[PATCH rtw-next v6 0/3] wifi: rtw88: rtw8822c: refactor DAC IQ calibration to s32

[PATCH rtw-next v6 0/3] wifi: rtw88: rtw8822c: refactor DAC IQ calibration to s32

[Arsenii Pashchenko]

This series refactors the Digital-to-Analog Converter (DAC) IQ
calibration routines in the rtw8822c driver, eliminating legacy
unsigned workarounds in favor of native signed math.

The original code heavily relies on unsigned 32-bit math mapped over
a 10-bit circular hardware register scale centered around 0x200. This
introduces complex nested boundary checks, custom bubble sort rules,
and custom min/max tracking helpers.

By migrating the temporary stack arrays and signatures to signed s32
and utilizing the kernel's FIELD_GET_SIGNED() API, the coordination
system is linearized. This allows the removal of internal custom
helpers, collapses unsigned wrap-around logic into standard linear
operations, and enables the drop-in integration of the kernel's
native heapsort library.

The series is broken down as follows:
Patch 1: Introduces GENMASK constants for register fields and replaces
         manual bit shifts with standard FIELD_GET() macros.
Patch 2: Converts stack buffers and function signatures to signed s32,
         switches sampling to FIELD_GET_SIGNED(), and straightens out
         the validation windows and hardware offset mapping.
Patch 3: Replaces custom bubble sort logic and unused helpers with a direct
         call to the kernel's native sort() library using a safe,
         overflow-proof relational comparator.

AI Disclosure:
An AI assistant was used for source code analysis and conceptual
consultation regarding the signed math transformation. All code
modifications, final implementations, and refactoring steps were
written, reviewed, and verified manually by the author.

Testing:
- Note: The author does not possess the actual rtw8822c hardware. Actual
  throughput and runtime performance verification is left to the vendor
  or community testers.
- Every patch in the series was verified with scripts/checkpatch.pl
  and yielded 0 errors and 0 warnings.
- Each patch was sequentially built (bisected and compiled) to ensure
  there are no compiler warnings, pointer type mismatches, or broken
  builds at any intermediate step.
---
Changes in v6:
 - Noted lack of physical hardware for throughput testing in the cover letter.
 - Fixed a typo in the subject prefix of patch 2 ("fi:" -> "wifi:").
 - Optimized the min/max search loop in rtw8822c_dac_cal_iq_search() by
   starting from index 1 since index 0 is used for initialization.
 - Reverted an accidental change that broke the compilation.

Changes in v5:
 - Fixed a typo in the subject prefix of patch 2 ("fi:" -> "wifi:").
 
Changes in v4:
 - Flattened the series from 4 to 3 patches to avoid intermediate broken
   states where sign-extended variables interacted with unsigned check
   logic, ensuring 100% clean bisectability.
 - Leveraged FIELD_GET_SIGNED() for modern, native handling of 10-bit
   signed hardware entries as suggested during review.
 - Shifted definition of register field masks from the .c file into the
   shared rtw8822c.h header file according to subsystem design patterns.
 - Stripped out custom rtw8822c_dac_iq_sort() wrapper, invoking the
   kernel sort() library directly inside the main calibration search loop.

Changes in v3:
 - Corrected the subject prefix target tree from wireless-next to rtw-next 
   as requested by the maintainer.
   
Changes in v2:
 - Fixed missing target tree name in the subject prefix (switched to wireless-next).

Arsenii Pashchenko (3):
  wifi: rtw88: rtw8822c: Use bitfield macros for DAC IQ sampling
  wifi: rtw88: rtw8822c: Convert DAC IQ calibration path to signed math
  wifi: rtw88: rtw8822c: Replace custom DAC IQ sorting with kernel sort

 drivers/net/wireless/realtek/rtw88/rtw8822c.c | 155 ++++++------------
 drivers/net/wireless/realtek/rtw88/rtw8822c.h |   3 +
 2 files changed, 49 insertions(+), 109 deletions(-)

-- 
2.55.0

[PATCH rtw-next v6 1/3] wifi: rtw88: rtw8822c: Use bitfield macros for DAC IQ sampling

[Arsenii Pashchenko]

Define proper GENMASK constants for the In-phase (I) and Quadrature
(Q) components of the DAC IQ data register in the header file.
Replace manual bit shifting, masking, and rtw_read32_mask() with
standard rtw_read32() and the FIELD_GET() macro to improve code
readability.

