carl9170: allow users to lower output power level

This patch implements a simple way of reducing the
output power of the device by a configurable upper
limit.

Requested-by: Harshal Chhaya <harshal@gmail.com>
Signed-off-by: Christian Lamparter <chunkeey@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

5 files changed, 50 insertions, 35 deletions

diff --git a/drivers/net/wireless/ath/carl9170/carl9170.h b/drivers/net/wireless/ath/carl9170/carl9170.h
index f0f44c30b2f7..0cea20e3e250 100644
--- a/drivers/net/wireless/ath/carl9170/carl9170.h
+++ b/drivers/net/wireless/ath/carl9170/carl9170.h
@@ -559,6 +559,7 @@ int carl9170_set_hwretry_limit(struct ar9170 *ar, const u32 max_retry);
 int carl9170_upload_key(struct ar9170 *ar, const u8 id, const u8 *mac,
         const u8 ktype, const u8 keyidx, const u8 *keydata, const int keylen);
 int carl9170_disable_key(struct ar9170 *ar, const u8 id);
+int carl9170_set_mac_tpc(struct ar9170 *ar, struct ieee80211_channel *channel);
 
 /* RX */
 void carl9170_rx(struct ar9170 *ar, void *buf, unsigned int len);
diff --git a/drivers/net/wireless/ath/carl9170/mac.c b/drivers/net/wireless/ath/carl9170/mac.c
index dfda91970995..53415bfd8bef 100644
--- a/drivers/net/wireless/ath/carl9170/mac.c
+++ b/drivers/net/wireless/ath/carl9170/mac.c
@@ -485,3 +485,38 @@ int carl9170_disable_key(struct ar9170 *ar, const u8 id)
         return carl9170_exec_cmd(ar, CARL9170_CMD_DKEY,
                 sizeof(key), (u8 *)&key, 0, NULL);
 }
+
+int carl9170_set_mac_tpc(struct ar9170 *ar, struct ieee80211_channel *channel)
+{
+        unsigned int power, chains;
+
+        if (ar->eeprom.tx_mask != 1)
+                chains = AR9170_TX_PHY_TXCHAIN_2;
+        else
+                chains = AR9170_TX_PHY_TXCHAIN_1;
+
+        switch (channel->band) {
+        case IEEE80211_BAND_2GHZ:
+                power = ar->power_2G_ofdm[0] & 0x3f;
+                break;
+        case IEEE80211_BAND_5GHZ:
+                power = ar->power_5G_leg[0] & 0x3f;
+                break;
+        default:
+                BUG_ON(1);
+        }
+
+        power = min_t(unsigned int, power, ar->hw->conf.power_level * 2);
+
+        carl9170_regwrite_begin(ar);
+        carl9170_regwrite(AR9170_MAC_REG_ACK_TPC,
+                          0x3c1e | power << 20 | chains << 26);
+        carl9170_regwrite(AR9170_MAC_REG_RTS_CTS_TPC,
+                          power << 5 | chains << 11 |
+                          power << 21 | chains << 27);
+        carl9170_regwrite(AR9170_MAC_REG_CFEND_QOSNULL_TPC,
+                          power << 5 | chains << 11 |
+                          power << 21 | chains << 27);
+        carl9170_regwrite_finish();
+        return carl9170_regwrite_result();
+}
diff --git a/drivers/net/wireless/ath/carl9170/main.c b/drivers/net/wireless/ath/carl9170/main.c
index 6ee7c55f75a8..8d2523b3f722 100644
--- a/drivers/net/wireless/ath/carl9170/main.c
+++ b/drivers/net/wireless/ath/carl9170/main.c
@@ -853,11 +853,6 @@ static int carl9170_op_config(struct ieee80211_hw *hw, u32 changed)
                         goto out;
         }
 
-        if (changed & IEEE80211_CONF_CHANGE_POWER) {
-                /* TODO */
-                err = 0;
-        }
-
         if (changed & IEEE80211_CONF_CHANGE_SMPS) {
                 /* TODO */
                 err = 0;
@@ -891,6 +886,12 @@ static int carl9170_op_config(struct ieee80211_hw *hw, u32 changed)
                         goto out;
         }
 
