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[RFC,1/2] mmc: sdhci: Allow platform controlled voltage switching

Message ID 1529583826-42020-2-git-send-email-vviswana@codeaurora.org (mailing list archive)
State Not Applicable, archived
Headers show

Commit Message

Vijay Viswanath June 21, 2018, 12:23 p.m. UTC
Some controllers can have internal mechanism to inform the SW that it
is ready for voltage switching. For such controllers, changing voltage
before the HW is ready can result in various issues.

Add a quirk, which can be used by drivers of such controllers.

Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
---
 drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
 drivers/mmc/host/sdhci.h |  2 ++
 2 files changed, 17 insertions(+), 5 deletions(-)

Comments

Adrian Hunter July 10, 2018, 11:07 a.m. UTC | #1
On 21/06/18 15:23, Vijay Viswanath wrote:
> Some controllers can have internal mechanism to inform the SW that it
> is ready for voltage switching. For such controllers, changing voltage
> before the HW is ready can result in various issues.
> 
> Add a quirk, which can be used by drivers of such controllers.
> 
> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
> ---
>  drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>  drivers/mmc/host/sdhci.h |  2 ++
>  2 files changed, 17 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index 1c828e0..f0346d4 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
>  void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>  		     unsigned short vdd)
>  {
> -	if (IS_ERR(host->mmc->supply.vmmc))
> +	if (IS_ERR(host->mmc->supply.vmmc) ||
> +			(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))

I think you should provide your own ->set_power() instead of this

>  		sdhci_set_power_noreg(host, mode, vdd);
>  	else
>  		sdhci_set_power_reg(host, mode, vdd);
> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
>  		ctrl &= ~SDHCI_CTRL_VDD_180;
>  		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>  
> -		if (!IS_ERR(mmc->supply.vqmmc)) {
> +		if (!IS_ERR(mmc->supply.vqmmc) &&
> +				!(host->quirks2 &
> +					SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {

And your own ->start_signal_voltage_switch()

>  			ret = mmc_regulator_set_vqmmc(mmc, ios);
>  			if (ret) {
>  				pr_warn("%s: Switching to 3.3V signalling voltage failed\n",
> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
>  	case MMC_SIGNAL_VOLTAGE_180:
>  		if (!(host->flags & SDHCI_SIGNALING_180))
>  			return -EINVAL;
> -		if (!IS_ERR(mmc->supply.vqmmc)) {
> +		if (!IS_ERR(mmc->supply.vqmmc) &&
> +			!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>  			ret = mmc_regulator_set_vqmmc(mmc, ios);
>  			if (ret) {
>  				pr_warn("%s: Switching to 1.8V signalling voltage failed\n",
> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>  	 * the host can take the appropriate action if regulators are not
>  	 * available.
>  	 */
> -	ret = mmc_regulator_get_supply(mmc);
> +	if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))

Since we expect mmc_regulator_get_supply() to have been called, this could be:

	if (!mmc->supply.vmmc) {
		ret = mmc_regulator_get_supply(mmc);
		enable_vqmmc = true;
	} else {
		ret = 0;
	}

> +		ret = mmc_regulator_get_supply(mmc);
> +	else
> +		ret = 0;
>  	if (ret)
>  		return ret;
>  
> @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>  
>  	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
>  	if (!IS_ERR(mmc->supply.vqmmc)) {
> -		ret = regulator_enable(mmc->supply.vqmmc);
> +		if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))

And this could be:

		if (enable_vqmmc)
			ret = regulator_enable(mmc->supply.vqmmc);
		else
			ret = 0;

However, you still need to ensure regulator_disable(mmc->supply.vqmmc) is
only called if regulator_enable() was called.

> +			ret = regulator_enable(mmc->supply.vqmmc);
> +		else
> +			ret = 0;
>  		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>  						    1950000))
>  			host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
> index 23966f8..3b0c97a 100644
> --- a/drivers/mmc/host/sdhci.h
> +++ b/drivers/mmc/host/sdhci.h
> @@ -450,6 +450,8 @@ struct sdhci_host {
>   * obtainable timeout.
>   */
>  #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT			(1<<17)
> +/* Regulator voltage changes are being done from platform layer */
> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL				(1<<18)

So maybe the quirk is not needed.

>  
>  	int irq;		/* Device IRQ */
>  	void __iomem *ioaddr;	/* Mapped address */
> 

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Vijay Viswanath July 17, 2018, 5:14 a.m. UTC | #2
On 7/10/2018 4:37 PM, Adrian Hunter wrote:
> On 21/06/18 15:23, Vijay Viswanath wrote:
>> Some controllers can have internal mechanism to inform the SW that it
>> is ready for voltage switching. For such controllers, changing voltage
>> before the HW is ready can result in various issues.
>>
>> Add a quirk, which can be used by drivers of such controllers.
>>
>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>> ---
>>   drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>   drivers/mmc/host/sdhci.h |  2 ++
>>   2 files changed, 17 insertions(+), 5 deletions(-)
>>
>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>> index 1c828e0..f0346d4 100644
>> --- a/drivers/mmc/host/sdhci.c
>> +++ b/drivers/mmc/host/sdhci.c
>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
>>   void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>   		     unsigned short vdd)
>>   {
>> -	if (IS_ERR(host->mmc->supply.vmmc))
>> +	if (IS_ERR(host->mmc->supply.vmmc) ||
>> +			(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
> 
> I think you should provide your own ->set_power() instead of this
> 

will do

>>   		sdhci_set_power_noreg(host, mode, vdd);
>>   	else
>>   		sdhci_set_power_reg(host, mode, vdd);
>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
>>   		ctrl &= ~SDHCI_CTRL_VDD_180;
>>   		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>   
>> -		if (!IS_ERR(mmc->supply.vqmmc)) {
>> +		if (!IS_ERR(mmc->supply.vqmmc) &&
>> +				!(host->quirks2 &
>> +					SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
> 
> And your own ->start_signal_voltage_switch()
> 

sdhci_msm_start_signal_voltage_switch() would be an exact copy of 
sdhci_start_signal_voltage_switch()..... will incorporate this if not 
using quirk.

