linux-kernel - [PATCH 09/17] Input: joystick - Replace open-coded parity calculation with parity32()

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Message-Id: <20250223164217.2139331-10-visitorckw@gmail.com>
Date: Mon, 24 Feb 2025 00:42:09 +0800
From: Kuan-Wei Chiu <visitorckw@...il.com>
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	Kuan-Wei Chiu <visitorckw@...il.com>,
	Yu-Chun Lin <eleanor15x@...il.com>
Subject: [PATCH 09/17] Input: joystick - Replace open-coded parity calculation with parity32()

Refactor parity calculations to use the standard parity32() helper.
This change eliminates redundant implementations and improves code
efficiency.

Co-developed-by: Yu-Chun Lin <eleanor15x@...il.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@...il.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@...il.com>
---
 drivers/input/joystick/grip_mp.c | 17 ++---------------
 1 file changed, 2 insertions(+), 15 deletions(-)

diff --git a/drivers/input/joystick/grip_mp.c b/drivers/input/joystick/grip_mp.c
index 5eadb5a3ca37..897ce13753dc 100644
--- a/drivers/input/joystick/grip_mp.c
+++ b/drivers/input/joystick/grip_mp.c
@@ -18,6 +18,7 @@
 #include <linux/delay.h>
 #include <linux/proc_fs.h>
 #include <linux/jiffies.h>
+#include <linux/bitops.h>
 
 #define DRIVER_DESC	"Gravis Grip Multiport driver"
 
@@ -112,20 +113,6 @@ static const int axis_map[] = { 5, 9, 1, 5, 6, 10, 2, 6, 4, 8, 0, 4, 5, 9, 1, 5
 
 static int register_slot(int i, struct grip_mp *grip);
 
-/*
- * Returns whether an odd or even number of bits are on in pkt.
- */
-
-static int bit_parity(u32 pkt)
-{
-	int x = pkt ^ (pkt >> 16);
-	x ^= x >> 8;
-	x ^= x >> 4;
-	x ^= x >> 2;
-	x ^= x >> 1;
-	return x & 1;
-}
-
 /*
  * Poll gameport; return true if all bits set in 'onbits' are on and
  * all bits set in 'offbits' are off.
@@ -236,7 +223,7 @@ static int mp_io(struct gameport* gameport, int sendflags, int sendcode, u32 *pa
 		pkt = (pkt >> 2) | 0xf0000000;
 	}
 
-	if (bit_parity(pkt) == 1)
+	if (parity32(pkt) == 1)
 		return IO_RESET;
 
 	/* Acknowledge packet receipt */
-- 
2.34.1