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

Dmitry Osipenko
2019-12-12T00:54:20Z

11.12.2019 19:03, Michał Mirosław пишет:
> 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;

Did you copy this from the downstream driver as-is? I'm looking at the
Nexus 7 driver and it does the following for older format:

u8 size_idx[] = { 35, 35, 36, 36, 37, 37, 38, 38, 39, 39 };
unsigned int s;

if (i & 1)
s = buf[size_idx[i]];
else
s = buf[size_idx[i]] / 16;

w = s & 0xf;
p = s * 16;

> + } 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;
>
>