>>   			ret = mmc_regulator_set_vqmmc(mmc, ios);
>>   			if (ret) {
>>   				pr_warn("%s: Switching to 3.3V signalling voltage failed\n",
>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
>>   	case MMC_SIGNAL_VOLTAGE_180:
>>   		if (!(host->flags & SDHCI_SIGNALING_180))
>>   			return -EINVAL;
>> -		if (!IS_ERR(mmc->supply.vqmmc)) {
>> +		if (!IS_ERR(mmc->supply.vqmmc) &&
>> +			!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>   			ret = mmc_regulator_set_vqmmc(mmc, ios);
>>   			if (ret) {
>>   				pr_warn("%s: Switching to 1.8V signalling voltage failed\n",
>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   	 * the host can take the appropriate action if regulators are not
>>   	 * available.
>>   	 */
>> -	ret = mmc_regulator_get_supply(mmc);
>> +	if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
> 
> Since we expect mmc_regulator_get_supply() to have been called, this could be:
> 
> 	if (!mmc->supply.vmmc) {
> 		ret = mmc_regulator_get_supply(mmc);
> 		enable_vqmmc = true;
> 	} else {
> 		ret = 0;
> 	}
> >> +		ret = mmc_regulator_get_supply(mmc);
>> +	else
>> +		ret = 0;
>>   	if (ret)
>>   		return ret;
>>   
>> @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>   
>>   	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
>>   	if (!IS_ERR(mmc->supply.vqmmc)) {
>> -		ret = regulator_enable(mmc->supply.vqmmc);
>> +		if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
> 
> And this could be:
> 
> 		if (enable_vqmmc)
> 			ret = regulator_enable(mmc->supply.vqmmc);
> 		else
> 			ret = 0;
>  > However, you still need to ensure regulator_disable(mmc->supply.vqmmc) is
> only called if regulator_enable() was called.
I missed this. Will cover it.

Also I missed one more place where we are doing regulator_disable. 
During sdhci-msm unbinding, we would end up doing an extra regulator 
disable (thanks Evan for pointing it out) in sdhci_remove_host.

To avoid the quirk( or having any flag), it would require copying the 
code of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and 
creating 2 new functions in sdhci_msm layer which would do the exact 
same as above, with just the regulator parts removed.

This looks messy (considering any future changes to the 2 sdhci API will 
need to be copied to their duplicate sdhci_msm API) and a bit overkill 
to avoid quirk. At the same time, I don't know how useful such a quirk 
would be to other platform drivers.

Please let me know your view/suggestions.
> 
>> +			ret = regulator_enable(mmc->supply.vqmmc);
>> +		else
>> +			ret = 0;
>>   		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>>   						    1950000))
>>   			host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>> index 23966f8..3b0c97a 100644
>> --- a/drivers/mmc/host/sdhci.h
>> +++ b/drivers/mmc/host/sdhci.h
>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>    * obtainable timeout.
>>    */
>>   #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT			(1<<17)
>> +/* Regulator voltage changes are being done from platform layer */
>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL				(1<<18)
> 
> So maybe the quirk is not needed.
> 
>>   
>>   	int irq;		/* Device IRQ */
>>   	void __iomem *ioaddr;	/* Mapped address */
>>
> 

Thanks for the review & suggestions!
Vijay
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Adrian Hunter July 17, 2018, 7:30 a.m. UTC | #3
On 17/07/18 08:14, Vijay Viswanath wrote:
> 
> 
> On 7/10/2018 4:37 PM, Adrian Hunter wrote:
>> On 21/06/18 15:23, Vijay Viswanath wrote:
>>> Some controllers can have internal mechanism to inform the SW that it
>>> is ready for voltage switching. For such controllers, changing voltage
>>> before the HW is ready can result in various issues.
>>>
>>> Add a quirk, which can be used by drivers of such controllers.
>>>
>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>>> ---
>>>   drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>>   drivers/mmc/host/sdhci.h |  2 ++
>>>   2 files changed, 17 insertions(+), 5 deletions(-)
>>>
>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>> index 1c828e0..f0346d4 100644
>>> --- a/drivers/mmc/host/sdhci.c
>>> +++ b/drivers/mmc/host/sdhci.c
>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host,
>>> unsigned char mode,
>>>   void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>>                unsigned short vdd)
>>>   {
>>> -    if (IS_ERR(host->mmc->supply.vmmc))
>>> +    if (IS_ERR(host->mmc->supply.vmmc) ||
>>> +            (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>
>> I think you should provide your own ->set_power() instead of this
>>
> 
> will do
> 
>>>           sdhci_set_power_noreg(host, mode, vdd);
>>>       else
>>>           sdhci_set_power_reg(host, mode, vdd);
>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct
>>> mmc_host *mmc,
>>>           ctrl &= ~SDHCI_CTRL_VDD_180;
>>>           sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>>   -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>> +                !(host->quirks2 &
>>> +                    SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>
>> And your own ->start_signal_voltage_switch()
>>
> 
> sdhci_msm_start_signal_voltage_switch() would be an exact copy of
> sdhci_start_signal_voltage_switch()..... will incorporate this if not using
> quirk.
> 
>>>               ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>               if (ret) {
>>>                   pr_warn("%s: Switching to 3.3V signalling voltage
>>> failed\n",
>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct
>>> mmc_host *mmc,
>>>       case MMC_SIGNAL_VOLTAGE_180:
>>>           if (!(host->flags & SDHCI_SIGNALING_180))
>>>               return -EINVAL;
>>> -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>> +            !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>               ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>               if (ret) {
>>>                   pr_warn("%s: Switching to 1.8V signalling voltage
>>> failed\n",
>>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>        * the host can take the appropriate action if regulators are not
>>>        * available.
>>>        */
>>> -    ret = mmc_regulator_get_supply(mmc);
>>> +    if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>
>> Since we expect mmc_regulator_get_supply() to have been called, this could
>> be:
>>
>>     if (!mmc->supply.vmmc) {
>>         ret = mmc_regulator_get_supply(mmc);
>>         enable_vqmmc = true;
>>     } else {
>>         ret = 0;
>>     }
>> >> +        ret = mmc_regulator_get_supply(mmc);
>>> +    else
>>> +        ret = 0;
>>>       if (ret)
>>>           return ret;
>>>   @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>         /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
>>>       if (!IS_ERR(mmc->supply.vqmmc)) {
>>> -        ret = regulator_enable(mmc->supply.vqmmc);
>>> +        if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>
>> And this could be:
>>
>>         if (enable_vqmmc)
>>             ret = regulator_enable(mmc->supply.vqmmc);
>>         else
>>             ret = 0;
>>  > However, you still need to ensure regulator_disable(mmc->supply.vqmmc) is
>> only called if regulator_enable() was called.
> I missed this. Will cover it.
> 
> Also I missed one more place where we are doing regulator_disable. During
> sdhci-msm unbinding, we would end up doing an extra regulator disable
> (thanks Evan for pointing it out) in sdhci_remove_host.
> 
> To avoid the quirk( or having any flag), it would require copying the code
> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and creating

You do not need to duplicate sdhci_remove_host(), just change it so that it
only  disables what was enabled i.e.

	if (host->vqmmc_enabled)
		regulator_disable(mmc->supply.vqmmc);

> 2 new functions in sdhci_msm layer which would do the exact same as above,
> with just the regulator parts removed.
> 
> This looks messy (considering any future changes to the 2 sdhci API will
> need to be copied to their duplicate sdhci_msm API) and a bit overkill to
> avoid quirk. At the same time, I don't know how useful such a quirk would be
> to other platform drivers.
> 
> Please let me know your view/suggestions.

