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From:   Viresh Kumar <viresh.kumar@linaro.org>
Date:   Thu, 5 Nov 2020 15:28:34 +0530
Message-ID: <CAOh2x==sy1w7_oEV8=toC6uQnSN44wyOixbP_X0BrMsnm1AUFg@mail.gmail.com>
Subject: Re: [PATCH v1 17/30] mmc: sdhci-tegra: Support OPP and core voltage scaling
To:     Dmitry Osipenko <digetx@gmail.com>
Cc:     Thierry Reding <thierry.reding@gmail.com>,
        Jonathan Hunter <jonathanh@nvidia.com>,
        Alan Stern <stern@rowland.harvard.edu>,
        Peter Chen <Peter.Chen@nxp.com>,
        Mark Brown <broonie@kernel.org>,
        Liam Girdwood <lgirdwood@gmail.com>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Krzysztof Kozlowski <krzk@kernel.org>,
        Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        Lee Jones <lee.jones@linaro.org>,
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        <u.kleine-koenig@pengutronix.de>,
        Ulf Hansson <ulf.hansson@linaro.org>,
        Mauro Carvalho Chehab <mchehab@kernel.org>,
        Rob Herring <robh+dt@kernel.org>,
        Marek Szyprowski <m.szyprowski@samsung.com>,
        Peter Geis <pgwipeout@gmail.com>,
        Nicolas Chauvet <kwizart@gmail.com>,
        driver-dev <devel@driverdev.osuosl.org>,
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        "open list:SECURE DIGITAL HO..." <linux-mmc@vger.kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
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On Thu, Nov 5, 2020 at 5:15 AM Dmitry Osipenko <digetx@gmail.com> wrote:

> diff --git a/drivers/mmc/host/sdhci-tegra.c b/drivers/mmc/host/sdhci-tegra.c

> +static void sdhci_tegra_deinit_opp_table(void *data)
> +{
> +       struct device *dev = data;
> +       struct opp_table *opp_table;
> +
> +       opp_table = dev_pm_opp_get_opp_table(dev);

So you need to get an OPP table to put one :)
You need to save the pointer returned by dev_pm_opp_set_regulators() instead.

> +       dev_pm_opp_of_remove_table(dev);
> +       dev_pm_opp_put_regulators(opp_table);
> +       dev_pm_opp_put_opp_table(opp_table);
> +}
> +
> +static int devm_sdhci_tegra_init_opp_table(struct device *dev)
> +{
> +       struct opp_table *opp_table;
> +       const char *rname = "core";
> +       int err;
> +
> +       /* voltage scaling is optional */
> +       if (device_property_present(dev, "core-supply"))
> +               opp_table = dev_pm_opp_set_regulators(dev, &rname, 1);
> +       else


> +               opp_table = dev_pm_opp_get_opp_table(dev);

Nice. I didn't think that someone will end up abusing this API and so made it
available for all, but someone just did that. I will fix that in the OPP core.

Any idea why you are doing what you are doing here ?

> +
> +       if (IS_ERR(opp_table))
> +               return dev_err_probe(dev, PTR_ERR(opp_table),
> +                                   "failed to prepare OPP table\n");
> +
> +       /*
> +        * OPP table presence is optional and we want the set_rate() of OPP
> +        * API to work similarly to clk_set_rate() if table is missing in a
> +        * device-tree.  The add_table() errors out if OPP is missing in DT.
> +        */
> +       if (device_property_present(dev, "operating-points-v2")) {
> +               err = dev_pm_opp_of_add_table(dev);
> +               if (err) {
> +                       dev_err(dev, "failed to add OPP table: %d\n", err);
> +                       goto put_table;
> +               }
> +       }
> +
> +       err = devm_add_action(dev, sdhci_tegra_deinit_opp_table, dev);
> +       if (err)
> +               goto remove_table;
> +
> +       return 0;
> +
> +remove_table:
> +       dev_pm_opp_of_remove_table(dev);
> +put_table:
> +       dev_pm_opp_put_regulators(opp_table);
> +
> +       return err;
> +}
> +
>  static int sdhci_tegra_probe(struct platform_device *pdev)
>  {
>         const struct of_device_id *match;
> @@ -1621,6 +1681,10 @@ static int sdhci_tegra_probe(struct platform_device *pdev)
>                 goto err_power_req;
>         }
>
> +       rc = devm_sdhci_tegra_init_opp_table(&pdev->dev);
> +       if (rc)
> +               goto err_parse_dt;
> +
>         /*
>          * Tegra210 has a separate SDMMC_LEGACY_TM clock used for host
>          * timeout clock and SW can choose TMCLK or SDCLK for hardware
> --
> 2.27.0
>
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