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.
Signed-off-by: Eric Millbrandt <emillbra...@dekaresearch.com>
---
Scope shots availible upon request
changes since v1
- amended with comments from Wolfram Sang
arch/powerpc/platforms/52xx/mpc52xx_common.c | 8 ++++++--
1 files changed, 6 insertions(+), 2 deletions(-)
diff --git a/arch/powerpc/platforms/52xx/mpc52xx_common.c
b/arch/powerpc/platforms/52xx/mpc52xx_common.c
index 6e90531..41f3a7e 100644
--- a/arch/powerpc/platforms/52xx/mpc52xx_common.c
+++ b/arch/powerpc/platforms/52xx/mpc52xx_common.c
@@ -325,12 +325,16 @@ int mpc5200_psc_ac97_gpio_reset(int psc_number)
clrbits32(&simple_gpio->simple_dvo, sync | out);
clrbits8(&wkup_gpio->wkup_dvo, reset);
- /* wait at lease 1 us */
- udelay(2);
+ /* wait for 1 us */
+ udelay(1);
/* Deassert reset */
setbits8(&wkup_gpio->wkup_dvo, reset);
+ /* wait at least 200ns */
+ /* 7 ~= (200ns * timebase) / ns2sec */
+ __delay(7);
+
/* Restore pin-muxing */
out_be32(&simple_gpio->port_config, mux);
--
1.6.3.1
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