Let's try without the quirk.

>>
>>> +            ret = regulator_enable(mmc->supply.vqmmc);
>>> +        else
>>> +            ret = 0;
>>>           if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>>>                               1950000))
>>>               host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>> index 23966f8..3b0c97a 100644
>>> --- a/drivers/mmc/host/sdhci.h
>>> +++ b/drivers/mmc/host/sdhci.h
>>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>>    * obtainable timeout.
>>>    */
>>>   #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT            (1<<17)
>>> +/* Regulator voltage changes are being done from platform layer */
>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL                (1<<18)
>>
>> So maybe the quirk is not needed.
>>
>>>         int irq;        /* Device IRQ */
>>>       void __iomem *ioaddr;    /* Mapped address */
>>>
>>
> 
> Thanks for the review & suggestions!
> Vijay
> 

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Vijay Viswanath July 17, 2018, 8:40 a.m. UTC | #4
On 7/17/2018 1:00 PM, Adrian Hunter wrote:
> On 17/07/18 08:14, Vijay Viswanath wrote:
>>
>>
>> On 7/10/2018 4:37 PM, Adrian Hunter wrote:
>>> On 21/06/18 15:23, Vijay Viswanath wrote:
>>>> Some controllers can have internal mechanism to inform the SW that it
>>>> is ready for voltage switching. For such controllers, changing voltage
>>>> before the HW is ready can result in various issues.
>>>>
>>>> Add a quirk, which can be used by drivers of such controllers.
>>>>
>>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>>>> ---
>>>>    drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>>>    drivers/mmc/host/sdhci.h |  2 ++
>>>>    2 files changed, 17 insertions(+), 5 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>> index 1c828e0..f0346d4 100644
>>>> --- a/drivers/mmc/host/sdhci.c
>>>> +++ b/drivers/mmc/host/sdhci.c
>>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host,
>>>> unsigned char mode,
>>>>    void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>>>                 unsigned short vdd)
>>>>    {
>>>> -    if (IS_ERR(host->mmc->supply.vmmc))
>>>> +    if (IS_ERR(host->mmc->supply.vmmc) ||
>>>> +            (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>
>>> I think you should provide your own ->set_power() instead of this
>>>
>>
>> will do
>>
>>>>            sdhci_set_power_noreg(host, mode, vdd);
>>>>        else
>>>>            sdhci_set_power_reg(host, mode, vdd);
>>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct
>>>> mmc_host *mmc,
>>>>            ctrl &= ~SDHCI_CTRL_VDD_180;
>>>>            sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>>>    -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>> +                !(host->quirks2 &
>>>> +                    SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>
>>> And your own ->start_signal_voltage_switch()
>>>
>>
>> sdhci_msm_start_signal_voltage_switch() would be an exact copy of
>> sdhci_start_signal_voltage_switch()..... will incorporate this if not using
>> quirk.
>>
>>>>                ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>                if (ret) {
>>>>                    pr_warn("%s: Switching to 3.3V signalling voltage
>>>> failed\n",
>>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct
>>>> mmc_host *mmc,
>>>>        case MMC_SIGNAL_VOLTAGE_180:
>>>>            if (!(host->flags & SDHCI_SIGNALING_180))
>>>>                return -EINVAL;
>>>> -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>> +            !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>                ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>                if (ret) {
>>>>                    pr_warn("%s: Switching to 1.8V signalling voltage
>>>> failed\n",
>>>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>         * the host can take the appropriate action if regulators are not
>>>>         * available.
>>>>         */
>>>> -    ret = mmc_regulator_get_supply(mmc);
>>>> +    if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>
>>> Since we expect mmc_regulator_get_supply() to have been called, this could
>>> be:
>>>
>>>      if (!mmc->supply.vmmc) {
>>>          ret = mmc_regulator_get_supply(mmc);
>>>          enable_vqmmc = true;
>>>      } else {
>>>          ret = 0;
>>>      }
>>>>> +        ret = mmc_regulator_get_supply(mmc);
>>>> +    else
>>>> +        ret = 0;
>>>>        if (ret)
>>>>            return ret;
>>>>    @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>          /* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
>>>>        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>> -        ret = regulator_enable(mmc->supply.vqmmc);
>>>> +        if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>
>>> And this could be:
>>>
>>>          if (enable_vqmmc)
>>>              ret = regulator_enable(mmc->supply.vqmmc);
>>>          else
>>>              ret = 0;
>>>   > However, you still need to ensure regulator_disable(mmc->supply.vqmmc) is
>>> only called if regulator_enable() was called.
>> I missed this. Will cover it.
>>
>> Also I missed one more place where we are doing regulator_disable. During
>> sdhci-msm unbinding, we would end up doing an extra regulator disable
>> (thanks Evan for pointing it out) in sdhci_remove_host.
>>
>> To avoid the quirk( or having any flag), it would require copying the code
>> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and creating
> 
> You do not need to duplicate sdhci_remove_host(), just change it so that it
> only  disables what was enabled i.e.
> 
> 	if (host->vqmmc_enabled)
> 		regulator_disable(mmc->supply.vqmmc);
> 

Ok, so we will be adding a new flag "vqmmc_enabled" in sdhci_host, ryt ?
Just wanted to clarify

