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Input: elo - fix checksum calculation

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Fix 10-byte protocol checksum calculation and do not discard packet early
unless it is missing lead in byte.

Signed-off-by: Shaun Jackman <sjackman@gmail.com>
Signed-off-by: Dmitry Torokhov <dtor@mail.ru>
This commit is contained in:
Shaun Jackman 2006-08-05 00:27:59 -04:00 • committed by Dmitry Torokhov
parent 6b50d8b862
commit 1ce316efb5
1 changed files with 29 additions and 26 deletions
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35
drivers/input/touchscreen/elo.c
View file

@ -36,6 +36,10 @@ MODULE_LICENSE("GPL");
#define ELO_MAX_LENGTH 10
#define ELO10_LEAD_BYTE 'U'
#define ELO10_TOUCH_PACKET 'T'
/*
* Per-touchscreen data.
*/
@ -54,37 +58,36 @@ static void elo_process_data_10(struct elo* elo, unsigned char data, struct pt_r
{
struct input_dev *dev = elo->dev;
elo->csum += elo->data[elo->idx] = data;
elo->data[elo->idx] = data;
switch (elo->idx++) {
case 0:
if (data != 'U') {
elo->csum = 0xaa;
if (data != ELO10_LEAD_BYTE) {
pr_debug("elo: unsynchronized data: 0x%02x\n", data);
elo->idx = 0;
elo->csum = 0;
}
break;
case 1:
if (data != 'T') {
elo->idx = 0;
elo->csum = 0;
}
break;
case 9:
if (elo->csum) {
elo->idx = 0;
if (data != elo->csum) {
pr_debug("elo: bad checksum: 0x%02x, expected 0x%02x\n",
data, elo->csum);
break;
}
if (elo->data[1] != ELO10_TOUCH_PACKET) {
pr_debug(elo: "unexpected packet: 0x%02x\n", elo->data[1]);
break;
}
input_regs(dev, regs);
input_report_abs(dev, ABS_X, (elo->data[4] << 8) | elo->data[3]);
input_report_abs(dev, ABS_Y, (elo->data[6] << 8) | elo->data[5]);
input_report_abs(dev, ABS_PRESSURE, (elo->data[8] << 8) | elo->data[7]);
input_report_key(dev, BTN_TOUCH, elo->data[8] || elo->data[7]);
input_sync(dev);
}
elo->idx = 0;
elo->csum = 0;
break;
}
elo->csum += data;
}
static void elo_process_data_6(struct elo *elo, unsigned char data, struct pt_regs *regs)