[RESEND,v6,1/5] hwmon: (pmbus/core): Add interrupt support

  From: Patrick Rudolph <patrick.rudolph@9elements.com>

Implement PMBUS irq handler.

Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
---
 drivers/hwmon/pmbus/pmbus.h      |  2 +-
 drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
 2 files changed, 85 insertions(+), 1 deletion(-)


base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
  

On Wed, Dec 14, 2022 at 09:07:11AM +0100, Naresh Solanki wrote:
> From: Patrick Rudolph <patrick.rudolph@9elements.com>
> 
> Implement PMBUS irq handler.
> 
> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>

$ scripts/checkpatch.pl --strict index.html
CHECK: Blank lines aren't necessary after an open brace '{'
#131: FILE: drivers/hwmon/pmbus/pmbus_core.c:3088:
+	for (i = 0; i < data->info->pages; i++) {
+

CHECK: Alignment should match open parenthesis
#183: FILE: drivers/hwmon/pmbus/pmbus_core.c:3140:
+	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
+			      0, "pmbus-irq", data);

CHECK: Please use a blank line after function/struct/union/enum declarations
#197: FILE: drivers/hwmon/pmbus/pmbus_core.c:3154:
 }
+static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)

total: 0 errors, 0 warnings, 3 checks, 109 lines checked

NOTE: For some of the reported defects, checkpatch may be able to
      mechanically convert to the typical style using --fix or --fix-inplace.

index.html has style problems, please review.

Please run checkpatch --strict on your patches.
Also see Documentation/hwmon/submitting-patches.rst.

> ---
>  drivers/hwmon/pmbus/pmbus.h      |  2 +-
>  drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
>  2 files changed, 85 insertions(+), 1 deletion(-)
> 
> 
> base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
> 
> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> index 10fb17879f8e..6b2e6cf93b19 100644
> --- a/drivers/hwmon/pmbus/pmbus.h
> +++ b/drivers/hwmon/pmbus/pmbus.h
> @@ -26,7 +26,7 @@ enum pmbus_regs {
>  
>  	PMBUS_CAPABILITY		= 0x19,
>  	PMBUS_QUERY			= 0x1A,
> -
> +	PMBUS_SMBALERT_MASK		= 0x1B,
>  	PMBUS_VOUT_MODE			= 0x20,
>  	PMBUS_VOUT_COMMAND		= 0x21,
>  	PMBUS_VOUT_TRIM			= 0x22,
> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> index 95e95783972a..244fd2597252 100644
> --- a/drivers/hwmon/pmbus/pmbus_core.c
> +++ b/drivers/hwmon/pmbus/pmbus_core.c
> @@ -3072,11 +3072,89 @@ static int pmbus_regulator_register(struct pmbus_data *data)
>  
>  	return 0;
>  }
> +
> +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
> +{
> +	return pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
> +}
> +
> +static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
> +{
> +	struct pmbus_data *data = pdata;
> +	struct i2c_client *client = to_i2c_client(data->dev);
> +	int i, status;
> +
> +	for (i = 0; i < data->info->pages; i++) {
> +
> +		mutex_lock(&data->update_lock);
> +		status = pmbus_read_status_word(client, i);
> +		if (status < 0) {
> +			mutex_unlock(&data->update_lock);
> +			return status;
> +		}
> +
> +		if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
> +			pmbus_clear_fault_page(client, i);
> +
> +		mutex_unlock(&data->update_lock);
> +	}
> +
> +	return IRQ_HANDLED;
> +}
> +
> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> +{
> +	struct device *dev = &client->dev;
> +	const struct pmbus_regulator_status_category *cat;
> +	const struct pmbus_regulator_status_assoc *bit;
> +	int i, j, err, ret, func;
> +	u8 mask;
> +
> +	for (i = 0; i < data->info->pages; i++) {
> +		func = data->info->func[i];
> +
> +		for (j = 0; j < ARRAY_SIZE(pmbus_regulator_flag_map); j++) {
> +			cat = &pmbus_regulator_flag_map[j];
> +			if (!(func & cat->func))
> +				continue;
> +			mask = 0;
> +			for (bit = cat->bits; bit->pflag; bit++)
> +				mask |= bit->pflag;
> +
> +			err = pmbus_write_smbalert_mask(client, i, cat->reg, ~mask);
> +			if (err)
> +				dev_err(dev, "Failed to set smbalert for reg 0x%02x\n",	cat->reg);

This concerns me. It might mean that the chip does not support
PMBUS_SMBALERT_MASK. If so, there would be lots of error messages.

> +		}
> +
> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_CML, 0xff);
> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_OTHER, 0xff);
> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_MFR_SPECIFIC, 0xff);

Why check the return value from pmbus_write_smbalert_mask above but not here ?

