diff mbox series

[v2] hwmon: pm_bus: core: Implement regulator get_status

Message ID 20221118084637.1973838-1-Naresh.Solanki@9elements.com
State New
Headers
Series [v2] hwmon: pm_bus: core: Implement regulator get_status |

Commit Message

Naresh Solanki Nov. 18, 2022, 8:46 a.m. UTC 
  From: Patrick Rudolph <patrick.rudolph@9elements.com>

Add get_status for pmbus_regulator_ops.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
 drivers/hwmon/pmbus/pmbus_core.c | 72 ++++++++++++++++++++++++++++++++
 1 file changed, 72 insertions(+)


base-commit: 27fea302952d8c90cafbdbee96bafeca03544401

Comments

Guenter Roeck Nov. 18, 2022, 12:10 p.m. UTC | #1 
On Fri, Nov 18, 2022 at 09:46:36AM +0100, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> Add get_status for pmbus_regulator_ops.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> ---

Please provide change logs.

>  drivers/hwmon/pmbus/pmbus_core.c | 72 ++++++++++++++++++++++++++++++++
>  1 file changed, 72 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 7ec04934747e..5dde345c7679 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2851,6 +2851,77 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
>  	return 0;
>  }
>  
> +static int pmbus_regulator_get_status(struct regulator_dev *rdev)
> +{
> +	struct device *dev = rdev_get_dev(rdev);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +	u8 page = rdev_get_id(rdev);
> +	int status, status2;
> +
> +	mutex_lock(&data->update_lock);
> +	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
> +	mutex_unlock(&data->update_lock);

I do not see the point of this lock here and elsewhere in this function.
If you want to ensure that the status is consistent, you would need to
hold the lock over the entire function, not repeatedly acquire and release
it. Even then there would be no guarantee that the status is consistent
because it can change anytime on the chip side.

> +	if (status < 0)
> +		return status;
> +
> +	if (status & (PB_STATUS_VIN_UV | PB_STATUS_IOUT_OC | PB_STATUS_VOUT_OV |
> +	    PB_STATUS_UNKNOWN))

Please align continuation lines with the matching '('.

> +		return REGULATOR_STATUS_ERROR;
> +
> +	if (status & (PB_STATUS_OFF | PB_STATUS_POWER_GOOD_N))
> +		return REGULATOR_STATUS_OFF;
> +
> +	if (status & PB_STATUS_VOUT &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_VOUT) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +					 PMBUS_STATUS_VOUT);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_VOLTAGE_OV_FAULT | PB_VOLTAGE_UV_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_IOUT_POUT &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_IOUT) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +						 PMBUS_STATUS_IOUT);

Ok to avoid continuation lines as long as the result has less then 100
columns.

> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_POUT_OP_FAULT | PB_IOUT_UC_FAULT |
> +		    PB_IOUT_OC_LV_FAULT | PB_IOUT_OC_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_INPUT &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_INPUT) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +						 PMBUS_STATUS_INPUT);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_IIN_OC_FAULT | PB_VOLTAGE_OV_FAULT |
> +		    PB_VOLTAGE_UV_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_TEMPERATURE &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_TEMP) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +						 PMBUS_STATUS_TEMPERATURE);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_TEMP_UT_FAULT | PB_TEMP_OT_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +
> +	return REGULATOR_STATUS_ON;
> +}
> +
>  static int pmbus_regulator_get_low_margin(struct i2c_client *client, int page)
>  {
>  	struct pmbus_data *data = i2c_get_clientdata(client);
> @@ -2991,6 +3062,7 @@ const struct regulator_ops pmbus_regulator_ops = {
>  	.disable = pmbus_regulator_disable,
>  	.is_enabled = pmbus_regulator_is_enabled,
>  	.get_error_flags = pmbus_regulator_get_error_flags,
> +	.get_status = pmbus_regulator_get_status,
>  	.get_voltage = pmbus_regulator_get_voltage,
>  	.set_voltage = pmbus_regulator_set_voltage,
>  	.list_voltage = pmbus_regulator_list_voltage,
> 
> base-commit: 27fea302952d8c90cafbdbee96bafeca03544401
> -- 
> 2.37.3
>
Guenter Roeck Nov. 18, 2022, 12:11 p.m. UTC | #2 
On Fri, Nov 18, 2022 at 09:46:36AM +0100, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> Add get_status for pmbus_regulator_ops.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>

