[PATCH v3 08/16] Input: joystick - Replace open-coded parity calculation with parity32()

Kuan-Wei Chiu
2025-03-06T16:27:18Z

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@gmail.com>
Signed-off-by: Yu-Chun Lin <eleanor15x@gmail.com>
Signed-off-by: Kuan-Wei Chiu <visitorckw@gmail.com>
---
Changes in v3:
- Change condition if(parity32(pkt) == 1) to if(parity32(pkt)).

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..26a7ae785942 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))
return IO_RESET;

/* Acknowledge packet receipt */
--
2.34.1