linux-kernel - [PATCH 4/9] Input: edt-ft5x06

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Date:   Sun,  2 Apr 2023 22:09:46 +0200
From:   Dario Binacchi <dario.binacchi@...rulasolutions.com>
To:     linux-kernel@...r.kernel.org
Cc:     michael@...rulasolutions.com, linux-amarula@...rulasolutions.com,
        Dario Binacchi <dario.binacchi@...rulasolutions.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Jonathan Cameron <Jonathan.Cameron@...wei.com>,
        Oliver Graute <oliver.graute@...oconnector.com>,
        Uwe Kleine-König 
        <u.kleine-koenig@...gutronix.de>,
        Wolfram Sang <wsa+renesas@...g-engineering.com>,
        linux-input@...r.kernel.org
Subject: [PATCH 4/9] Input: edt-ft5x06 - don't recalculate the CRC

There is no need to recalculate the CRC when the data has not changed.

Signed-off-by: Dario Binacchi <dario.binacchi@...rulasolutions.com>
---

 drivers/input/touchscreen/edt-ft5x06.c | 8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/input/touchscreen/edt-ft5x06.c b/drivers/input/touchscreen/edt-ft5x06.c
index c96fe6520578..d4f39724b259 100644
--- a/drivers/input/touchscreen/edt-ft5x06.c
+++ b/drivers/input/touchscreen/edt-ft5x06.c
@@ -319,7 +319,7 @@ static int edt_ft5x06_register_write(struct edt_ft5x06_ts_data *tsdata,
 static int edt_ft5x06_register_read(struct edt_ft5x06_ts_data *tsdata,
 				    u8 addr)
 {
-	u8 wrbuf[2], rdbuf[2];
+	u8 wrbuf[2], rdbuf[2], crc;
 	int error;
 
 	switch (tsdata->version) {
@@ -333,11 +333,11 @@ static int edt_ft5x06_register_read(struct edt_ft5x06_ts_data *tsdata,
 		if (error)
 			return error;
 
-		if ((wrbuf[0] ^ wrbuf[1] ^ rdbuf[0]) != rdbuf[1]) {
+		crc = wrbuf[0] ^ wrbuf[1] ^ rdbuf[0];
+		if (crc != rdbuf[1]) {
 			dev_err(&tsdata->client->dev,
 				"crc error: 0x%02x expected, got 0x%02x\n",
-				wrbuf[0] ^ wrbuf[1] ^ rdbuf[0],
-				rdbuf[1]);
+				crc, rdbuf[1]);
 			return -EIO;
 		}
 		break;
-- 
2.32.0