Just noticed: The subject should start with "hwmon: (pmbus/core)"

Thanks,
Guenter

> ---
>  drivers/hwmon/pmbus/pmbus_core.c | 72 ++++++++++++++++++++++++++++++++
>  1 file changed, 72 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 7ec04934747e..5dde345c7679 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2851,6 +2851,77 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
>  	return 0;
>  }
>  
> +static int pmbus_regulator_get_status(struct regulator_dev *rdev)
> +{
> +	struct device *dev = rdev_get_dev(rdev);
> +	struct i2c_client *client = to_i2c_client(dev->parent);
> +	struct pmbus_data *data = i2c_get_clientdata(client);
> +	u8 page = rdev_get_id(rdev);
> +	int status, status2;
> +
> +	mutex_lock(&data->update_lock);
> +	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
> +	mutex_unlock(&data->update_lock);
> +	if (status < 0)
> +		return status;
> +
> +	if (status & (PB_STATUS_VIN_UV | PB_STATUS_IOUT_OC | PB_STATUS_VOUT_OV |
> +	    PB_STATUS_UNKNOWN))
> +		return REGULATOR_STATUS_ERROR;
> +
> +	if (status & (PB_STATUS_OFF | PB_STATUS_POWER_GOOD_N))
> +		return REGULATOR_STATUS_OFF;
> +
> +	if (status & PB_STATUS_VOUT &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_VOUT) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +					 PMBUS_STATUS_VOUT);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_VOLTAGE_OV_FAULT | PB_VOLTAGE_UV_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_IOUT_POUT &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_IOUT) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +						 PMBUS_STATUS_IOUT);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_POUT_OP_FAULT | PB_IOUT_UC_FAULT |
> +		    PB_IOUT_OC_LV_FAULT | PB_IOUT_OC_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_INPUT &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_INPUT) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +						 PMBUS_STATUS_INPUT);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_IIN_OC_FAULT | PB_VOLTAGE_OV_FAULT |
> +		    PB_VOLTAGE_UV_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +	if (status & PB_STATUS_TEMPERATURE &&
> +	    data->info->func[page] & PMBUS_HAVE_STATUS_TEMP) {
> +		mutex_lock(&data->update_lock);
> +		status2 = _pmbus_read_byte_data(client, page,
> +						 PMBUS_STATUS_TEMPERATURE);
> +		mutex_unlock(&data->update_lock);
> +		if (status2 < 0)
> +			return status2;
> +		if (status2 & (PB_TEMP_UT_FAULT | PB_TEMP_OT_FAULT))
> +			return REGULATOR_STATUS_ERROR;
> +	}
> +
> +	return REGULATOR_STATUS_ON;
> +}
> +
>  static int pmbus_regulator_get_low_margin(struct i2c_client *client, int page)
>  {
>  	struct pmbus_data *data = i2c_get_clientdata(client);
> @@ -2991,6 +3062,7 @@ const struct regulator_ops pmbus_regulator_ops = {
>  	.disable = pmbus_regulator_disable,
>  	.is_enabled = pmbus_regulator_is_enabled,
>  	.get_error_flags = pmbus_regulator_get_error_flags,
> +	.get_status = pmbus_regulator_get_status,
>  	.get_voltage = pmbus_regulator_get_voltage,
>  	.set_voltage = pmbus_regulator_set_voltage,
>  	.list_voltage = pmbus_regulator_list_voltage,
> 
> base-commit: 27fea302952d8c90cafbdbee96bafeca03544401
> -- 
> 2.37.3
>
Naresh Solanki Nov. 18, 2022, 3:02 p.m. UTC | #3 
Hi Guenter,

