[PATCH] powerpc/5200: tighten up ac97 reset timing
w.sang at pengutronix.de
Sat Sep 4 02:02:09 EST 2010
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?
> - udelay(2);
> + udelay(1);
> /* Deassert reset */
> setbits8(&wkup_gpio->wkup_dvo, reset);
> + /* wait at least 200ns */
> + __delay(7);
> /* Restore pin-muxing */
> out_be32(&simple_gpio->port_config, mux);
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Pengutronix e.K. | Wolfram Sang |
Industrial Linux Solutions | http://www.pengutronix.de/ |
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