>> 2 new functions in sdhci_msm layer which would do the exact same as above,
>> with just the regulator parts removed.
>>
>> This looks messy (considering any future changes to the 2 sdhci API will
>> need to be copied to their duplicate sdhci_msm API) and a bit overkill to
>> avoid quirk. At the same time, I don't know how useful such a quirk would be
>> to other platform drivers.
>>
>> Please let me know your view/suggestions.
> 
> Let's try without the quirk.
> 
>>>
>>>> +            ret = regulator_enable(mmc->supply.vqmmc);
>>>> +        else
>>>> +            ret = 0;
>>>>            if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>>>>                                1950000))
>>>>                host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>> index 23966f8..3b0c97a 100644
>>>> --- a/drivers/mmc/host/sdhci.h
>>>> +++ b/drivers/mmc/host/sdhci.h
>>>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>>>     * obtainable timeout.
>>>>     */
>>>>    #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT            (1<<17)
>>>> +/* Regulator voltage changes are being done from platform layer */
>>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL                (1<<18)
>>>
>>> So maybe the quirk is not needed.
>>>
>>>>          int irq;        /* Device IRQ */
>>>>        void __iomem *ioaddr;    /* Mapped address */
>>>>
>>>
>>
>> Thanks for the review & suggestions!
>> Vijay
>>
> 
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Adrian Hunter July 17, 2018, 8:42 a.m. UTC | #5
On 17/07/18 11:40, Vijay Viswanath wrote:
> 
> 
> On 7/17/2018 1:00 PM, Adrian Hunter wrote:
>> On 17/07/18 08:14, Vijay Viswanath wrote:
>>>
>>>
>>> On 7/10/2018 4:37 PM, Adrian Hunter wrote:
>>>> On 21/06/18 15:23, Vijay Viswanath wrote:
>>>>> Some controllers can have internal mechanism to inform the SW that it
>>>>> is ready for voltage switching. For such controllers, changing voltage
>>>>> before the HW is ready can result in various issues.
>>>>>
>>>>> Add a quirk, which can be used by drivers of such controllers.
>>>>>
>>>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>>>>> ---
>>>>>    drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>>>>    drivers/mmc/host/sdhci.h |  2 ++
>>>>>    2 files changed, 17 insertions(+), 5 deletions(-)
>>>>>
>>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>>> index 1c828e0..f0346d4 100644
>>>>> --- a/drivers/mmc/host/sdhci.c
>>>>> +++ b/drivers/mmc/host/sdhci.c
>>>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host,
>>>>> unsigned char mode,
>>>>>    void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>>>>                 unsigned short vdd)
>>>>>    {
>>>>> -    if (IS_ERR(host->mmc->supply.vmmc))
>>>>> +    if (IS_ERR(host->mmc->supply.vmmc) ||
>>>>> +            (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>
>>>> I think you should provide your own ->set_power() instead of this
>>>>
>>>
>>> will do
>>>
>>>>>            sdhci_set_power_noreg(host, mode, vdd);
>>>>>        else
>>>>>            sdhci_set_power_reg(host, mode, vdd);
>>>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct
>>>>> mmc_host *mmc,
>>>>>            ctrl &= ~SDHCI_CTRL_VDD_180;
>>>>>            sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>>>>    -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>> +                !(host->quirks2 &
>>>>> +                    SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>
>>>> And your own ->start_signal_voltage_switch()
>>>>
>>>
>>> sdhci_msm_start_signal_voltage_switch() would be an exact copy of
>>> sdhci_start_signal_voltage_switch()..... will incorporate this if not using
>>> quirk.
>>>
>>>>>                ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>                if (ret) {
>>>>>                    pr_warn("%s: Switching to 3.3V signalling voltage
>>>>> failed\n",
>>>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct
>>>>> mmc_host *mmc,
>>>>>        case MMC_SIGNAL_VOLTAGE_180:
>>>>>            if (!(host->flags & SDHCI_SIGNALING_180))
>>>>>                return -EINVAL;
>>>>> -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>> +            !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>                ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>                if (ret) {
>>>>>                    pr_warn("%s: Switching to 1.8V signalling voltage
>>>>> failed\n",
>>>>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>         * the host can take the appropriate action if regulators are not
>>>>>         * available.
>>>>>         */
>>>>> -    ret = mmc_regulator_get_supply(mmc);
>>>>> +    if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>
>>>> Since we expect mmc_regulator_get_supply() to have been called, this could
>>>> be:
>>>>
>>>>      if (!mmc->supply.vmmc) {
>>>>          ret = mmc_regulator_get_supply(mmc);
>>>>          enable_vqmmc = true;
>>>>      } else {
>>>>          ret = 0;
>>>>      }
>>>>>> +        ret = mmc_regulator_get_supply(mmc);
>>>>> +    else
>>>>> +        ret = 0;
>>>>>        if (ret)
>>>>>            return ret;
>>>>>    @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>          /* If vqmmc regulator and no 1.8V signalling, then there's no
>>>>> UHS */
>>>>>        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>> -        ret = regulator_enable(mmc->supply.vqmmc);
>>>>> +        if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>
>>>> And this could be:
>>>>
>>>>          if (enable_vqmmc)
>>>>              ret = regulator_enable(mmc->supply.vqmmc);
>>>>          else
>>>>              ret = 0;
>>>>   > However, you still need to ensure
>>>> regulator_disable(mmc->supply.vqmmc) is
>>>> only called if regulator_enable() was called.
>>> I missed this. Will cover it.
>>>
>>> Also I missed one more place where we are doing regulator_disable. During
>>> sdhci-msm unbinding, we would end up doing an extra regulator disable
>>> (thanks Evan for pointing it out) in sdhci_remove_host.
>>>
>>> To avoid the quirk( or having any flag), it would require copying the code
>>> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and creating
>>
>> You do not need to duplicate sdhci_remove_host(), just change it so that it
>> only  disables what was enabled i.e.
>>
>>     if (host->vqmmc_enabled)
>>         regulator_disable(mmc->supply.vqmmc);
>>
> 
> Ok, so we will be adding a new flag "vqmmc_enabled" in sdhci_host, ryt ?

Yes

> Just wanted to clarify
> 
>>> 2 new functions in sdhci_msm layer which would do the exact same as above,
>>> with just the regulator parts removed.
>>>
>>> This looks messy (considering any future changes to the 2 sdhci API will
>>> need to be copied to their duplicate sdhci_msm API) and a bit overkill to
>>> avoid quirk. At the same time, I don't know how useful such a quirk would be
>>> to other platform drivers.
>>>
>>> Please let me know your view/suggestions.
>>
>> Let's try without the quirk.
>>
>>>>
>>>>> +            ret = regulator_enable(mmc->supply.vqmmc);
>>>>> +        else
>>>>> +            ret = 0;
>>>>>            if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>>>>>                                1950000))
>>>>>                host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>>> index 23966f8..3b0c97a 100644
>>>>> --- a/drivers/mmc/host/sdhci.h
>>>>> +++ b/drivers/mmc/host/sdhci.h
>>>>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>>>>     * obtainable timeout.
>>>>>     */
>>>>>    #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT            (1<<17)
>>>>> +/* Regulator voltage changes are being done from platform layer */
>>>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL                (1<<18)
>>>>
>>>> So maybe the quirk is not needed.
>>>>
>>>>>          int irq;        /* Device IRQ */
>>>>>        void __iomem *ioaddr;    /* Mapped address */
>>>>>
>>>>
>>>
>>> Thanks for the review & suggestions!
>>> Vijay
>>>
>>
> 

