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authorShaun Jackman <sjackman@gmail.com>2006-08-05 00:27:59 -0400
committerDmitry Torokhov <dtor@insightbb.com>2006-08-05 00:27:59 -0400
commit1ce316efb55a1497d07d518853e60a4356abceb6 (patch)
tree5b80f90e5ddc7ff36b1ce30bdbf796d8741d7bc2 /drivers/input
parent6b50d8b862284929314e9ff09e5b1cce2c43d32b (diff)
Input: elo - fix checksum calculation
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>
Diffstat (limited to 'drivers/input')
-rw-r--r--drivers/input/touchscreen/elo.c55
1 files changed, 29 insertions, 26 deletions
diff --git a/drivers/input/touchscreen/elo.c b/drivers/input/touchscreen/elo.c
index b7ac016219d..fe6e1a42867 100644
--- a/drivers/input/touchscreen/elo.c
+++ b/drivers/input/touchscreen/elo.c
@@ -34,7 +34,11 @@ MODULE_LICENSE("GPL");
* Definitions & global arrays.
*/
-#define ELO_MAX_LENGTH 10
+#define ELO_MAX_LENGTH 10
+
+#define ELO10_LEAD_BYTE 'U'
+
+#define ELO10_TOUCH_PACKET 'T'
/*
* Per-touchscreen data.
@@ -50,44 +54,43 @@ struct elo {
char phys[32];
};
-static void elo_process_data_10(struct elo* elo, unsigned char data, struct pt_regs *regs)
+static void elo_process_data_10(struct elo *elo, unsigned char data, struct pt_regs *regs)
{
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->idx = 0;
- elo->csum = 0;
- }
- break;
-
- case 1:
- if (data != 'T') {
+ 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 9:
- if (elo->csum) {
- 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;
+ 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);
break;
}
+ elo->csum += data;
}
-static void elo_process_data_6(struct elo* elo, unsigned char data, struct pt_regs *regs)
+static void elo_process_data_6(struct elo *elo, unsigned char data, struct pt_regs *regs)
{
struct input_dev *dev = elo->dev;
@@ -135,7 +138,7 @@ static void elo_process_data_6(struct elo* elo, unsigned char data, struct pt_re
}
}
-static void elo_process_data_3(struct elo* elo, unsigned char data, struct pt_regs *regs)
+static void elo_process_data_3(struct elo *elo, unsigned char data, struct pt_regs *regs)
{
struct input_dev *dev = elo->dev;
@@ -161,7 +164,7 @@ static void elo_process_data_3(struct elo* elo, unsigned char data, struct pt_re
static irqreturn_t elo_interrupt(struct serio *serio,
unsigned char data, unsigned int flags, struct pt_regs *regs)
{
- struct elo* elo = serio_get_drvdata(serio);
+ struct elo *elo = serio_get_drvdata(serio);
switch(elo->id) {
case 0: