iwl3945: streamline iwl3945_rfkill_poll()

iwl3945_rfkill_poll() has been silently calling wiphy_rfkill_set_hw_state()
every 2 seconds, regardless of whether hardware RF KILL switch changed state.

Call wiphy_rfkill_set_hw_state() only when RFKILL switch changes.
Add IWL_DEBUG_RF_KILL log message and documentation.

Signed-off-by: Ben Cahill <ben.m.cahill@intel.com>
Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 21 insertions, 6 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl3945-base.c b/drivers/net/wireless/iwlwifi/iwl3945-base.c
index ab4c4bae7600..2406b73e9093 100644
--- a/drivers/net/wireless/iwlwifi/iwl3945-base.c
+++ b/drivers/net/wireless/iwlwifi/iwl3945-base.c
@@ -2717,19 +2717,34 @@ static void iwl3945_bg_alive_start(struct work_struct *data)
         mutex_unlock(&priv->mutex);
 }
 
+/*
+ * 3945 cannot interrupt driver when hardware rf kill switch toggles;
+ * driver must poll CSR_GP_CNTRL_REG register for change.  This register
+ * *is* readable even when device has been SW_RESET into low power mode
+ * (e.g. during RF KILL).
+ */
 static void iwl3945_rfkill_poll(struct work_struct *data)
 {
         struct iwl_priv *priv =
             container_of(data, struct iwl_priv, rfkill_poll.work);
+        bool old_rfkill = test_bit(STATUS_RF_KILL_HW, &priv->status);
+        bool new_rfkill = !(iwl_read32(priv, CSR_GP_CNTRL)
+                        & CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW);
 
-        if (iwl_read32(priv, CSR_GP_CNTRL) & CSR_GP_CNTRL_REG_FLAG_HW_RF_KILL_SW)
-                clear_bit(STATUS_RF_KILL_HW, &priv->status);
-        else
-                set_bit(STATUS_RF_KILL_HW, &priv->status);
+        if (new_rfkill != old_rfkill) {
+                if (new_rfkill)
+                        set_bit(STATUS_RF_KILL_HW, &priv->status);
+                else
+                        clear_bit(STATUS_RF_KILL_HW, &priv->status);
 
-        wiphy_rfkill_set_hw_state(priv->hw->wiphy,
-                        test_bit(STATUS_RF_KILL_HW, &priv->status));
+                wiphy_rfkill_set_hw_state(priv->hw->wiphy, new_rfkill);
+
+                IWL_DEBUG_RF_KILL(priv, "RF_KILL bit toggled to %s.\n",
+                                new_rfkill ? "disable radio" : "enable radio");
+        }
 
+        /* Keep this running, even if radio now enabled.  This will be
+         * cancelled in mac_start() if system decides to start again */
         queue_delayed_work(priv->workqueue, &priv->rfkill_poll,
                            round_jiffies_relative(2 * HZ));