rt2800: comment tx power settings

Signed-off-by: Stanislaw Gruszka <sgruszka@redhat.com>
Acked-by: Gertjan van Wingerde <gwingerde@gmail.com>
Acked-by: Ivo van Doorn <IvDoorn@gmail.com>
Acked-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
This commit is contained in:
Stanislaw Gruszka 2012-10-05 13:44:15 +02:00 committed by John W. Linville
parent 1e4cf249a4
commit 7a66205a21

View file

@ -2586,6 +2586,15 @@ static u8 rt2800_compensate_txpower(struct rt2x00_dev *rt2x00dev, int is_rate_b,
return min_t(u8, txpower, 0xc);
}
/*
* We configure transmit power using MAC TX_PWR_CFG_{0,...,N} registers and
* BBP R1 register. TX_PWR_CFG_X allow to configure per rate TX power values,
* 4 bits for each rate (tune from 0 to 15 dBm). BBP_R1 controls transmit power
* for all rates, but allow to set only 4 discrete values: -12, -6, 0 and 6 dBm.
* Reference per rate transmit power values are located in the EEPROM at
* EEPROM_TXPOWER_BYRATE offset. We adjust them and BBP R1 settings according to
* current conditions (i.e. band, bandwidth, temperature, user settings).
*/
static void rt2800_config_txpower(struct rt2x00_dev *rt2x00dev,
struct ieee80211_channel *chan,
int power_level)
@ -2597,17 +2606,24 @@ static void rt2800_config_txpower(struct rt2x00_dev *rt2x00dev,
enum ieee80211_band band = chan->band;
/*
* Calculate HT40 compensation delta
* Calculate HT40 compensation. For 40MHz we need to add or subtract
* value read from EEPROM (different for 2GHz and for 5GHz).
*/
delta = rt2800_get_txpower_bw_comp(rt2x00dev, band);
/*
* calculate temperature compensation delta
* Calculate temperature compensation. Depends on measurement of current
* TSSI (Transmitter Signal Strength Indication) we know TX power (due
* to temperature or maybe other factors) is smaller or bigger than
* expected. We adjust it, based on TSSI reference and boundaries values
* provided in EEPROM.
*/
delta += rt2800_get_gain_calibration_delta(rt2x00dev);
/*
* Apply regulatory delta.
* Decrease power according to user settings, on devices with unknown
* maximum tx power. For other devices we take user power_level into
* consideration on rt2800_compensate_txpower().
*/
delta += rt2800_get_txpower_reg_delta(rt2x00dev, power_level,
chan->max_power);