[bug report] wifi: rtw89: coex: Add Bluetooth binding for Bluetooth RX gain setting

Hello Ching-Te Ku,

Commit fe8f6ddb9095 ("wifi: rtw89: coex: Add Bluetooth binding for
Bluetooth RX gain setting") from Jul 6, 2026 (linux-next), leads to
the following Smatch static checker warning:

	drivers/net/wireless/realtek/rtw89/coex.c:3943 _set_bt_rx_gain()
	warn: duplicate check 'rf_band' (previous on line 3927)

drivers/net/wireless/realtek/rtw89/coex.c
    3914 static void _set_bt_rx_gain(struct rtw89_dev *rtwdev, bool force_exec, u8 bid,
    3915                             u8 rf_band, u8 level)
    3916 {
    3917         struct rtw89_btc *btc = &rtwdev->btc;
    3918         struct rtw89_btc_cx *cx = &btc->cx;
    3919         struct rtw89_btc_bt_info *bt = &cx->bt0;
    3920         u8 h2c_func = SET_BT_LNA_CONSTRAIN;
    3921         u8 i, id_start, id_stop;
    3922         bool state = false;
    3923         u32 scbd_bit = 0;
    3924         u8 buf[2] = {};
    3925         u8 len = sizeof(*buf);
    3926 
    3927         if (bt->bcnt[BTC_BCNT_INFOUPDATE] == 0 || !rf_band)
                                                            ^^^^^^^
The patch adds a check here

    3928                 return;
    3929 
    3930         if (bt->rf_para.rx_gain_freerun == level ||
    3931             level > BTC_BT_RX_NORMAL_LVL || !rtwdev->chip->scbd ||
    3932             bid > BTC_ALL_BT)
    3933                 return;
    3934 
    3935         if (bid == BTC_ALL_BT) {
    3936                 id_start = BTC_BT_1ST;
    3937                 id_stop = BTC_BT_2ND;
    3938         } else {
    3939                 id_start = bid;
    3940                 id_stop = bid;
    3941         }
    3942 
--> 3943         if (rf_band == RTW89_BAND_2G)
                     ^^^^^^^^^^^^^^^^^^^^^^^^
RTW89_BAND_2G is zero so this is dead code.

    3944                 scbd_bit |= BTC_WSCB_RXGAIN;
    3945         else
    3946                 scbd_bit |= BTC_WSCB_RXGAIN_56G;
    3947 

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regards,
dan carpenter