Re: [RFC PATCH 4/9] opp: core: Don't warn if required OPP device does not exist

From: Viresh Kumar <viresh.kumar@linaro.org>
To: Ulf Hansson <ulf.hansson@linaro.org>, Hector Martin <marcan@marcan.st>
Cc: Sibi Sankar <sibis@codeaurora.org>,
	Saravana Kannan <saravanak@google.com>,
	linux-arm-kernel@lists.infradead.org,
	Alyssa Rosenzweig <alyssa@rosenzweig.io>,
	Sven Peter <sven@svenpeter.dev>, Marc Zyngier <maz@kernel.org>,
	Mark Kettenis <mark.kettenis@xs4all.nl>,
	Michael Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>, Rob Herring <robh+dt@kernel.org>,
	Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>,
	Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	"Rafael J. Wysocki" <rafael@kernel.org>,
	Kevin Hilman <khilman@kernel.org>,
	linux-clk@vger.kernel.org, devicetree@vger.kernel.org,
	linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [RFC PATCH 4/9] opp: core: Don't warn if required OPP device does not exist
Date: Thu, 14 Oct 2021 12:26:36 +0530	[thread overview]
Message-ID: <20211014065636.lkv77aqbugp3qhif@vireshk-i7> (raw)
In-Reply-To: <0db8e994-ac2c-8fad-55d0-1b5a9e2e21f2@marcan.st>

On 14-10-21, 15:52, Hector Martin wrote:
> The CPU devices aren't attached to their genpd, so the required OPP
> transition fails with the same error.
> 
> However, this was easier to fix than I expected. With this patch to
> cpufreq-dt, it all works properly, and I can drop the parent genpd
> from the clock node and related handling. Thoughts?
> 
> commit c4f88743374c1f4678ee7f17fb6cae30ded9ed59
> Author: Hector Martin <marcan@marcan.st>
> Date:   Thu Oct 14 15:47:45 2021 +0900
> 
>     cpufreq: dt: Attach CPU devices to power domains
>     This allows the required-opps mechanism to work for CPU OPP tables,
>     triggering specific OPP levels in a parent power domain.
>     Signed-off-by: Hector Martin <marcan@marcan.st>
> 
> diff --git a/drivers/cpufreq/cpufreq-dt.c b/drivers/cpufreq/cpufreq-dt.c
> index 8fcaba541539..5b22846b557d 100644
> --- a/drivers/cpufreq/cpufreq-dt.c
> +++ b/drivers/cpufreq/cpufreq-dt.c
> @@ -16,6 +16,7 @@
>  #include <linux/list.h>
>  #include <linux/module.h>
>  #include <linux/of.h>
> +#include <linux/pm_domain.h>
>  #include <linux/pm_opp.h>
>  #include <linux/platform_device.h>
>  #include <linux/regulator/consumer.h>
> @@ -264,6 +265,16 @@ static int dt_cpufreq_early_init(struct device *dev, int cpu)
>  		goto out;
>  	}
> +	/*
> +	 * Attach the CPU device to its genpd domain (if any), to allow OPP
> +	 * dependencies to be satisfied.
> +	 */
> +	ret = genpd_dev_pm_attach(cpu_dev);
> +	if (ret <= 0) {
> +		dev_err(cpu_dev, "Failed to attach CPU device to genpd\n");
> +		goto out;
> +	}
> +

Other platform do this from some other place I think.

Ulf, where should this code be moved ? cpu-clk driver ?

-- 
viresh

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