linux-kernel - Re: [PATCH] driver:st1633: fixed multitouch incorrect coordinates

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Date:   Mon, 21 Oct 2019 10:13:50 -0700
From:   Dmitry Torokhov <dmitry.torokhov@...il.com>
To:     Martin Kepplinger <martink@...teo.de>
Cc:     Dixit Parmar <dixitparmar19@...il.com>, rydberg@...math.org,
        kuninori.morimoto.gx@...esas.com, robh@...nel.org,
        matthias.fend@...fvision.net, linux-input@...r.kernel.org,
        linux-kernel@...r.kernel.org
Subject: Re: [PATCH] driver:st1633: fixed multitouch incorrect coordinates

On Mon, Oct 21, 2019 at 09:10:23AM +0200, Martin Kepplinger wrote:
> On 20.10.19 10:29, Dixit Parmar wrote:
> > Any review comments for this?
> > Or it should be merged?
> > 
> > Thanks.
> 
> My comment and tag is there. This fixes multitouch and should be merged.

Missed it earlier, sorry. I am applying it, but I wonder if we shoudl
not do the patch below as I find the version with 2 loop variables quite
confusing.

Thanks.

-- 
Dmitry

Input: st1232 - simplify parsing of read buffer

From: Dmitry Torokhov <dmitry.torokhov@...il.com>

Signed-off-by: Dmitry Torokhov <dmitry.torokhov@...il.com>
---
 drivers/input/touchscreen/st1232.c |   50 ++++++++++++++++++------------------
 1 file changed, 25 insertions(+), 25 deletions(-)

diff --git a/drivers/input/touchscreen/st1232.c b/drivers/input/touchscreen/st1232.c
index 1139714e72e2..47033ef3749a 100644
--- a/drivers/input/touchscreen/st1232.c
+++ b/drivers/input/touchscreen/st1232.c
@@ -57,38 +57,38 @@ static int st1232_ts_read_data(struct st1232_ts_data *ts)
 {
 	struct st1232_ts_finger *finger = ts->finger;
 	struct i2c_client *client = ts->client;
-	struct i2c_msg msg[2];
-	int error;
-	int i, y;
 	u8 start_reg = ts->chip_info->start_reg;
-	u8 *buf = ts->read_buf;
-
-	/* read touchscreen data */
-	msg[0].addr = client->addr;
-	msg[0].flags = 0;
-	msg[0].len = 1;
-	msg[0].buf = &start_reg;
-
-	msg[1].addr = ts->client->addr;
-	msg[1].flags = I2C_M_RD;
-	msg[1].len = ts->read_buf_len;
-	msg[1].buf = buf;
+	struct i2c_msg msg[] = {
+		{
+			.addr	= client->addr,
+			.len	= sizeof(start_reg),
+			.buf	= &start_reg,
+		},
+		{
+			.addr	= client->addr,
+			.flags	= I2C_M_RD,
+			.len	= ts->read_buf_len,
+			.buf	= ts->read_buf,
+		}
+	};
+	int ret;
+	int i;
+	u8 *buf;
 
-	error = i2c_transfer(client->adapter, msg, 2);
-	if (error < 0)
-		return error;
+	ret = i2c_transfer(client->adapter, msg, ARRAY_SIZE(msg));
+	if (ret != ARRAY_SIZE(msg))
+		return ret < 0 ? ret : -EIO;
 
-	for (i = 0, y = 0; i < ts->chip_info->max_fingers; i++, y += 3) {
-		finger[i].is_valid = buf[i + y] >> 7;
+	for (i = 0; i < ts->chip_info->max_fingers; i++) {
+		buf = &ts->read_buf[i * 4];
+		finger[i].is_valid = buf[0] >> 7;
 		if (finger[i].is_valid) {
-			finger[i].x = ((buf[i + y] & 0x0070) << 4) |
-					buf[i + y + 1];
-			finger[i].y = ((buf[i + y] & 0x0007) << 8) |
-					buf[i + y + 2];
+			finger[i].x = ((buf[0] & 0x70) << 4) | buf[1];
+			finger[i].y = ((buf[0] & 0x07) << 8) | buf[2];
 
 			/* st1232 includes a z-axis / touch strength */
 			if (ts->chip_info->have_z)
-				finger[i].t = buf[i + 6];
+				finger[i].t = ts->read_buf[i + 6];
 		}
 	}