On 18-11-2022 05:40 pm, Guenter Roeck wrote:
> On Fri, Nov 18, 2022 at 09:46:36AM +0100, Naresh Solanki wrote:
>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>>
>> Add get_status for pmbus_regulator_ops.
>>
>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>> ---
> 
> Please provide change logs.
Sure
> 
>>   drivers/hwmon/pmbus/pmbus_core.c | 72 ++++++++++++++++++++++++++++++++
>>   1 file changed, 72 insertions(+)
>>
>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>> index 7ec04934747e..5dde345c7679 100644
>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>> @@ -2851,6 +2851,77 @@ static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
>>   	return 0;
>>   }
>>   
>> +static int pmbus_regulator_get_status(struct regulator_dev *rdev)
>> +{
>> +	struct device *dev = rdev_get_dev(rdev);
>> +	struct i2c_client *client = to_i2c_client(dev->parent);
>> +	struct pmbus_data *data = i2c_get_clientdata(client);
>> +	u8 page = rdev_get_id(rdev);
>> +	int status, status2;
>> +
>> +	mutex_lock(&data->update_lock);
>> +	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
>> +	mutex_unlock(&data->update_lock);
> 
> I do not see the point of this lock here and elsewhere in this function.
> If you want to ensure that the status is consistent, you would need to
> hold the lock over the entire function, not repeatedly acquire and release
> it. Even then there would be no guarantee that the status is consistent
> because it can change anytime on the chip side.
Will hold the lock till end of function. Agree that chip side, status 
may change any moment.

With this I got a question i.e., what should regulator status be 
reported if regulator had previously encountered some fault but 
currently while reading the status found that pgood bit indicate output 
power is good.
Should we continue to still report historical fault or instead report 
current regulator output status based on pgood ?

IMHO, it should report regulator status as ON if pgood bit is 
clear(i.e., output is good) & leave previously encountered error 
reporting to get_error_flag function.

I need your Suggestion here.

