[PATCH] input/spi: add ads7843 support to ads7846 touchscreen driver

From: Nicolas FERRE
Date: Fri Dec 15 2006 - 10:17:19 EST

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Add support for the ads7843 touchscreen controller to the ads7846
driver code.
The "pen down" information is managed quite differently as we
do not have a touch-pressure measurement on the ads7843.

Signed-off-by: Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
---

I add a ads7843_rx function to manage the end of a measurement cycle.
As for ads7846_rx, it does the real work and communicates with the
input subsystem.
The timer function is responsible of taking the pen up/pen down state
through the board specific get_pendown_state() callback.

As the SPI underlying code behaves quite differently from a controller
driver to another while not having a tx_buf filled, I have add a
zeroed buffer to give to the SPI layer while receiving data.

===================================================================
--- a/input/touchscreen/ads7846.c (.../linux-2.6.19-at91/drivers) (revision 634)
+++ b/input/touchscreen/ads7846.c (.../linux-2.6.19-atmel-devel/drivers) (revision 634)
@@ -4,6 +4,7 @@
* Copyright (c) 2005 David Brownell
* Copyright (c) 2006 Nokia Corporation
* Various changes: Imre Deak <imre.deak@xxxxxxxxx>
+ * Ads7843 support: Atmel, Nicolas Ferre <nicolas.ferre@xxxxxxxxxxxxx>
*
* Using code from:
* - corgi_ts.c
@@ -38,7 +39,8 @@
/*
* This code has been heavily tested on a Nokia 770, and lightly
* tested on other ads7846 devices (OSK/Mistral, Lubbock).
- * Support for ads7843 and ads7845 has only been stubbed in.
+ * Support for ads7843 tested on Atmel at91sam926x-EK.
+ * Support for ads7845 has only been stubbed in.
*
* IRQ handling needs a workaround because of a shortcoming in handling
* edge triggered IRQs on some platforms like the OMAP1/2. These
@@ -82,6 +84,7 @@ struct ads7846 {
u16 pressure_max;

u8 read_x, read_y, read_z1, read_z2, pwrdown;
+ u16 zerro; /* to send zerros while receiving */
u16 dummy; /* for the pwrdown read */
struct ts_event tc;

@@ -151,6 +154,10 @@ struct ads7846 {
#define READ_X (READ_12BIT_DFR(x) | ADS_PD10_ADC_ON)
#define PWRDOWN (READ_12BIT_DFR(y) | ADS_PD10_PDOWN) /* LAST */

+/* alternate ads7843 commands */
+#define ALT_READ_Y (READ_12BIT_DFR(y) | ADS_PD10_ALL_ON)
+#define ALT_READ_X (READ_12BIT_DFR(x) | ADS_PD10_ALL_ON)
+
/* single-ended samples need to first power up reference voltage;
* we leave both ADC and VREF powered
*/
@@ -171,6 +178,7 @@ struct ser_req {
u8 command;
u8 ref_off;
u16 scratch;
+ u16 zerro;
__be16 sample;
struct spi_message msg;
struct spi_transfer xfer[6];
@@ -203,6 +211,7 @@ static int ads7846_read12_ser(struct dev
req->ref_on = REF_ON;
req->xfer[0].tx_buf = &req->ref_on;
req->xfer[0].len = 1;
+ req->xfer[1].tx_buf = &req->zerro;
req->xfer[1].rx_buf = &req->scratch;
req->xfer[1].len = 2;

@@ -217,6 +226,7 @@ static int ads7846_read12_ser(struct dev
req->command = (u8) command;
req->xfer[2].tx_buf = &req->command;
req->xfer[2].len = 1;
+ req->xfer[3].tx_buf = &req->zerro;
req->xfer[3].rx_buf = &req->sample;
req->xfer[3].len = 2;

@@ -226,6 +236,7 @@ static int ads7846_read12_ser(struct dev
req->ref_off = REF_OFF;
req->xfer[4].tx_buf = &req->ref_off;
req->xfer[4].len = 1;
+ req->xfer[3].tx_buf = &req->zerro;
req->xfer[5].rx_buf = &req->scratch;
req->xfer[5].len = 2;

@@ -410,6 +421,50 @@ static void ads7846_rx(void *ads)
spin_unlock_irqrestore(&ts->lock, flags);
}

+static void ads7843_rx(void *ads)
+{
+ struct ads7846 *ts = ads;
+ struct input_dev *input_dev = ts->input;
+ u16 x, y;
+ 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 = (be16_to_cpu(ts->tc.x) >> 3) & 0x0fff;
+ y = (be16_to_cpu(ts->tc.y) >> 3) & 0x0fff;
+
+ /* range filtering */
+ if (x == MAX_12BIT)
+ x = 0;
+
+ if (ts->pendown) {
+ input_report_key(input_dev, BTN_TOUCH, 1);
+ input_report_abs(input_dev, ABS_PRESSURE, ts->pressure_max / 2);
+ input_report_abs(input_dev, ABS_X, x);
+ input_report_abs(input_dev, ABS_Y, y);
+ } else {
+ input_report_key(input_dev, BTN_TOUCH, 0);
+ input_report_abs(input_dev, ABS_PRESSURE, 0);
+ }
+
+ input_sync(input_dev);
+
+#ifdef VERBOSE
+ pr_debug("%s: %d/%d%s\n", ts->spi->dev.bus_id,
+ x, y, ts->pendown ? "" : " UP");
+#endif
+
+ if (ts->pendown) {
+ spin_lock_irqsave(&ts->lock, flags);
+
+ mod_timer(&ts->timer, jiffies + TS_POLL_PERIOD);
+
+ spin_unlock_irqrestore(&ts->lock, flags);
+ }
+}
+
static void ads7846_debounce(void *ads)
{
struct ads7846 *ts = ads;
@@ -465,11 +520,25 @@ static void ads7846_timer(unsigned long {
struct ads7846 *ts = (void *)handle;
int status = 0;
+ int alt_end_cycle = 0; /* ads7843 alternative cycle end */
+
+ if (ts->model == 7843) {
+ /* get sample */
+ ts->pendown = ts->get_pendown_state();
+ alt_end_cycle = ts->pending;
+ }

spin_lock_irq(&ts->lock);

