iwlwifi: Add chain noise scaling factor

6x50 device requires a different scaling factor for Rx gain values sent to
device via PHY_CALIBRATION_CMD (CHAIN_NOISE_GAIN_CMD).  Rather than create
a new iwlXXXX_gain_computation() function, add new chain_noise_scale member
to struct iwl_cfg, and keep using iwl5000_gain_computation().

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, 19 insertions, 2 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-5000.c b/drivers/net/wireless/iwlwifi/iwl-5000.c
index 6d598890134..f3d662c8cbc 100644
--- a/drivers/net/wireless/iwlwifi/iwl-5000.c
+++ b/drivers/net/wireless/iwlwifi/iwl-5000.c
@@ -179,14 +179,24 @@ static void iwl5000_gain_computation(struct iwl_priv *priv,
                         data->delta_gain_code[i] = 0;
                         continue;
                 }
-                delta_g = (1000 * ((s32)average_noise[default_chain] -
+
+                delta_g = (priv->cfg->chain_noise_scale *
+                        ((s32)average_noise[default_chain] -
                         (s32)average_noise[i])) / 1500;
+
                 /* bound gain by 2 bits value max, 3rd bit is sign */
                 data->delta_gain_code[i] =
                         min(abs(delta_g), (long) CHAIN_NOISE_MAX_DELTA_GAIN_CODE);
 
                 if (delta_g < 0)
-                        /* set negative sign */
+                        /*
+                         * set negative sign ...
+                         * note to Intel developers:  This is uCode API format,
+                         *   not the format of any internal device registers.
+                         *   Do not change this format for e.g. 6050 or similar
+                         *   devices.  Change format only if more resolution
+                         *   (i.e. more than 2 bits magnitude) is needed.
+                         */
                         data->delta_gain_code[i] |= (1 << 2);
         }
 
@@ -1587,6 +1597,7 @@ struct iwl_cfg iwl5300_agn_cfg = {
         .use_rts_for_ht = true, /* use rts/cts protection */
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5100_bgn_cfg = {
@@ -1612,6 +1623,7 @@ struct iwl_cfg iwl5100_bgn_cfg = {
         .use_rts_for_ht = true, /* use rts/cts protection */
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5100_abg_cfg = {
@@ -1635,6 +1647,7 @@ struct iwl_cfg iwl5100_abg_cfg = {
         .led_compensation = 51,
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5100_agn_cfg = {
@@ -1660,6 +1673,7 @@ struct iwl_cfg iwl5100_agn_cfg = {
         .use_rts_for_ht = true, /* use rts/cts protection */
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5350_agn_cfg = {
@@ -1685,6 +1699,7 @@ struct iwl_cfg iwl5350_agn_cfg = {
         .use_rts_for_ht = true, /* use rts/cts protection */
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5150_agn_cfg = {
@@ -1710,6 +1725,7 @@ struct iwl_cfg iwl5150_agn_cfg = {
         .use_rts_for_ht = true, /* use rts/cts protection */
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 struct iwl_cfg iwl5150_abg_cfg = {
@@ -1733,6 +1749,7 @@ struct iwl_cfg iwl5150_abg_cfg = {
         .led_compensation = 51,
         .chain_noise_num_beacons = IWL_CAL_NUM_BEACONS,
         .plcp_delta_threshold = IWL_MAX_PLCP_ERR_LONG_THRESHOLD_DEF,
+        .chain_noise_scale = 1000,
 };
 
 MODULE_FIRMWARE(IWL5000_MODULE_FIRMWARE(IWL5000_UCODE_API_MAX));