p54: better rssi->dbm conversion for longbow phys

This patch should fix the dodgy signal and noise value
reports for most longbow (p54spi) users:

e.g.: (an older tcpdump extract)
> 2.0 Mb/s 2437 MHz (0x00a0) -49dB signal -41dB noise
> 1.0 Mb/s 2437 MHz (0x00a0) 4dB signal -41dB noise

The formula is taken from stlc45xx:
http://gitorious.org/stlc45xx/mainline/blobs/master/stlc45xx.c#line1199

Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 4 insertions, 4 deletions

diff --git a/drivers/net/wireless/p54/txrx.c b/drivers/net/wireless/p54/txrx.c
index 34447d1ad80d..8f67db487f57 100644
--- a/drivers/net/wireless/p54/txrx.c
+++ b/drivers/net/wireless/p54/txrx.c
@@ -275,15 +275,15 @@ static int p54_rssi_to_dbm(struct p54_common *priv, int rssi)
 {
         int band = priv->hw->conf.channel->band;
 
-        if (priv->rxhw != 5)
+        if (priv->rxhw != 5) {
                 return ((rssi * priv->rssical_db[band].mul) / 64 +
                          priv->rssical_db[band].add) / 4;
-        else
+        } else {
                 /*
                  * TODO: find the correct formula
                  */
-                return ((rssi * priv->rssical_db[band].mul) / 64 +
-                         priv->rssical_db[band].add) / 4;
+                return rssi / 2 - 110;
+        }
 }
 
 /*