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Date: Mon, 6 Dec 2010 17:24:10 +0530
From: Vasanthakumar Thiagarajan <vasanth@atheros.com>
To: Felix Fietkau <nbd@openwrt.org>
CC: Vasanth Thiagarajan <Vasanth.Thiagarajan@Atheros.com>,
	"linville@tuxdriver.com" <linville@tuxdriver.com>,
	"linux-wireless@vger.kernel.org" <linux-wireless@vger.kernel.org>
Subject: Re: [PATCH V2 12/27] ath9k_hw: Find chansel of
	AR_PHY_65NM_CH0_SYNTH7 from an array for AR9485
Message-ID: <20101206115410.GU12908@vasanth-laptop>
References: <1291288031-3409-13-git-send-email-vasanth@atheros.com> <4CF84BB8.8090007@openwrt.org> <20101203045054.GP12908@vasanth-laptop> <4CF8DF08.2060307@openwrt.org> <20101203124050.GR12908@vasanth-laptop> <4CF8E718.9070207@openwrt.org> <20101206060310.GS12908@vasanth-laptop> <4CFCBE04.7070509@openwrt.org> <20101206114401.GT12908@vasanth-laptop> <4CFCCE0E.6020906@openwrt.org>
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On Mon, Dec 06, 2010 at 05:20:38PM +0530, Felix Fietkau wrote:
> On 2010-12-06 12:44 PM, Vasanthakumar Thiagarajan wrote:
> >> > I don't have any doc for this register yet.
> >> I'm pretty sure that the format of the register is still exactly the
> >> same. I guess they added a small frequency offset to reduce spur.
> >> 
> >> >> But how exactly is *one* magic number (and it's even a very small one)
> >> >> worse than 14 of them, especially since anybody can verify that the
> >> >> generated raw values are exactly the same?
> >> > 
> >> > Anyway, still this formula gets it wrong for channel 14.
> >> > Lets have this table for now, I'll clean this up once I
> >> > get the proper doc for this register?.
> >> How did you test this? When I put this part into a test program, it
> >> generates exactly the same values as the table  all channels,
> >> including 14.
> > 
> > I just did the following
> > 
> > #define CHANSEL_2G_9485(_freq) ((((freq) * 0x10000) - 215) / CHANSEL_DIV)
> >  for (i = 0; i < 14; i++) {
> >                freq = 2412 + (i * 5);
> >                printk("chan %d : %x \n",i + 1,CHANSEL_2G_9485(freq));
> >       }
> > 
> > output:
> > 
> > chan 1 : a0ccbe
> > chan 2 : a12213
> > chan 3 : a17769
> > chan 4 : a1ccbe
> > chan 5 : a22213
> > chan 6 : a27769
> > chan 7 : a2ccbe
> > chan 8 : a32213
> > chan 9 : a37769
> > chan 10 : a3ccbe
> > chan 11 : a42213
> > chan 12 : a47769
> > chan 13 : a4ccbe
> > chan 14 : a52213
> 2412 + 13 * 5 == 2477, not 2484.
oops, sorry.

Vasanth