diff mbox series

[1/4] hwmon: (pmbus) Add get_error_flags support to regulator ops

Message ID 20220217104444.7695-2-zev@bewilderbeest.net
State New
Headers show
Series misc: Add power-efuse driver | expand

Commit Message

Zev Weiss Feb. 17, 2022, 10:44 a.m. UTC
The various PMBus status bits don't all map perfectly to the more
limited set of REGULATOR_ERROR_* flags, but there's a reasonable
number where they correspond well enough.

Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
---
 drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++++++++++++++++++++++++++
 1 file changed, 97 insertions(+)

Comments

Guenter Roeck Feb. 17, 2022, 6:11 p.m. UTC | #1
On 2/17/22 02:44, Zev Weiss wrote:
> The various PMBus status bits don't all map perfectly to the more
> limited set of REGULATOR_ERROR_* flags, but there's a reasonable
> number where they correspond well enough.
> 
> Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
> ---
>   drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++++++++++++++++++++++++++
>   1 file changed, 97 insertions(+)
> 
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 776ee2237be2..a274e8e524a5 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -2417,10 +2417,107 @@ static int pmbus_regulator_disable(struct regulator_dev *rdev)
>   	return _pmbus_regulator_on_off(rdev, 0);
>   }
>   
> +/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
> +struct pmbus_regulator_status_assoc {
> +	int pflag, rflag;
> +};
> +
> +/* PMBus->regulator bit mappings for a PMBus status register */
> +struct pmbus_regulator_status_category {
> +	int func;
> +	int reg;
> +	const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
> +};
> +
> +static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
> +	{
> +		.func = PMBUS_HAVE_STATUS_VOUT,
> +		.reg = PMBUS_STATUS_VOUT,
> +		.bits = (const struct pmbus_regulator_status_assoc[]) {
> +			{ PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
> +			{ PB_VOLTAGE_UV_FAULT,   REGULATOR_ERROR_UNDER_VOLTAGE },
> +			{ PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
> +			{ PB_VOLTAGE_OV_FAULT,   REGULATOR_ERROR_REGULATION_OUT },
> +			{ },
> +		},
> +	}, {
> +		.func = PMBUS_HAVE_STATUS_IOUT,
> +		.reg = PMBUS_STATUS_IOUT,
> +		.bits = (const struct pmbus_regulator_status_assoc[]) {
> +			{ PB_IOUT_OC_WARNING,    REGULATOR_ERROR_OVER_CURRENT_WARN },
> +			{ PB_IOUT_OC_FAULT,      REGULATOR_ERROR_OVER_CURRENT },
> +			{ PB_IOUT_OC_LV_FAULT,   REGULATOR_ERROR_OVER_CURRENT },
> +			{ },
> +		},
> +	}, {
> +		.func = PMBUS_HAVE_STATUS_TEMP,
> +		.reg = PMBUS_STATUS_TEMPERATURE,
> +		.bits = (const struct pmbus_regulator_status_assoc[]) {
> +			{ PB_TEMP_OT_WARNING,    REGULATOR_ERROR_OVER_TEMP_WARN },
> +			{ PB_TEMP_OT_FAULT,      REGULATOR_ERROR_OVER_TEMP },
> +			{ },
> +		},
> +	},
> +};
> +
> +static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
> +{
> +	int i, status, statusreg;
> +	const struct pmbus_regulator_status_category *cat;
> +	const struct pmbus_regulator_status_assoc *bit;
> +	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 func = data->info->func[page];
> +
> +	*flags = 0;
> +
> +	for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
> +		cat = &pmbus_regulator_flag_map[i];
> +		if (!(func & cat->func))
> +			continue;
> +
> +		status = pmbus_read_byte_data(client, page, cat->reg);
> +		if (status < 0)
> +			return status;
> +
> +		for (bit = cat->bits; bit->pflag; bit++) {
> +			if (status & bit->pflag)
> +				*flags |= bit->rflag;
> +		}
> +	}
> +
> +	/*
> +	 * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
> +	 * bits.  Some of the other bits are tempting (especially for cases
> +	 * where we don't have the relevant PMBUS_HAVE_STATUS_*
> +	 * functionality), but there's an unfortunate ambiguity in that
> +	 * they're defined as indicating a fault *or* a warning, so we can't
> +	 * easily determine whether to report REGULATOR_ERROR_<foo> or
> +	 * REGULATOR_ERROR_<foo>_WARN.
> +	 */
> +	statusreg = data->has_status_word ? PMBUS_STATUS_WORD : PMBUS_STATUS_BYTE;
> +	status = pmbus_get_status(client, page, statusreg);
> +