Signed-off-by: Arsenii Pashchenko <ulijg308@gmail.com>
---
 drivers/net/wireless/realtek/rtw88/rtw8822c.c | 18 +++++++++---------
 drivers/net/wireless/realtek/rtw88/rtw8822c.h |  3 +++
 2 files changed, 12 insertions(+), 9 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.c b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
index 244c80264..137544649 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
@@ -291,9 +291,9 @@ static void rtw8822c_dac_cal_iq_sample(struct rtw_dev *rtwdev, u32 *iv, u32 *qv)
 
 	while (i < DACK_SN_8822C && cnt < 10000) {
 		cnt++;
-		temp = rtw_read32_mask(rtwdev, 0x2dbc, 0x3fffff);
-		iv[i] = (temp & 0x3ff000) >> 12;
-		qv[i] = temp & 0x3ff;
+		temp = rtw_read32(rtwdev, 0x2dbc);
+		iv[i] = FIELD_GET(RTW8822C_DAC_IV_MASK, temp);
+		qv[i] = FIELD_GET(RTW8822C_DAC_QV_MASK, temp);
 
 		if (rtw8822c_dac_iq_check(rtwdev, iv[i]) &&
 		    rtw8822c_dac_iq_check(rtwdev, qv[i]))
@@ -344,12 +344,12 @@ static void rtw8822c_dac_cal_iq_search(struct rtw_dev *rtwdev,
 		rtw8822c_dac_iq_sort(rtwdev, iv, qv);
 
 		if (i_delta > 5 || q_delta > 5) {
-			temp = rtw_read32_mask(rtwdev, 0x2dbc, 0x3fffff);
-			iv[0] = (temp & 0x3ff000) >> 12;
-			qv[0] = temp & 0x3ff;
-			temp = rtw_read32_mask(rtwdev, 0x2dbc, 0x3fffff);
-			iv[DACK_SN_8822C - 1] = (temp & 0x3ff000) >> 12;
-			qv[DACK_SN_8822C - 1] = temp & 0x3ff;
+			temp = rtw_read32(rtwdev, 0x2dbc);
+			iv[0] = FIELD_GET(RTW8822C_DAC_IV_MASK, temp);
+			qv[0] = FIELD_GET(RTW8822C_DAC_QV_MASK, temp);
+			temp = rtw_read32(rtwdev, 0x2dbc);
+			iv[DACK_SN_8822C - 1] = FIELD_GET(RTW8822C_DAC_IV_MASK, temp);
+			qv[DACK_SN_8822C - 1] = FIELD_GET(RTW8822C_DAC_QV_MASK, temp);
 		} else {
 			break;
 		}
diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.h b/drivers/net/wireless/realtek/rtw88/rtw8822c.h
index fc62b67a1..7bea99614 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.h
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.h
@@ -141,6 +141,9 @@ const struct rtw_table name ## _tbl = {			\
 #define DACK_RF_8822C		1
 #define DACK_SN_8822C		100
 
+#define RTW8822C_DAC_IV_MASK GENMASK(21, 12)
+#define RTW8822C_DAC_QV_MASK GENMASK(9, 0)
+
 /* phy status page0 */
 #define GET_PHY_STAT_P0_PWDB_A(phy_stat)                                       \
 	le32_get_bits(*((__le32 *)(phy_stat) + 0x00), GENMASK(15, 8))
-- 
2.55.0

[PATCH rtw-next v6 2/3] wifi: rtw88: rtw8822c: Convert DAC IQ calibration path to signed math

[Arsenii Pashchenko]

Convert the temporary stack arrays 'iv' and 'qv' from u32 to s32.
Update all internal function signatures to accept s32 pointers and
handle signed values natively.

Use sign_extend32() combined with FIELD_GET() to properly interpret
the 10-bit hardware values as signed integers. This allows flattening
the complex nested unsigned boundary conditions in
rtw8822c_dac_iq_check() into a simple amplitude boundary check. Ensure
rtw8822c_dac_iq_offset() properly maps the signed average back to a
10-bit unsigned format expected by the hardware registers.

Signed-off-by: Arsenii Pashchenko <ulijg308@gmail.com>
---
 drivers/net/wireless/realtek/rtw88/rtw8822c.c | 135 ++++++------------
 1 file changed, 40 insertions(+), 95 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.c b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
index 137544649..a10e87d6e 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
@@ -153,49 +153,14 @@ static void rtw8822c_dac_restore_reg(struct rtw_dev *rtwdev,
 	}
 }
 
-static void rtw8822c_rf_minmax_cmp(struct rtw_dev *rtwdev, u32 value,
-				   u32 *min, u32 *max)
+static void __rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, s32 *v1, s32 *v2)
 {
-	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 void __rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, u32 *v1, u32 *v2)
-{
-	if (*v1 >= 0x200 && *v2 >= 0x200) {
-		if (*v1 > *v2)
-			swap(*v1, *v2);
-	} else if (*v1 < 0x200 && *v2 < 0x200) {
-		if (*v1 > *v2)
-			swap(*v1, *v2);
-	} else if (*v1 < 0x200 && *v2 >= 0x200) {
+	if (*v1 > *v2)
 		swap(*v1, *v2);
-	}
+
 }
 
