,
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ADS7846_FILTER_IGNORE,
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};
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struct ads7846_platform_data {
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u16 model; /* 7843, 7845, 7846. */
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u16 vref_delay_usecs; /* 0 for external vref; etc */
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@ -21,5 +27,9 @@ struct ads7846_platform_data {
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u16 debounce_rep; /* additional consecutive good readings
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* required after the first two */
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int (*get_pendown_state)(void);
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int (*filter_init) (struct ads7846_platform_data *pdata,
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void **filter_data);
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int (*filter) (void *filter_data, int data_idx, int *val);
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void (*filter_cleanup)(void *filter_data);
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};
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