From 6af1bdccabe956a08a37f2ae049d37307ec0c91c Mon Sep 17 00:00:00 2001 From: Gabor Juhos Date: Sat, 17 Aug 2013 14:09:29 +0200 Subject: [PATCH] rt2x00: rt2800lib: optimize frequency offset adjustment 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 Signed-off-by: John W. Linville --- drivers/net/wireless/rt2x00/rt2800lib.c | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/drivers/net/wireless/rt2x00/rt2800lib.c b/drivers/net/wireless/rt2x00/rt2800lib.c index de27277..3407ac9 100644 --- a/drivers/net/wireless/rt2x00/rt2800lib.c +++ b/drivers/net/wireless/rt2x00/rt2800lib.c @@ -2497,13 +2497,18 @@ 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); } -- 2.7.4