diff mbox

mmc: fix handling NULL returned from regulator_get()

Message ID 1305754664-2917-1-git-send-email-ospite@studenti.unina.it (mailing list archive)
State New, archived
Headers show

Commit Message

Antonio Ospite May 18, 2011, 9:37 p.m. UTC
When regulator_get() is stubbed down it returns NULL, handle this case
when deciding whether the driver can use the regulator or not.

Remember: IS_ERR(NULL) is false, see also this discussion for more
insight: http://comments.gmane.org/gmane.linux.kernel.mmc/7934

Now that regulator_get() is handled correctly, the ifdef on
CONFIG_REGULATOR in mmci.c can go away as well.

Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
---

 drivers/mmc/host/dw_mmc.c     |    2 +-
 drivers/mmc/host/mmci.c       |    4 +---
 drivers/mmc/host/mxcmmc.c     |    2 +-
 drivers/mmc/host/omap_hsmmc.c |    4 ++--
 drivers/mmc/host/sdhci.c      |    2 +-
 5 files changed, 6 insertions(+), 8 deletions(-)

Comments

Chris Ball May 18, 2011, 9:47 p.m. UTC | #1
Hi Antonio, thanks for doing this,

On Wed, May 18 2011, Antonio Ospite wrote:
> When regulator_get() is stubbed down it returns NULL, handle this case
> when deciding whether the driver can use the regulator or not.
>
> Remember: IS_ERR(NULL) is false, see also this discussion for more
> insight: http://comments.gmane.org/gmane.linux.kernel.mmc/7934
>
> Now that regulator_get() is handled correctly, the ifdef on
> CONFIG_REGULATOR in mmci.c can go away as well.
>
> Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
> ---
>
>  drivers/mmc/host/dw_mmc.c     |    2 +-
>  drivers/mmc/host/mmci.c       |    4 +---
>  drivers/mmc/host/mxcmmc.c     |    2 +-
>  drivers/mmc/host/omap_hsmmc.c |    4 ++--
>  drivers/mmc/host/sdhci.c      |    2 +-
>  5 files changed, 6 insertions(+), 8 deletions(-)
>
> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
> index 87e1f57..5be1325 100644
> --- a/drivers/mmc/host/dw_mmc.c
> +++ b/drivers/mmc/host/dw_mmc.c
> @@ -1442,7 +1442,7 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>  #endif /* CONFIG_MMC_DW_IDMAC */
>  
>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
> -	if (IS_ERR(host->vmmc)) {
> +	if (IS_ERR_OR_NULL(host->vmmc)) {
>  		printk(KERN_INFO "%s: no vmmc regulator found\n", mmc_hostname(mmc));
>  		host->vmmc = NULL;
>  	} else
> diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
> index b4a7e4f..6fac353 100644
> --- a/drivers/mmc/host/mmci.c
> +++ b/drivers/mmc/host/mmci.c
> @@ -1058,10 +1058,9 @@ static int __devinit mmci_probe(struct amba_device *dev,
>  		mmc->f_max = min(host->mclk, fmax);
>  	dev_dbg(mmc_dev(mmc), "clocking block at %u Hz\n", mmc->f_max);
>  
> -#ifdef CONFIG_REGULATOR
>  	/* If we're using the regulator framework, try to fetch a regulator */
>  	host->vcc = regulator_get(&dev->dev, "vmmc");
> -	if (IS_ERR(host->vcc))
> +	if (IS_ERR_OR_NULL(host->vcc))
>  		host->vcc = NULL;
>  	else {
>  		int mask = mmc_regulator_get_ocrmask(host->vcc);
> @@ -1077,7 +1076,6 @@ static int __devinit mmci_probe(struct amba_device *dev,
>  				 "(using regulator instead)\n");
>  		}
>  	}
> -#endif
>  	/* Fall back to platform data if no regulator is found */
>  	if (host->vcc == NULL)
>  		mmc->ocr_avail = plat->ocr_mask;
> diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
> index cc20e02..a9152da 100644
> --- a/drivers/mmc/host/mxcmmc.c
> +++ b/drivers/mmc/host/mxcmmc.c
> @@ -155,7 +155,7 @@ static inline void mxcmci_init_ocr(struct mxcmci_host *host)
>  {
>  	host->vcc = regulator_get(mmc_dev(host->mmc), "vmmc");
>  
> -	if (IS_ERR(host->vcc)) {
> +	if (IS_ERR_OR_NULL(host->vcc)) {
>  		host->vcc = NULL;
>  	} else {
>  		host->mmc->ocr_avail = mmc_regulator_get_ocrmask(host->vcc);
> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
> index 259ece0..45fd4fe 100644
> --- a/drivers/mmc/host/omap_hsmmc.c
> +++ b/drivers/mmc/host/omap_hsmmc.c
> @@ -405,7 +405,7 @@ static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
>  	}
>  
>  	reg = regulator_get(host->dev, "vmmc");
> -	if (IS_ERR(reg)) {
> +	if (IS_ERR_OR_NULL(reg)) {
>  		dev_dbg(host->dev, "vmmc regulator missing\n");
>  		/*
>  		* HACK: until fixed.c regulator is usable,
> @@ -433,7 +433,7 @@ static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
>  
>  		/* Allow an aux regulator */
>  		reg = regulator_get(host->dev, "vmmc_aux");
> -		host->vcc_aux = IS_ERR(reg) ? NULL : reg;
> +		host->vcc_aux = IS_ERR_OR_NULL(reg) ? NULL : reg;
>  
>  		/*
>  		* UGLY HACK:  workaround regulator framework bugs.
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 5d20661..d3585d4 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2004,7 +2004,7 @@ int sdhci_add_host(struct sdhci_host *host)
>  		goto untasklet;
>  
>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
> -	if (IS_ERR(host->vmmc)) {
> +	if (IS_ERR_OR_NULL(host->vmmc)) {
>  		printk(KERN_INFO "%s: no vmmc regulator found\n", mmc_hostname(mmc));
>  		host->vmmc = NULL;
>  	} else {

