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SubjectRe: [spi-devel-general] [patch 2.6.14-rc6-git 2/6] SPI ads7846 protocol driver
Date

> > > Also use input_allocate_device() instead of init_input_dev().
> > Thanx.
> >
> > Got patch? :)
>
> I will do it with latest -mm next week.

Well, here's an update against 2.6.16-rc1-git. It builds and
initializes, but lower level issues prevent my re-testing it.

- Dave
This updates the ads7846 touchscreen driver

- to match changes to the input subsystem that kicked in since it
was first written and debugged;

- 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>


Index: o2/drivers/input/touchscreen/ads7846.c
===================================================================
--- o2.orig/drivers/input/touchscreen/ads7846.c 2006-01-24 11:39:52.000000000 -0800
+++ o2/drivers/input/touchscreen/ads7846.c 2006-01-24 20:35:54.000000000 -0800
@@ -51,10 +51,13 @@

#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;
@@ -63,7 +66,7 @@ struct ts_event {
};

struct ads7846 {
- struct input_dev input;
+ struct input_dev *input;
char phys[32];

struct spi_device *spi;
@@ -71,6 +74,7 @@ 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];
@@ -141,7 +145,9 @@ static const u8 ref_off = READ_12BIT_DFR
*/

struct ser_req {
+ u8 ref_on;
u8 command;
+ u8 ref_off;
u16 scratch;
__be16 sample;
struct spi_message msg;
@@ -163,7 +169,8 @@ static int ads7846_read12_ser(struct dev
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;
@@ -185,7 +192,8 @@ static int ads7846_read12_ser(struct dev
/* 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;
@@ -279,21 +287,21 @@ static void ads7846_rx(void *ads)
* won't notice that, even if nPENIRQ never fires ...
*/
if (!ts->pendown && Rt != 0) {
- input_report_key(&ts->input, BTN_TOUCH, 1);
+ input_report_key(ts->input, BTN_TOUCH, 1);
sync = 1;
} else if (ts->pendown && Rt == 0) {
- input_report_key(&ts->input, BTN_TOUCH, 0);
+ input_report_key(ts->input, BTN_TOUCH, 0);
sync = 1;
}

if (Rt) {
- input_report_abs(&ts->input, ABS_X, x);
- input_report_abs(&ts->input, ABS_Y, y);
- input_report_abs(&ts->input, ABS_PRESSURE, Rt);
+ input_report_abs(ts->input, ABS_X, x);
+ input_report_abs(ts->input, ABS_Y, y);
+ input_report_abs(ts->input, ABS_PRESSURE, Rt);
sync = 1;
}
if (sync)
- input_sync(&ts->input);
+ input_sync(ts->input);

#ifdef VERBOSE
if (Rt || ts->pendown)
@@ -401,7 +409,7 @@ static int __devinit ads7846_probe(struc
struct ads7846 *ts;
struct ads7846_platform_data *pdata = spi->dev.platform_data;
struct spi_transfer *x;
- int i;
+ int status;

if (!spi->irq) {
dev_dbg(&spi->dev, "no IRQ?\n");
@@ -414,9 +422,9 @@ static int __devinit ads7846_probe(struc
}

/* 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;
}

@@ -442,79 +450,100 @@ static int __devinit ads7846_probe(struc
ts->vref_delay_usecs = pdata->vref_delay_usecs ? : 100;
ts->x_plate_ohms = pdata->x_plate_ohms ? : 400;

- init_input_dev(&ts->input);
-
- ts->input.dev = &spi->dev;
- ts->input.name = "ADS784x Touchscreen";
- snprintf(ts->phys, sizeof ts->phys, "%s/input0", spi->dev.bus_id);
- ts->input.phys = ts->phys;
-
- ts->input.evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
- ts->input.keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
- input_set_abs_params(&ts->input, ABS_X,
+ ts->input = input_allocate_device();
+ if (ts->input == NULL) {
+ status = -ENOMEM;
+ goto fail;
+ }
+
+ init_input_dev(ts->input);
+
+ ts->input->dev = &spi->dev;
+ ts->input->name = "ADS784x Touchscreen";
+ snprintf(ts->phys, sizeof ts->phys, "%s/input", spi->dev.bus_id);
+ ts->input->phys = ts->phys;
+
+ ts->input->evbit[0] = BIT(EV_KEY) | BIT(EV_ABS);
+ ts->input->keybit[LONG(BTN_TOUCH)] = BIT(BTN_TOUCH);
+ input_set_abs_params(ts->input, ABS_X,
pdata->x_min ? : 0,
pdata->x_max ? : MAX_12BIT,
0, 0);
- input_set_abs_params(&ts->input, ABS_Y,
+ input_set_abs_params(ts->input, ABS_Y,
pdata->y_min ? : 0,
pdata->y_max ? : MAX_12BIT,
0, 0);
- input_set_abs_params(&ts->input, ABS_PRESSURE,
+ input_set_abs_params(ts->input, ABS_PRESSURE,
pdata->pressure_min, pdata->pressure_max, 0, 0);

- input_register_device(&ts->input);
+ status = input_register_device(ts->input);
+ if (status < 0)
+ goto fail;

/* 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[-1]);
+ CS_CHANGE(*x);
+ spi_message_add_tail(x, &ts->msg);

- 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;

if (request_irq(spi->irq, ads7846_irq, SA_SAMPLE_RANDOM,
- spi->dev.bus_id, ts)) {
+ spi->dev.driver->name, ts)) {
dev_dbg(&spi->dev, "irq %d busy?\n", spi->irq);
- input_unregister_device(&ts->input);
- kfree(ts);
- return -EBUSY;
+ input_unregister_device(ts->input);
+ status = -EBUSY;
+ goto fail;
}
set_irq_type(spi->irq, IRQT_FALLING);

@@ -538,6 +567,12 @@ static int __devinit ads7846_probe(struc
device_create_file(&spi->dev, &dev_attr_vaux);

return 0;
+fail:
+ if (ts && ts->input)
+ input_free_device(ts->input);
+ if (ts)
+ kfree(ts);
+ return status;
}

static int __devexit ads7846_remove(struct spi_device *spi)
@@ -557,7 +592,8 @@ static int __devexit ads7846_remove(stru
device_remove_file(&spi->dev, &dev_attr_vbatt);
device_remove_file(&spi->dev, &dev_attr_vaux);

- input_unregister_device(&ts->input);
+ input_unregister_device(ts->input);
+ input_free_device(ts->input);
kfree(ts);

dev_dbg(&spi->dev, "unregistered touchscreen\n");
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