> +		if (data->info->func[i] & PMBUS_HAVE_FAN12)
> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_12, 0xff);
> +		if (data->info->func[i] & PMBUS_HAVE_FAN34)
> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_34, 0xff);
> +	}
> +
> +	/* Register notifiers - can fail if IRQ is not given */

The comment does not make sense. pmbus_irq_setup() is not called
if the interrupt "is not given".

> +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
> +			      0, "pmbus-irq", data);
> +	if (ret) {
> +		dev_warn(dev, "IRQ disabled %d\n", ret);

This is not a warning, it is an error.

> +		return ret;
> +	}
> +
> +	return 0;
> +}
> +
>  #else

This is still in regulator code. I said several times that this is not
acceptable.

>  static int pmbus_regulator_register(struct pmbus_data *data)
>  {
>  	return 0;
>  }
> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> +{
> +	return 0;
> +}
>  #endif
>  
>  static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
> @@ -3441,6 +3519,12 @@ int pmbus_do_probe(struct i2c_client *client, struct pmbus_driver_info *info)
>  	if (ret)
>  		return ret;
>  
> +	if (client->irq > 0) {
> +		ret = pmbus_irq_setup(client, data);
> +		if (ret)
> +			return ret;
> +	}
> +
>  	ret = pmbus_init_debugfs(client, data);
>  	if (ret)
>  		dev_warn(dev, "Failed to register debugfs\n");
  

