linux-kernel - Re: [PATCH 1/2] mmc: dw_mmc: Make sure we only adjust the clock when power is on

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Date:	Wed, 25 Feb 2015 19:34:48 +0900
From:	Jaehoon Chung <jh80.chung@...sung.com>
To:	Doug Anderson <dianders@...omium.org>,
	Seungwon Jeon <tgih.jun@...sung.com>,
	Ulf Hansson <ulf.hansson@...aro.org>
Cc:	Alim Akhtar <alim.akhtar@...sung.com>,
	Sonny Rao <sonnyrao@...omium.org>,
	Andrew Bresticker <abrestic@...omium.org>,
	Heiko Stuebner <heiko@...ech.de>,
	Addy Ke <addy.ke@...k-chips.com>,
	Alexandru Stan <amstan@...omium.org>,
	javier.martinez@...labora.co.uk, chris@...ntf.net,
	linux-mmc@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH 1/2] mmc: dw_mmc: Make sure we only adjust the clock when
 power is on

Hi, Doug.

It makes sense. Looks good to me. Thanks!

Acked-by: Jaehoon Chung <jh80.chung@...sung.com>

Best Regards,
Jaehoon Chung

On 02/21/2015 03:57 AM, Doug Anderson wrote:
> It appears that we can confuse things if we try to turn on the MMC
> clock when the power is off.  Adjust is so that we turn the clock on
> (using dw_mci_setup_bus) after power is all the way on and we turn the
> clock off before the power goes off.
> 
> Signed-off-by: Doug Anderson <dianders@...omium.org>
> ---
>  drivers/mmc/host/dw_mmc.c | 16 ++++++++++------
>  1 file changed, 10 insertions(+), 6 deletions(-)
> 
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 4d2e3c2..43fcae1 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1101,12 +1101,6 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  	if (drv_data && drv_data->set_ios)
>  		drv_data->set_ios(slot->host, ios);
>  
> -	/* Slot specific timing and width adjustment */
> -	dw_mci_setup_bus(slot, false);
> -
> -	if (slot->host->state == STATE_WAITING_CMD11_DONE && ios->clock != 0)
> -		slot->host->state = STATE_IDLE;
> -
>  	switch (ios->power_mode) {
>  	case MMC_POWER_UP:
>  		if (!IS_ERR(mmc->supply.vmmc)) {
> @@ -1133,8 +1127,15 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  			else
>  				slot->host->vqmmc_enabled = true;
>  		}
> +
> +		/* Adjust clock / bus width after power is up */
> +		dw_mci_setup_bus(slot, false);
> +
>  		break;
>  	case MMC_POWER_OFF:
> +		/* Turn clock off before power goes down */
> +		dw_mci_setup_bus(slot, false);
> +
>  		if (!IS_ERR(mmc->supply.vmmc))
>  			mmc_regulator_set_ocr(mmc, mmc->supply.vmmc, 0);
>  
> @@ -1150,6 +1151,9 @@ static void dw_mci_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>  	default:
>  		break;
>  	}
> +
> +	if (slot->host->state == STATE_WAITING_CMD11_DONE && ios->clock != 0)
> +		slot->host->state = STATE_IDLE;
>  }
>  
>  static int dw_mci_card_busy(struct mmc_host *mmc)
> 

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