Don't write the new value into the register if it is
the same as the old value to avoid unncessary USB bus
traffic with USB devices. The change also saves a few
cycle on MMIO based devices.
Based on the DPO_RT5572_LinuxSTA_2.6.0.1_20120629
driver.
Reference:
RTMPAdjustFrequencyOffset function in common/rt_rf.c
Signed-off-by: Gabor Juhos <juhosg@xxxxxxxxxxx>
---
drivers/net/wireless/rt2x00/rt2800lib.c | 6 +++++-
1 file changed, 5 insertions(+), 1 deletion(-)
diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c
index d4e6dea..c990a27 100644
--- a/drivers/net/wireless/rt2x00/rt2800lib.c
+++ b/drivers/net/wireless/rt2x00/rt2800lib.c
@@ -2495,13 +2495,17 @@ static void rt2800_config_channel_rf3053(struct rt2x00_dev *rt2x00dev,
static void rt2800_adjust_freq_offset(struct rt2x00_dev *rt2x00dev)
{
u8 freq_offset;
- u8 rfcsr;
+ u8 rfcsr, prev_rfcsr;
freq_offset = rt2x00_get_field8(rt2x00dev->freq_offset, RFCSR17_CODE);
freq_offset = min_t(u8, freq_offset, FREQ_OFFSET_BOUND);
rt2800_rfcsr_read(rt2x00dev, 17, &rfcsr);
+ prev_rfcsr = rfcsr;
rt2x00_set_field8(&rfcsr, RFCSR17_CODE, freq_offset);
+ if (rfcsr == prev_rfcsr)
+ return;
+
rt2800_rfcsr_write(rt2x00dev, 17, rfcsr);
}
--
1.7.10
--
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