linux-kernel - Re: [PATCH v2 2/2] ata: ahci_platform: runtime resume the device before use

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Date:	Thu, 17 Oct 2013 16:15:21 +0200
From:	Bartlomiej Zolnierkiewicz <b.zolnierkie@...sung.com>
To:	Roger Quadros <rogerq@...com>
Cc:	tj@...nel.org, sergei.shtylyov@...entembedded.com, kishon@...com,
	linux-ide@...r.kernel.org, linux-kernel@...r.kernel.org,
	Balaji T K <balajitk@...com>
Subject: Re: [PATCH v2 2/2] ata: ahci_platform: runtime resume the device
 before use


Hi,

On Wednesday, October 16, 2013 02:42:53 PM Roger Quadros wrote:
> On OMAP platforms the device needs to be runtime resumed before
> it can be accessed. The OMAP HWMOD framework takes care of
> enabling the module and its resources based on the
> device's runtime PM state.
> 
> In this patch we runtime resume during .probe() and runtime suspend
> during .remove() (i.e. ahci_host_stop()).
> 
> We also update the runtime PM state during .resume().
> 
> Signed-off-by: Roger Quadros <rogerq@...com>
> Signed-off-by: Balaji T K <balajitk@...com>
> ---
>  drivers/ata/ahci_platform.c |   12 ++++++++++++
>  1 file changed, 12 insertions(+)
> 
> diff --git a/drivers/ata/ahci_platform.c b/drivers/ata/ahci_platform.c
> index 5a0f1418..0da3b95 100644
> --- a/drivers/ata/ahci_platform.c
> +++ b/drivers/ata/ahci_platform.c
> @@ -23,6 +23,7 @@
>  #include <linux/platform_device.h>
>  #include <linux/libata.h>
>  #include <linux/ahci_platform.h>
> +#include <linux/pm_runtime.h>
>  #include "ahci.h"
>  
>  static void ahci_host_stop(struct ata_host *host);
> @@ -141,6 +142,9 @@ static int ahci_probe(struct platform_device *pdev)
>  		}
>  	}
>  
> +	pm_runtime_enable(dev);
> +	pm_runtime_get_sync(dev);
> +
>  	hpriv->phy = devm_phy_get(dev, "sata-phy");
>  	if (IS_ERR(hpriv->phy)) {
>  		dev_dbg(dev, "can't get sata-phy\n");
> @@ -268,6 +272,9 @@ static void ahci_host_stop(struct ata_host *host)
>  		clk_disable_unprepare(hpriv->clk);
>  		clk_put(hpriv->clk);
>  	}
> +
> +	pm_runtime_put_sync(dev);
> +	pm_runtime_disable(dev);

It would be better to add proper .remove callback (i.e. named
ahci_remove_one) and put this code there so it matches .probe
callback.

>  }
>  
>  #ifdef CONFIG_PM_SLEEP
> @@ -339,6 +346,11 @@ static int ahci_resume(struct device *dev)
>  
>  	ata_host_resume(host);
>  
> +	/* We resumed so update PM runtime state */
> +	pm_runtime_disable(dev);
> +	pm_runtime_set_active(dev);
> +	pm_runtime_enable(dev);
> +
>  	return 0;
>  
>  disable_unprepare_clk:

Best regards,
--
Bartlomiej Zolnierkiewicz
Samsung R&D Institute Poland
Samsung Electronics

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