rt2x00: rt2800lib: introduce rt2800_eeprom_read_from_array helper

Add a new helper function and use that for reading
single elements of various arrays in the EEPROM.

The patch does not change the current behaviour,
but it allows to use sequential values for the
rt2800_eeprom_word enums. The conversion will be
implemented in a subsequent change.

Signed-off-by: Gabor Juhos <juhosg@openwrt.org>
Acked-by: Stanislaw Gruszka <stf_xl@wp.pl>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

drivers/net/wireless/rt2x00/rt2800lib.c

@@ -239,6 +239,14 @@ static void rt2800_eeprom_write(struct rt2x00_dev *rt2x00dev,
 	rt2x00_eeprom_write(rt2x00dev, word, data);
 }
 
+static void rt2800_eeprom_read_from_array(struct rt2x00_dev *rt2x00dev,
+					  const enum rt2800_eeprom_word array,
+					  unsigned int offset,
+					  u16 *data)
+{
+	rt2x00_eeprom_read(rt2x00dev, array + offset, data);
+}
+
 static int rt2800_enable_wlan_rt3290(struct rt2x00_dev *rt2x00dev)
 {
 	u32 reg;
@@ -2995,8 +3003,8 @@ static u8 rt2800_compensate_txpower(struct rt2x00_dev *rt2x00dev, int is_rate_b,
 		 * .11b data rate need add additional 4dbm
 		 * when calculating eirp txpower.
 		 */
-		rt2800_eeprom_read(rt2x00dev, EEPROM_TXPOWER_BYRATE + 1,
-				   &eeprom);
+		rt2800_eeprom_read_from_array(rt2x00dev, EEPROM_TXPOWER_BYRATE,
+					      1, &eeprom);
 		criterion = rt2x00_get_field16(eeprom,
 					       EEPROM_TXPOWER_BYRATE_RATE0);
 
@@ -3101,8 +3109,8 @@ static void rt2800_config_txpower(struct rt2x00_dev *rt2x00dev,
 		rt2800_register_read(rt2x00dev, offset, &reg);
 
 		/* read the next four txpower values */
-		rt2800_eeprom_read(rt2x00dev, EEPROM_TXPOWER_BYRATE + i,
-				   &eeprom);
+		rt2800_eeprom_read_from_array(rt2x00dev, EEPROM_TXPOWER_BYRATE,
+					      i, &eeprom);
 
 		is_rate_b = i ? 0 : 1;
 		/*
@@ -3150,8 +3158,8 @@ static void rt2800_config_txpower(struct rt2x00_dev *rt2x00dev,
 		rt2x00_set_field32(&reg, TX_PWR_CFG_RATE3, txpower);
 
 		/* read the next four txpower values */
-		rt2800_eeprom_read(rt2x00dev, EEPROM_TXPOWER_BYRATE + i + 1,
-				   &eeprom);
+		rt2800_eeprom_read_from_array(rt2x00dev, EEPROM_TXPOWER_BYRATE,
+					      i + 1, &eeprom);
 
 		is_rate_b = 0;
 		/*
@@ -4579,7 +4587,8 @@ static void rt2800_init_bbp(struct rt2x00_dev *rt2x00dev)
 	}
 
 	for (i = 0; i < EEPROM_BBP_SIZE; i++) {
-		rt2800_eeprom_read(rt2x00dev, EEPROM_BBP_START + i, &eeprom);
+		rt2800_eeprom_read_from_array(rt2x00dev, EEPROM_BBP_START, i,
+					      &eeprom);
 
 		if (eeprom != 0xffff && eeprom != 0x0000) {
 			reg_id = rt2x00_get_field16(eeprom, EEPROM_BBP_REG_ID);