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

[Dmitry Osipenko <digetx@gmail.com>]

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;
>  
>