[PATCH v2 8/8] mmc: sunxi: Add runtime_pm support

[Ulf Hansson]

On 8 March 2018 at 15:52, Maxime Ripard <maxime.ripard at bootlin.com> wrote:
> So far, even if our card was not in use, we didn't shut down our main
> clock, which meant that it was still output on the MMC bus.
>
> While this obviously means that we could save some power there, it also
> created issues when it comes with EMC control since we'll have a perfect
> peak at the card clock rate.
>
> Let's implement runtime_pm with autosuspend so that we will shut down the
> clock when it's not been in use for quite some time.
>
> Signed-off-by: Maxime Ripard <maxime.ripard at bootlin.com>
> ---
>  drivers/mmc/host/sunxi-mmc.c | 46 +++++++++++++++++++++++++++++++++++++-
>  1 file changed, 46 insertions(+)
>
> diff --git a/drivers/mmc/host/sunxi-mmc.c b/drivers/mmc/host/sunxi-mmc.c
> index f6374066081b..0f98a5fcaade 100644
> --- a/drivers/mmc/host/sunxi-mmc.c
> +++ b/drivers/mmc/host/sunxi-mmc.c
> @@ -35,6 +35,7 @@
>  #include <linux/of_gpio.h>
>  #include <linux/of_platform.h>
>  #include <linux/platform_device.h>
> +#include <linux/pm_runtime.h>
>  #include <linux/regulator/consumer.h>
>  #include <linux/reset.h>
>  #include <linux/scatterlist.h>
> @@ -973,6 +974,9 @@ static void sunxi_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
>         unsigned long flags;
>         u32 imask;
>
> +       if (enable)
> +               pm_runtime_get_noresume(host->dev);
> +
>         spin_lock_irqsave(&host->lock, flags);
>
>         imask = mmc_readl(host, REG_IMASK);
> @@ -985,6 +989,9 @@ static void sunxi_mmc_enable_sdio_irq(struct mmc_host *mmc, int enable)
>         }
>         mmc_writel(host, REG_IMASK, imask);
>         spin_unlock_irqrestore(&host->lock, flags);
> +
> +       if (!enable)
> +               pm_runtime_put_noidle(host->mmc->parent);
>  }
>
>  static void sunxi_mmc_hw_reset(struct mmc_host *mmc)
> @@ -1398,6 +1405,11 @@ static int sunxi_mmc_probe(struct platform_device *pdev)
>         if (ret)
>                 goto error_free_dma;
>
> +       pm_runtime_set_active(&pdev->dev);
> +       pm_runtime_set_autosuspend_delay(&pdev->dev, 50);
> +       pm_runtime_use_autosuspend(&pdev->dev);
> +       pm_runtime_enable(&pdev->dev);
> +
>         ret = mmc_add_host(mmc);
>         if (ret)
>                 goto error_free_dma;
> @@ -1418,6 +1430,7 @@ static int sunxi_mmc_remove(struct platform_device *pdev)
>         struct sunxi_mmc_host *host = mmc_priv(mmc);
>
>         mmc_remove_host(mmc);
> +       pm_runtime_force_suspend(&pdev->dev);
>         disable_irq(host->irq);
>         sunxi_mmc_disable(host);
>         dma_free_coherent(&pdev->dev, PAGE_SIZE, host->sg_cpu, host->sg_dma);
> @@ -1426,10 +1439,43 @@ static int sunxi_mmc_remove(struct platform_device *pdev)
>         return 0;
>  }
>
> +static int sunxi_mmc_runtime_resume(struct device *dev)
> +{
> +       struct mmc_host *mmc = dev_get_drvdata(dev);
> +       struct sunxi_mmc_host *host = mmc_priv(mmc);
> +       int ret;
> +
> +       ret = sunxi_mmc_enable(host);
> +       if (ret)
> +               return ret;
> +
> +       sunxi_mmc_power_up(mmc, &mmc->ios);

Instead of doing power up, you may need restore some ios settings,
such as the clock rate for example.

You may also need to restore some registers in sunxi device, in case
it's possible that the controller loses context at runtime suspend.

> +
> +       return 0;
> +}
> +
> +static int sunxi_mmc_runtime_suspend(struct device *dev)
> +{
> +       struct mmc_host *mmc = dev_get_drvdata(dev);
> +       struct sunxi_mmc_host *host = mmc_priv(mmc);
> +
> +       sunxi_mmc_power_off(mmc, &mmc->ios);
> +       sunxi_mmc_disable(host);
> +
> +       return 0;
> +}
> +
> +static const struct dev_pm_ops sunxi_mmc_pm_ops = {
> +       SET_RUNTIME_PM_OPS(sunxi_mmc_runtime_suspend,
> +                          sunxi_mmc_runtime_resume,
> +                          NULL)
> +};
> +
>  static struct platform_driver sunxi_mmc_driver = {
>         .driver = {
>                 .name   = "sunxi-mmc",
>                 .of_match_table = of_match_ptr(sunxi_mmc_of_match),
> +               .pm = &sunxi_mmc_pm_ops,
>         },
>         .probe          = sunxi_mmc_probe,
>         .remove         = sunxi_mmc_remove,
> --
> git-series 0.9.1


Otherwise, overall, this looks rather okay to me.

Kind regards
Uffe