[v2,2/2] mmc: sdhci-of-aspeed: add inversion signal presence

Change the default .get_cd callback. Add inverted signal card detection
check.

Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>

On 14/11/19 2:54 PM, Ivan Mikhaylov wrote:
> Change the default .get_cd callback. Add inverted signal card detection
> check.
> 
> Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
> 
> diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-aspeed.c
> index 8962f6664381..186559ee8fcc 100644
> --- a/drivers/mmc/host/sdhci-of-aspeed.c
> +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> @@ -143,6 +143,19 @@ static inline int aspeed_sdhci_calculate_slot(struct aspeed_sdhci *dev,
>  	return (delta / 0x100) - 1;
>  }
>  
> +static int aspeed_get_cd(struct mmc_host *mmc)
> +{
> +	struct sdhci_host *host = mmc_priv(mmc);
> +
> +	int present = !!(sdhci_readl(host, SDHCI_PRESENT_STATE)
> +			 & SDHCI_CARD_PRESENT);
> +
> +	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> +		present = !present;

Perhaps safer to flip the bit using CONFIG_MMC_SDHCI_IO_ACCESSORS and
->readl() callback

> +
> +	return present;
> +}
> +
>  static int aspeed_sdhci_probe(struct platform_device *pdev)
>  {
>  	struct sdhci_pltfm_host *pltfm_host;
> @@ -183,6 +196,10 @@ static int aspeed_sdhci_probe(struct platform_device *pdev)
>  		goto err_pltfm_free;
>  	}
>  
> +	host->mmc_host_ops.get_cd = aspeed_get_cd;
> +	if (of_property_read_bool(pdev->dev.of_node, "cd-inverted"))
> +		dev_info(&pdev->dev, "aspeed: sdhci: presence signal inversion enabled\n");

Is this print really needed?

> +
>  	ret = mmc_of_parse(host->mmc);
>  	if (ret)
>  		goto err_sdhci_add;
>

On Thu, 2019-11-14 at 15:10 +0200, Adrian Hunter wrote:
> On 14/11/19 2:54 PM, Ivan Mikhaylov wrote:
> > Change the default .get_cd callback. Add inverted signal card detection
> > check.
> > 
> > Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
> > 
> > diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-
> > aspeed.c
> > index 8962f6664381..186559ee8fcc 100644
> > --- a/drivers/mmc/host/sdhci-of-aspeed.c
> > +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> > @@ -143,6 +143,19 @@ static inline int aspeed_sdhci_calculate_slot(struct
> > aspeed_sdhci *dev,
> >  	return (delta / 0x100) - 1;
> >  }
> >  
> > +static int aspeed_get_cd(struct mmc_host *mmc)
> > +{
> > +	struct sdhci_host *host = mmc_priv(mmc);
> > +
> > +	int present = !!(sdhci_readl(host, SDHCI_PRESENT_STATE)
> > +			 & SDHCI_CARD_PRESENT);
> > +
> > +	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> > +		present = !present;
> 
> Perhaps safer to flip the bit using CONFIG_MMC_SDHCI_IO_ACCESSORS and
> ->readl() callback
> 

Sorry, don't quite understand what you're saying. You want to instantiate
'.read_l' callback instead of '.get_cd' in sdhci_ops and substitute the real
value?

res = readl(base, reg);
if (reg == SDHCI_PRESENT_STATE)
	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
		return !res;
return res;

Something like this?

>  
> > +	host->mmc_host_ops.get_cd = aspeed_get_cd;
> > +	if (of_property_read_bool(pdev->dev.of_node, "cd-inverted"))
> > +		dev_info(&pdev->dev, "aspeed: sdhci: presence signal inversion
> > enabled\n");
> 
> Is this print really needed?
> 
I can remove it if you think it's redundant.

Thanks.

