wifi: rt2x00: add support for external PA on MT7620

Implement support for external PA connected to MT7620A.
Signed-off-by: Tomislav Požega <pozega.tomislav@gmail.com>
[pozega.tomislav@gmail.com: use chanreg and dccal helpers.]
Signed-off-by: Daniel Golle <daniel@makrotopia.org>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/af2c68ff831816a86fc39b0c10911c129a1f03dc.1663445157.git.daniel@makrotopia.org

drivers/net/wireless/ralink/rt2x00/rt2800.h

@@ -2739,6 +2739,7 @@ enum rt2800_eeprom_word {
 #define EEPROM_NIC_CONF2_RX_STREAM	FIELD16(0x000f)
 #define EEPROM_NIC_CONF2_TX_STREAM	FIELD16(0x00f0)
 #define EEPROM_NIC_CONF2_CRYSTAL	FIELD16(0x0600)
+#define EEPROM_NIC_CONF2_EXTERNAL_PA	FIELD16(0x8000)
 
 /*
  * EEPROM LNA

drivers/net/wireless/ralink/rt2x00/rt2800lib.c

@@ -4368,6 +4368,43 @@ static void rt2800_config_channel(struct rt2x00_dev *rt2x00dev,
 		rt2800_iq_calibrate(rt2x00dev, rf->channel);
 	}
 
+	if (rt2x00_rt(rt2x00dev, RT6352)) {
+		if (test_bit(CAPABILITY_EXTERNAL_PA_TX0,
+			     &rt2x00dev->cap_flags)) {
+			reg = rt2800_register_read(rt2x00dev, RF_CONTROL3);
+			reg |= 0x00000101;
+			rt2800_register_write(rt2x00dev, RF_CONTROL3, reg);
+
+			reg = rt2800_register_read(rt2x00dev, RF_BYPASS3);
+			reg |= 0x00000101;
+			rt2800_register_write(rt2x00dev, RF_BYPASS3, reg);
+
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 43, 0x73);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 44, 0x73);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 45, 0x73);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 46, 0x27);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 47, 0xC8);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 48, 0xA4);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 49, 0x05);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 54, 0x27);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 55, 0xC8);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 56, 0xA4);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 57, 0x05);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 58, 0x27);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 59, 0xC8);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 60, 0xA4);
+			rt2800_rfcsr_write_chanreg(rt2x00dev, 61, 0x05);
+			rt2800_rfcsr_write_dccal(rt2x00dev, 05, 0x00);
+
+			rt2800_register_write(rt2x00dev, TX0_RF_GAIN_CORRECT,
+					      0x36303636);
+			rt2800_register_write(rt2x00dev, TX0_RF_GAIN_ATTEN,
+					      0x6C6C6B6C);
+			rt2800_register_write(rt2x00dev, TX1_RF_GAIN_ATTEN,
+					      0x6C6C6B6C);
+		}
+	}
+
 	bbp = rt2800_bbp_read(rt2x00dev, 4);
 	rt2x00_set_field8(&bbp, BBP4_BANDWIDTH, 2 * conf_is_ht40(conf));
 	rt2800_bbp_write(rt2x00dev, 4, bbp);
@@ -9566,7 +9603,8 @@ static int rt2800_init_eeprom(struct rt2x00_dev *rt2x00dev)
 	 */
 	eeprom = rt2800_eeprom_read(rt2x00dev, EEPROM_NIC_CONF1);
 
-	if (rt2x00_rt(rt2x00dev, RT3352)) {
+	if (rt2x00_rt(rt2x00dev, RT3352) ||
+	    rt2x00_rt(rt2x00dev, RT6352)) {
 		if (rt2x00_get_field16(eeprom,
 		    EEPROM_NIC_CONF1_EXTERNAL_TX0_PA_3352))
 		    __set_bit(CAPABILITY_EXTERNAL_PA_TX0,
@@ -9577,6 +9615,18 @@ static int rt2800_init_eeprom(struct rt2x00_dev *rt2x00dev)
 			      &rt2x00dev->cap_flags);
 	}
 
+	eeprom = rt2800_eeprom_read(rt2x00dev, EEPROM_NIC_CONF2);
+
+	if (rt2x00_rt(rt2x00dev, RT6352) && eeprom != 0 && eeprom != 0xffff) {
+		if (!rt2x00_get_field16(eeprom,
+					EEPROM_NIC_CONF2_EXTERNAL_PA)) {
+			__clear_bit(CAPABILITY_EXTERNAL_PA_TX0,
+				    &rt2x00dev->cap_flags);
+			__clear_bit(CAPABILITY_EXTERNAL_PA_TX1,
+				    &rt2x00dev->cap_flags);
+		}
+	}
+
 	return 0;
 }