> 
>> +	if (status < 0)
>> +		return status;
>> +
>> +	if (status & (PB_STATUS_VIN_UV | PB_STATUS_IOUT_OC | PB_STATUS_VOUT_OV |
>> +	    PB_STATUS_UNKNOWN))
> 
> Please align continuation lines with the matching '('.
> 
Sure.
>> +		return REGULATOR_STATUS_ERROR;
>> +
>> +	if (status & (PB_STATUS_OFF | PB_STATUS_POWER_GOOD_N))
>> +		return REGULATOR_STATUS_OFF;
>> +
>> +	if (status & PB_STATUS_VOUT &&
>> +	    data->info->func[page] & PMBUS_HAVE_STATUS_VOUT) {
>> +		mutex_lock(&data->update_lock);
>> +		status2 = _pmbus_read_byte_data(client, page,
>> +					 PMBUS_STATUS_VOUT);
>> +		mutex_unlock(&data->update_lock);
>> +		if (status2 < 0)
>> +			return status2;
>> +		if (status2 & (PB_VOLTAGE_OV_FAULT | PB_VOLTAGE_UV_FAULT))
>> +			return REGULATOR_STATUS_ERROR;
>> +	}
>> +	if (status & PB_STATUS_IOUT_POUT &&
>> +	    data->info->func[page] & PMBUS_HAVE_STATUS_IOUT) {
>> +		mutex_lock(&data->update_lock);
>> +		status2 = _pmbus_read_byte_data(client, page,
>> +						 PMBUS_STATUS_IOUT);
> 
> Ok to avoid continuation lines as long as the result has less then 100
> columns.
> 
Sure
>> +		mutex_unlock(&data->update_lock);
>> +		if (status2 < 0)
>> +			return status2;
>> +		if (status2 & (PB_POUT_OP_FAULT | PB_IOUT_UC_FAULT |
>> +		    PB_IOUT_OC_LV_FAULT | PB_IOUT_OC_FAULT))
>> +			return REGULATOR_STATUS_ERROR;
>> +	}
>> +	if (status & PB_STATUS_INPUT &&
>> +	    data->info->func[page] & PMBUS_HAVE_STATUS_INPUT) {
>> +		mutex_lock(&data->update_lock);
>> +		status2 = _pmbus_read_byte_data(client, page,
>> +						 PMBUS_STATUS_INPUT);
>> +		mutex_unlock(&data->update_lock);
>> +		if (status2 < 0)
>> +			return status2;
>> +		if (status2 & (PB_IIN_OC_FAULT | PB_VOLTAGE_OV_FAULT |
>> +		    PB_VOLTAGE_UV_FAULT))
>> +			return REGULATOR_STATUS_ERROR;
>> +	}
>> +	if (status & PB_STATUS_TEMPERATURE &&
>> +	    data->info->func[page] & PMBUS_HAVE_STATUS_TEMP) {
>> +		mutex_lock(&data->update_lock);
>> +		status2 = _pmbus_read_byte_data(client, page,
>> +						 PMBUS_STATUS_TEMPERATURE);
>> +		mutex_unlock(&data->update_lock);
>> +		if (status2 < 0)
>> +			return status2;
>> +		if (status2 & (PB_TEMP_UT_FAULT | PB_TEMP_OT_FAULT))
>> +			return REGULATOR_STATUS_ERROR;
>> +	}
>> +
>> +	return REGULATOR_STATUS_ON;
>> +}
>> +
>>   static int pmbus_regulator_get_low_margin(struct i2c_client *client, int page)
>>   {
>>   	struct pmbus_data *data = i2c_get_clientdata(client);
>> @@ -2991,6 +3062,7 @@ const struct regulator_ops pmbus_regulator_ops = {
>>   	.disable = pmbus_regulator_disable,
>>   	.is_enabled = pmbus_regulator_is_enabled,
>>   	.get_error_flags = pmbus_regulator_get_error_flags,
>> +	.get_status = pmbus_regulator_get_status,
>>   	.get_voltage = pmbus_regulator_get_voltage,
>>   	.set_voltage = pmbus_regulator_set_voltage,
>>   	.list_voltage = pmbus_regulator_list_voltage,
>>
>> base-commit: 27fea302952d8c90cafbdbee96bafeca03544401
>> -- 
>> 2.37.3
>>
Guenter Roeck Nov. 18, 2022, 10:07 p.m. UTC | #4 
On Fri, Nov 18, 2022 at 08:32:26PM +0530, Naresh Solanki wrote:
> > > +
> > > +	mutex_lock(&data->update_lock);
> > > +	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
> > > +	mutex_unlock(&data->update_lock);
> > 
> > I do not see the point of this lock here and elsewhere in this function.
> > If you want to ensure that the status is consistent, you would need to
> > hold the lock over the entire function, not repeatedly acquire and release
> > it. Even then there would be no guarantee that the status is consistent
> > because it can change anytime on the chip side.
> Will hold the lock till end of function. Agree that chip side, status may
> change any moment.
> 
> With this I got a question i.e., what should regulator status be reported if
> regulator had previously encountered some fault but currently while reading
> the status found that pgood bit indicate output power is good.
> Should we continue to still report historical fault or instead report
> current regulator output status based on pgood ?
> 
> IMHO, it should report regulator status as ON if pgood bit is clear(i.e.,
> output is good) & leave previously encountered error reporting to
> get_error_flag function.
> 
> I need your Suggestion here.
> 
That is really a question for the regulator subsystem. Personally I think
the current status should be reported, but that is just me.

