Input: libps2 - remove special handling of ACK for command byte

When getting unexpected data while waiting for an acknowledgement it does
not matter what command phase is currently executed, and ps2_handle_ack()
should indicate that no further processing is needed for the received data
byte. Remove PS2_FLAG_ACK_CMD and associated handling.

Note that while it is possible to make ps2_handle_ack (and
ps2_handle_repsonse) return void, it will be done when the code will be
converted to common PS/2 interrupt handler later.

Reviewed-by: Raul E Rangel <rrangel@chromium.org>
Link: https://lore.kernel.org/r/20230511185252.386941-3-dmitry.torokhov@gmail.com
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>

Author: dtor

drivers/input/serio/libps2.c

@@ -253,9 +253,6 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 		for (i = 0; i < receive; i++)
 			ps2dev->cmdbuf[(receive - 1) - i] = param[i];
 
-	/* Signal that we are sending the command byte */
-	ps2dev->flags |= PS2_FLAG_ACK_CMD;
-
 	/*
 	 * Some devices (Synaptics) peform the reset before
 	 * ACKing the reset command, and so it can take a long
@@ -267,9 +264,7 @@ int __ps2_command(struct ps2dev *ps2dev, u8 *param, unsigned int command)
 	if (rc)
 		goto out_reset_flags;
 
-	/* Now we are sending command parameters, if any */
-	ps2dev->flags &= ~PS2_FLAG_ACK_CMD;
-
+	/* Send command parameters, if any. */
 	for (i = 0; i < send; i++) {
 		rc = ps2_do_sendbyte(ps2dev, param[i], 200, 2);
 		if (rc)
@@ -436,7 +431,7 @@ bool ps2_handle_ack(struct ps2dev *ps2dev, u8 data)
 		 */
 		dev_dbg(&ps2dev->serio->dev, "unexpected %#02x\n", data);
 		ps2dev->flags &= ~PS2_FLAG_WAITID;
-		return ps2dev->flags & PS2_FLAG_ACK_CMD;
+		return true;
 	}
 
 	if (!ps2dev->nak) {

include/linux/libps2.h

@@ -28,7 +28,6 @@
 #define PS2_FLAG_CMD1		BIT(2)	/* Waiting for the first byte of command response */
 #define PS2_FLAG_WAITID		BIT(3)	/* Command executing is GET ID */
 #define PS2_FLAG_NAK		BIT(4)	/* Last transmission was NAKed */
-#define PS2_FLAG_ACK_CMD	BIT(5)	/* Waiting to ACK the command (first) byte */
 
 struct ps2dev {
 	struct serio *serio;