Re: [PATCH V3 9/9] PM / OPP: Don't assume platform doesn't have regulators

Stephen Boyd
2016-11-10T01:17:33Z

On 10/26, Viresh Kumar wrote:
> If the regulators aren't set explicitly by the platform, the OPP core
> assumes that the platform doesn't have any regulator and uses the
> clk-only callback.
>
> If the platform failed to register a regulator with the core, then this
> can turn out to be a dangerous assumption as the OPP core will try to
> change clk without changing regulators.
>
> Handle that properly by making sure that the DT didn't had any entries

s/had/have/

> for supply voltages as well.
>
> diff --git a/drivers/base/power/opp/core.c b/drivers/base/power/opp/core.c
> index 3298fac01bb0..34cd48dfe89e 100644
> --- a/drivers/base/power/opp/core.c
> +++ b/drivers/base/power/opp/core.c
> @@ -734,7 +734,17 @@ int dev_pm_opp_set_rate(struct device *dev, unsigned long target_freq)
>
> /* Only frequency scaling */
> if (!regulators) {
> - rcu_read_unlock();
> + /*
> + * DT contained supply ratings? Consider platform failed to set
> + * regulators.
> + */
> + if (unlikely(opp->supplies[0].u_volt)) {
> + rcu_read_unlock();
> + dev_err(dev, "%s: Regulator not registered with OPP core\n",
> + __func__);
> + return -EINVAL;
> + }
> +

Don't we need an rcu_read_unlock() here as well?

> return _generic_set_opp_clk_only(dev, clk, old_freq, freq);
> }
>

--
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