• Eric Millbrandt's avatar
    powerpc/5200: add mpc5200_psc_ac97_gpio_reset · cfa6a88c
    Eric Millbrandt authored
    Work around a silicon bug in the ac97 reset functionality of the
    mpc5200(b).  The implementation of the ac97 "cold" reset is flawed.
    If the sync and output lines are high when reset is asserted the
    attached ac97 device may go into test mode.  Avoid this by
    reconfiguring the psc to gpio mode and generating the reset manually.
    
    From MPC5200B User's Manual:
    "Some AC97 devices goes to a test mode, if the Sync line is high
    during the Res line is low (reset phase). To avoid this behavior the
    Sync line must be also forced to zero during the reset phase. To do
    that, the pin muxing should switch to GPIO mode and the GPIO control
    register should be used to control the output lines."
    Signed-off-by: default avatarEric Millbrandt <emillbrandt@dekaresearch.com>
    Signed-off-by: default avatarGrant Likely <grant.likely@secretlab.ca>
    cfa6a88c
mpc52xx_psc.h 8.84 KB