linux-kernel - Re: [PATCH] mmc: sdhci-omap: Add Support for Suspend/Resume

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Message-ID: <52f4cb0c-2b4e-65bf-d669-b9b5cdc44cb7@ti.com>
Date:   Wed, 19 Feb 2020 13:35:05 +0530
From:   Kishon Vijay Abraham I <kishon@...com>
To:     Faiz Abbas <faiz_abbas@...com>, <linux-kernel@...r.kernel.org>,
        <linux-mmc@...r.kernel.org>, <linux-omap@...r.kernel.org>
CC:     <ulf.hansson@...aro.org>, <adrian.hunter@...el.com>,
        <tony@...mide.com>
Subject: Re: [PATCH] mmc: sdhci-omap: Add Support for Suspend/Resume

Hi Faiz,

On 18/02/20 7:40 pm, Faiz Abbas wrote:
> Add power management ops which save and restore the driver context and
> facilitate a system suspend and resume.
> 
> Signed-off-by: Faiz Abbas <faiz_abbas@...com>
> ---
>  drivers/mmc/host/sdhci-omap.c | 59 +++++++++++++++++++++++++++++++++++
>  1 file changed, 59 insertions(+)
> 
> diff --git a/drivers/mmc/host/sdhci-omap.c b/drivers/mmc/host/sdhci-omap.c
> index 882053151a47..a524c01da8de 100644
> --- a/drivers/mmc/host/sdhci-omap.c
> +++ b/drivers/mmc/host/sdhci-omap.c
> @@ -108,6 +108,11 @@ struct sdhci_omap_host {
>  	struct pinctrl		*pinctrl;
>  	struct pinctrl_state	**pinctrl_state;
>  	bool			is_tuning;
> +	/* Omap specific context save */
> +	u32			con;
> +	u32			hctl;
> +	u32			sysctl;
> +	u32			capa;

Except CON register which is specific to OMAP, others are SDHCI
registers. Shouldn't the save and restore of these registers be in
sdhci.c? Doesn't set_ios() already take care of configuring HCTL, SYSCTL
etc..?

Thanks
Kishon

>  };
>  
>  static void sdhci_omap_start_clock(struct sdhci_omap_host *omap_host);
> @@ -1233,11 +1238,65 @@ static int sdhci_omap_remove(struct platform_device *pdev)
>  	return 0;
>  }
>  
> +static void sdhci_omap_context_save(struct sdhci_omap_host *omap_host)
> +{
> +	omap_host->con = sdhci_omap_readl(omap_host, SDHCI_OMAP_CON);
> +	omap_host->hctl = sdhci_omap_readl(omap_host, SDHCI_OMAP_HCTL);
> +	omap_host->sysctl = sdhci_omap_readl(omap_host, SDHCI_OMAP_SYSCTL);
> +	omap_host->capa = sdhci_omap_readl(omap_host, SDHCI_OMAP_CAPA);
> +}
> +
> +static void sdhci_omap_context_restore(struct sdhci_omap_host *omap_host)
> +{
> +	sdhci_omap_writel(omap_host, SDHCI_OMAP_CON, omap_host->con);
> +	sdhci_omap_writel(omap_host, SDHCI_OMAP_HCTL, omap_host->hctl);
> +	sdhci_omap_writel(omap_host, SDHCI_OMAP_SYSCTL, omap_host->sysctl);
> +	sdhci_omap_writel(omap_host, SDHCI_OMAP_CAPA, omap_host->capa);
> +}
> +
> +static int __maybe_unused sdhci_omap_suspend(struct device *dev)
> +{
> +	struct sdhci_host *host = dev_get_drvdata(dev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
> +
> +	sdhci_suspend_host(host);
> +
> +	sdhci_omap_context_save(omap_host);
> +
> +	pinctrl_pm_select_idle_state(dev);
> +
> +	pm_runtime_put_sync(dev);
> +
> +	return 0;
> +}
> +
> +static int __maybe_unused sdhci_omap_resume(struct device *dev)
> +{
> +	struct sdhci_host *host = dev_get_drvdata(dev);
> +	struct sdhci_pltfm_host *pltfm_host = sdhci_priv(host);
> +	struct sdhci_omap_host *omap_host = sdhci_pltfm_priv(pltfm_host);
> +
> +	pm_runtime_get_sync(dev);
> +
> +	pinctrl_pm_select_default_state(dev);
> +
> +	sdhci_omap_context_restore(omap_host);
> +
> +	sdhci_resume_host(host);
> +
> +	return 0;
> +}
> +
> +static SIMPLE_DEV_PM_OPS(sdhci_omap_dev_pm_ops, sdhci_omap_suspend,
> +			 sdhci_omap_resume);
> +
>  static struct platform_driver sdhci_omap_driver = {
>  	.probe = sdhci_omap_probe,
>  	.remove = sdhci_omap_remove,
>  	.driver = {
>  		   .name = "sdhci-omap",
> +		   .pm = &sdhci_omap_dev_pm_ops,
>  		   .of_match_table = omap_sdhci_match,
>  		  },
>  };
>