pmbus_get_status() calls data->read_status if PMBUS_STATUS_WORD is provided
as parameter, and data->read_status is set to pmbus_read_status_byte()
if reading the word status is not supported. Given that, why not just call
pmbus_get_status(client, page, PMBUS_STATUS_WORD) ?

> +	if (status < 0)
> +		return status;
> +
> +	if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
> +		*flags |= REGULATOR_ERROR_FAIL;
> +	if (status & PB_STATUS_IOUT_OC)
> +		*flags |= REGULATOR_ERROR_OVER_CURRENT;

If the current status register is supported, this effectively means that
an overcurrent warning is always reported as both REGULATOR_ERROR_OVER_CURRENT
and REGULATOR_ERROR_OVER_CURRENT_WARN. Is that intentional ?


> +	if (status & PB_STATUS_VOUT_OV)
> +		*flags |= REGULATOR_ERROR_REGULATION_OUT;

Same for voltage. On the other side, temperature limit violations are not
reported at all unless the temperature status register exists.
That seems to be a bit inconsistent to me.

> +
> +	return 0;
> +}
> +
>   const struct regulator_ops pmbus_regulator_ops = {
>   	.enable = pmbus_regulator_enable,
>   	.disable = pmbus_regulator_disable,
>   	.is_enabled = pmbus_regulator_is_enabled,
> +	.get_error_flags = pmbus_regulator_get_error_flags,
>   };
>   EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);
>
Zev Weiss Feb. 17, 2022, 11:37 p.m. UTC | #2
On Thu, Feb 17, 2022 at 10:11:32AM PST, Guenter Roeck wrote:
>On 2/17/22 02:44, Zev Weiss wrote:
>>The various PMBus status bits don't all map perfectly to the more
>>limited set of REGULATOR_ERROR_* flags, but there's a reasonable
>>number where they correspond well enough.
>>
>>Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
>>---
>>  drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++++++++++++++++++++++++++
>>  1 file changed, 97 insertions(+)
>>
>>diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>>index 776ee2237be2..a274e8e524a5 100644
>>--- a/drivers/hwmon/pmbus/pmbus_core.c
>>+++ b/drivers/hwmon/pmbus/pmbus_core.c
>>@@ -2417,10 +2417,107 @@ static int pmbus_regulator_disable(struct regulator_dev *rdev)
>>  	return _pmbus_regulator_on_off(rdev, 0);
>>  }
>>+/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
>>+struct pmbus_regulator_status_assoc {
>>+	int pflag, rflag;
>>+};
>>+
>>+/* PMBus->regulator bit mappings for a PMBus status register */
>>+struct pmbus_regulator_status_category {
>>+	int func;
>>+	int reg;
>>+	const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
>>+};
>>+
>>+static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
>>+	{
>>+		.func = PMBUS_HAVE_STATUS_VOUT,
>>+		.reg = PMBUS_STATUS_VOUT,
>>+		.bits = (const struct pmbus_regulator_status_assoc[]) {
>>+			{ PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
>>+			{ PB_VOLTAGE_UV_FAULT,   REGULATOR_ERROR_UNDER_VOLTAGE },
>>+			{ PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
>>+			{ PB_VOLTAGE_OV_FAULT,   REGULATOR_ERROR_REGULATION_OUT },
>>+			{ },
>>+		},
>>+	}, {
>>+		.func = PMBUS_HAVE_STATUS_IOUT,
>>+		.reg = PMBUS_STATUS_IOUT,
>>+		.bits = (const struct pmbus_regulator_status_assoc[]) {
>>+			{ PB_IOUT_OC_WARNING,    REGULATOR_ERROR_OVER_CURRENT_WARN },
>>+			{ PB_IOUT_OC_FAULT,      REGULATOR_ERROR_OVER_CURRENT },
>>+			{ PB_IOUT_OC_LV_FAULT,   REGULATOR_ERROR_OVER_CURRENT },
>>+			{ },
>>+		},
>>+	}, {
>>+		.func = PMBUS_HAVE_STATUS_TEMP,
>>+		.reg = PMBUS_STATUS_TEMPERATURE,
>>+		.bits = (const struct pmbus_regulator_status_assoc[]) {
>>+			{ PB_TEMP_OT_WARNING,    REGULATOR_ERROR_OVER_TEMP_WARN },
>>+			{ PB_TEMP_OT_FAULT,      REGULATOR_ERROR_OVER_TEMP },
>>+			{ },
>>+		},
>>+	},
>>+};
>>+
>>+static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
>>+{
>>+	int i, status, statusreg;
>>+	const struct pmbus_regulator_status_category *cat;
>>+	const struct pmbus_regulator_status_assoc *bit;
>>+	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 func = data->info->func[page];
>>+
>>+	*flags = 0;
>>+
>>+	for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
>>+		cat = &pmbus_regulator_flag_map[i];
>>+		if (!(func & cat->func))
>>+			continue;
>>+
>>+		status = pmbus_read_byte_data(client, page, cat->reg);
>>+		if (status < 0)
>>+			return status;
>>+
>>+		for (bit = cat->bits; bit->pflag; bit++) {
>>+			if (status & bit->pflag)
>>+				*flags |= bit->rflag;
>>+		}
>>+	}
>>+
>>+	/*
>>+	 * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
>>+	 * bits.  Some of the other bits are tempting (especially for cases
>>+	 * where we don't have the relevant PMBUS_HAVE_STATUS_*
>>+	 * functionality), but there's an unfortunate ambiguity in that
>>+	 * they're defined as indicating a fault *or* a warning, so we can't
>>+	 * easily determine whether to report REGULATOR_ERROR_<foo> or
>>+	 * REGULATOR_ERROR_<foo>_WARN.
>>+	 */
>>+	statusreg = data->has_status_word ? PMBUS_STATUS_WORD : PMBUS_STATUS_BYTE;
>>+	status = pmbus_get_status(client, page, statusreg);
>>+
>
>pmbus_get_status() calls data->read_status if PMBUS_STATUS_WORD is provided
>as parameter, and data->read_status is set to pmbus_read_status_byte()
>if reading the word status is not supported. Given that, why not just call
>pmbus_get_status(client, page, PMBUS_STATUS_WORD) ?