I think I like this change for every driver *except* sdhci -- users who
compile with CONFIG_REGULATOR=n (i.e. most distros) will start seeing
"mmc0: no vmmc regulator found" when they boot their x86 laptops, and
printing a cryptic regulator error message when regulator support isn't
even compiled in seems uncalled for.

So, I think my suggestion is to merge all but the last hunk of the
patch.  How do others feel about it?

Thanks,

- Chris.
Lars-Peter Clausen May 19, 2011, 2:10 a.m. UTC | #2
On 05/18/2011 02:47 PM, Chris Ball wrote:
> Hi Antonio, thanks for doing this,
> 
> On Wed, May 18 2011, Antonio Ospite wrote:
>> When regulator_get() is stubbed down it returns NULL, handle this case
>> when deciding whether the driver can use the regulator or not.
>>
>> Remember: IS_ERR(NULL) is false, see also this discussion for more
>> insight: http://comments.gmane.org/gmane.linux.kernel.mmc/7934
>>
>> Now that regulator_get() is handled correctly, the ifdef on
>> CONFIG_REGULATOR in mmci.c can go away as well.
>>
>> Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
>> ---
>>
>>  drivers/mmc/host/dw_mmc.c     |    2 +-
>>  drivers/mmc/host/mmci.c       |    4 +---
>>  drivers/mmc/host/mxcmmc.c     |    2 +-
>>  drivers/mmc/host/omap_hsmmc.c |    4 ++--
>>  drivers/mmc/host/sdhci.c      |    2 +-
>>  5 files changed, 6 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>> index 87e1f57..5be1325 100644
>> --- a/drivers/mmc/host/dw_mmc.c
>> +++ b/drivers/mmc/host/dw_mmc.c
>> @@ -1442,7 +1442,7 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>>  #endif /* CONFIG_MMC_DW_IDMAC */
>>  
>>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
>> -	if (IS_ERR(host->vmmc)) {
>> +	if (IS_ERR_OR_NULL(host->vmmc)) {
>>  		printk(KERN_INFO "%s: no vmmc regulator found\n", mmc_hostname(mmc));
>>  		host->vmmc = NULL;
>>  	} else
>> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
>> index 259ece0..45fd4fe 100644
>> --- a/drivers/mmc/host/omap_hsmmc.c
>> +++ b/drivers/mmc/host/omap_hsmmc.c
>> @@ -405,7 +405,7 @@ static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
>>  	}
>>  
>>  	reg = regulator_get(host->dev, "vmmc");
>> -	if (IS_ERR(reg)) {
>> +	if (IS_ERR_OR_NULL(reg)) {
>>  		dev_dbg(host->dev, "vmmc regulator missing\n");
>>  		/*
>>  		* HACK: until fixed.c regulator is usable,
>>  	} else {
>> [...] 
> I think I like this change for every driver *except* sdhci -- users who
> compile with CONFIG_REGULATOR=n (i.e. most distros) will start seeing
> "mmc0: no vmmc regulator found" when they boot their x86 laptops, and
> printing a cryptic regulator error message when regulator support isn't
> even compiled in seems uncalled for.
> 
> So, I think my suggestion is to merge all but the last hunk of the
> patch.  How do others feel about it?
> 

dw_mmc and omap_hsmmc will also print error messages if the regulator framework
is not build-in. I suggest to use something like:

if (IS_ERR(vmmc)) {
	... do error handling
} else if(vmmc) {
	... use regulator
} else {
	... fallback code to initialize ocr_avail
}

