[PATCH] powerpc/5200: tighten up ac97 reset timing

[Eric Millbrandt]

On Fri, 3 Sep 2010 at 12:02:09 Wolfram Sang wrote:
> On Fri, Sep 03, 2010 at 11:45:22AM -0400, Eric Millbrandt wrote:
>> Tighten up time timing around the gpio reset functionality. Add a 200ns
>> delay before remuxing the pins back to ac97 to comply with the ac97
>> spec. This delay ensures that sync and sdata_out are held low while
>> reset transitions to high.
>>
>> Signed-off-by: Eric Millbrandt <emillbrandt at dekaresearch.com>
>> ---
>>
>> Scope shots are availible upon request.
>>
>>  arch/powerpc/platforms/52xx/mpc52xx_common.c |    5 ++++-
>>  1 files changed, 4 insertions(+), 1 deletions(-)
>>  diff --git a/arch/powerpc/platforms/52xx/mpc52xx_common.c
>> b/arch/powerpc/platforms/52xx/mpc52xx_common.c index 6e90531..79adfe7
>> 100644 --- a/arch/powerpc/platforms/52xx/mpc52xx_common.c +++
>> b/arch/powerpc/platforms/52xx/mpc52xx_common.c @@ -326,11 +326,14 @@
>> int mpc5200_psc_ac97_gpio_reset(int
> psc_number)
>>         clrbits8(&wkup_gpio->wkup_dvo, reset);
>>
>>         /* wait at lease 1 us */
>
> Maybe you could fix this typo as well while you are here?

Can do.
>
>> -       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

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