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Input: ads7846 - extend the driver for ads7845 controller support
ADS7845 is a controller for 5-wire touch screens and somewhat different from 7846. It requires three serial communications to accomplish one complete conversion. Unlike 7846 it doesn't allow Z1-/Z2- position measurement. The patch extends the ads7846 driver to also support ads7845. The packet struct is extended to contain needed command and conversion buffers. ads7846_rx() and ads7846_rx_val() now differentiate between 7845 and 7846 case. ads7846_probe() is modified to setup ads7845 specific command and conversion messages and to switch ads7845 into power-down mode, since this is needed to be prepared to respond to pendown interrupts. Signed-off-by: Anatolij Gustschin <agust@denx.de> Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
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@ -68,6 +68,8 @@ struct ts_event {
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u16 y;
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u16 z1, z2;
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int ignore;
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u8 x_buf[3];
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u8 y_buf[3];
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};
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/*
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@ -79,6 +81,8 @@ struct ads7846_packet {
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u8 read_x, read_y, read_z1, read_z2, pwrdown;
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u16 dummy; /* for the pwrdown read */
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struct ts_event tc;
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/* for ads7845 with mpc5121 psc spi we use 3-byte buffers */
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u8 read_x_cmd[3], read_y_cmd[3], pwrdown_cmd[3];
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};
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struct ads7846 {
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@ -207,6 +211,14 @@ struct ser_req {
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struct spi_transfer xfer[6];
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};
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struct ads7845_ser_req {
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u8 command[3];
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u8 pwrdown[3];
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u8 sample[3];
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struct spi_message msg;
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struct spi_transfer xfer[2];
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};
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static void ads7846_enable(struct ads7846 *ts);
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static void ads7846_disable(struct ads7846 *ts);
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@ -287,6 +299,41 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
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return status;
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}
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static int ads7845_read12_ser(struct device *dev, unsigned command)
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{
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struct spi_device *spi = to_spi_device(dev);
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struct ads7846 *ts = dev_get_drvdata(dev);
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struct ads7845_ser_req *req = kzalloc(sizeof *req, GFP_KERNEL);
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int status;
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if (!req)
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return -ENOMEM;
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spi_message_init(&req->msg);
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req->command[0] = (u8) command;
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req->xfer[0].tx_buf = req->command;
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req->xfer[0].rx_buf = req->sample;
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req->xfer[0].len = 3;
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spi_message_add_tail(&req->xfer[0], &req->msg);
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ts->irq_disabled = 1;
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disable_irq(spi->irq);
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status = spi_sync(spi, &req->msg);
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ts->irq_disabled = 0;
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enable_irq(spi->irq);
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if (status == 0) {
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/* BE12 value, then padding */
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status = be16_to_cpu(*((u16 *)&req->sample[1]));
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status = status >> 3;
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status &= 0x0fff;
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}
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kfree(req);
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return status;
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}
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#if defined(CONFIG_HWMON) || defined(CONFIG_HWMON_MODULE)
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#define SHOW(name, var, adjust) static ssize_t \
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@ -540,10 +587,17 @@ static void ads7846_rx(void *ads)
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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 = packet->tc.x;
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y = packet->tc.y;
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z1 = packet->tc.z1;
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z2 = packet->tc.z2;
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if (ts->model == 7845) {
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x = *(u16 *)packet->tc.x_buf;
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y = *(u16 *)packet->tc.y_buf;
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z1 = 0;
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z2 = 0;
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} else {
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x = packet->tc.x;
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y = packet->tc.y;
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z1 = packet->tc.z1;
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z2 = packet->tc.z2;
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}
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/* range filtering */
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if (x == MAX_12BIT)
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@ -551,6 +605,12 @@ static void ads7846_rx(void *ads)
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if (ts->model == 7843) {
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Rt = ts->pressure_max / 2;
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} else if (ts->model == 7845) {
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if (get_pendown_state(ts))
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Rt = ts->pressure_max / 2;
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else
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Rt = 0;
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dev_vdbg(&ts->spi->dev, "x/y: %d/%d, PD %d\n", x, y, Rt);
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} else if (likely(x && z1)) {
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/* compute touch pressure resistance using equation #2 */
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Rt = z2;
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@ -671,10 +731,14 @@ static void ads7846_rx_val(void *ads)
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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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/* 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_cpup((__be16 *)t->rx_buf) >> 3;
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if (ts->model == 7845) {
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val = be16_to_cpup((__be16 *)&(((char*)t->rx_buf)[1])) >> 3;
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} else {
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/* adjust: on-wire is a must-ignore bit, a BE12 value, then
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* padding; built from two 8 bit values written msb-first.
