[PATCH wireless-next v2 4/4] wifi: rtw88: rtw8822c: simplify amplitude search and offset via s32

[Arsenii Pashchenko <ulijg308@gmail.com>]

Complete the signed data transition by removing the complex
rtw8822c_rf_minmax_cmp() helper. On a true linear s32 scale, finding
the delta amplitude simplifies to a direct difference (max - min)
without any nested circular wrap-around conditions.

Refactor rtw8822c_dac_iq_offset() to directly calculate the trimmed
arithmetic mean, casting back to the hardware register's offset
orientation only at the final assignment using a ternary operator.

Signed-off-by: Arsenii Pashchenko <ulijg308@gmail.com>
---
 drivers/net/wireless/realtek/rtw88/rtw8822c.c | 103 +++++-------------
 1 file changed, 25 insertions(+), 78 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.c b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
index 642ac2e2b..6fcdfc64c 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
@@ -155,38 +155,6 @@ static void rtw8822c_dac_restore_reg(struct rtw_dev *rtwdev,
 	}
 }
 
-static void rtw8822c_rf_minmax_cmp(struct rtw_dev *rtwdev, s32 value_s32,
-				   s32 *min_s32, s32 *max_s32)
-{
-	u32 value = (u32)value_s32;
-	u32 *min = (u32 *)min_s32;
-	u32 *max = (u32 *)max_s32;
-	if (value >= 0x200) {
-		if (*min >= 0x200) {
-			if (*min > value)
-				*min = value;
-		} else {
-			*min = value;
-		}
-		if (*max >= 0x200) {
-			if (*max < value)
-				*max = value;
-		}
-	} else {
-		if (*min < 0x200) {
-			if (*min > value)
-				*min = value;
-		}
-
-		if (*max  >= 0x200) {
-			*max = value;
-		} else {
-			if (*max < value)
-				*max = value;
-		}
-	}
-}
-
 static int rtw8822c_dac_iq_cmp_s32(const void *a, const void *b)
 {
 	s32 va = *(const s32 *)a;
@@ -201,31 +169,16 @@ static void rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, s32 *iv, s32 *qv)
 	sort(qv, DACK_SN_8822C, sizeof(s32), rtw8822c_dac_iq_cmp_s32, NULL);
 }
 
-static void rtw8822c_dac_iq_offset(struct rtw_dev *rtwdev, s32 *vec_s32, u32 *val)
+static s32 rtw8822c_dac_iq_offset(struct rtw_dev *rtwdev, s32 *vec)
 {
-	u32 *vec = (u32 *)vec_s32;
-	u32 p, m, t, i;
+	s32 sum = 0;
 
-	m = 0;
-	p = 0;
-	for (i = 10; i < DACK_SN_8822C - 10; i++) {
-		if (vec[i] > 0x200)
-			m = (0x400 - vec[i]) + m;
-		else
-			p = vec[i] + p;
-	}
+	for (u32 i = 10; i < DACK_SN_8822C - 10; i++)
+		sum += vec[i];
 
-	if (p > m) {
-		t = p - m;
-		t = t / (DACK_SN_8822C - 20);
-	} else {
-		t = m - p;
-		t = t / (DACK_SN_8822C - 20);
-		if (t != 0x0)
-			t = 0x400 - t;
-	}
+	s32 avg = sum / (DACK_SN_8822C - 20);
 
-	*val = t;
+	return avg >= 0 ? avg : 0x400 + avg;
 }
 
 static u32 rtw8822c_get_path_write_addr(u8 path)
@@ -280,7 +233,7 @@ static bool rtw8822c_dac_iq_check(struct rtw_dev *rtwdev, s32 value)
 static void rtw8822c_dac_cal_iq_sample(struct rtw_dev *rtwdev, s32 *iv, s32 *qv)
 {
 	u32 temp;
-	int i = 0, cnt = 0;
+	u32 i = 0, cnt = 0;
 
 	while (i < DACK_SN_8822C && cnt < 10000) {
 		cnt++;
@@ -298,34 +251,28 @@ static void rtw8822c_dac_cal_iq_search(struct rtw_dev *rtwdev,
 				       s32 *iv, s32 *qv,
 				       u32 *i_value, u32 *q_value)
 {
-	u32 i_max = 0, q_max = 0, i_min = 0, q_min = 0;
-	u32 i_delta, q_delta;
+	s32 i_max = 0, q_max = 0, i_min = 0, q_min = 0;
 	u32 temp;
-	int i, cnt = 0;
+	u32 i, cnt = 0;
 
 	do {
-		i_min = (u32)iv[0];
-		i_max = (u32)iv[0];
-		q_min = (u32)qv[0];
-		q_max = (u32)qv[0];
+		i_min = iv[0];
+		i_max = iv[0];
+		q_min = qv[0];
+		q_max = qv[0];
 		for (i = 0; i < DACK_SN_8822C; i++) {
-			rtw8822c_rf_minmax_cmp(rtwdev, iv[i], (s32 *)&i_min, (s32 *)&i_max);
-			rtw8822c_rf_minmax_cmp(rtwdev, qv[i], (s32 *)&q_min, (s32 *)&q_max);
+			if (iv[i] < i_min)
+				i_min = iv[i];
+			if (iv[i] > i_max)
+				i_max = iv[i];
+			if (qv[i] < q_min)
+				q_min = qv[i];
+			if (qv[i] > q_max)
+				q_max = qv[i];
 		}
 
-		if (i_max < 0x200 && i_min < 0x200)
-			i_delta = i_max - i_min;
-		else if (i_max >= 0x200 && i_min >= 0x200)
-			i_delta = i_max - i_min;
-		else
-			i_delta = i_max + (0x400 - i_min);
-
-		if (q_max < 0x200 && q_min < 0x200)
-			q_delta = q_max - q_min;
-		else if (q_max >= 0x200 && q_min >= 0x200)
-			q_delta = q_max - q_min;
-		else
-			q_delta = q_max + (0x400 - q_min);
+		u32 i_delta = (u32)(i_max - i_min);
+		u32 q_delta = (u32)(q_max - q_min);
 
 		rtw_dbg(rtwdev, RTW_DBG_RFK,
 			"[DACK] i: min=0x%08x, max=0x%08x, delta=0x%08x\n",
@@ -348,8 +295,8 @@ static void rtw8822c_dac_cal_iq_search(struct rtw_dev *rtwdev,
 		}
 	} while (cnt++ < 100);
 
-	rtw8822c_dac_iq_offset(rtwdev, iv, i_value);
-	rtw8822c_dac_iq_offset(rtwdev, qv, q_value);
+	*i_value = rtw8822c_dac_iq_offset(rtwdev, iv);
+	*q_value = rtw8822c_dac_iq_offset(rtwdev, qv);
 }
 
 static void rtw8822c_dac_cal_rf_mode(struct rtw_dev *rtwdev,
-- 
2.55.0