Good point, I'll change it to do that instead.  (And send v2 separately 
from the power-efuse driver patches.)

>
>>+	if (status < 0)
>>+		return status;
>>+
>>+	if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
>>+		*flags |= REGULATOR_ERROR_FAIL;
>>+	if (status & PB_STATUS_IOUT_OC)
>>+		*flags |= REGULATOR_ERROR_OVER_CURRENT;
>
>If the current status register is supported, this effectively means that
>an overcurrent warning is always reported as both REGULATOR_ERROR_OVER_CURRENT
>and REGULATOR_ERROR_OVER_CURRENT_WARN. Is that intentional ?
>

No, but I don't think (by my reading of the spec) that's what would 
happen?

I'm looking at table 16 ("STATUS_WORD Message Contents") in section 17.2 
("STATUS_WORD") of Part II of revision 1.3.1 of the PMBus spec, which 
says that bit 4 of the low byte (PB_STATUS_IOUT_OC) indicates an output 
overcurrent fault, not a warning (in contrast to most of the other bits, 
which may indicate either).

>
>>+	if (status & PB_STATUS_VOUT_OV)
>>+		*flags |= REGULATOR_ERROR_REGULATION_OUT;
>
>Same for voltage.

Likewise, PB_STATUS_VOUT_OV is specified as indicating a fault, not a 
warning.

>On the other side, temperature limit violations are not
>reported at all unless the temperature status register exists.
>That seems to be a bit inconsistent to me.
>

Right -- that's because PB_STATUS_TEMPERATURE is one of the "fault or 
warning" bits (unlike VOUT_OV and IOUT_OC), and hence it's an ambiguous 
case as described in the comment before the pmbus_get_status() call.