+        if (changed & IEEE80211_CONF_CHANGE_POWER) {
+                err = carl9170_set_mac_tpc(ar, ar->hw->conf.channel);
+                if (err)
+                        goto out;
+        }
+
 out:
         mutex_unlock(&ar->mutex);
         return err;
diff --git a/drivers/net/wireless/ath/carl9170/phy.c b/drivers/net/wireless/ath/carl9170/phy.c
index 472efc7e3402..b72c09cf43a4 100644
--- a/drivers/net/wireless/ath/carl9170/phy.c
+++ b/drivers/net/wireless/ath/carl9170/phy.c
@@ -1426,15 +1426,15 @@ static void carl9170_calc_ctl(struct ar9170 *ar, u32 freq, enum carl9170_bw bw)
 #undef EDGES
 }
 
-static int carl9170_set_power_cal(struct ar9170 *ar, u32 freq,
-                                  enum carl9170_bw bw)
+static void carl9170_set_power_cal(struct ar9170 *ar, u32 freq,
+                                   enum carl9170_bw bw)
 {
         struct ar9170_calibration_target_power_legacy *ctpl;
         struct ar9170_calibration_target_power_ht *ctph;
         u8 *ctpres;
         int ntargets;
         int idx, i, n;
-        u8 ackpower, ackchains, f;
+        u8 f;
         u8 pwr_freqs[AR5416_MAX_NUM_TGT_PWRS];
 
         if (freq < 3000)
@@ -1523,32 +1523,6 @@ static int carl9170_set_power_cal(struct ar9170 *ar, u32 freq,
 
         /* calc. conformance test limits and apply to ar->power*[] */
         carl9170_calc_ctl(ar, freq, bw);
-
-        /* set ACK/CTS TX power */
-        carl9170_regwrite_begin(ar);
-
-        if (ar->eeprom.tx_mask != 1)
-                ackchains = AR9170_TX_PHY_TXCHAIN_2;
-        else
-                ackchains = AR9170_TX_PHY_TXCHAIN_1;
-
-        if (freq < 3000)
-                ackpower = ar->power_2G_ofdm[0] & 0x3f;
-        else
-                ackpower = ar->power_5G_leg[0] & 0x3f;
-
-        carl9170_regwrite(AR9170_MAC_REG_ACK_TPC,
-                          0x3c1e | ackpower << 20 | ackchains << 26);
-        carl9170_regwrite(AR9170_MAC_REG_RTS_CTS_TPC,
-                          ackpower << 5 | ackchains << 11 |
-                          ackpower << 21 | ackchains << 27);
-
-        carl9170_regwrite(AR9170_MAC_REG_CFEND_QOSNULL_TPC,
-                          ackpower << 5 | ackchains << 11 |
-                          ackpower << 21 | ackchains << 27);
-
-        carl9170_regwrite_finish();
-        return carl9170_regwrite_result();
 }
 
 int carl9170_get_noisefloor(struct ar9170 *ar)
@@ -1712,7 +1686,9 @@ int carl9170_set_channel(struct ar9170 *ar, struct ieee80211_channel *channel,
         if (err)
                 return err;
 
-        err = carl9170_set_power_cal(ar, channel->center_freq, bw);
+        carl9170_set_power_cal(ar, channel->center_freq, bw);
+
+        err = carl9170_set_mac_tpc(ar, channel);
         if (err)
                 return err;
 
diff --git a/drivers/net/wireless/ath/carl9170/tx.c b/drivers/net/wireless/ath/carl9170/tx.c
index d19a9ee9d057..771e1a9294c5 100644
--- a/drivers/net/wireless/ath/carl9170/tx.c
+++ b/drivers/net/wireless/ath/carl9170/tx.c
@@ -719,6 +719,8 @@ static void carl9170_tx_rate_tpc_chains(struct ar9170 *ar,
                 else
                         *chains = AR9170_TX_PHY_TXCHAIN_2;
         }
+
+        *tpc = min_t(unsigned int, *tpc, ar->hw->conf.power_level * 2);
 }
 
 static __le32 carl9170_tx_physet(struct ar9170 *ar,