Caesar,
On Fri, Jun 5, 2015 at 8:11 AM, Caesar Wang <wxt at rock-chips.com> wrote:
> We need different orderings when turning a core on and turning a core
> off. In one case we need to assert reset before turning power off.
> In ther other case we need to turn power on and the deassert reset.
>
> In general, the correct flow is:
>
> CPU off:
> reset_control_assert
> regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), BIT(pd))
Add: "ensure power domain is on" to this list.
> CPU on:
> regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), 0)
> reset_control_deassert
Add: "ensure power domain is on" to this list.
Adding the "ensure power domain is on" step helps document that patch
set version 2 is not what you want and that you thought about it.
> @@ -88,18 +88,24 @@ static int pmu_set_power_domain(int pd, bool on)
> return PTR_ERR(rstc);
> }
>
> - if (on)
> - reset_control_deassert(rstc);
> - else
> + if (!on)
> reset_control_assert(rstc);
>
> - reset_control_put(rstc);
> - }
> + ret = regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), val);
> + if (ret < 0) {
> + pr_err("%s: could not update power domain\n", __func__);
> + reset_control_put(rstc);
> + return ret;
> + }
>
> - ret = regmap_update_bits(pmu, PMU_PWRDN_CON, BIT(pd), val);
> - if (ret < 0) {
> - pr_err("%s: could not update power domain\n", __func__);
> - return ret;
> + if (on)
> + reset_control_deassert(rstc);
I think you need a "reset_control_put(rstc);" here in the non-error case.
Otherwise this looks reasonable to me and you can add my Reviewed-by
tag. I'll also kick off some tests with this series today to confirm
as well.
-Doug