It's certainly not ideal, but it seemed like the best approach I could 
see given the semantics of the available flags -- I'm open to other 
possibilities though if there's something else that would work better.

Thanks for the review,
Zev
Guenter Roeck Feb. 18, 2022, 12:02 a.m. UTC | #3
On 2/17/22 15:37, Zev Weiss wrote:
> On Thu, Feb 17, 2022 at 10:11:32AM PST, Guenter Roeck wrote:
>> On 2/17/22 02:44, Zev Weiss wrote:
>>> The various PMBus status bits don't all map perfectly to the more
>>> limited set of REGULATOR_ERROR_* flags, but there's a reasonable
>>> number where they correspond well enough.
>>>
>>> Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
>>> ---
>>>  drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++++++++++++++++++++++++++
>>>  1 file changed, 97 insertions(+)
>>>
>>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>>> index 776ee2237be2..a274e8e524a5 100644
>>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>>> @@ -2417,10 +2417,107 @@ static int pmbus_regulator_disable(struct regulator_dev *rdev)
>>>      return _pmbus_regulator_on_off(rdev, 0);
>>>  }
>>> +/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
>>> +struct pmbus_regulator_status_assoc {
>>> +    int pflag, rflag;
>>> +};
>>> +
>>> +/* PMBus->regulator bit mappings for a PMBus status register */
>>> +struct pmbus_regulator_status_category {
>>> +    int func;
>>> +    int reg;
>>> +    const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
>>> +};
>>> +
>>> +static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
>>> +    {
>>> +        .func = PMBUS_HAVE_STATUS_VOUT,
>>> +        .reg = PMBUS_STATUS_VOUT,
>>> +        .bits = (const struct pmbus_regulator_status_assoc[]) {
>>> +            { PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
>>> +            { PB_VOLTAGE_UV_FAULT,   REGULATOR_ERROR_UNDER_VOLTAGE },
>>> +            { PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
>>> +            { PB_VOLTAGE_OV_FAULT,   REGULATOR_ERROR_REGULATION_OUT },
>>> +            { },
>>> +        },
>>> +    }, {
>>> +        .func = PMBUS_HAVE_STATUS_IOUT,
>>> +        .reg = PMBUS_STATUS_IOUT,
>>> +        .bits = (const struct pmbus_regulator_status_assoc[]) {
>>> +            { PB_IOUT_OC_WARNING,    REGULATOR_ERROR_OVER_CURRENT_WARN },
>>> +            { PB_IOUT_OC_FAULT,      REGULATOR_ERROR_OVER_CURRENT },
>>> +            { PB_IOUT_OC_LV_FAULT,   REGULATOR_ERROR_OVER_CURRENT },
>>> +            { },
>>> +        },
>>> +    }, {
>>> +        .func = PMBUS_HAVE_STATUS_TEMP,
>>> +        .reg = PMBUS_STATUS_TEMPERATURE,
>>> +        .bits = (const struct pmbus_regulator_status_assoc[]) {
>>> +            { PB_TEMP_OT_WARNING,    REGULATOR_ERROR_OVER_TEMP_WARN },
>>> +            { PB_TEMP_OT_FAULT,      REGULATOR_ERROR_OVER_TEMP },
>>> +            { },
>>> +        },
>>> +    },
>>> +};
>>> +
>>> +static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