Guenter
diff mbox series

Patch

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 7ec04934747e..5dde345c7679 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2851,6 +2851,77 @@  static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned
 	return 0;
 }
 
+static int pmbus_regulator_get_status(struct regulator_dev *rdev)
+{
+	struct device *dev = rdev_get_dev(rdev);
+	struct i2c_client *client = to_i2c_client(dev->parent);
+	struct pmbus_data *data = i2c_get_clientdata(client);
+	u8 page = rdev_get_id(rdev);
+	int status, status2;
+
+	mutex_lock(&data->update_lock);
+	status = pmbus_get_status(client, page, PMBUS_STATUS_WORD);
+	mutex_unlock(&data->update_lock);
+	if (status < 0)
+		return status;
+
+	if (status & (PB_STATUS_VIN_UV | PB_STATUS_IOUT_OC | PB_STATUS_VOUT_OV |
+	    PB_STATUS_UNKNOWN))
+		return REGULATOR_STATUS_ERROR;
+
+	if (status & (PB_STATUS_OFF | PB_STATUS_POWER_GOOD_N))
+		return REGULATOR_STATUS_OFF;
+
+	if (status & PB_STATUS_VOUT &&
+	    data->info->func[page] & PMBUS_HAVE_STATUS_VOUT) {
+		mutex_lock(&data->update_lock);
+		status2 = _pmbus_read_byte_data(client, page,
+					 PMBUS_STATUS_VOUT);
+		mutex_unlock(&data->update_lock);
+		if (status2 < 0)
+			return status2;
+		if (status2 & (PB_VOLTAGE_OV_FAULT | PB_VOLTAGE_UV_FAULT))
+			return REGULATOR_STATUS_ERROR;
+	}
+	if (status & PB_STATUS_IOUT_POUT &&
+	    data->info->func[page] & PMBUS_HAVE_STATUS_IOUT) {
+		mutex_lock(&data->update_lock);
+		status2 = _pmbus_read_byte_data(client, page,
+						 PMBUS_STATUS_IOUT);
+		mutex_unlock(&data->update_lock);
+		if (status2 < 0)
+			return status2;
+		if (status2 & (PB_POUT_OP_FAULT | PB_IOUT_UC_FAULT |
+		    PB_IOUT_OC_LV_FAULT | PB_IOUT_OC_FAULT))
+			return REGULATOR_STATUS_ERROR;
+	}
+	if (status & PB_STATUS_INPUT &&
+	    data->info->func[page] & PMBUS_HAVE_STATUS_INPUT) {
+		mutex_lock(&data->update_lock);
+		status2 = _pmbus_read_byte_data(client, page,
+						 PMBUS_STATUS_INPUT);
+		mutex_unlock(&data->update_lock);
+		if (status2 < 0)
+			return status2;
+		if (status2 & (PB_IIN_OC_FAULT | PB_VOLTAGE_OV_FAULT |
+		    PB_VOLTAGE_UV_FAULT))
+			return REGULATOR_STATUS_ERROR;
+	}
+	if (status & PB_STATUS_TEMPERATURE &&
+	    data->info->func[page] & PMBUS_HAVE_STATUS_TEMP) {
+		mutex_lock(&data->update_lock);
+		status2 = _pmbus_read_byte_data(client, page,
+						 PMBUS_STATUS_TEMPERATURE);
+		mutex_unlock(&data->update_lock);
+		if (status2 < 0)
+			return status2;
+		if (status2 & (PB_TEMP_UT_FAULT | PB_TEMP_OT_FAULT))
+			return REGULATOR_STATUS_ERROR;
+	}
+
+	return REGULATOR_STATUS_ON;
+}
+
 static int pmbus_regulator_get_low_margin(struct i2c_client *client, int page)
 {
 	struct pmbus_data *data = i2c_get_clientdata(client);
@@ -2991,6 +3062,7 @@  const struct regulator_ops pmbus_regulator_ops = {
 	.disable = pmbus_regulator_disable,
 	.is_enabled = pmbus_regulator_is_enabled,
 	.get_error_flags = pmbus_regulator_get_error_flags,
+	.get_status = pmbus_regulator_get_status,
 	.get_voltage = pmbus_regulator_get_voltage,
 	.set_voltage = pmbus_regulator_set_voltage,
 	.list_voltage = pmbus_regulator_list_voltage,