linux-kernel - Re: [PATCH v2 3/5] mmc: mediatek: Add PM support for MMC driver

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Date:	Mon, 20 Apr 2015 08:49:10 +0200
From:	Sascha Hauer <s.hauer@...gutronix.de>
To:	Chaotian Jing <chaotian.jing@...iatek.com>
Cc:	Rob Herring <robh+dt@...nel.org>,
	Matthias Brugger <matthias.bgg@...il.com>,
	Chris Ball <chris@...ntf.net>,
	Ulf Hansson <ulf.hansson@...aro.org>,
	Mark Rutland <mark.rutland@....com>,
	James Liao <jamesjj.liao@...iatek.com>,
	srv_heupstream@...iatek.com, Arnd Bergmann <arnd@...db.de>,
	devicetree@...r.kernel.org,
	Hongzhou Yang <hongzhou.yang@...iatek.com>,
	Catalin Marinas <catalin.marinas@....com>,
	bin.zhang@...iatek.com, linux-mmc@...r.kernel.org,
	linux-kernel@...r.kernel.org, Will Deacon <will.deacon@....com>,
	linux-gpio@...r.kernel.org, linux-mediatek@...ts.infradead.org,
	Sascha Hauer <kernel@...gutronix.de>,
	"Joe.C" <yingjoe.chen@...iatek.com>,
	Eddie Huang <eddie.huang@...iatek.com>,
	linux-arm-kernel@...ts.infradead.org
Subject: Re: [PATCH v2 3/5] mmc: mediatek: Add PM support for MMC driver

On Tue, Mar 17, 2015 at 11:13:53AM +0800, Chaotian Jing wrote:
> Add PM support for Mediatek MMC driver
> 
> Signed-off-by: Chaotian Jing <chaotian.jing@...iatek.com>
> ---
>  drivers/mmc/host/mtk-sd.c | 94 ++++++++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 93 insertions(+), 1 deletion(-)
> 
> @@ -1003,6 +1042,8 @@ static int msdc_ops_switch_volt(struct mmc_host *mmc, struct mmc_ios *ios)
>  
>  	if (!IS_ERR(mmc->supply.vqmmc)) {
>  
> +		pm_runtime_get_sync(host->dev);
> +
>  		if (ios->signal_voltage == MMC_SIGNAL_VOLTAGE_330) {
>  			min_uv = 3300000;
>  			max_uv = 3300000;
> @@ -1011,6 +1052,9 @@ static int msdc_ops_switch_volt(struct mmc_host *mmc, struct mmc_ios *ios)
>  			max_uv = 1800000;
>  		} else {
>  			dev_err(host->dev, "Unsupported signal voltage!\n");
> +
> +			pm_runtime_mark_last_busy(host->dev);
> +			pm_runtime_put_autosuspend(host->dev);
>  			return -EINVAL;
>  		}
>  
> @@ -1022,6 +1066,8 @@ static int msdc_ops_switch_volt(struct mmc_host *mmc, struct mmc_ios *ios)
>  		}
>  	}
>  
> +	pm_runtime_mark_last_busy(host->dev);
> +	pm_runtime_put_autosuspend(host->dev);

This is unbalanced. You do a pm_runtime_get_sync() depending on
!IS_ERR(mmc->supply.vqmmc), but you call pm_runtime_put_autosuspend()
unconditionally. Besides, I don't see that the pm_ops are necessary here
at all. This function does nothing on the controller.

Sascha


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