- if (unlikely(ts->msg_idx && !ts->pendown)) {
+ if (unlikely(!ts->pendown && (ts->msg_idx || alt_end_cycle))) {
/* measurement cycle ended */
+ if (ts->model == 7843) {
+ status = spi_async(ts->spi, ts->last_msg);
+ if (status)
+ dev_err(&ts->spi->dev,
+ "spi_async --> %d\n", status);
+ }
+
if (!device_suspended(&ts->spi->dev)) {
ts->irq_disabled = 0;
enable_irq(ts->spi->irq);
@@ -684,12 +753,17 @@ static int __devinit ads7846_probe(struc
spi_message_init(m);

/* y- still on; turn on only y+ (and ADC) */
- ts->read_y = READ_Y;
+ if (ts->model == 7843) {
+ ts->read_y = ALT_READ_Y;
+ } else {
+ ts->read_y = READ_Y;
+ }
x->tx_buf = &ts->read_y;
x->len = 1;
spi_message_add_tail(x, m);

x++;
+ x->tx_buf = &ts->zerro;
x->rx_buf = &ts->tc.y;
x->len = 2;
spi_message_add_tail(x, m);
@@ -702,12 +776,17 @@ static int __devinit ads7846_probe(struc

/* turn y- off, x+ on, then leave in lowpower */
x++;
- ts->read_x = READ_X;
+ if (ts->model == 7843) {
+ ts->read_x = ALT_READ_X;
+ } else {
+ ts->read_x = READ_X;
+ }
x->tx_buf = &ts->read_x;
x->len = 1;
spi_message_add_tail(x, m);

x++;
+ x->tx_buf = &ts->zerro;
x->rx_buf = &ts->tc.x;
x->len = 2;
spi_message_add_tail(x, m);
@@ -763,12 +842,17 @@ static int __devinit ads7846_probe(struc
spi_message_add_tail(x, m);

x++;
+ x->tx_buf = &ts->zerro;
x->rx_buf = &ts->dummy;
x->len = 2;
CS_CHANGE(*x);
spi_message_add_tail(x, m);

- m->complete = ads7846_rx;
+ if (ts->model == 7843) {
+ m->complete = ads7843_rx;
+ } else {
+ m->complete = ads7846_rx;
+ }
m->context = ts;

ts->last_msg = m;
@@ -782,11 +866,16 @@ static int __devinit ads7846_probe(struc

dev_info(&spi->dev, "touchscreen, irq %d\n", spi->irq);

- /* 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);
+ if (ts->model != 7843) {
+ /* 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);
+ } else {
+ (void) ads7846_read12_ser(&spi->dev,
+ READ_12BIT_DFR(y) | ADS_PD10_ALL_ON);
+ }

/* ads7843/7845 don't have temperature sensors, and
* use the other sensors a bit differently too
@@ -795,12 +884,14 @@ static int __devinit ads7846_probe(struc
device_create_file(&spi->dev, &dev_attr_temp0);
device_create_file(&spi->dev, &dev_attr_temp1);
}
- if (ts->model != 7845)
+ if (ts->model != 7845 && ts->model != 7843)
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);
+ if (ts->model != 7843) {
+ 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);
@@ -816,9 +907,12 @@ static int __devinit ads7846_probe(struc
device_remove_file(&spi->dev, &dev_attr_temp1);
device_remove_file(&spi->dev, &dev_attr_temp0);
}
- if (ts->model != 7845)
+ if (ts->model != 7845 && ts->model != 7843)
device_remove_file(&spi->dev, &dev_attr_vbatt);
- device_remove_file(&spi->dev, &dev_attr_vaux);
+
+ if (ts->model != 7843) {
+ device_remove_file(&spi->dev, &dev_attr_vaux);
+ }

free_irq(spi->irq, ts);
err_free_mem:
@@ -841,9 +935,12 @@ static int __devexit ads7846_remove(stru
device_remove_file(&spi->dev, &dev_attr_temp1);
device_remove_file(&spi->dev, &dev_attr_temp0);
}
- if (ts->model != 7845)
+ if (ts->model != 7845 && ts->model != 7843)
device_remove_file(&spi->dev, &dev_attr_vbatt);
- device_remove_file(&spi->dev, &dev_attr_vaux);
+
+ if (ts->model != 7843) {
+ device_remove_file(&spi->dev, &dev_attr_vaux);
+ }

free_irq(ts->spi->irq, ts);
/* suspend left the IRQ disabled */

-
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Next message: Jean Delvare: "Re: sysfs file creation result nightmare"
Previous message: Kristian Høgsberg: "Re: [PATCH 3/3] Import fw-sbp2 driver."
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