rt2x00: Implement tx power temperature compensation

rt2800 devices should adjust their tx power in accordance with the
eeproms temperature calibration values. Add a new driver callback
gain_calibration that is called every 4 seconds.

The rt2800 gain calibration routine simply runs the tx power
configuration that takes care of calculating the temperature
compensation delta.

We don't need to synchronize the calls to rt2800_config_txpower
as they should all happen from mac80211's single threaded workqueue.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: Ivo van Doorn <IvDoorn@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
diff --git a/drivers/net/wireless/rt2x00/rt2x00lib.h b/drivers/net/wireless/rt2x00/rt2x00lib.h
index 63c40d4..88f2f92 100644
--- a/drivers/net/wireless/rt2x00/rt2x00lib.h
+++ b/drivers/net/wireless/rt2x00/rt2x00lib.h
@@ -32,6 +32,7 @@
  */
 #define WATCHDOG_INTERVAL	round_jiffies_relative(HZ)
 #define LINK_TUNE_INTERVAL	round_jiffies_relative(HZ)
+#define AGC_INTERVAL		round_jiffies_relative(4 * HZ)
 
 /*
  * rt2x00_rate: Per rate device information
@@ -271,6 +272,18 @@
 void rt2x00link_stop_watchdog(struct rt2x00_dev *rt2x00dev);
 
 /**
+ * rt2x00link_start_agc - Start periodic gain calibration
+ * @rt2x00dev: Pointer to &struct rt2x00_dev.
+ */
+void rt2x00link_start_agc(struct rt2x00_dev *rt2x00dev);
+
+/**
+ * rt2x00link_stop_agc - Stop periodic gain calibration
+ * @rt2x00dev: Pointer to &struct rt2x00_dev.
+ */
+void rt2x00link_stop_agc(struct rt2x00_dev *rt2x00dev);
+
+/**
  * rt2x00link_register - Initialize link tuning & watchdog functionality
  * @rt2x00dev: Pointer to &struct rt2x00_dev.
  *