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Input: wacom_w8001 - simplify querying logic
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There is no need for locking when we send query and start commands
to the touchscreen since there is no concurrency.

Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
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Dmitry Torokhov committed Sep 4, 2009
1 parent 1ba36e1 commit 41c372d
Showing 1 changed file with 40 additions and 81 deletions.
121 changes: 40 additions & 81 deletions drivers/input/touchscreen/wacom_w8001.c
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Original file line number Diff line number Diff line change
Expand Up @@ -25,18 +25,16 @@ MODULE_AUTHOR("Jaya Kumar <jayakumar.lkml@gmail.com>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");

/*
* Definitions & global arrays.
*/

#define W8001_MAX_LENGTH 11
#define W8001_PACKET_LEN 11
#define W8001_LEAD_MASK 0x80
#define W8001_LEAD_BYTE 0x80
#define W8001_TAB_MASK 0x40
#define W8001_TAB_BYTE 0x40
#define W8001_LEAD_MASK 0x80
#define W8001_LEAD_BYTE 0x80
#define W8001_TAB_MASK 0x40
#define W8001_TAB_BYTE 0x40

#define W8001_QUERY_PACKET 0x20
#define W8001_QUERY_PACKET 0x20

#define W8001_CMD_START '1'
#define W8001_CMD_QUERY '*'

struct w8001_coord {
u8 rdy;
Expand All @@ -57,18 +55,19 @@ struct w8001_coord {
struct w8001 {
struct input_dev *dev;
struct serio *serio;
struct mutex cmd_mutex;
struct completion cmd_done;
int id;
int idx;
unsigned char expected_packet;
unsigned char response_type;
unsigned char response[W8001_MAX_LENGTH];
unsigned char data[W8001_MAX_LENGTH];
unsigned char response[W8001_PACKET_LEN];
char phys[32];
};

static int parse_data(u8 *data, struct w8001_coord *coord)
static void parse_data(u8 *data, struct w8001_coord *coord)
{
memset(coord, 0, sizeof(*coord));

coord->rdy = data[0] & 0x20;
coord->tsw = data[0] & 0x01;
coord->f1 = data[0] & 0x02;
Expand All @@ -87,15 +86,15 @@ static int parse_data(u8 *data, struct w8001_coord *coord)

coord->tilt_x = data[7] & 0x7F;
coord->tilt_y = data[8] & 0x7F;

return 0;
}

static void w8001_process_data(struct w8001 *w8001, unsigned char data)
static irqreturn_t w8001_interrupt(struct serio *serio,
unsigned char data, unsigned int flags)
{
struct w8001 *w8001 = serio_get_drvdata(serio);
struct input_dev *dev = w8001->dev;
u8 tmp;
struct w8001_coord coord;
unsigned char tmp;

w8001->data[w8001->idx] = data;
switch (w8001->idx++) {
Expand All @@ -105,110 +104,70 @@ static void w8001_process_data(struct w8001 *w8001, unsigned char data)
w8001->idx = 0;
}
break;

case 8:
tmp = w8001->data[0] & W8001_TAB_MASK;
if (unlikely(tmp == W8001_TAB_BYTE))
break;

w8001->idx = 0;
memset(&coord, 0, sizeof(coord));
parse_data(w8001->data, &coord);
input_report_abs(dev, ABS_X, coord.x);
input_report_abs(dev, ABS_Y, coord.y);
input_report_abs(dev, ABS_PRESSURE, coord.pen_pressure);
input_report_key(dev, BTN_TOUCH, coord.tsw);
input_sync(dev);
break;

case 10:
w8001->idx = 0;
memcpy(w8001->response, &w8001->data, W8001_PACKET_LEN);
w8001->expected_packet = W8001_QUERY_PACKET;
memcpy(w8001->response, w8001->data, W8001_MAX_LENGTH);
w8001->response_type = W8001_QUERY_PACKET;
complete(&w8001->cmd_done);
break;
}
}


static irqreturn_t w8001_interrupt(struct serio *serio,
unsigned char data, unsigned int flags)
{
struct w8001 *w8001 = serio_get_drvdata(serio);

w8001_process_data(w8001, data);

return IRQ_HANDLED;
}

static int w8001_async_command(struct w8001 *w8001, unsigned char *packet,
int len)
{
int rc = -1;
int i;

mutex_lock(&w8001->cmd_mutex);

for (i = 0; i < len; i++) {
if (serio_write(w8001->serio, packet[i]))
goto out;
}
rc = 0;

out:
mutex_unlock(&w8001->cmd_mutex);
return rc;
}

static int w8001_command(struct w8001 *w8001, unsigned char *packet, int len)
static int w8001_command(struct w8001 *w8001, unsigned char command,
bool wait_response)
{
int rc = -1;
int i;
int rc;

mutex_lock(&w8001->cmd_mutex);

serio_pause_rx(w8001->serio);
w8001->response_type = 0;
init_completion(&w8001->cmd_done);
serio_continue_rx(w8001->serio);

for (i = 0; i < len; i++) {
if (serio_write(w8001->serio, packet[i]))
goto out;
}

wait_for_completion_timeout(&w8001->cmd_done, HZ);
rc = serio_write(w8001->serio, command);
if (rc == 0 && wait_response) {

if (w8001->expected_packet == W8001_QUERY_PACKET) {
/* We are back in reporting mode, the query was ACKed */
memcpy(packet, w8001->response, W8001_PACKET_LEN);
rc = 0;
wait_for_completion_timeout(&w8001->cmd_done, HZ);
if (w8001->response_type != W8001_QUERY_PACKET)
rc = -EIO;
}

out:
mutex_unlock(&w8001->cmd_mutex);
return rc;
}

static int w8001_setup(struct w8001 *w8001)
{
struct w8001_coord coord;
struct input_dev *dev = w8001->dev;
unsigned char start[1] = { '1' };
unsigned char query[11] = { '*' };
struct w8001_coord coord;
int error;

if (w8001_command(w8001, query, 1))
return -1;
error = w8001_command(w8001, W8001_CMD_QUERY, true);
if (error)
return error;

memset(&coord, 0, sizeof(coord));
parse_data(query, &coord);
parse_data(w8001->response, &coord);

input_set_abs_params(dev, ABS_X, 0, coord.x, 0, 0);
input_set_abs_params(dev, ABS_Y, 0, coord.y, 0, 0);
input_set_abs_params(dev, ABS_PRESSURE, 0, coord.pen_pressure, 0, 0);
input_set_abs_params(dev, ABS_TILT_X, 0, coord.tilt_x, 0, 0);
input_set_abs_params(dev, ABS_TILT_Y, 0, coord.tilt_y, 0, 0);

if (w8001_async_command(w8001, start, 1))
return -1;

return 0;
return w8001_command(w8001, W8001_CMD_START, false);
}

/*
Expand Down Expand Up @@ -249,7 +208,6 @@ static int w8001_connect(struct serio *serio, struct serio_driver *drv)
w8001->serio = serio;
w8001->id = serio->id.id;
w8001->dev = input_dev;
mutex_init(&w8001->cmd_mutex);
init_completion(&w8001->cmd_done);
snprintf(w8001->phys, sizeof(w8001->phys), "%s/input0", serio->phys);

Expand All @@ -269,7 +227,8 @@ static int w8001_connect(struct serio *serio, struct serio_driver *drv)
if (err)
goto fail2;

if (w8001_setup(w8001))
err = w8001_setup(w8001);
if (err)
goto fail3;

err = input_register_device(w8001->dev);
Expand Down

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