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Vijay Viswanath July 17, 2018, 9:45 a.m. UTC | #6
On 7/17/2018 2:12 PM, Adrian Hunter wrote:
> On 17/07/18 11:40, Vijay Viswanath wrote:
>>
>>
>> On 7/17/2018 1:00 PM, Adrian Hunter wrote:
>>> On 17/07/18 08:14, Vijay Viswanath wrote:
>>>>
>>>>
>>>> On 7/10/2018 4:37 PM, Adrian Hunter wrote:
>>>>> On 21/06/18 15:23, Vijay Viswanath wrote:
>>>>>> Some controllers can have internal mechanism to inform the SW that it
>>>>>> is ready for voltage switching. For such controllers, changing voltage
>>>>>> before the HW is ready can result in various issues.
>>>>>>
>>>>>> Add a quirk, which can be used by drivers of such controllers.
>>>>>>
>>>>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>>>>>> ---
>>>>>>     drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>>>>>     drivers/mmc/host/sdhci.h |  2 ++
>>>>>>     2 files changed, 17 insertions(+), 5 deletions(-)
>>>>>>
>>>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>>>> index 1c828e0..f0346d4 100644
>>>>>> --- a/drivers/mmc/host/sdhci.c
>>>>>> +++ b/drivers/mmc/host/sdhci.c
>>>>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host *host,
>>>>>> unsigned char mode,
>>>>>>     void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>>>>>                  unsigned short vdd)
>>>>>>     {
>>>>>> -    if (IS_ERR(host->mmc->supply.vmmc))
>>>>>> +    if (IS_ERR(host->mmc->supply.vmmc) ||
>>>>>> +            (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>
>>>>> I think you should provide your own ->set_power() instead of this
>>>>>
>>>>
>>>> will do
>>>>
>>>>>>             sdhci_set_power_noreg(host, mode, vdd);
>>>>>>         else
>>>>>>             sdhci_set_power_reg(host, mode, vdd);
>>>>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct
>>>>>> mmc_host *mmc,
>>>>>>             ctrl &= ~SDHCI_CTRL_VDD_180;
>>>>>>             sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>>>>>     -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>>> +                !(host->quirks2 &
>>>>>> +                    SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>
>>>>> And your own ->start_signal_voltage_switch()
>>>>>
>>>>
>>>> sdhci_msm_start_signal_voltage_switch() would be an exact copy of
>>>> sdhci_start_signal_voltage_switch()..... will incorporate this if not using
>>>> quirk.
>>>>
>>>>>>                 ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>>                 if (ret) {
>>>>>>                     pr_warn("%s: Switching to 3.3V signalling voltage
>>>>>> failed\n",
>>>>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct
>>>>>> mmc_host *mmc,
>>>>>>         case MMC_SIGNAL_VOLTAGE_180:
>>>>>>             if (!(host->flags & SDHCI_SIGNALING_180))
>>>>>>                 return -EINVAL;
>>>>>> -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>>> +            !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>>                 ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>>                 if (ret) {
>>>>>>                     pr_warn("%s: Switching to 1.8V signalling voltage
>>>>>> failed\n",
>>>>>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>>          * the host can take the appropriate action if regulators are not
>>>>>>          * available.
>>>>>>          */
>>>>>> -    ret = mmc_regulator_get_supply(mmc);
>>>>>> +    if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>
>>>>> Since we expect mmc_regulator_get_supply() to have been called, this could
>>>>> be:
>>>>>
>>>>>       if (!mmc->supply.vmmc) {
>>>>>           ret = mmc_regulator_get_supply(mmc);
>>>>>           enable_vqmmc = true;
>>>>>       } else {
>>>>>           ret = 0;
>>>>>       }
>>>>>>> +        ret = mmc_regulator_get_supply(mmc);
>>>>>> +    else
>>>>>> +        ret = 0;
>>>>>>         if (ret)
>>>>>>             return ret;
>>>>>>     @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>>           /* If vqmmc regulator and no 1.8V signalling, then there's no
>>>>>> UHS */
>>>>>>         if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>> -        ret = regulator_enable(mmc->supply.vqmmc);
>>>>>> +        if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>
>>>>> And this could be:
>>>>>
>>>>>           if (enable_vqmmc)
>>>>>               ret = regulator_enable(mmc->supply.vqmmc);
>>>>>           else
>>>>>               ret = 0;
>>>>>    > However, you still need to ensure
>>>>> regulator_disable(mmc->supply.vqmmc) is
>>>>> only called if regulator_enable() was called.
>>>> I missed this. Will cover it.
>>>>
>>>> Also I missed one more place where we are doing regulator_disable. During
>>>> sdhci-msm unbinding, we would end up doing an extra regulator disable
>>>> (thanks Evan for pointing it out) in sdhci_remove_host.
>>>>
>>>> To avoid the quirk( or having any flag), it would require copying the code
>>>> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and creating
>>>
>>> You do not need to duplicate sdhci_remove_host(), just change it so that it
>>> only  disables what was enabled i.e.
>>>
>>>      if (host->vqmmc_enabled)
>>>          regulator_disable(mmc->supply.vqmmc);
>>>
>>
>> Ok, so we will be adding a new flag "vqmmc_enabled" in sdhci_host, ryt ?
> 
> Yes
> 

Ok.
Any particular reason why we are avoiding quirk and instead adding a new 
flag ?

