[ath5k-devel] [PATCH 1/4] ath5k: correct channel setting for 2.5 mhz spacing

[Bob Copeland]

These channels aren't selectable anyway, but our calculations
for 2.5 mhz frequencies are incorrect.  The value is supposed to
be:

  (frequency - reference) * (10/25)

i.e., divide by 2.5, but we were instead doing:

  (10 * frequency - reference) / 25.

Additionally, the check for (frequency % 5 == 2) had an extra
subtraction that wasn't in madwifi HAL.

Signed-off-by: Bob Copeland <m...@bobcopeland.com>
---
 drivers/net/wireless/ath/ath5k/phy.c |    8 ++++----
 1 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ath/ath5k/phy.c 
b/drivers/net/wireless/ath/ath5k/phy.c
index b83ca8a..81bdebd 100644
--- a/drivers/net/wireless/ath/ath5k/phy.c
+++ b/drivers/net/wireless/ath/ath5k/phy.c
@@ -979,7 +979,7 @@ static int ath5k_hw_rf5112_channel(struct ath5k_hw *ah,
                        return -EINVAL;
 
                data0 = ath5k_hw_bitswap((data0 << 2) & 0xff, 8);
-       } else if ((c - (c % 5)) != 2 || c > 5435) {
+       } else if ((c % 5) != 2 || c > 5435) {
                if (!(c % 20) && c >= 5120) {
                        data0 = ath5k_hw_bitswap(((c - 4800) / 20 << 2), 8);
                        data2 = ath5k_hw_bitswap(3, 2);
@@ -992,7 +992,7 @@ static int ath5k_hw_rf5112_channel(struct ath5k_hw *ah,
                } else
                        return -EINVAL;
        } else {
-               data0 = ath5k_hw_bitswap((10 * (c - 2) - 4800) / 25 + 1, 8);
+               data0 = ath5k_hw_bitswap((10 * (c - 2 - 4800)) / 25 + 1, 8);
                data2 = ath5k_hw_bitswap(0, 2);
        }
 
@@ -1020,7 +1020,7 @@ static int ath5k_hw_rf2425_channel(struct ath5k_hw *ah,
                data0 = ath5k_hw_bitswap((c - 2272), 8);
                data2 = 0;
        /* ? 5GHz ? */
-       } else if ((c - (c % 5)) != 2 || c > 5435) {
+       } else if ((c % 5) != 2 || c > 5435) {
                if (!(c % 20) && c < 5120)
                        data0 = ath5k_hw_bitswap(((c - 4800) / 20 << 2), 8);
                else if (!(c % 10))
@@ -1031,7 +1031,7 @@ static int ath5k_hw_rf2425_channel(struct ath5k_hw *ah,
                        return -EINVAL;
                data2 = ath5k_hw_bitswap(1, 2);
        } else {
-               data0 = ath5k_hw_bitswap((10 * (c - 2) - 4800) / 25 + 1, 8);
+               data0 = ath5k_hw_bitswap((10 * (c - 2 - 4800)) / 25 + 1, 8);
                data2 = ath5k_hw_bitswap(0, 2);
        }
 
-- 
1.6.3.3


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