[PATCH RESEND] ARM: OMAP2+: Fix Wake-up power domain power status

[Kevin Hilman]

Jon Hunter <jon-hunter at ti.com> writes:

> Note: Re-sending with updated kernel doc.
>
> The wake-up power domain is an alway-on power domain and so this power domain
> does not have a power state status (PM_PWSTST_xxx) register that indicates the
> current state. However, during the registering of the wake-up power domain the
> state of the domain is queried by calling pwrdm_read_pwrst(). This actually
> tries to read a register that does not exist and returns a value of 0 that
> indicates that the current state is OFF. The OFF state count of the wake-up
> power domain is then set to 1 and the current state to OFF. Both of which are
> incorrect.
>
> To fix this, if a power domain only supports the ON state, do not attempt to
> read the power state status register and simply return ON as the current power
> state.
>
> This is based upon Tony's current linux-omap master branch.
>
> Testing:
> - Boot tested on OMAP4460 panda.
> - Boot tested on OMAP3430 beagle and validated CORE RET still working (using
>   Paul's 32k timer patch [1]).
>
> [1] http://marc.info/?l=linux-omap&m=134000053229888&w=2
>
> Signed-off-by: Jon Hunter <jon-hunter at ti.com>

Acked-by: Kevin Hilman <khilman at ti.com>


> ---
>  arch/arm/mach-omap2/powerdomain.c |    6 +++++-
>  1 file changed, 5 insertions(+), 1 deletion(-)
>
> diff --git a/arch/arm/mach-omap2/powerdomain.c b/arch/arm/mach-omap2/powerdomain.c
> index eefe179..69b36e1 100644
> --- a/arch/arm/mach-omap2/powerdomain.c
> +++ b/arch/arm/mach-omap2/powerdomain.c
> @@ -526,7 +526,8 @@ int pwrdm_read_next_pwrst(struct powerdomain *pwrdm)
>   *
>   * Return the powerdomain @pwrdm's current power state.	Returns -EINVAL
>   * if the powerdomain pointer is null or returns the current power state
> - * upon success.
> + * upon success. Note that if the power domain only supports the ON state
> + * then just return ON as the current state.
>   */
>  int pwrdm_read_pwrst(struct powerdomain *pwrdm)
>  {
> @@ -535,6 +536,9 @@ int pwrdm_read_pwrst(struct powerdomain *pwrdm)
>  	if (!pwrdm)
>  		return -EINVAL;
>  
> +	if (pwrdm->pwrsts == PWRSTS_ON)
> +		return PWRDM_POWER_ON;
> +
>  	if (arch_pwrdm && arch_pwrdm->pwrdm_read_pwrst)
>  		ret = arch_pwrdm->pwrdm_read_pwrst(pwrdm);