- Lars
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Jaehoon Chung May 19, 2011, 5:14 a.m. UTC | #3
Lars-Peter Clausen wrote:
> On 05/18/2011 02:47 PM, Chris Ball wrote:
>> Hi Antonio, thanks for doing this,
>>
>> On Wed, May 18 2011, Antonio Ospite wrote:
>>> When regulator_get() is stubbed down it returns NULL, handle this case
>>> when deciding whether the driver can use the regulator or not.
>>>
>>> Remember: IS_ERR(NULL) is false, see also this discussion for more
>>> insight: http://comments.gmane.org/gmane.linux.kernel.mmc/7934
>>>
>>> Now that regulator_get() is handled correctly, the ifdef on
>>> CONFIG_REGULATOR in mmci.c can go away as well.
>>>
>>> Signed-off-by: Antonio Ospite <ospite@studenti.unina.it>
>>> ---
>>>
>>>  drivers/mmc/host/dw_mmc.c     |    2 +-
>>>  drivers/mmc/host/mmci.c       |    4 +---
>>>  drivers/mmc/host/mxcmmc.c     |    2 +-
>>>  drivers/mmc/host/omap_hsmmc.c |    4 ++--
>>>  drivers/mmc/host/sdhci.c      |    2 +-
>>>  5 files changed, 6 insertions(+), 8 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
>>> index 87e1f57..5be1325 100644
>>> --- a/drivers/mmc/host/dw_mmc.c
>>> +++ b/drivers/mmc/host/dw_mmc.c
>>> @@ -1442,7 +1442,7 @@ static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
>>>  #endif /* CONFIG_MMC_DW_IDMAC */
>>>  
>>>  	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
>>> -	if (IS_ERR(host->vmmc)) {
>>> +	if (IS_ERR_OR_NULL(host->vmmc)) {
>>>  		printk(KERN_INFO "%s: no vmmc regulator found\n", mmc_hostname(mmc));
>>>  		host->vmmc = NULL;
>>>  	} else
>>> diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
>>> index 259ece0..45fd4fe 100644
>>> --- a/drivers/mmc/host/omap_hsmmc.c
>>> +++ b/drivers/mmc/host/omap_hsmmc.c
>>> @@ -405,7 +405,7 @@ static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
>>>  	}
>>>  
>>>  	reg = regulator_get(host->dev, "vmmc");
>>> -	if (IS_ERR(reg)) {
>>> +	if (IS_ERR_OR_NULL(reg)) {
>>>  		dev_dbg(host->dev, "vmmc regulator missing\n");
>>>  		/*
>>>  		* HACK: until fixed.c regulator is usable,
>>>  	} else {
>>> [...] 
>> I think I like this change for every driver *except* sdhci -- users who
>> compile with CONFIG_REGULATOR=n (i.e. most distros) will start seeing
>> "mmc0: no vmmc regulator found" when they boot their x86 laptops, and
>> printing a cryptic regulator error message when regulator support isn't
>> even compiled in seems uncalled for.
>>
>> So, I think my suggestion is to merge all but the last hunk of the
>> patch.  How do others feel about it?
>>
> 
> dw_mmc and omap_hsmmc will also print error messages if the regulator framework
> is not build-in. I suggest to use something like:
> 
> if (IS_ERR(vmmc)) {
> 	... do error handling
> } else if(vmmc) {
> 	... use regulator
> } else {
> 	... fallback code to initialize ocr_avail
> }
> 

if we use IS_ERR_OR_NULL(), i think that we can confuse sometimes.
Because, When we set CONFIG_REGULATOR = n, we can find "mmc0: no vmmc regulator found".
That message means "error or not use regulator framework".
But by that message, we can't know whether error or not use regulator framework.

So i think that Lars's suggestion is better than IS_ERR_OR_NULL.

