ath9k: allow disabling bands via platform data

Some devices have multiple bands enables in the EEPROM data, even though
they are only calibrated for one. Allow platform data to disable
unsupported bands.

Signed-off-by: Gabor Juhos <[e-mail]>
Signed-off-by: Felix Fietkau <[e-mail]>
Signed-off-by: John W. Linville <[e-mail]>

drivers/net/wireless/ath/ath9k/hw.c

···
 	}
 
 	eeval = ah->eep_ops->get_eeprom(ah, EEP_OP_MODE);
-	if ((eeval & (AR5416_OPFLAGS_11G | AR5416_OPFLAGS_11A)) == 0) {
-		ath_err(common,
-			"no band has been marked as supported in EEPROM\n");
-		return -EINVAL;
+
+	if (eeval & AR5416_OPFLAGS_11A) {
+		if (ah->disable_5ghz)
+			ath_warn(common, "disabling 5GHz band\n");
+		else
+			pCap->hw_caps |= ATH9K_HW_CAP_5GHZ;
 	}
 
-	if (eeval & AR5416_OPFLAGS_11A)
-		pCap->hw_caps |= ATH9K_HW_CAP_5GHZ;
+	if (eeval & AR5416_OPFLAGS_11G) {
+		if (ah->disable_2ghz)
+			ath_warn(common, "disabling 2GHz band\n");
+		else
+			pCap->hw_caps |= ATH9K_HW_CAP_2GHZ;
+	}
 
-	if (eeval & AR5416_OPFLAGS_11G)
-		pCap->hw_caps |= ATH9K_HW_CAP_2GHZ;
+	if ((pCap->hw_caps & (ATH9K_HW_CAP_2GHZ | ATH9K_HW_CAP_5GHZ)) == 0) {
+		ath_err(common, "both bands are disabled\n");
+		return -EINVAL;
+	}
 
 	if (AR_SREV_9485(ah) ||
 	    AR_SREV_9285(ah) ||

drivers/net/wireless/ath/ath9k/hw.h

···
 	bool is_clk_25mhz;
 	int (*get_mac_revision)(void);
 	int (*external_reset)(void);
+	bool disable_2ghz;
+	bool disable_5ghz;
 
 	const struct firmware *eeprom_blob;
 

drivers/net/wireless/ath/ath9k/init.c

···
 		ah->is_clk_25mhz = pdata->is_clk_25mhz;
 		ah->get_mac_revision = pdata->get_mac_revision;
 		ah->external_reset = pdata->external_reset;
+		ah->disable_2ghz = pdata->disable_2ghz;
+		ah->disable_5ghz = pdata->disable_5ghz;
 		if (!pdata->endian_check)
 			ah->ah_flags |= AH_NO_EEP_SWAP;
 	}

include/linux/ath9k_platform.h

···
 	bool endian_check;
 	bool is_clk_25mhz;
 	bool tx_gain_buffalo;
+	bool disable_2ghz;
+	bool disable_5ghz;
 
 	int (*get_mac_revision)(void);
 	int (*external_reset)(void);