-static void rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, u32 *iv, u32 *qv)
+static void rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, s32 *iv, s32 *qv)
 {
 	u32 i, j;
 
@@ -207,30 +172,16 @@ static void rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, u32 *iv, u32 *qv)
 	}
 }
 
-static void rtw8822c_dac_iq_offset(struct rtw_dev *rtwdev, u32 *vec, u32 *val)
+static u32 rtw8822c_dac_iq_offset(struct rtw_dev *rtwdev, s32 *vec)
 {
-	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 ? (u32)avg : (u32)(0x400 + avg);
 }
 
 static u32 rtw8822c_get_path_write_addr(u8 path)
@@ -271,20 +222,18 @@ static u32 rtw8822c_get_path_read_addr(u8 path)
 	return base_addr;
 }
 
-static bool rtw8822c_dac_iq_check(struct rtw_dev *rtwdev, u32 value)
+static bool rtw8822c_dac_iq_check(struct rtw_dev *rtwdev, s32 value)
 {
-	bool ret = true;
 
-	if ((value >= 0x200 && (0x400 - value) > 0x64) ||
-	    (value < 0x200 && value > 0x64)) {
-		ret = false;
+	if (value > 100 || value < -100) {
 		rtw_dbg(rtwdev, RTW_DBG_RFK, "[DACK] Error overflow\n");
+		return false;
 	}
 
-	return ret;
+	return true;
 }
 
-static void rtw8822c_dac_cal_iq_sample(struct rtw_dev *rtwdev, u32 *iv, u32 *qv)
+static void rtw8822c_dac_cal_iq_sample(struct rtw_dev *rtwdev, s32 *iv, s32 *qv)
 {
 	u32 temp;
 	int i = 0, cnt = 0;
@@ -292,8 +241,8 @@ static void rtw8822c_dac_cal_iq_sample(struct rtw_dev *rtwdev, u32 *iv, u32 *qv)
 	while (i < DACK_SN_8822C && cnt < 10000) {
 		cnt++;
 		temp = rtw_read32(rtwdev, 0x2dbc);
-		iv[i] = FIELD_GET(RTW8822C_DAC_IV_MASK, temp);
-		qv[i] = FIELD_GET(RTW8822C_DAC_QV_MASK, temp);
+		iv[i] = FIELD_GET_SIGNED(RTW8822C_DAC_IV_MASK, temp);
+		qv[i] = FIELD_GET_SIGNED(RTW8822C_DAC_QV_MASK, temp);
 
 		if (rtw8822c_dac_iq_check(rtwdev, iv[i]) &&
 		    rtw8822c_dac_iq_check(rtwdev, qv[i]))
@@ -302,67 +251,63 @@ static void rtw8822c_dac_cal_iq_sample(struct rtw_dev *rtwdev, u32 *iv, u32 *qv)
 }
 
 static void rtw8822c_dac_cal_iq_search(struct rtw_dev *rtwdev,
-				       u32 *iv, u32 *qv,
+				       s32 *iv, s32 *qv,
 				       u32 *i_value, u32 *q_value)
 {
-	u32 i_max = 0, q_max = 0, i_min = 0, q_min = 0;
+	s32 i_max = 0, q_max = 0, i_min = 0, q_min = 0;
 	u32 i_delta, q_delta;
 	u32 temp;
-	int i, cnt = 0;
+	u32 i, cnt = 0;
 
 	do {
 		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], &i_min, &i_max);
-			rtw8822c_rf_minmax_cmp(rtwdev, qv[i], &q_min, &q_max);
+		for (i = 1; i < DACK_SN_8822C; i++) {
+			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);
+		i_delta = i_max - i_min;
+		q_delta = q_max - q_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);
 
 		rtw_dbg(rtwdev, RTW_DBG_RFK,
-			"[DACK] i: min=0x%08x, max=0x%08x, delta=0x%08x\n",
+			"[DACK] i: min=%d, max=%d, delta=%d\n",
 			i_min, i_max, i_delta);
 		rtw_dbg(rtwdev, RTW_DBG_RFK,
-			"[DACK] q: min=0x%08x, max=0x%08x, delta=0x%08x\n",
+			"[DACK] q: min=%d, max=%d, delta=%d",
 			q_min, q_max, q_delta);
 
 		rtw8822c_dac_iq_sort(rtwdev, iv, qv);
 