>> Just wanted to clarify
>>
>>>> 2 new functions in sdhci_msm layer which would do the exact same as above,
>>>> with just the regulator parts removed.
>>>>
>>>> This looks messy (considering any future changes to the 2 sdhci API will
>>>> need to be copied to their duplicate sdhci_msm API) and a bit overkill to
>>>> avoid quirk. At the same time, I don't know how useful such a quirk would be
>>>> to other platform drivers.
>>>>
>>>> Please let me know your view/suggestions.
>>>
>>> Let's try without the quirk.
>>>
>>>>>
>>>>>> +            ret = regulator_enable(mmc->supply.vqmmc);
>>>>>> +        else
>>>>>> +            ret = 0;
>>>>>>             if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
>>>>>>                                 1950000))
>>>>>>                 host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>>>> index 23966f8..3b0c97a 100644
>>>>>> --- a/drivers/mmc/host/sdhci.h
>>>>>> +++ b/drivers/mmc/host/sdhci.h
>>>>>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>>>>>      * obtainable timeout.
>>>>>>      */
>>>>>>     #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT            (1<<17)
>>>>>> +/* Regulator voltage changes are being done from platform layer */
>>>>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL                (1<<18)
>>>>>
>>>>> So maybe the quirk is not needed.
>>>>>
>>>>>>           int irq;        /* Device IRQ */
>>>>>>         void __iomem *ioaddr;    /* Mapped address */
>>>>>>
>>>>>
>>>>
>>>> Thanks for the review & suggestions!
>>>> Vijay
>>>>
>>>
>>
> 
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Adrian Hunter July 17, 2018, 9:54 a.m. UTC | #7
On 17/07/18 12:45, Vijay Viswanath wrote:
> 
> 
> On 7/17/2018 2:12 PM, Adrian Hunter wrote:
>> On 17/07/18 11:40, Vijay Viswanath wrote:
>>>
>>>
>>> On 7/17/2018 1:00 PM, Adrian Hunter wrote:
>>>> On 17/07/18 08:14, Vijay Viswanath wrote:
>>>>>
>>>>>
>>>>> On 7/10/2018 4:37 PM, Adrian Hunter wrote:
>>>>>> On 21/06/18 15:23, Vijay Viswanath wrote:
>>>>>>> Some controllers can have internal mechanism to inform the SW that it
>>>>>>> is ready for voltage switching. For such controllers, changing voltage
>>>>>>> before the HW is ready can result in various issues.
>>>>>>>
>>>>>>> Add a quirk, which can be used by drivers of such controllers.
>>>>>>>
>>>>>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>>>>>>> ---
>>>>>>>     drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>>>>>>     drivers/mmc/host/sdhci.h |  2 ++
>>>>>>>     2 files changed, 17 insertions(+), 5 deletions(-)
>>>>>>>
>>>>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>>>>> index 1c828e0..f0346d4 100644
>>>>>>> --- a/drivers/mmc/host/sdhci.c
>>>>>>> +++ b/drivers/mmc/host/sdhci.c
>>>>>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host
>>>>>>> *host,
>>>>>>> unsigned char mode,
>>>>>>>     void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>>>>>>                  unsigned short vdd)
>>>>>>>     {
>>>>>>> -    if (IS_ERR(host->mmc->supply.vmmc))
>>>>>>> +    if (IS_ERR(host->mmc->supply.vmmc) ||
>>>>>>> +            (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>>
>>>>>> I think you should provide your own ->set_power() instead of this
>>>>>>
>>>>>
>>>>> will do
>>>>>
>>>>>>>             sdhci_set_power_noreg(host, mode, vdd);
>>>>>>>         else
>>>>>>>             sdhci_set_power_reg(host, mode, vdd);
>>>>>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct
>>>>>>> mmc_host *mmc,
>>>>>>>             ctrl &= ~SDHCI_CTRL_VDD_180;
>>>>>>>             sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>>>>>>     -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>>>> +                !(host->quirks2 &
>>>>>>> +                    SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>>
>>>>>> And your own ->start_signal_voltage_switch()
>>>>>>
>>>>>
>>>>> sdhci_msm_start_signal_voltage_switch() would be an exact copy of
>>>>> sdhci_start_signal_voltage_switch()..... will incorporate this if not
>>>>> using
>>>>> quirk.
>>>>>
>>>>>>>                 ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>>>                 if (ret) {
>>>>>>>                     pr_warn("%s: Switching to 3.3V signalling voltage
>>>>>>> failed\n",
>>>>>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct
>>>>>>> mmc_host *mmc,
>>>>>>>         case MMC_SIGNAL_VOLTAGE_180:
>>>>>>>             if (!(host->flags & SDHCI_SIGNALING_180))
>>>>>>>                 return -EINVAL;
>>>>>>> -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>>>> +            !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>>>                 ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>>>                 if (ret) {
>>>>>>>                     pr_warn("%s: Switching to 1.8V signalling voltage
>>>>>>> failed\n",
>>>>>>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>>>          * the host can take the appropriate action if regulators are
>>>>>>> not
>>>>>>>          * available.
>>>>>>>          */
>>>>>>> -    ret = mmc_regulator_get_supply(mmc);
>>>>>>> +    if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>>
>>>>>> Since we expect mmc_regulator_get_supply() to have been called, this
>>>>>> could
>>>>>> be:
>>>>>>
>>>>>>       if (!mmc->supply.vmmc) {
>>>>>>           ret = mmc_regulator_get_supply(mmc);
>>>>>>           enable_vqmmc = true;
>>>>>>       } else {
>>>>>>           ret = 0;
>>>>>>       }
>>>>>>>> +        ret = mmc_regulator_get_supply(mmc);
>>>>>>> +    else
>>>>>>> +        ret = 0;
>>>>>>>         if (ret)
>>>>>>>             return ret;
>>>>>>>     @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>>>           /* If vqmmc regulator and no 1.8V signalling, then there's no
>>>>>>> UHS */
>>>>>>>         if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>>> -        ret = regulator_enable(mmc->supply.vqmmc);
>>>>>>> +        if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>>
>>>>>> And this could be:
>>>>>>
>>>>>>           if (enable_vqmmc)
>>>>>>               ret = regulator_enable(mmc->supply.vqmmc);
>>>>>>           else
>>>>>>               ret = 0;
>>>>>>    > However, you still need to ensure
>>>>>> regulator_disable(mmc->supply.vqmmc) is
>>>>>> only called if regulator_enable() was called.
>>>>> I missed this. Will cover it.
>>>>>
>>>>> Also I missed one more place where we are doing regulator_disable. During
>>>>> sdhci-msm unbinding, we would end up doing an extra regulator disable
>>>>> (thanks Evan for pointing it out) in sdhci_remove_host.
>>>>>
>>>>> To avoid the quirk( or having any flag), it would require copying the code
>>>>> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and
>>>>> creating
>>>>
>>>> You do not need to duplicate sdhci_remove_host(), just change it so that it
>>>> only  disables what was enabled i.e.
>>>>
>>>>      if (host->vqmmc_enabled)
>>>>          regulator_disable(mmc->supply.vqmmc);
>>>>
>>>
>>> Ok, so we will be adding a new flag "vqmmc_enabled" in sdhci_host, ryt ?
>>
>> Yes
>>
> 
> Ok.
> Any particular reason why we are avoiding quirk and instead adding a new flag ?

It moves more in the direction of letting drivers do what they want, rather
than trying to make making SDHCI do everything.

> 
>>> Just wanted to clarify
>>>
>>>>> 2 new functions in sdhci_msm layer which would do the exact same as above,
>>>>> with just the regulator parts removed.
>>>>>
>>>>> This looks messy (considering any future changes to the 2 sdhci API will
>>>>> need to be copied to their duplicate sdhci_msm API) and a bit overkill to
>>>>> avoid quirk. At the same time, I don't know how useful such a quirk
>>>>> would be
>>>>> to other platform drivers.
>>>>>
>>>>> Please let me know your view/suggestions.
>>>>
>>>> Let's try without the quirk.
>>>>
>>>>>>
>>>>>>> +            ret = regulator_enable(mmc->supply.vqmmc);
>>>>>>> +        else
>>>>>>> +            ret = 0;
>>>>>>>             if (!regulator_is_supported_voltage(mmc->supply.vqmmc,
>>>>>>> 1700000,
>>>>>>>                                 1950000))
>>>>>>>                 host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>>>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>>>>> index 23966f8..3b0c97a 100644
>>>>>>> --- a/drivers/mmc/host/sdhci.h
>>>>>>> +++ b/drivers/mmc/host/sdhci.h
>>>>>>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>>>>>>      * obtainable timeout.
>>>>>>>      */
>>>>>>>     #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT            (1<<17)
>>>>>>> +/* Regulator voltage changes are being done from platform layer */
>>>>>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL                (1<<18)
>>>>>>
>>>>>> So maybe the quirk is not needed.
>>>>>>
>>>>>>>           int irq;        /* Device IRQ */
>>>>>>>         void __iomem *ioaddr;    /* Mapped address */
>>>>>>>
>>>>>>
>>>>>
>>>>> Thanks for the review & suggestions!
>>>>> Vijay
>>>>>
>>>>
>>>
>>
>> -- 
>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>> the body of a message to majordomo@vger.kernel.org
>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>
> 