>>> +{
>>> +    int i, status, statusreg;
>>> +    const struct pmbus_regulator_status_category *cat;
>>> +    const struct pmbus_regulator_status_assoc *bit;
>>> +    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 func = data->info->func[page];
>>> +
>>> +    *flags = 0;
>>> +
>>> +    for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
>>> +        cat = &pmbus_regulator_flag_map[i];
>>> +        if (!(func & cat->func))
>>> +            continue;
>>> +
>>> +        status = pmbus_read_byte_data(client, page, cat->reg);
>>> +        if (status < 0)
>>> +            return status;
>>> +
>>> +        for (bit = cat->bits; bit->pflag; bit++) {
>>> +            if (status & bit->pflag)
>>> +                *flags |= bit->rflag;
>>> +        }
>>> +    }
>>> +
>>> +    /*
>>> +     * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
>>> +     * bits.  Some of the other bits are tempting (especially for cases
>>> +     * where we don't have the relevant PMBUS_HAVE_STATUS_*
>>> +     * functionality), but there's an unfortunate ambiguity in that
>>> +     * they're defined as indicating a fault *or* a warning, so we can't
>>> +     * easily determine whether to report REGULATOR_ERROR_<foo> or
>>> +     * REGULATOR_ERROR_<foo>_WARN.
>>> +     */
>>> +    statusreg = data->has_status_word ? PMBUS_STATUS_WORD : PMBUS_STATUS_BYTE;
>>> +    status = pmbus_get_status(client, page, statusreg);
>>> +
>>
>> pmbus_get_status() calls data->read_status if PMBUS_STATUS_WORD is provided
>> as parameter, and data->read_status is set to pmbus_read_status_byte()
>> if reading the word status is not supported. Given that, why not just call
>> pmbus_get_status(client, page, PMBUS_STATUS_WORD) ?
> 
> Good point, I'll change it to do that instead.  (And send v2 separately from the power-efuse driver patches.)
> 
>>
>>> +    if (status < 0)
>>> +        return status;
>>> +
>>> +    if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
>>> +        *flags |= REGULATOR_ERROR_FAIL;
>>> +    if (status & PB_STATUS_IOUT_OC)
>>> +        *flags |= REGULATOR_ERROR_OVER_CURRENT;
>>
>> If the current status register is supported, this effectively means that
>> an overcurrent warning is always reported as both REGULATOR_ERROR_OVER_CURRENT
>> and REGULATOR_ERROR_OVER_CURRENT_WARN. Is that intentional ?
>>
> 
> No, but I don't think (by my reading of the spec) that's what would happen?
> 
> I'm looking at table 16 ("STATUS_WORD Message Contents") in section 17.2 ("STATUS_WORD") of Part II of revision 1.3.1 of the PMBus spec, which says that bit 4 of the low byte (PB_STATUS_IOUT_OC) indicates an output overcurrent fault, not a warning (in contrast to most of the other bits, which may indicate either).
> 
>>
>>> +    if (status & PB_STATUS_VOUT_OV)
>>> +        *flags |= REGULATOR_ERROR_REGULATION_OUT;
>>
>> Same for voltage.
> 
> Likewise, PB_STATUS_VOUT_OV is specified as indicating a fault, not a warning.
> 

