[PATCH 3/4] wifi: rtw89: 8852ce: fix gray code conversion for filter out EQ

[Ping-Ke Shih <pkshih@realtek.com>]

To use manual mode to set value of filter out EQ, read the source value of
filter out EQ coded in gray code, and write to the target register in
binary number. The function to convert from gray code to binary number is
wrong originally, causing unexpected EQ, so fix it.

Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
---
 drivers/net/wireless/realtek/rtw89/pci.c | 17 +++++++----------
 1 file changed, 7 insertions(+), 10 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw89/pci.c b/drivers/net/wireless/realtek/rtw89/pci.c
index c1e0861b7b3f..45d536b818e9 100644
--- a/drivers/net/wireless/realtek/rtw89/pci.c
+++ b/drivers/net/wireless/realtek/rtw89/pci.c
@@ -3724,19 +3724,16 @@ static void rtw89_pci_free_irq(struct rtw89_dev *rtwdev,
 	pci_free_irq_vectors(pdev);
 }
 
-static u16 gray_code_to_bin(u16 gray_code, u32 bit_num)
+static u16 gray_code_to_bin(u16 gray_code)
 {
-	u16 bin = 0, gray_bit;
-	u32 bit_idx;
+	u16 binary = gray_code;
 
-	for (bit_idx = 0; bit_idx < bit_num; bit_idx++) {
-		gray_bit = (gray_code >> bit_idx) & 0x1;
-		if (bit_num - bit_idx > 1)
-			gray_bit ^= (gray_code >> (bit_idx + 1)) & 0x1;
-		bin |= (gray_bit << bit_idx);
+	while (gray_code) {
+		gray_code >>= 1;
+		binary ^= gray_code;
 	}
 
-	return bin;
+	return binary;
 }
 
 static int rtw89_pci_filter_out(struct rtw89_dev *rtwdev)
@@ -3772,7 +3769,7 @@ static int rtw89_pci_filter_out(struct rtw89_dev *rtwdev)
 		val16 = rtw89_read16_mask(rtwdev,
 					  phy_offset + RAC_ANA1F * RAC_MULT,
 					  FILTER_OUT_EQ_MASK);
-		val16 = gray_code_to_bin(val16, hweight16(val16));
+		val16 = gray_code_to_bin(val16);
 		filter_out_val = rtw89_read16(rtwdev, phy_offset + RAC_ANA24 *
 					      RAC_MULT);
 		filter_out_val &= ~REG_FILTER_OUT_MASK;
-- 
2.25.1