linux-kernel - Re: [PATCH V2 5/7] coresight: tmc: Move ACPI support from AMBA driver to platform driver

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Message-ID: <ZW26u_2pHz9bNoTx@bogus>
Date:   Mon, 4 Dec 2023 11:40:43 +0000
From:   Sudeep Holla <sudeep.holla@....com>
To:     James Clark <james.clark@....com>
Cc:     Anshuman Khandual <anshuman.khandual@....com>,
        linux-arm-kernel@...ts.infradead.org, suzuki.poulose@....com,
        Sudeep Holla <sudeep.holla@....com>,
        Lorenzo Pieralisi <lpieralisi@...nel.org>,
        Mike Leach <mike.leach@...aro.org>,
        Maxime Coquelin <mcoquelin.stm32@...il.com>,
        Alexandre Torgue <alexandre.torgue@...s.st.com>,
        linux-acpi@...r.kernel.org, linux-kernel@...r.kernel.org,
        coresight@...ts.linaro.org,
        linux-stm32@...md-mailman.stormreply.com
Subject: Re: [PATCH V2 5/7] coresight: tmc: Move ACPI support from AMBA
 driver to platform driver

On Mon, Dec 04, 2023 at 10:54:15AM +0000, James Clark wrote:
>
>
> On 01/12/2023 06:20, Anshuman Khandual wrote:
> > Add support for the tmc devices in the platform driver, which can then be
> > used on ACPI based platforms. This change would now allow runtime power
> > management for ACPI based systems. The driver would try to enable the APB
> > clock if available.
> >
> [...]
> > -module_amba_driver(tmc_driver);
> > +static int tmc_platform_probe(struct platform_device *pdev)
> > +{
> > +	struct resource *res = platform_get_resource(pdev, IORESOURCE_MEM, 0);
> > +	struct tmc_drvdata *drvdata;
> > +	int ret = 0;
> > +
> > +	drvdata = devm_kzalloc(&pdev->dev, sizeof(*drvdata), GFP_KERNEL);
> > +	if (!drvdata)
> > +		return -ENOMEM;
> > +
> > +	drvdata->pclk = coresight_get_enable_apb_pclk(&pdev->dev);
> > +	if (IS_ERR(drvdata->pclk))
> > +		return -ENODEV;
> > +
> > +	dev_set_drvdata(&pdev->dev, drvdata);
> > +	pm_runtime_get_noresume(&pdev->dev);
> > +	pm_runtime_set_active(&pdev->dev);
> > +	pm_runtime_enable(&pdev->dev);
> > +
> > +	ret = __tmc_probe(&pdev->dev, res, NULL);
> > +	if (ret) {
> > +		pm_runtime_put_noidle(&pdev->dev);
> > +		pm_runtime_disable(&pdev->dev);
> > +	}
>
> I'm not sure if these pm_runtime()s are right because there is already a
> put inside of __tmc_probe() if it fails. If you unload and then reload
> all the coresight modules with these patches you get these errors which
> are new:
>

Ah good find. I have just tested with ACPI and these modules as built-in
to be more specific.

--
Regards,
Sudeep