linux-kernel - Re: [PATCH V3] MMC: PM: add suspend/resume in atmel-mci

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Date:	Mon, 04 Jul 2011 14:43:39 +0200
From:	Nicolas Ferre <nicolas.ferre@...el.com>
To:	balbi@...com
CC:	cjb@...top.org, linux-mmc@...r.kernel.org,
	hans-christian.egtvedt@...el.com, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, kernel@...32linux.org,
	u.kleine-koenig@...gutronix.de
Subject: Re: [PATCH V3] MMC: PM: add suspend/resume in atmel-mci

Le 04/07/2011 13:06, Felipe Balbi :
> Hi,
> 
> On Mon, Jul 04, 2011 at 01:38:25PM +0200, Nicolas Ferre wrote:
>> Take care of slots while going to suspend state.
>>
>> Signed-off-by: Nicolas Ferre <nicolas.ferre@...el.com>
>> ---
>> V3: take care of each slot SUSPENDED state
>>     (adding a status bit in the slot "flags")
>> V2: move to pm_ops
>>
>>  drivers/mmc/host/atmel-mci.c |   60 ++++++++++++++++++++++++++++++++++++++++++
>>  1 files changed, 60 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/host/atmel-mci.c b/drivers/mmc/host/atmel-mci.c
>> index aa8039f..ed63bcd 100644
>> --- a/drivers/mmc/host/atmel-mci.c
>> +++ b/drivers/mmc/host/atmel-mci.c
>> @@ -203,6 +203,7 @@ struct atmel_mci_slot {
>>  #define ATMCI_CARD_PRESENT	0
>>  #define ATMCI_CARD_NEED_INIT	1
>>  #define ATMCI_SHUTDOWN		2
>> +#define ATMCI_SUSPENDED		3
>>  
>>  	int			detect_pin;
>>  	int			wp_pin;
>> @@ -1878,10 +1879,69 @@ static int __exit atmci_remove(struct platform_device *pdev)
>>  	return 0;
>>  }
>>  
>> +#ifdef CONFIG_PM
>> +static int atmci_suspend(struct device *dev)
>> +{
>> +	struct atmel_mci *host = dev_get_drvdata(dev);
>> +	int i;
>> +
>> +	 for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
>> +		struct atmel_mci_slot *slot = host->slot[i];
>> +		int ret;
>> +
>> +		if (!slot)
>> +			continue;
>> +		ret = mmc_suspend_host(slot->mmc);
>> +		if (ret < 0) {
>> +			while (--i >= 0) {
>> +				slot = host->slot[i];
>> +				if (slot
>> +				&& test_bit(ATMCI_SUSPENDED, &slot->flags)) {
>> +					mmc_resume_host(host->slot[i]->mmc);
>> +					clear_bit(ATMCI_SUSPENDED, &slot->flags);
>> +				}
>> +			}
>> +			return ret;
>> +		} else {
>> +			set_bit(ATMCI_SUSPENDED, &slot->flags);
>> +		}
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>> +static int atmci_resume(struct device *dev)
>> +{
>> +	struct atmel_mci *host = dev_get_drvdata(dev);
>> +	int i;
>> +	int ret = 0;
>> +
>> +	for (i = 0; i < ATMEL_MCI_MAX_NR_SLOTS; i++) {
>> +		struct atmel_mci_slot *slot = host->slot[i];
>> +		int err;
>> +
>> +		slot = host->slot[i];
>> +		if (!slot)
>> +			continue;
>> +		if (!test_bit(ATMCI_SUSPENDED, &slot->flags))
>> +			continue;
>> +		err = mmc_resume_host(slot->mmc);
>> +		if (err < 0)
>> +			ret = err;
>> +		else
>> +			clear_bit(ATMCI_SUSPENDED, &slot->flags);
>> +	}
>> +
>> +	return ret;
>> +}
>> +#endif
>> +static SIMPLE_DEV_PM_OPS(atmci_pm, atmci_suspend, atmci_resume);
> 
> if you disable CONFIG_PM this won't work. atmci_resume and atmci_suspend
> will be undefined.
> 
>>  static struct platform_driver atmci_driver = {
>>  	.remove		= __exit_p(atmci_remove),
>>  	.driver		= {
>>  		.name		= "atmel_mci",
>> +		.pm		= &atmci_pm,
> 
> this pointer will also be invalid.
> 
> what most people do is:
> 
> #ifdef CONFIG_PM
> 
> suspend()
> resume()
> 
> static SIMPLE_DEV_PM_OPS(atmci_pm, suspend, resume);
> 
> #define DEV_PM_OPS	(&atmci_pm)
> #else
> #define DEV_PM_OPS	NULL
> #endif

Yes, sure that makes sense.

Thanks, I will cook a V4.

Best regards,
-- 
Nicolas Ferre

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