Return-path: Received: from arrakis.dune.hu ([78.24.191.176]:46460 "EHLO arrakis.dune.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752943Ab3HQMJk (ORCPT ); Sat, 17 Aug 2013 08:09:40 -0400 From: Gabor Juhos To: "John W. Linville" Cc: linux-wireless@vger.kernel.org, users@rt2x00.serialmonkey.com, Gabor Juhos Subject: [PATCH v2 2/6] rt2x00: rt2800lib: optimize frequency offset adjustment Date: Sat, 17 Aug 2013 14:09:29 +0200 Message-Id: <1376741373-10032-3-git-send-email-juhosg@openwrt.org> (sfid-20130817_140946_633999_416913A9) In-Reply-To: <1376741373-10032-1-git-send-email-juhosg@openwrt.org> References: <1376741373-10032-1-git-send-email-juhosg@openwrt.org> Sender: linux-wireless-owner@vger.kernel.org List-ID: 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 --- Changes since v1: --- --- 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); } -- 1.7.10