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Date: Mon, 15 Apr 2024 23:59:05 +0300
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From: Bitterblue Smith <rtl8821cerfe2@gmail.com>
Subject: [PATCH v2] wifi: rtl8xxxu: Fix the TX power of RTL8192CU, RTL8723AU
To: "linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Cc: Jes Sorensen <Jes.Sorensen@gmail.com>, Ping-Ke Shih <pkshih@realtek.com>
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Don't subtract 1 from the power index. This was added in commit
2fc0b8e5a17d ("rtl8xxxu: Add TX power base values for gen1 parts")
for unknown reasons. The vendor drivers don't do this.

Also correct the calculations of values written to
REG_OFDM0_X{C,D}_TX_IQ_IMBALANCE. According to the vendor driver,
these are used for TX power training.

With these changes rtl8xxxu sets the TX power of RTL8192CU the same
as the vendor driver.

None of this appears to have any effect on my RTL8192CU device.

Cc: stable@vger.kernel.org
Signed-off-by: Bitterblue Smith <rtl8821cerfe2@gmail.com>
---
v1 was a long time ago:
https://lore.kernel.org/linux-wireless/52c28b65-6f28-2cc0-7281-179bb1087c2a@gmail.com/

v2:
 - Use ternary operator and max_t in the for loops.
---
 .../wireless/realtek/rtl8xxxu/rtl8xxxu_core.c | 25 ++++++++-----------
 1 file changed, 10 insertions(+), 15 deletions(-)

diff --git a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
index 7bf0bbbd52c1..af58e5b2c846 100644
--- a/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
+++ b/drivers/net/wireless/realtek/rtl8xxxu/rtl8xxxu_core.c
@@ -1480,13 +1480,13 @@ rtl8xxxu_gen1_set_tx_power(struct rtl8xxxu_priv *priv, int channel, bool ht40)
 	u8 cck[RTL8723A_MAX_RF_PATHS], ofdm[RTL8723A_MAX_RF_PATHS];
 	u8 ofdmbase[RTL8723A_MAX_RF_PATHS], mcsbase[RTL8723A_MAX_RF_PATHS];
 	u32 val32, ofdm_a, ofdm_b, mcs_a, mcs_b;
-	u8 val8;
+	u8 val8, base;
 	int group, i;
 
 	group = rtl8xxxu_gen1_channel_to_group(channel);
 
-	cck[0] = priv->cck_tx_power_index_A[group] - 1;
-	cck[1] = priv->cck_tx_power_index_B[group] - 1;
+	cck[0] = priv->cck_tx_power_index_A[group];
+	cck[1] = priv->cck_tx_power_index_B[group];
 
 	if (priv->hi_pa) {
 		if (cck[0] > 0x20)
@@ -1497,10 +1497,6 @@ rtl8xxxu_gen1_set_tx_power(struct rtl8xxxu_priv *priv, int channel, bool ht40)
 
 	ofdm[0] = priv->ht40_1s_tx_power_index_A[group];
 	ofdm[1] = priv->ht40_1s_tx_power_index_B[group];
-	if (ofdm[0])
-		ofdm[0] -= 1;
-	if (ofdm[1])
-		ofdm[1] -= 1;
 
 	ofdmbase[0] = ofdm[0] +	priv->ofdm_tx_power_index_diff[group].a;
 	ofdmbase[1] = ofdm[1] +	priv->ofdm_tx_power_index_diff[group].b;
@@ -1589,20 +1585,19 @@ rtl8xxxu_gen1_set_tx_power(struct rtl8xxxu_priv *priv, int channel, bool ht40)
 
 	rtl8xxxu_write32(priv, REG_TX_AGC_A_MCS15_MCS12,
 			 mcs_a + power_base->reg_0e1c);
+	val8 = u32_get_bits(mcs_a + power_base->reg_0e1c, 0xff000000);
 	for (i = 0; i < 3; i++) {
-		if (i != 2)
-			val8 = (mcsbase[0] > 8) ? (mcsbase[0] - 8) : 0;
-		else
-			val8 = (mcsbase[0] > 6) ? (mcsbase[0] - 6) : 0;
+		base = i != 2 ? 8 : 6;
+		val8 = max_t(int, val8 - base, 0);
 		rtl8xxxu_write8(priv, REG_OFDM0_XC_TX_IQ_IMBALANCE + i, val8);
 	}
+
 	rtl8xxxu_write32(priv, REG_TX_AGC_B_MCS15_MCS12,
 			 mcs_b + power_base->reg_0868);
+	val8 = u32_get_bits(mcs_b + power_base->reg_0868, 0xff000000);
 	for (i = 0; i < 3; i++) {
-		if (i != 2)
-			val8 = (mcsbase[1] > 8) ? (mcsbase[1] - 8) : 0;
-		else
-			val8 = (mcsbase[1] > 6) ? (mcsbase[1] - 6) : 0;
+		base = i != 2 ? 8 : 6;
+		val8 = max_t(int, val8 - base, 0);
 		rtl8xxxu_write8(priv, REG_OFDM0_XD_TX_IQ_IMBALANCE + i, val8);
 	}
 }
-- 
2.44.0