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

Rafael J. Wysocki
2021-10-29T15:56:35Z

On Fri, Oct 29, 2021 at 5:20 PM Dmitry Osipenko <digetx@gmail.com> wrote:
>
> 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.

Well, for the record, IMV using pm_runtime_force_suspend() is
generally a questionable idea.