From: Wolfram Sang <w.sang@pengutronix.de>
To: Eric Millbrandt <emillbrandt@dekaresearch.com>
Cc: "linuxppc-dev@lists.ozlabs.org" <linuxppc-dev@lists.ozlabs.org>
Subject: Re: [PATCH] powerpc/5200: tighten up ac97 reset timing
Date: Fri, 3 Sep 2010 18:22:24 +0200 [thread overview]
Message-ID: <20100903162224.GF4813@pengutronix.de> (raw)
In-Reply-To: <0A40042D85E7C84DB443060EC44B3FD3254AA09E8E@dekaexchange07.deka.local>
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> >> - udelay(2);
> >> + udelay(1);
> >>
> >> /* Deassert reset */
> >> setbits8(&wkup_gpio->wkup_dvo, reset);
> >>
> >> + /* wait at least 200ns */
> >> + __delay(7);
> >
> > ndelay(200)?
>
> Is ndelay defined for powerpc? I was under the impression that it was
> being redefined to udelay in linux/delay.h.
>
> #ifndef ndelay
> static inline void ndelay(unsigned long x)
> {
> udelay(DIV_ROUND_UP(x, 1000));
> }
> #define ndelay(x) ndelay(x)
> #endif
Yes, but it is way more readable. Does the extra delay hurt? The value
of 7 looks a bit magic to me. Are you sure it will do for various clock
frequencies?
--
Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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next prev parent reply other threads:[~2010-09-03 16:22 UTC|newest]
Thread overview: 6+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-09-03 15:45 [PATCH] powerpc/5200: tighten up ac97 reset timing Eric Millbrandt
2010-09-03 16:02 ` Wolfram Sang
2010-09-03 16:17 ` Eric Millbrandt
2010-09-03 16:22 ` Wolfram Sang [this message]
2010-09-03 16:40 ` Eric Millbrandt
2010-09-03 16:49 ` Wolfram Sang
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