On 14/11/19 7:19 PM, Ivan Mikhaylov wrote:
> On Thu, 2019-11-14 at 15:10 +0200, Adrian Hunter wrote:
>> On 14/11/19 2:54 PM, Ivan Mikhaylov wrote:
>>> Change the default .get_cd callback. Add inverted signal card detection
>>> check.
>>>
>>> Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
>>>
>>> diff --git a/drivers/mmc/host/sdhci-of-aspeed.c b/drivers/mmc/host/sdhci-of-
>>> aspeed.c
>>> index 8962f6664381..186559ee8fcc 100644
>>> --- a/drivers/mmc/host/sdhci-of-aspeed.c
>>> +++ b/drivers/mmc/host/sdhci-of-aspeed.c
>>> @@ -143,6 +143,19 @@ static inline int aspeed_sdhci_calculate_slot(struct
>>> aspeed_sdhci *dev,
>>>  	return (delta / 0x100) - 1;
>>>  }
>>>  
>>> +static int aspeed_get_cd(struct mmc_host *mmc)
>>> +{
>>> +	struct sdhci_host *host = mmc_priv(mmc);
>>> +
>>> +	int present = !!(sdhci_readl(host, SDHCI_PRESENT_STATE)
>>> +			 & SDHCI_CARD_PRESENT);
>>> +
>>> +	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
>>> +		present = !present;
>>
>> Perhaps safer to flip the bit using CONFIG_MMC_SDHCI_IO_ACCESSORS and
>> ->readl() callback
>>
> 
> Sorry, don't quite understand what you're saying. You want to instantiate
> '.read_l' callback instead of '.get_cd' in sdhci_ops and substitute the real
> value?
> 
> res = readl(base, reg);
> if (reg == SDHCI_PRESENT_STATE)
> 	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> 		return !res;

Presumably just flip the SDHCI_CARD_PRESENT bit i.e.

		return res ^ SDHCI_CARD_PRESENT;

> return res;
> 
> Something like this?

Yes

> 
>>  
>>> +	host->mmc_host_ops.get_cd = aspeed_get_cd;
>>> +	if (of_property_read_bool(pdev->dev.of_node, "cd-inverted"))
>>> +		dev_info(&pdev->dev, "aspeed: sdhci: presence signal inversion
>>> enabled\n");
>>
>> Is this print really needed?
>>
> I can remove it if you think it's redundant.
> 
> Thanks.
> 
>

On Fri, 2019-11-15 at 09:20 +0200, Adrian Hunter wrote:
> On 14/11/19 7:19 PM, Ivan Mikhaylov wrote:
> > On Thu, 2019-11-14 at 15:10 +0200, Adrian Hunter wrote:
> > On 14/11/19 2:54 PM, Ivan Mikhaylov wrote:
> > > > Change the default .get_cd callback. Add inverted signal card detection
> > > > check.
> > > > 
> > > > Signed-off-by: Ivan Mikhaylov <i.mikhaylov@yadro.com>
> > > > 
> > > > diff --git a/drivers/mmc/host/sdhci-of-aspeed.c
> > > > b/drivers/mmc/host/sdhci-of-
> > > > aspeed.c
> > > > index 8962f6664381..186559ee8fcc 100644
> > > > --- a/drivers/mmc/host/sdhci-of-aspeed.c
> > > > +++ b/drivers/mmc/host/sdhci-of-aspeed.c
> > > > @@ -143,6 +143,19 @@ static inline int
> > > > aspeed_sdhci_calculate_slot(struct
> > > > aspeed_sdhci *dev,
> > > >  	return (delta / 0x100) - 1;
> > > >  }
> > > >  
> > > > +static int aspeed_get_cd(struct mmc_host *mmc)
> > > > +{
> > > > +	struct sdhci_host *host = mmc_priv(mmc);
> > > > +
> > > > +	int present = !!(sdhci_readl(host, SDHCI_PRESENT_STATE)
> > > > +			 & SDHCI_CARD_PRESENT);
> > > > +
> > > > +	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> > > > +		present = !present;
> > > 
> > > Perhaps safer to flip the bit using CONFIG_MMC_SDHCI_IO_ACCESSORS and
> > > ->readl() callback
> 
> 
> > Sorry, don't quite understand what you're saying. You want to instantiate
> > '.read_l' callback instead of '.get_cd' in sdhci_ops and substitute the real
> > value?
> > 
> > res = readl(base, reg);
> > if (reg == SDHCI_PRESENT_STATE)
> > 	if (mmc->caps2 & MMC_CAP2_CD_ACTIVE_HIGH)
> > 		return !res;
> 
> Presumably just flip the SDHCI_CARD_PRESENT bit i.e.
> 
> 		return res ^ SDHCI_CARD_PRESENT;
> 
> > return res;
> > 
> > Something like this?
> 
> Yes
> 

Don't you think it will bring a little overhead on any sdhci_readl plus
sdhci_readl will not get the real value in case of inverted signal which seems
is not right from communication fairness between hw and sw? I took that approach
with .get_cd from variety of drivers in host/mmc but if you think it will be
better and safer with .read_l - I'll do that way. 

Sorry for the link in subject, didn't notice that I put it in previous message
somehow.

Thanks.