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*/
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val = be16_to_cpup((__be16 *)t->rx_buf) >> 3;
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}
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action = ts->filter(ts->filter_data, ts->msg_idx, &val);
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switch (action) {
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@ -1009,16 +1073,26 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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spi_message_init(m);
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/* y- still on; turn on only y+ (and ADC) */
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packet->read_y = READ_Y(vref);
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x->tx_buf = &packet->read_y;
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x->len = 1;
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spi_message_add_tail(x, m);
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if (ts->model == 7845) {
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packet->read_y_cmd[0] = READ_Y(vref);
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packet->read_y_cmd[1] = 0;
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packet->read_y_cmd[2] = 0;
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x->tx_buf = &packet->read_y_cmd[0];
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x->rx_buf = &packet->tc.y_buf[0];
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x->len = 3;
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spi_message_add_tail(x, m);
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} else {
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/* y- still on; turn on only y+ (and ADC) */
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packet->read_y = READ_Y(vref);
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x->tx_buf = &packet->read_y;
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x->len = 1;
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spi_message_add_tail(x, m);
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x++;
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x->rx_buf = &packet->tc.y;
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x->len = 2;
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spi_message_add_tail(x, m);
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x++;
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x->rx_buf = &packet->tc.y;
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x->len = 2;
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spi_message_add_tail(x, m);
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}
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/* the first sample after switching drivers can be low quality;
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* optionally discard it, using a second one after the signals
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@ -1044,17 +1118,28 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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m++;
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spi_message_init(m);
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/* turn y- off, x+ on, then leave in lowpower */
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x++;
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packet->read_x = READ_X(vref);
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x->tx_buf = &packet->read_x;
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x->len = 1;
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spi_message_add_tail(x, m);
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if (ts->model == 7845) {
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x++;
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packet->read_x_cmd[0] = READ_X(vref);
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packet->read_x_cmd[1] = 0;
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packet->read_x_cmd[2] = 0;
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x->tx_buf = &packet->read_x_cmd[0];
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x->rx_buf = &packet->tc.x_buf[0];
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x->len = 3;
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spi_message_add_tail(x, m);
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} else {
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/* turn y- off, x+ on, then leave in lowpower */
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x++;
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packet->read_x = READ_X(vref);
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x->tx_buf = &packet->read_x;
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x->len = 1;
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spi_message_add_tail(x, m);
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x++;
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x->rx_buf = &packet->tc.x;
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x->len = 2;
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spi_message_add_tail(x, m);
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x++;
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x->rx_buf = &packet->tc.x;
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x->len = 2;
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spi_message_add_tail(x, m);
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}
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/* ... maybe discard first sample ... */
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if (pdata->settle_delay_usecs) {
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@ -1145,15 +1230,25 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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m++;
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spi_message_init(m);
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x++;
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packet->pwrdown = PWRDOWN;
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x->tx_buf = &packet->pwrdown;
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x->len = 1;
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spi_message_add_tail(x, m);
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if (ts->model == 7845) {
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x++;
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packet->pwrdown_cmd[0] = PWRDOWN;
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packet->pwrdown_cmd[1] = 0;
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packet->pwrdown_cmd[2] = 0;
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x->tx_buf = &packet->pwrdown_cmd[0];
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x->len = 3;
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} else {
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x++;
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packet->pwrdown = PWRDOWN;
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x->tx_buf = &packet->pwrdown;
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x->len = 1;
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spi_message_add_tail(x, m);
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x++;
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x->rx_buf = &packet->dummy;
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x->len = 2;
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}
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x++;
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x->rx_buf = &packet->dummy;
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x->len = 2;
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CS_CHANGE(*x);
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spi_message_add_tail(x, m);
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@ -1202,8 +1297,11 @@ static int __devinit ads7846_probe(struct spi_device *spi)
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/* take a first sample, leaving nPENIRQ active and vREF off; avoid
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* the touchscreen, in case it's not connected.
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*/
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(void) ads7846_read12_ser(&spi->dev,
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READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
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if (ts->model == 7845)
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ads7845_read12_ser(&spi->dev, PWRDOWN);
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else
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(void) ads7846_read12_ser(&spi->dev,
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READ_12BIT_SER(vaux) | ADS_PD10_ALL_ON);
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err = sysfs_create_group(&spi->dev.kobj, &ads784x_attr_group);
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if (err)
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