Ok, that makes sense.

>> On the other side, temperature limit violations are not
>> reported at all unless the temperature status register exists.
>> That seems to be a bit inconsistent to me.
>>
> 
> Right -- that's because PB_STATUS_TEMPERATURE is one of the "fault or warning" bits (unlike VOUT_OV and IOUT_OC), and hence it's an ambiguous case as described in the comment before the pmbus_get_status() call.
> 
> It's certainly not ideal, but it seemed like the best approach I could see given the semantics of the available flags -- I'm open to other possibilities though if there's something else that would work better.
> 

My approach would be to report a warning if no temperature warning/fault
is set from PMBUS_STATUS_TEMPERATURE but PB_STATUS_TEMPERATURE is set
in the status register.

Something like

	if (!(*flags & (REGULATOR_ERROR_OVER_TEMP | REGULATOR_ERROR_OVER_TEMP_WARN))
	    && (status & PB_STATUS_TEMPERATURE))
		*flags |= REGULATOR_ERROR_OVER_TEMP_WARN;

While not perfect, it would be better than reporting nothing.

Guenter
Zev Weiss Feb. 18, 2022, 12:23 a.m. UTC | #4
On Thu, Feb 17, 2022 at 04:02:58PM PST, Guenter Roeck wrote:
>On 2/17/22 15:37, Zev Weiss wrote:
>>On Thu, Feb 17, 2022 at 10:11:32AM PST, Guenter Roeck wrote:
>>>On 2/17/22 02:44, Zev Weiss wrote:
>>>>The various PMBus status bits don't all map perfectly to the more
>>>>limited set of REGULATOR_ERROR_* flags, but there's a reasonable
>>>>number where they correspond well enough.
>>>>
>>>>Signed-off-by: Zev Weiss <zev@bewilderbeest.net>
>>>>---
>>>> drivers/hwmon/pmbus/pmbus_core.c | 97 ++++++++++++++++++++++++++++++++
>>>> 1 file changed, 97 insertions(+)
>>>>
>>>>diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>>>>index 776ee2237be2..a274e8e524a5 100644
>>>>--- a/drivers/hwmon/pmbus/pmbus_core.c
>>>>+++ b/drivers/hwmon/pmbus/pmbus_core.c
>>>>@@ -2417,10 +2417,107 @@ static int pmbus_regulator_disable(struct regulator_dev *rdev)
>>>>     return _pmbus_regulator_on_off(rdev, 0);
>>>> }
>>>>+/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
>>>>+struct pmbus_regulator_status_assoc {
>>>>+    int pflag, rflag;
>>>>+};
>>>>+
>>>>+/* PMBus->regulator bit mappings for a PMBus status register */
>>>>+struct pmbus_regulator_status_category {
>>>>+    int func;
>>>>+    int reg;
>>>>+    const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
>>>>+};
>>>>+
>>>>+static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
>>>>+    {
>>>>+        .func = PMBUS_HAVE_STATUS_VOUT,
>>>>+        .reg = PMBUS_STATUS_VOUT,
>>>>+        .bits = (const struct pmbus_regulator_status_assoc[]) {
>>>>+            { PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
>>>>+            { PB_VOLTAGE_UV_FAULT,   REGULATOR_ERROR_UNDER_VOLTAGE },
>>>>+            { PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
>>>>+            { PB_VOLTAGE_OV_FAULT,   REGULATOR_ERROR_REGULATION_OUT },
>>>>+            { },
>>>>+        },
>>>>+    }, {
>>>>+        .func = PMBUS_HAVE_STATUS_IOUT,
>>>>+        .reg = PMBUS_STATUS_IOUT,
>>>>+        .bits = (const struct pmbus_regulator_status_assoc[]) {
>>>>+            { PB_IOUT_OC_WARNING,    REGULATOR_ERROR_OVER_CURRENT_WARN },
>>>>+            { PB_IOUT_OC_FAULT,      REGULATOR_ERROR_OVER_CURRENT },
>>>>+            { PB_IOUT_OC_LV_FAULT,   REGULATOR_ERROR_OVER_CURRENT },
>>>>+            { },
>>>>+        },
>>>>+    }, {
>>>>+        .func = PMBUS_HAVE_STATUS_TEMP,
>>>>+        .reg = PMBUS_STATUS_TEMPERATURE,
>>>>+        .bits = (const struct pmbus_regulator_status_assoc[]) {
>>>>+            { PB_TEMP_OT_WARNING,    REGULATOR_ERROR_OVER_TEMP_WARN },
>>>>+            { PB_TEMP_OT_FAULT,      REGULATOR_ERROR_OVER_TEMP },
>>>>+            { },
>>>>+        },
>>>>+    },
>>>>+};
>>>>+
>>>>+static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
>>>>+{
>>>>+    int i, status, statusreg;
>>>>+    const struct pmbus_regulator_status_category *cat;
