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

From: Sascha Hauer <s.hauer@pengutronix.de>
To: Chaotian Jing <chaotian.jing@mediatek.com>
Cc: Rob Herring <robh+dt@kernel.org>,
	Matthias Brugger <matthias.bgg@gmail.com>,
	Chris Ball <chris@printf.net>,
	Ulf Hansson <ulf.hansson@linaro.org>,
	Mark Rutland <mark.rutland@arm.com>,
	James Liao <jamesjj.liao@mediatek.com>,
	srv_heupstream@mediatek.com, Arnd Bergmann <arnd@arndb.de>,
	devicetree@vger.kernel.org,
	Hongzhou Yang <hongzhou.yang@mediatek.com>,
	Catalin Marinas <catalin.marinas@arm.com>,
	bin.zhang@mediatek.com, linux-mmc@vger.kernel.org,
	linux-kernel@vger.kernel.org, Will Deacon <will.deacon@arm.com>,
	linux-gpio@vger.kernel.org, linux-mediatek@lists.infradead.org,
	Sascha Hauer <kernel@pengutronix.de>,
	"Joe.C" <yingjoe.chen@mediatek.com>,
	Eddie Huang <eddie.huang@mediatek.com>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH v2 3/5] mmc: mediatek: Add PM support for MMC driver
Date: Mon, 20 Apr 2015 08:49:10 +0200	[thread overview]
Message-ID: <20150420064910.GO4946@pengutronix.de> (raw)
In-Reply-To: <1426562035-16709-4-git-send-email-chaotian.jing@mediatek.com>

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@mediatek.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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