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Vijay Viswanath July 17, 2018, 10:22 a.m. UTC | #8
On 7/17/2018 3:24 PM, Adrian Hunter wrote:
> On 17/07/18 12:45, Vijay Viswanath wrote:
>>
>>
>> On 7/17/2018 2:12 PM, Adrian Hunter wrote:
>>> On 17/07/18 11:40, Vijay Viswanath wrote:
>>>>
>>>>
>>>> On 7/17/2018 1:00 PM, Adrian Hunter wrote:
>>>>> On 17/07/18 08:14, Vijay Viswanath wrote:
>>>>>>
>>>>>>
>>>>>> On 7/10/2018 4:37 PM, Adrian Hunter wrote:
>>>>>>> On 21/06/18 15:23, Vijay Viswanath wrote:
>>>>>>>> Some controllers can have internal mechanism to inform the SW that it
>>>>>>>> is ready for voltage switching. For such controllers, changing voltage
>>>>>>>> before the HW is ready can result in various issues.
>>>>>>>>
>>>>>>>> Add a quirk, which can be used by drivers of such controllers.
>>>>>>>>
>>>>>>>> Signed-off-by: Vijay Viswanath <vviswana@codeaurora.org>
>>>>>>>> ---
>>>>>>>>      drivers/mmc/host/sdhci.c | 20 +++++++++++++++-----
>>>>>>>>      drivers/mmc/host/sdhci.h |  2 ++
>>>>>>>>      2 files changed, 17 insertions(+), 5 deletions(-)
>>>>>>>>
>>>>>>>> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
>>>>>>>> index 1c828e0..f0346d4 100644
>>>>>>>> --- a/drivers/mmc/host/sdhci.c
>>>>>>>> +++ b/drivers/mmc/host/sdhci.c
>>>>>>>> @@ -1615,7 +1615,8 @@ void sdhci_set_power_noreg(struct sdhci_host
>>>>>>>> *host,
>>>>>>>> unsigned char mode,
>>>>>>>>      void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
>>>>>>>>                   unsigned short vdd)
>>>>>>>>      {
>>>>>>>> -    if (IS_ERR(host->mmc->supply.vmmc))
>>>>>>>> +    if (IS_ERR(host->mmc->supply.vmmc) ||
>>>>>>>> +            (host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>>>
>>>>>>> I think you should provide your own ->set_power() instead of this
>>>>>>>
>>>>>>
>>>>>> will do
>>>>>>
>>>>>>>>              sdhci_set_power_noreg(host, mode, vdd);
>>>>>>>>          else
>>>>>>>>              sdhci_set_power_reg(host, mode, vdd);
>>>>>>>> @@ -2009,7 +2010,9 @@ int sdhci_start_signal_voltage_switch(struct
>>>>>>>> mmc_host *mmc,
>>>>>>>>              ctrl &= ~SDHCI_CTRL_VDD_180;
>>>>>>>>              sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>>>>>>>>      -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>>>>> +                !(host->quirks2 &
>>>>>>>> +                    SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>>>
>>>>>>> And your own ->start_signal_voltage_switch()
>>>>>>>
>>>>>>
>>>>>> sdhci_msm_start_signal_voltage_switch() would be an exact copy of
>>>>>> sdhci_start_signal_voltage_switch()..... will incorporate this if not
>>>>>> using
>>>>>> quirk.
>>>>>>
>>>>>>>>                  ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>>>>                  if (ret) {
>>>>>>>>                      pr_warn("%s: Switching to 3.3V signalling voltage
>>>>>>>> failed\n",
>>>>>>>> @@ -2032,7 +2035,8 @@ int sdhci_start_signal_voltage_switch(struct
>>>>>>>> mmc_host *mmc,
>>>>>>>>          case MMC_SIGNAL_VOLTAGE_180:
>>>>>>>>              if (!(host->flags & SDHCI_SIGNALING_180))
>>>>>>>>                  return -EINVAL;
>>>>>>>> -        if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>>>> +        if (!IS_ERR(mmc->supply.vqmmc) &&
>>>>>>>> +            !(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
>>>>>>>>                  ret = mmc_regulator_set_vqmmc(mmc, ios);
>>>>>>>>                  if (ret) {
>>>>>>>>                      pr_warn("%s: Switching to 1.8V signalling voltage
>>>>>>>> failed\n",
>>>>>>>> @@ -3485,7 +3489,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>>>>           * the host can take the appropriate action if regulators are
>>>>>>>> not
>>>>>>>>           * available.
>>>>>>>>           */
>>>>>>>> -    ret = mmc_regulator_get_supply(mmc);
>>>>>>>> +    if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>>>
>>>>>>> Since we expect mmc_regulator_get_supply() to have been called, this
>>>>>>> could
>>>>>>> be:
>>>>>>>
>>>>>>>        if (!mmc->supply.vmmc) {
>>>>>>>            ret = mmc_regulator_get_supply(mmc);
>>>>>>>            enable_vqmmc = true;
>>>>>>>        } else {
>>>>>>>            ret = 0;
>>>>>>>        }
>>>>>>>>> +        ret = mmc_regulator_get_supply(mmc);
>>>>>>>> +    else
>>>>>>>> +        ret = 0;
>>>>>>>>          if (ret)
>>>>>>>>              return ret;
>>>>>>>>      @@ -3736,7 +3743,10 @@ int sdhci_setup_host(struct sdhci_host *host)
>>>>>>>>            /* If vqmmc regulator and no 1.8V signalling, then there's no
>>>>>>>> UHS */
>>>>>>>>          if (!IS_ERR(mmc->supply.vqmmc)) {
>>>>>>>> -        ret = regulator_enable(mmc->supply.vqmmc);
>>>>>>>> +        if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
>>>>>>>
>>>>>>> And this could be:
>>>>>>>
>>>>>>>            if (enable_vqmmc)
>>>>>>>                ret = regulator_enable(mmc->supply.vqmmc);
>>>>>>>            else
>>>>>>>                ret = 0;
>>>>>>>     > However, you still need to ensure
>>>>>>> regulator_disable(mmc->supply.vqmmc) is
>>>>>>> only called if regulator_enable() was called.
>>>>>> I missed this. Will cover it.
>>>>>>
>>>>>> Also I missed one more place where we are doing regulator_disable. During
>>>>>> sdhci-msm unbinding, we would end up doing an extra regulator disable
>>>>>> (thanks Evan for pointing it out) in sdhci_remove_host.
>>>>>>
>>>>>> To avoid the quirk( or having any flag), it would require copying the code
>>>>>> of sdhci_start_signal_voltage_switch() and sdhci_remove_host() and
>>>>>> creating
>>>>>
>>>>> You do not need to duplicate sdhci_remove_host(), just change it so that it
>>>>> only  disables what was enabled i.e.
>>>>>
>>>>>       if (host->vqmmc_enabled)
>>>>>           regulator_disable(mmc->supply.vqmmc);
>>>>>
>>>>
>>>> Ok, so we will be adding a new flag "vqmmc_enabled" in sdhci_host, ryt ?
>>>
>>> Yes
>>>
>>
>> Ok.
>> Any particular reason why we are avoiding quirk and instead adding a new flag ?
> 
> It moves more in the direction of letting drivers do what they want, rather
> than trying to make making SDHCI do everything.
> 