>>>>+    const struct pmbus_regulator_status_assoc *bit;
>>>>+    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 func = data->info->func[page];
>>>>+
>>>>+    *flags = 0;
>>>>+
>>>>+    for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
>>>>+        cat = &pmbus_regulator_flag_map[i];
>>>>+        if (!(func & cat->func))
>>>>+            continue;
>>>>+
>>>>+        status = pmbus_read_byte_data(client, page, cat->reg);
>>>>+        if (status < 0)
>>>>+            return status;
>>>>+
>>>>+        for (bit = cat->bits; bit->pflag; bit++) {
>>>>+            if (status & bit->pflag)
>>>>+                *flags |= bit->rflag;
>>>>+        }
>>>>+    }
>>>>+
>>>>+    /*
>>>>+     * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
>>>>+     * bits.  Some of the other bits are tempting (especially for cases
>>>>+     * where we don't have the relevant PMBUS_HAVE_STATUS_*
>>>>+     * functionality), but there's an unfortunate ambiguity in that
>>>>+     * they're defined as indicating a fault *or* a warning, so we can't
>>>>+     * easily determine whether to report REGULATOR_ERROR_<foo> or
>>>>+     * REGULATOR_ERROR_<foo>_WARN.
>>>>+     */
>>>>+    statusreg = data->has_status_word ? PMBUS_STATUS_WORD : PMBUS_STATUS_BYTE;
>>>>+    status = pmbus_get_status(client, page, statusreg);
>>>>+
>>>
>>>pmbus_get_status() calls data->read_status if PMBUS_STATUS_WORD is provided
>>>as parameter, and data->read_status is set to pmbus_read_status_byte()
>>>if reading the word status is not supported. Given that, why not just call
>>>pmbus_get_status(client, page, PMBUS_STATUS_WORD) ?
>>
>>Good point, I'll change it to do that instead.  (And send v2 separately from the power-efuse driver patches.)
>>
>>>
>>>>+    if (status < 0)
>>>>+        return status;
>>>>+
>>>>+    if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
>>>>+        *flags |= REGULATOR_ERROR_FAIL;
>>>>+    if (status & PB_STATUS_IOUT_OC)
>>>>+        *flags |= REGULATOR_ERROR_OVER_CURRENT;
>>>
>>>If the current status register is supported, this effectively means that
>>>an overcurrent warning is always reported as both REGULATOR_ERROR_OVER_CURRENT
>>>and REGULATOR_ERROR_OVER_CURRENT_WARN. Is that intentional ?
>>>
>>
>>No, but I don't think (by my reading of the spec) that's what would happen?
>>
>>I'm looking at table 16 ("STATUS_WORD Message Contents") in section 17.2 ("STATUS_WORD") of Part II of revision 1.3.1 of the PMBus spec, which says that bit 4 of the low byte (PB_STATUS_IOUT_OC) indicates an output overcurrent fault, not a warning (in contrast to most of the other bits, which may indicate either).
>>
>>>
>>>>+    if (status & PB_STATUS_VOUT_OV)
>>>>+        *flags |= REGULATOR_ERROR_REGULATION_OUT;
>>>
>>>Same for voltage.
>>
>>Likewise, PB_STATUS_VOUT_OV is specified as indicating a fault, not a warning.
>>
>
>Ok, that makes sense.
>
>>>On the other side, temperature limit violations are not
>>>reported at all unless the temperature status register exists.
>>>That seems to be a bit inconsistent to me.
>>>
>>
>>Right -- that's because PB_STATUS_TEMPERATURE is one of the "fault or warning" bits (unlike VOUT_OV and IOUT_OC), and hence it's an ambiguous case as described in the comment before the pmbus_get_status() call.
>>
>>It's certainly not ideal, but it seemed like the best approach I could see given the semantics of the available flags -- I'm open to other possibilities though if there's something else that would work better.
>>
>
>My approach would be to report a warning if no temperature warning/fault
>is set from PMBUS_STATUS_TEMPERATURE but PB_STATUS_TEMPERATURE is set
>in the status register.
>
>Something like
>
>	if (!(*flags & (REGULATOR_ERROR_OVER_TEMP | REGULATOR_ERROR_OVER_TEMP_WARN))
>	    && (status & PB_STATUS_TEMPERATURE))
>		*flags |= REGULATOR_ERROR_OVER_TEMP_WARN;
>
>While not perfect, it would be better than reporting nothing.
>