 		if (i_delta > 5 || q_delta > 5) {
 			temp = rtw_read32(rtwdev, 0x2dbc);
-			iv[0] = FIELD_GET(RTW8822C_DAC_IV_MASK, temp);
-			qv[0] = FIELD_GET(RTW8822C_DAC_QV_MASK, temp);
+			iv[0] = FIELD_GET_SIGNED(RTW8822C_DAC_IV_MASK, temp);
+			qv[0] = FIELD_GET_SIGNED(RTW8822C_DAC_QV_MASK, temp);
 			temp = rtw_read32(rtwdev, 0x2dbc);
-			iv[DACK_SN_8822C - 1] = FIELD_GET(RTW8822C_DAC_IV_MASK, temp);
-			qv[DACK_SN_8822C - 1] = FIELD_GET(RTW8822C_DAC_QV_MASK, temp);
+			iv[DACK_SN_8822C - 1] = FIELD_GET_SIGNED(RTW8822C_DAC_IV_MASK, temp);
+			qv[DACK_SN_8822C - 1] = FIELD_GET_SIGNED(RTW8822C_DAC_QV_MASK, temp);
 		} else {
 			break;
 		}
 	} 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,
 				     u32 *i_value, u32 *q_value)
 {
-	u32 iv[DACK_SN_8822C], qv[DACK_SN_8822C];
+	s32 iv[DACK_SN_8822C], qv[DACK_SN_8822C];
 	u32 rf_a, rf_b;
 
 	rf_a = rtw_read_rf(rtwdev, RF_PATH_A, 0x0, RFREG_MASK);
-- 
2.55.0

[PATCH rtw-next v6 3/3] wifi: rtw88: rtw8822c: Replace custom DAC IQ sorting with kernel sort

[Arsenii Pashchenko]

Replace the custom, nested bubble-sort logic in the calibration loop
with direct calls to the kernel's optimized heapsort implementation
inside rtw8822c_dac_cal_iq_search().

Implement a safe, overflow-proof s32 comparator using the subtraction
of relationals pattern. Since the input values are already properly
sign-extended into signed arrays, the custom circular index sorting
rules and helper functions completely disappear, reducing lines of code.

Signed-off-by: Arsenii Pashchenko <ulijg308@gmail.com>
---
 drivers/net/wireless/realtek/rtw88/rtw8822c.c | 22 ++++++-------------
 1 file changed, 7 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtw88/rtw8822c.c b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
index a10e87d6e..8a6a8bbf9 100644
--- a/drivers/net/wireless/realtek/rtw88/rtw8822c.c
+++ b/drivers/net/wireless/realtek/rtw88/rtw8822c.c
@@ -3,6 +3,7 @@
  */
 
 #include <linux/module.h>
+#include <linux/sort.h>
 #include "main.h"
 #include "coex.h"
 #include "fw.h"
@@ -153,24 +154,14 @@ static void rtw8822c_dac_restore_reg(struct rtw_dev *rtwdev,
 	}
 }
 
-static void __rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, s32 *v1, s32 *v2)
+static int rtw8822c_dac_iq_cmp_s32(const void *a, const void *b)
 {
-	if (*v1 > *v2)
-		swap(*v1, *v2);
+	s32 val_a = *(const s32 *)a;
+	s32 val_b = *(const s32 *)b;
 
+	return (val_a > val_b) - (val_a < val_b);
 }
 
-static void rtw8822c_dac_iq_sort(struct rtw_dev *rtwdev, s32 *iv, s32 *qv)
-{
-	u32 i, j;
-
-	for (i = 0; i < DACK_SN_8822C - 1; i++) {
-		for (j = 0; j < (DACK_SN_8822C - 1 - i) ; j++) {
-			__rtw8822c_dac_iq_sort(rtwdev, &iv[j], &iv[j + 1]);
-			__rtw8822c_dac_iq_sort(rtwdev, &qv[j], &qv[j + 1]);
-		}
-	}
-}
 
 static u32 rtw8822c_dac_iq_offset(struct rtw_dev *rtwdev, s32 *vec)
 {
@@ -286,7 +277,8 @@ static void rtw8822c_dac_cal_iq_search(struct rtw_dev *rtwdev,
 			"[DACK] q: min=%d, max=%d, delta=%d",
 			q_min, q_max, q_delta);
 
-		rtw8822c_dac_iq_sort(rtwdev, iv, qv);
+		sort(iv, DACK_SN_8822C, sizeof(s32), rtw8822c_dac_iq_cmp_s32, NULL);
+		sort(qv, DACK_SN_8822C, sizeof(s32), rtw8822c_dac_iq_cmp_s32, NULL);
 
 		if (i_delta > 5 || q_delta > 5) {
 			temp = rtw_read32(rtwdev, 0x2dbc);
-- 
2.55.0