ath5k: fix interpolation with equal power levels

When the EEPROM contains weird values for the power levels we have to
fix the interpolation process.

Signed-off-by: Fabio Rossi <rossi.f@inwind.it>
Acked-by: Nick Kossifidis <mickflemm@gmail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 28 insertions, 21 deletions

diff --git a/drivers/net/wireless/ath/ath5k/phy.c b/drivers/net/wireless/ath/ath5k/phy.c
index 9e2faae5ae94..b48b29dca3d2 100644
--- a/drivers/net/wireless/ath/ath5k/phy.c
+++ b/drivers/net/wireless/ath/ath5k/phy.c
@@ -1487,28 +1487,35 @@ ath5k_get_linear_pcdac_min(const u8 *stepL, const u8 *stepR,
 {
         s8 tmp;
         s16 min_pwrL, min_pwrR;
-        s16 pwr_i = pwrL[0];
-
-        do {
-                pwr_i--;
-                tmp = (s8) ath5k_get_interpolated_value(pwr_i,
-                                                pwrL[0], pwrL[1],
-                                                stepL[0], stepL[1]);
-
-        } while (tmp > 1);
-
-        min_pwrL = pwr_i;
-
-        pwr_i = pwrR[0];
-        do {
-                pwr_i--;
-                tmp = (s8) ath5k_get_interpolated_value(pwr_i,
-                                                pwrR[0], pwrR[1],
-                                                stepR[0], stepR[1]);
-
-        } while (tmp > 1);
+        s16 pwr_i;
+
+        if (pwrL[0] == pwrL[1])
+                min_pwrL = pwrL[0];
+        else {
+                pwr_i = pwrL[0];
+                do {
+                        pwr_i--;
+                        tmp = (s8) ath5k_get_interpolated_value(pwr_i,
+                                                        pwrL[0], pwrL[1],
+                                                        stepL[0], stepL[1]);
+                } while (tmp > 1);
+
+                min_pwrL = pwr_i;
+        }
 
-        min_pwrR = pwr_i;
+        if (pwrR[0] == pwrR[1])
+                min_pwrR = pwrR[0];
+        else {
+                pwr_i = pwrR[0];
+                do {
+                        pwr_i--;
+                        tmp = (s8) ath5k_get_interpolated_value(pwr_i,
+                                                        pwrR[0], pwrR[1],
+                                                        stepR[0], stepR[1]);
+                } while (tmp > 1);
+
+                min_pwrR = pwr_i;
+        }
 
         /* Keep the right boundary so that it works for both curves */
         return max(min_pwrL, min_pwrR);