[PATCH v2 2/9] input: elants: support old touch report format

Michał Mirosław
2019-12-11T16:04:20Z

Support ELAN touchpad sensor with older firmware as found on eg. Asus
Transformer Pads.

Signed-off-by: Michał Mirosław <mirq-linux@rere.qmqm.pl>
---
drivers/input/touchscreen/elants_i2c.c | 36 ++++++++++++++++++--------
1 file changed, 25 insertions(+), 11 deletions(-)

diff --git a/drivers/input/touchscreen/elants_i2c.c b/drivers/input/touchscreen/elants_i2c.c
index 887888c53996..eadd26d5a06f 100644
--- a/drivers/input/touchscreen/elants_i2c.c
+++ b/drivers/input/touchscreen/elants_i2c.c
@@ -65,6 +65,7 @@
#define CMD_HEADER_REK 0x66

/* FW position data */
+#define PACKET_SIZE_OLD 40
#define PACKET_SIZE 55
#define MAX_CONTACT_NUM 10
#define FW_POS_HEADER 0
@@ -792,7 +793,8 @@ static int elants_i2c_fw_update(struct elants_data *ts)
* Event reporting.
*/

-static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
+static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf,
+ size_t report_len)
{
struct input_dev *input = ts->input;
unsigned int n_fingers;
@@ -804,7 +806,8 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
buf[FW_POS_STATE];

dev_dbg(&ts->client->dev,
- "n_fingers: %u, state: %04x\n", n_fingers, finger_state);
+ "n_fingers: %u, state: %04x, report_len: %zu\n",
+ n_fingers, finger_state, report_len);

for (i = 0; i < MAX_CONTACT_NUM && n_fingers; i++) {
if (finger_state & 1) {
@@ -814,8 +817,16 @@ static void elants_i2c_mt_event(struct elants_data *ts, u8 *buf)
pos = &buf[FW_POS_XY + i * 3];
x = (((u16)pos[0] & 0xf0) << 4) | pos[1];
y = (((u16)pos[0] & 0x0f) << 8) | pos[2];
- p = buf[FW_POS_PRESSURE + i];
- w = buf[FW_POS_WIDTH + i];
+ if (report_len == PACKET_SIZE_OLD) {
+ w = buf[FW_POS_WIDTH + i / 2];
+ w >>= 4 * (~i & 1); // little-endian-nibbles
+ w |= w << 4;
+ w |= !w;
+ p = w;
+ } else {
+ p = buf[FW_POS_PRESSURE + i];
+ w = buf[FW_POS_WIDTH + i];
+ }

dev_dbg(&ts->client->dev, "i=%d x=%d y=%d p=%d w=%d\n",
i, x, y, p, w);
@@ -848,7 +859,8 @@ static u8 elants_i2c_calculate_checksum(u8 *buf)
return checksum;
}

-static void elants_i2c_event(struct elants_data *ts, u8 *buf)
+static void elants_i2c_event(struct elants_data *ts, u8 *buf,
+ size_t report_len)
{
u8 checksum = elants_i2c_calculate_checksum(buf);

@@ -862,7 +874,7 @@ static void elants_i2c_event(struct elants_data *ts, u8 *buf)
"%s: unknown packet type: %02x\n",
__func__, buf[FW_POS_HEADER]);
else
- elants_i2c_mt_event(ts, buf);
+ elants_i2c_mt_event(ts, buf, report_len);
}

static irqreturn_t elants_i2c_irq(int irq, void *_dev)
@@ -920,7 +932,8 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
break;

case QUEUE_HEADER_SINGLE:
- elants_i2c_event(ts, &ts->buf[HEADER_SIZE]);
+ elants_i2c_event(ts, &ts->buf[HEADER_SIZE],
+ ts->buf[FW_HDR_LENGTH]);
break;

case QUEUE_HEADER_NORMAL:
@@ -933,17 +946,18 @@ static irqreturn_t elants_i2c_irq(int irq, void *_dev)
}

report_len = ts->buf[FW_HDR_LENGTH] / report_count;
- if (report_len != PACKET_SIZE) {
+ if (report_len != PACKET_SIZE &&
+ report_len != PACKET_SIZE_OLD) {
dev_err(&client->dev,
- "mismatching report length: %*ph\n",
+ "unsupported report length: %*ph\n",
HEADER_SIZE, ts->buf);
break;
}

for (i = 0; i < report_count; i++) {
u8 *buf = ts->buf + HEADER_SIZE +
- i * PACKET_SIZE;
- elants_i2c_event(ts, buf);
+ i * report_len;
+ elants_i2c_event(ts, buf, report_len);
}
break;

--
2.20.1