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Input: ads7846 - assorted updates

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This updates the ads7846 touchscreen driver:
  - to allow faster clocking (this driver doesn't push sample rates);
  - bugfixes the conversion of spi_transfer to lists;
  - some dma-unsafe command buffers are fixed.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
David Brownell 2006-02-15 00:49:35 -05:00 committed by Dmitry Torokhov
parent a90f7e98b7
commit d93f70b2d7
1 changed files with 44 additions and 24 deletions
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68
drivers/input/touchscreen/ads7846.c
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@ -48,10 +48,13 @@
#define TS_POLL_PERIOD msecs_to_jiffies(10)
/* this driver doesn't aim at the peak continuous sample rate */
#define SAMPLE_BITS (8 /*cmd*/ + 16 /*sample*/ + 2 /* before, after */)
struct ts_event {
/* For portability, we can't read 12 bit values using SPI (which
* would make the controller deliver them as native byteorder u16
* with msbs zeroed). Instead, we read them as two 8-byte values,
* with msbs zeroed). Instead, we read them as two 8-bit values,
* which need byteswapping then range adjustment.
*/
__be16 x;
@ -68,6 +71,7 @@ struct ads7846 {
u16 vref_delay_usecs;
u16 x_plate_ohms;
u8 read_x, read_y, read_z1, read_z2;
struct ts_event tc;
struct spi_transfer xfer[8];
@ -117,10 +121,10 @@ struct ads7846 {
#define READ_12BIT_DFR(x) (ADS_START | ADS_A2A1A0_d_ ## x \
| ADS_12_BIT | ADS_DFR)
static const u8 read_y = READ_12BIT_DFR(y) | ADS_PD10_ADC_ON;
static const u8 read_z1 = READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON;
static const u8 read_z2 = READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON;
static const u8 read_x = READ_12BIT_DFR(x) | ADS_PD10_PDOWN; /* LAST */
#define READ_Y (READ_12BIT_DFR(y) | ADS_PD10_ADC_ON)
#define READ_Z1 (READ_12BIT_DFR(z1) | ADS_PD10_ADC_ON)
#define READ_Z2 (READ_12BIT_DFR(z2) | ADS_PD10_ADC_ON)
#define READ_X (READ_12BIT_DFR(x) | ADS_PD10_PDOWN) /* LAST */
/* single-ended samples need to first power up reference voltage;
* we leave both ADC and VREF powered
@ -128,8 +132,8 @@ static const u8 read_x = READ_12BIT_DFR(x) | ADS_PD10_PDOWN; /* LAST */
#define READ_12BIT_SER(x) (ADS_START | ADS_A2A1A0_ ## x \
| ADS_12_BIT | ADS_SER)
static const u8 ref_on = READ_12BIT_DFR(x) | ADS_PD10_ALL_ON;
static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
#define REF_ON (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
#define REF_OFF (READ_12BIT_DFR(y) | ADS_PD10_PDOWN)
/*--------------------------------------------------------------------------*/
@ -138,7 +142,9 @@ static const u8 ref_off = READ_12BIT_DFR(y) | ADS_PD10_PDOWN;
*/
struct ser_req {
u8 ref_on;
u8 command;
u8 ref_off;
u16 scratch;
__be16 sample;
struct spi_message msg;
@ -160,7 +166,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
INIT_LIST_HEAD(&req->msg.transfers);
/* activate reference, so it has time to settle; */
req->xfer[0].tx_buf = &ref_on;
req->ref_on = REF_ON;
req->xfer[0].tx_buf = &req->ref_on;
req->xfer[0].len = 1;
req->xfer[1].rx_buf = &req->scratch;
req->xfer[1].len = 2;
@ -182,7 +189,8 @@ static int ads7846_read12_ser(struct device *dev, unsigned command)
/* REVISIT: take a few more samples, and compare ... */
/* turn off reference */
req->xfer[4].tx_buf = &ref_off;
req->ref_off = REF_OFF;
req->xfer[4].tx_buf = &req->ref_off;
req->xfer[4].len = 1;
req->xfer[5].rx_buf = &req->scratch;
req->xfer[5].len = 2;
@ -400,7 +408,6 @@ static int __devinit ads7846_probe(struct spi_device *spi)
struct input_dev *input_dev;
struct ads7846_platform_data *pdata = spi->dev.platform_data;
struct spi_transfer *x;
int i;
int err;
if (!spi->irq) {
@ -414,9 +421,9 @@ static int __devinit ads7846_probe(struct spi_device *spi)
}
/* don't exceed max specified sample rate */
if (spi->max_speed_hz > (125000 * 16)) {
if (spi->max_speed_hz > (125000 * SAMPLE_BITS)) {
dev_dbg(&spi->dev, "f(sample) %d KHz?\n",
(spi->max_speed_hz/16)/1000);
(spi->max_speed_hz/SAMPLE_BITS)/1000);
return -EINVAL;
}
@ -469,45 +476,58 @@ 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);
x = ts->xfer;
/* y- still on; turn on only y+ (and ADC) */
x->tx_buf = &read_y;
ts->read_y = READ_Y;
x->tx_buf = &ts->read_y;
x->len = 1;
spi_message_add_tail(x, &ts->msg);
x++;
x->rx_buf = &ts->tc.y;
x->len = 2;
x++;
spi_message_add_tail(x, &ts->msg);
/* turn y+ off, x- on; we'll use formula #2 */
if (ts->model == 7846) {
x->tx_buf = &read_z1;
x++;
ts->read_z1 = READ_Z1;
x->tx_buf = &ts->read_z1;
x->len = 1;
spi_message_add_tail(x, &ts->msg);
x++;
x->rx_buf = &ts->tc.z1;
x->len = 2;
x++;
spi_message_add_tail(x, &ts->msg);
x->tx_buf = &read_z2;
x++;
ts->read_z2 = READ_Z2;
x->tx_buf = &ts->read_z2;
x->len = 1;
spi_message_add_tail(x, &ts->msg);
x++;
x->rx_buf = &ts->tc.z2;
x->len = 2;
x++;
spi_message_add_tail(x, &ts->msg);
}
/* turn y- off, x+ on, then leave in lowpower */
x->tx_buf = &read_x;
x++;
ts->read_x = READ_X;
x->tx_buf = &ts->read_x;
x->len = 1;
spi_message_add_tail(x, &ts->msg);
x++;
x->rx_buf = &ts->tc.x;
x->len = 2;
x++;
CS_CHANGE(*x);
spi_message_add_tail(x, &ts->msg);
CS_CHANGE(x[-1]);
for (i = 0; i < x - ts->xfer; i++)
spi_message_add_tail(&ts->xfer[i], &ts->msg);
ts->msg.complete = ads7846_rx;
ts->msg.context = ts;