linux-kernel - Re: [PATCH v14 20/39] pwm: tegra: Add runtime PM and OPP support

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Message-ID: <09c05206-c0e5-9a25-8ffa-b9291f6ea5ae@gmail.com>
Date:   Fri, 29 Oct 2021 18:20:48 +0300
From:   Dmitry Osipenko <digetx@...il.com>
To:     Thierry Reding <thierry.reding@...il.com>,
        Jonathan Hunter <jonathanh@...dia.com>,
        Ulf Hansson <ulf.hansson@...aro.org>,
        Viresh Kumar <vireshk@...nel.org>,
        Stephen Boyd <sboyd@...nel.org>,
        Peter De Schrijver <pdeschrijver@...dia.com>,
        Mikko Perttunen <mperttunen@...dia.com>,
        Lee Jones <lee.jones@...aro.org>,
        Uwe Kleine-König <u.kleine-koenig@...gutronix.de>,
        Nishanth Menon <nm@...com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Michael Turquette <mturquette@...libre.com>
Cc:     linux-kernel@...r.kernel.org, linux-tegra@...r.kernel.org,
        linux-pm@...r.kernel.org, linux-pwm@...r.kernel.org,
        linux-mmc@...r.kernel.org, dri-devel@...ts.freedesktop.org,
        linux-clk@...r.kernel.org, David Heidelberg <david@...t.cz>
Subject: Re: [PATCH v14 20/39] pwm: tegra: Add runtime PM and OPP support

26.10.2021 01:40, Dmitry Osipenko пишет:
> +	ret = devm_pm_runtime_enable(&pdev->dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = devm_tegra_core_dev_init_opp_table_common(&pdev->dev);
> +	if (ret)
> +		return ret;
> +
> +	ret = pm_runtime_resume_and_get(&pdev->dev);
> +	if (ret)
> +		return ret;
> +
>  	/* Set maximum frequency of the IP */
> -	ret = clk_set_rate(pwm->clk, pwm->soc->max_frequency);
> +	ret = dev_pm_opp_set_rate(pwm->dev, pwm->soc->max_frequency);
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "Failed to set max frequency: %d\n", ret);
> -		return ret;
> +		goto put_pm;
>  	}
>  
>  	/*
> @@ -278,7 +294,7 @@ static int tegra_pwm_probe(struct platform_device *pdev)
>  	if (IS_ERR(pwm->rst)) {
>  		ret = PTR_ERR(pwm->rst);
>  		dev_err(&pdev->dev, "Reset control is not found: %d\n", ret);
> -		return ret;
> +		goto put_pm;
>  	}
>  
>  	reset_control_deassert(pwm->rst);
> @@ -291,10 +307,15 @@ static int tegra_pwm_probe(struct platform_device *pdev)
>  	if (ret < 0) {
>  		dev_err(&pdev->dev, "pwmchip_add() failed: %d\n", ret);
>  		reset_control_assert(pwm->rst);
> -		return ret;
> +		goto put_pm;
>  	}
>  
> +	pm_runtime_put(&pdev->dev);
> +
>  	return 0;
> +put_pm:
> +	pm_runtime_put_sync_suspend(&pdev->dev);
> +	return ret;
>  }
>  
>  static int tegra_pwm_remove(struct platform_device *pdev)
> @@ -305,20 +326,44 @@ static int tegra_pwm_remove(struct platform_device *pdev)
>  
>  	reset_control_assert(pc->rst);
>  
> +	pm_runtime_force_suspend(&pdev->dev);

I just noticed that RPM core doesn't reset RPM-enable count of a device
on driver's unbind (pm_runtime_reinit). It was a bad idea to use
devm_pm_runtime_enable() + pm_runtime_force_suspend() here, since RPM is
disabled twice on driver's removal, and thus, RPM will never be enabled
again.

I'll fix it for PWM and other drivers in this series, in v15.