Regards,
Jaeehoon Chung

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diff mbox

Patch

diff --git a/drivers/mmc/host/dw_mmc.c b/drivers/mmc/host/dw_mmc.c
index 87e1f57..5be1325 100644
--- a/drivers/mmc/host/dw_mmc.c
+++ b/drivers/mmc/host/dw_mmc.c
@@ -1442,7 +1442,7 @@  static int __init dw_mci_init_slot(struct dw_mci *host, unsigned int id)
 #endif /* CONFIG_MMC_DW_IDMAC */
 
 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
-	if (IS_ERR(host->vmmc)) {
+	if (IS_ERR_OR_NULL(host->vmmc)) {
 		printk(KERN_INFO "%s: no vmmc regulator found\n", mmc_hostname(mmc));
 		host->vmmc = NULL;
 	} else
diff --git a/drivers/mmc/host/mmci.c b/drivers/mmc/host/mmci.c
index b4a7e4f..6fac353 100644
--- a/drivers/mmc/host/mmci.c
+++ b/drivers/mmc/host/mmci.c
@@ -1058,10 +1058,9 @@  static int __devinit mmci_probe(struct amba_device *dev,
 		mmc->f_max = min(host->mclk, fmax);
 	dev_dbg(mmc_dev(mmc), "clocking block at %u Hz\n", mmc->f_max);
 
-#ifdef CONFIG_REGULATOR
 	/* If we're using the regulator framework, try to fetch a regulator */
 	host->vcc = regulator_get(&dev->dev, "vmmc");
-	if (IS_ERR(host->vcc))
+	if (IS_ERR_OR_NULL(host->vcc))
 		host->vcc = NULL;
 	else {
 		int mask = mmc_regulator_get_ocrmask(host->vcc);
@@ -1077,7 +1076,6 @@  static int __devinit mmci_probe(struct amba_device *dev,
 				 "(using regulator instead)\n");
 		}
 	}
-#endif
 	/* Fall back to platform data if no regulator is found */
 	if (host->vcc == NULL)
 		mmc->ocr_avail = plat->ocr_mask;
diff --git a/drivers/mmc/host/mxcmmc.c b/drivers/mmc/host/mxcmmc.c
index cc20e02..a9152da 100644
--- a/drivers/mmc/host/mxcmmc.c
+++ b/drivers/mmc/host/mxcmmc.c
@@ -155,7 +155,7 @@  static inline void mxcmci_init_ocr(struct mxcmci_host *host)
 {
 	host->vcc = regulator_get(mmc_dev(host->mmc), "vmmc");
 
-	if (IS_ERR(host->vcc)) {
+	if (IS_ERR_OR_NULL(host->vcc)) {
 		host->vcc = NULL;
 	} else {
 		host->mmc->ocr_avail = mmc_regulator_get_ocrmask(host->vcc);
diff --git a/drivers/mmc/host/omap_hsmmc.c b/drivers/mmc/host/omap_hsmmc.c
index 259ece0..45fd4fe 100644
--- a/drivers/mmc/host/omap_hsmmc.c
+++ b/drivers/mmc/host/omap_hsmmc.c
@@ -405,7 +405,7 @@  static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
 	}
 
 	reg = regulator_get(host->dev, "vmmc");
-	if (IS_ERR(reg)) {
+	if (IS_ERR_OR_NULL(reg)) {
 		dev_dbg(host->dev, "vmmc regulator missing\n");
 		/*
 		* HACK: until fixed.c regulator is usable,
@@ -433,7 +433,7 @@  static int omap_hsmmc_reg_get(struct omap_hsmmc_host *host)
 
 		/* Allow an aux regulator */
 		reg = regulator_get(host->dev, "vmmc_aux");
-		host->vcc_aux = IS_ERR(reg) ? NULL : reg;
+		host->vcc_aux = IS_ERR_OR_NULL(reg) ? NULL : reg;
 
 		/*
 		* UGLY HACK:  workaround regulator framework bugs.
diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 5d20661..d3585d4 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -2004,7 +2004,7 @@  int sdhci_add_host(struct sdhci_host *host)
 		goto untasklet;
 
 	host->vmmc = regulator_get(mmc_dev(mmc), "vmmc");
-	if (IS_ERR(host->vmmc)) {
+	if (IS_ERR_OR_NULL(host->vmmc)) {
 		printk(KERN_INFO "%s: no vmmc regulator found\n", mmc_hostname(mmc));
 		host->vmmc = NULL;
 	} else {