[PATCH 1/8] Input: st1232 - simplify parsing of read buffer

Dmitry Torokhov
2019-10-22T19:56:30Z

Avoid complex 2-variable loop when parsing touchscreen data to make the
code clearer.

Acked-by: Martin Kepplinger <martink@posteo.de>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.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];
}
}

--
2.23.0.866.gb869b98d4c-goog