• Mika Westerberg's avatar
    pwm: lpss: Rework the sequence of programming PWM_SW_UPDATE · 37670676
    Mika Westerberg authored
    Setting of PWM_SW_UPDATE is bit different in Intel Broxton compared to the
    previous generation SoCs. Previously it was OK to set the bit many times
    (from userspace via sysfs for example) before the PWM is actually enabled.
    
    Starting from Intel Broxton it seems that we must set PWM_SW_UPDATE only
    once before the PWM is enabled. Otherwise it is possible that the PWM does
    not start properly.
    
    Change the sequence of how PWM_SW_UPDATE is programmed so that we only set
    it in pwm_lpss_config() when the PWM is already enabled. The initial
    setting of PWM_SW_UPDATE will be done when PWM gets enabled. This should
    make the driver work with the previous generation Intel SoCs and Broxton.
    
    Add also small delay after the bit is set to let the hardware propagate it
    properly.
    Signed-off-by: default avatarMika Westerberg <mika.westerberg@linux.intel.com>
    Signed-off-by: default avatarThierry Reding <thierry.reding@gmail.com>
    37670676
pwm-lpss.c 4.92 KB