Subject: [PATCH v7 1/3] power-domain: add power domain drivers for Rockchip platform

From: [email-masked] (Dmitry Torokhov)
Date: Fri, 24 Oct 2014 09:44:31 -0700

Hi Jinkun,

On Fri, Oct 24, 2014 at 12:29:19AM -0700, jinkun.hong wrote:
> +static int rockchip_pd_power(struct rockchip_domain *pd, bool power_on)
> +{
> +	int ret = 0;
> +	struct rockchip_dev_entry *de;
> +
> +	mutex_lock(&pd->dev_lock);
> +	/* no clk, set power domain will fail */
> +	if (list_empty(&pd->dev_list)) {
> +		pr_err("%s: no devices in %s power domain\n", __func__,
> +			pd->base.name);
> +		goto out;
> +	}
> +
> +	list_for_each_entry(de, &pd->dev_list, node) {
> +		pm_clk_resume(de->dev);
> +	}
> +
> +	ret = rockchip_pmu_set_power_domain(pd, power_on);
> +
> +	list_for_each_entry(de, &pd->dev_list, node) {
> +		pm_clk_suspend(de->dev);
> +	}
> +out:
> +	mutex_unlock(&pd->dev_lock);
> +	return ret;
> +}

For my education, could you please tell me why we need to enable all
clocks of all devices in a power domain when we are talking to the PMU
and then turn them immediately off? Would not we want to enable clocks
in start()) callbacks, like Ulf mentioned?

Thanks.

-- 
Dmitry