wifi: rtw89: support U-NII-4 channels on 5GHz band

U-NII-4 band, i.e 5.9GHz channels, can be supported by chip 8852C, 8852B
and 8851B. But, it is not supported by chip 8852A. Flag support_unii4 is
added in chip info and defined by chip accordingly to indicate that.
We reference this flag of runtime chip to decide whether to register
5.9GHz channels.

After that, we consider if U-NII-4 band is allowed by our regulatory
rule of U-NII-4. If chip::support_unii4 but not regd::allow_unii4,
we stll do not register 5.9GHz channels.

Signed-off-by: Zong-Zhe Yang <kevin_yang@realtek.com>
Signed-off-by: Ping-Ke Shih <pkshih@realtek.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230508081211.38760-4-pkshih@realtek.com

drivers/net/wireless/realtek/rtw89/core.c

@@ -77,6 +77,9 @@ static struct ieee80211_channel rtw89_channels_5ghz[] = {
 	RTW89_DEF_CHAN_5G(5785, 157),
 	RTW89_DEF_CHAN_5G(5805, 161),
 	RTW89_DEF_CHAN_5G_NO_HT40MINUS(5825, 165),
+	RTW89_DEF_CHAN_5G(5845, 169),
+	RTW89_DEF_CHAN_5G(5865, 173),
+	RTW89_DEF_CHAN_5G(5885, 177),
 };
 
 static struct ieee80211_channel rtw89_channels_6ghz[] = {

drivers/net/wireless/realtek/rtw89/regd.c

@@ -288,6 +288,7 @@ static void rtw89_regd_setup_unii4(struct rtw89_dev *rtwdev,
 {
 	const struct rtw89_chip_info *chip = rtwdev->chip;
 	bool regd_allow_unii_4 = chip->support_unii4;
+	struct ieee80211_supported_band *sband;
 	int ret;
 	u8 val;
 
@@ -318,6 +319,15 @@ static void rtw89_regd_setup_unii4(struct rtw89_dev *rtwdev,
 bottom:
 	rtw89_debug(rtwdev, RTW89_DBG_REGD, "regd: allow unii 4: %d\n",
 		    regd_allow_unii_4);
+
+	if (regd_allow_unii_4)
+		return;
+
+	sband = wiphy->bands[NL80211_BAND_5GHZ];
+	if (!sband)
+		return;
+
+	sband->n_channels -= 3;
 }
 
 int rtw89_regd_setup(struct rtw89_dev *rtwdev)