ok will incorporate the changes in next version.

>>
>>>> Just wanted to clarify
>>>>
>>>>>> 2 new functions in sdhci_msm layer which would do the exact same as above,
>>>>>> with just the regulator parts removed.
>>>>>>
>>>>>> This looks messy (considering any future changes to the 2 sdhci API will
>>>>>> need to be copied to their duplicate sdhci_msm API) and a bit overkill to
>>>>>> avoid quirk. At the same time, I don't know how useful such a quirk
>>>>>> would be
>>>>>> to other platform drivers.
>>>>>>
>>>>>> Please let me know your view/suggestions.
>>>>>
>>>>> Let's try without the quirk.
>>>>>
>>>>>>>
>>>>>>>> +            ret = regulator_enable(mmc->supply.vqmmc);
>>>>>>>> +        else
>>>>>>>> +            ret = 0;
>>>>>>>>              if (!regulator_is_supported_voltage(mmc->supply.vqmmc,
>>>>>>>> 1700000,
>>>>>>>>                                  1950000))
>>>>>>>>                  host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
>>>>>>>> diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
>>>>>>>> index 23966f8..3b0c97a 100644
>>>>>>>> --- a/drivers/mmc/host/sdhci.h
>>>>>>>> +++ b/drivers/mmc/host/sdhci.h
>>>>>>>> @@ -450,6 +450,8 @@ struct sdhci_host {
>>>>>>>>       * obtainable timeout.
>>>>>>>>       */
>>>>>>>>      #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT            (1<<17)
>>>>>>>> +/* Regulator voltage changes are being done from platform layer */
>>>>>>>> +#define SDHCI_QUIRK2_INTERNAL_PWR_CTL                (1<<18)
>>>>>>>
>>>>>>> So maybe the quirk is not needed.
>>>>>>>
>>>>>>>>            int irq;        /* Device IRQ */
>>>>>>>>          void __iomem *ioaddr;    /* Mapped address */
>>>>>>>>
>>>>>>>
>>>>>>
>>>>>> Thanks for the review & suggestions!
>>>>>> Vijay
>>>>>>
>>>>>
>>>>
>>>
>>> -- 
>>> To unsubscribe from this list: send the line "unsubscribe linux-mmc" in
>>> the body of a message to majordomo@vger.kernel.org
>>> More majordomo info at  http://vger.kernel.org/majordomo-info.html
>>>
>>
> 

Thanks,
Vijay
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diff mbox

Patch

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 1c828e0..f0346d4 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1615,7 +1615,8 @@  void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
 void sdhci_set_power(struct sdhci_host *host, unsigned char mode,
 		     unsigned short vdd)
 {
-	if (IS_ERR(host->mmc->supply.vmmc))
+	if (IS_ERR(host->mmc->supply.vmmc) ||
+			(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
 		sdhci_set_power_noreg(host, mode, vdd);
 	else
 		sdhci_set_power_reg(host, mode, vdd);
@@ -2009,7 +2010,9 @@  int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 		ctrl &= ~SDHCI_CTRL_VDD_180;
 		sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
 
-		if (!IS_ERR(mmc->supply.vqmmc)) {
+		if (!IS_ERR(mmc->supply.vqmmc) &&
+				!(host->quirks2 &
+					SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
 			ret = mmc_regulator_set_vqmmc(mmc, ios);
 			if (ret) {
 				pr_warn("%s: Switching to 3.3V signalling voltage failed\n",
@@ -2032,7 +2035,8 @@  int sdhci_start_signal_voltage_switch(struct mmc_host *mmc,
 	case MMC_SIGNAL_VOLTAGE_180:
 		if (!(host->flags & SDHCI_SIGNALING_180))
 			return -EINVAL;
-		if (!IS_ERR(mmc->supply.vqmmc)) {
+		if (!IS_ERR(mmc->supply.vqmmc) &&
+			!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL)) {
 			ret = mmc_regulator_set_vqmmc(mmc, ios);
 			if (ret) {
 				pr_warn("%s: Switching to 1.8V signalling voltage failed\n",
@@ -3485,7 +3489,10 @@  int sdhci_setup_host(struct sdhci_host *host)
 	 * the host can take the appropriate action if regulators are not
 	 * available.
 	 */
-	ret = mmc_regulator_get_supply(mmc);
+	if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
+		ret = mmc_regulator_get_supply(mmc);
+	else
+		ret = 0;
 	if (ret)
 		return ret;
 
@@ -3736,7 +3743,10 @@  int sdhci_setup_host(struct sdhci_host *host)
 
 	/* If vqmmc regulator and no 1.8V signalling, then there's no UHS */
 	if (!IS_ERR(mmc->supply.vqmmc)) {
-		ret = regulator_enable(mmc->supply.vqmmc);
+		if (!(host->quirks2 & SDHCI_QUIRK2_INTERNAL_PWR_CTL))
+			ret = regulator_enable(mmc->supply.vqmmc);
+		else
+			ret = 0;
 		if (!regulator_is_supported_voltage(mmc->supply.vqmmc, 1700000,
 						    1950000))
 			host->caps1 &= ~(SDHCI_SUPPORT_SDR104 |
diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 23966f8..3b0c97a 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -450,6 +450,8 @@  struct sdhci_host {
  * obtainable timeout.
  */
 #define SDHCI_QUIRK2_DISABLE_HW_TIMEOUT			(1<<17)
+/* Regulator voltage changes are being done from platform layer */
+#define SDHCI_QUIRK2_INTERNAL_PWR_CTL				(1<<18)
 
 	int irq;		/* Device IRQ */
 	void __iomem *ioaddr;	/* Mapped address */