That sounds like a good idea -- I'll add it in v2.


Thanks,
Zev
diff mbox series

Patch

diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
index 776ee2237be2..a274e8e524a5 100644
--- a/drivers/hwmon/pmbus/pmbus_core.c
+++ b/drivers/hwmon/pmbus/pmbus_core.c
@@ -2417,10 +2417,107 @@  static int pmbus_regulator_disable(struct regulator_dev *rdev)
 	return _pmbus_regulator_on_off(rdev, 0);
 }
 
+/* A PMBus status flag and the corresponding REGULATOR_ERROR_* flag */
+struct pmbus_regulator_status_assoc {
+	int pflag, rflag;
+};
+
+/* PMBus->regulator bit mappings for a PMBus status register */
+struct pmbus_regulator_status_category {
+	int func;
+	int reg;
+	const struct pmbus_regulator_status_assoc *bits; /* zero-terminated */
+};
+
+static const struct pmbus_regulator_status_category pmbus_regulator_flag_map[] = {
+	{
+		.func = PMBUS_HAVE_STATUS_VOUT,
+		.reg = PMBUS_STATUS_VOUT,
+		.bits = (const struct pmbus_regulator_status_assoc[]) {
+			{ PB_VOLTAGE_UV_WARNING, REGULATOR_ERROR_UNDER_VOLTAGE_WARN },
+			{ PB_VOLTAGE_UV_FAULT,   REGULATOR_ERROR_UNDER_VOLTAGE },
+			{ PB_VOLTAGE_OV_WARNING, REGULATOR_ERROR_OVER_VOLTAGE_WARN },
+			{ PB_VOLTAGE_OV_FAULT,   REGULATOR_ERROR_REGULATION_OUT },
+			{ },
+		},
+	}, {
+		.func = PMBUS_HAVE_STATUS_IOUT,
+		.reg = PMBUS_STATUS_IOUT,
+		.bits = (const struct pmbus_regulator_status_assoc[]) {
+			{ PB_IOUT_OC_WARNING,    REGULATOR_ERROR_OVER_CURRENT_WARN },
+			{ PB_IOUT_OC_FAULT,      REGULATOR_ERROR_OVER_CURRENT },
+			{ PB_IOUT_OC_LV_FAULT,   REGULATOR_ERROR_OVER_CURRENT },
+			{ },
+		},
+	}, {
+		.func = PMBUS_HAVE_STATUS_TEMP,
+		.reg = PMBUS_STATUS_TEMPERATURE,
+		.bits = (const struct pmbus_regulator_status_assoc[]) {
+			{ PB_TEMP_OT_WARNING,    REGULATOR_ERROR_OVER_TEMP_WARN },
+			{ PB_TEMP_OT_FAULT,      REGULATOR_ERROR_OVER_TEMP },
+			{ },
+		},
+	},
+};
+
+static int pmbus_regulator_get_error_flags(struct regulator_dev *rdev, unsigned int *flags)
+{
+	int i, status, statusreg;
+	const struct pmbus_regulator_status_category *cat;
+	const struct pmbus_regulator_status_assoc *bit;
+	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 func = data->info->func[page];
+
+	*flags = 0;
+
+	for (i = 0; i < ARRAY_SIZE(pmbus_regulator_flag_map); i++) {
+		cat = &pmbus_regulator_flag_map[i];
+		if (!(func & cat->func))
+			continue;
+
+		status = pmbus_read_byte_data(client, page, cat->reg);
+		if (status < 0)
+			return status;
+
+		for (bit = cat->bits; bit->pflag; bit++) {
+			if (status & bit->pflag)
+				*flags |= bit->rflag;
+		}
+	}
+
+	/*
+	 * Map what bits of STATUS_{WORD,BYTE} we can to REGULATOR_ERROR_*
+	 * bits.  Some of the other bits are tempting (especially for cases
+	 * where we don't have the relevant PMBUS_HAVE_STATUS_*
+	 * functionality), but there's an unfortunate ambiguity in that
+	 * they're defined as indicating a fault *or* a warning, so we can't
+	 * easily determine whether to report REGULATOR_ERROR_<foo> or
+	 * REGULATOR_ERROR_<foo>_WARN.
+	 */
+	statusreg = data->has_status_word ? PMBUS_STATUS_WORD : PMBUS_STATUS_BYTE;
+	status = pmbus_get_status(client, page, statusreg);
+
+	if (status < 0)
+		return status;
+
+	if (pmbus_regulator_is_enabled(rdev) && (status & PB_STATUS_OFF))
+		*flags |= REGULATOR_ERROR_FAIL;
+	if (status & PB_STATUS_IOUT_OC)
+		*flags |= REGULATOR_ERROR_OVER_CURRENT;
+	if (status & PB_STATUS_VOUT_OV)
+		*flags |= REGULATOR_ERROR_REGULATION_OUT;
+
+	return 0;
+}
+
 const struct regulator_ops pmbus_regulator_ops = {
 	.enable = pmbus_regulator_enable,
 	.disable = pmbus_regulator_disable,
 	.is_enabled = pmbus_regulator_is_enabled,
+	.get_error_flags = pmbus_regulator_get_error_flags,
 };
 EXPORT_SYMBOL_NS_GPL(pmbus_regulator_ops, PMBUS);