Hi Guenter,

On 29-12-2022 08:10 pm, Guenter Roeck wrote:
> On Wed, Dec 14, 2022 at 09:07:11AM +0100, Naresh Solanki wrote:
>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>>
>> Implement PMBUS irq handler.
>>
>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> 
> $ scripts/checkpatch.pl --strict index.html
> CHECK: Blank lines aren't necessary after an open brace '{'
> #131: FILE: drivers/hwmon/pmbus/pmbus_core.c:3088:
> +	for (i = 0; i < data->info->pages; i++) {
> +
> 
> CHECK: Alignment should match open parenthesis
> #183: FILE: drivers/hwmon/pmbus/pmbus_core.c:3140:
> +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
> +			      0, "pmbus-irq", data);
> 
> CHECK: Please use a blank line after function/struct/union/enum declarations
> #197: FILE: drivers/hwmon/pmbus/pmbus_core.c:3154:
>   }
> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> 
> total: 0 errors, 0 warnings, 3 checks, 109 lines checked
> 
> NOTE: For some of the reported defects, checkpatch may be able to
>        mechanically convert to the typical style using --fix or --fix-inplace.
> 
> index.html has style problems, please review.
> 
> Please run checkpatch --strict on your patches.
> Also see Documentation/hwmon/submitting-patches.rst.
I will take care of these errors in the updated version.
> 
>> ---
>>   drivers/hwmon/pmbus/pmbus.h      |  2 +-
>>   drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
>>   2 files changed, 85 insertions(+), 1 deletion(-)
>>
>>
>> base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
>>
>> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
>> index 10fb17879f8e..6b2e6cf93b19 100644
>> --- a/drivers/hwmon/pmbus/pmbus.h
>> +++ b/drivers/hwmon/pmbus/pmbus.h
>> @@ -26,7 +26,7 @@ enum pmbus_regs {
>>   
>>   	PMBUS_CAPABILITY		= 0x19,
>>   	PMBUS_QUERY			= 0x1A,
>> -
>> +	PMBUS_SMBALERT_MASK		= 0x1B,
>>   	PMBUS_VOUT_MODE			= 0x20,
>>   	PMBUS_VOUT_COMMAND		= 0x21,
>>   	PMBUS_VOUT_TRIM			= 0x22,
>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>> index 95e95783972a..244fd2597252 100644
>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>> @@ -3072,11 +3072,89 @@ static int pmbus_regulator_register(struct pmbus_data *data)
>>   
>>   	return 0;
>>   }
>> +
>> +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
>> +{
>> +	return pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
>> +}
>> +
>> +static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
>> +{
>> +	struct pmbus_data *data = pdata;
>> +	struct i2c_client *client = to_i2c_client(data->dev);
>> +	int i, status;
>> +
>> +	for (i = 0; i < data->info->pages; i++) {
>> +
>> +		mutex_lock(&data->update_lock);
>> +		status = pmbus_read_status_word(client, i);
>> +		if (status < 0) {
>> +			mutex_unlock(&data->update_lock);
>> +			return status;
>> +		}
>> +
>> +		if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
>> +			pmbus_clear_fault_page(client, i);
>> +
>> +		mutex_unlock(&data->update_lock);
>> +	}
>> +
>> +	return IRQ_HANDLED;
>> +}
>> +
>> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
>> +{
>> +	struct device *dev = &client->dev;
>> +	const struct pmbus_regulator_status_category *cat;
>> +	const struct pmbus_regulator_status_assoc *bit;
>> +	int i, j, err, ret, func;
>> +	u8 mask;
>> +
>> +	for (i = 0; i < data->info->pages; i++) {
>> +		func = data->info->func[i];
>> +
>> +		for (j = 0; j < ARRAY_SIZE(pmbus_regulator_flag_map); j++) {
>> +			cat = &pmbus_regulator_flag_map[j];
>> +			if (!(func & cat->func))
>> +				continue;
>> +			mask = 0;
>> +			for (bit = cat->bits; bit->pflag; bit++)
>> +				mask |= bit->pflag;
>> +
>> +			err = pmbus_write_smbalert_mask(client, i, cat->reg, ~mask);
>> +			if (err)
>> +				dev_err(dev, "Failed to set smbalert for reg 0x%02x\n",	cat->reg);
> 
> This concerns me. It might mean that the chip does not support
> PMBUS_SMBALERT_MASK. If so, there would be lots of error messages.
After going through the PMBus specification, it appears that this should 
not be an issue unless there is a violation of the specification.
> 
>> +		}
>> +
>> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_CML, 0xff);
>> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_OTHER, 0xff);
>> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_MFR_SPECIFIC, 0xff);
> 
> Why check the return value from pmbus_write_smbalert_mask above but not here ?
Thank you for pointing out the oversight. I will make sure to include an 
error check at this point.
> 
>> +		if (data->info->func[i] & PMBUS_HAVE_FAN12)
>> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_12, 0xff);
>> +		if (data->info->func[i] & PMBUS_HAVE_FAN34)
>> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_34, 0xff);
>> +	}
>> +
>> +	/* Register notifiers - can fail if IRQ is not given */
> 
> The comment does not make sense. pmbus_irq_setup() is not called
> if the interrupt "is not given".
Yes. The comment here is not relevant and will be removed.
> 
>> +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
>> +			      0, "pmbus-irq", data);
>> +	if (ret) {
>> +		dev_warn(dev, "IRQ disabled %d\n", ret);
> 
> This is not a warning, it is an error.
Thank you for bringing this to my attention. I will make sure to update 
the code to reflect that this is an error.
> 
>> +		return ret;
>> +	}
>> +
>> +	return 0;
>> +}
>> +
>>   #else
> 
> This is still in regulator code. I said several times that this is not
> acceptable.
Thank you for pointing out the mistake. I will make sure to correct this 
in the next revision.
> 
>>   static int pmbus_regulator_register(struct pmbus_data *data)
>>   {
>>   	return 0;
>>   }
>> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
>> +{
>> +	return 0;
>> +}
>>   #endif
>>   
>>   static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
>> @@ -3441,6 +3519,12 @@ int pmbus_do_probe(struct i2c_client *client, struct pmbus_driver_info *info)
>>   	if (ret)
>>   		return ret;
>>   
>> +	if (client->irq > 0) {
>> +		ret = pmbus_irq_setup(client, data);
>> +		if (ret)
>> +			return ret;
>> +	}
>> +
>>   	ret = pmbus_init_debugfs(client, data);
>>   	if (ret)
>>   		dev_warn(dev, "Failed to register debugfs\n");

Thanks,
Naresh
  

On Tue, Jan 03, 2023 at 12:18:49PM +0530, Naresh Solanki wrote:
> Hi Guenter,
> 
> On 29-12-2022 08:10 pm, Guenter Roeck wrote:
> > On Wed, Dec 14, 2022 at 09:07:11AM +0100, Naresh Solanki wrote:
> > > From: Patrick Rudolph <patrick.rudolph@9elements.com>
> > > 
> > > Implement PMBUS irq handler.
> > > 
> > > Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> > > Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> > 
> > $ scripts/checkpatch.pl --strict index.html
> > CHECK: Blank lines aren't necessary after an open brace '{'
> > #131: FILE: drivers/hwmon/pmbus/pmbus_core.c:3088:
> > +	for (i = 0; i < data->info->pages; i++) {
> > +
> > 
> > CHECK: Alignment should match open parenthesis
> > #183: FILE: drivers/hwmon/pmbus/pmbus_core.c:3140:
> > +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
> > +			      0, "pmbus-irq", data);
> > 
> > CHECK: Please use a blank line after function/struct/union/enum declarations
> > #197: FILE: drivers/hwmon/pmbus/pmbus_core.c:3154:
> >   }
> > +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> > 
> > total: 0 errors, 0 warnings, 3 checks, 109 lines checked
> > 
> > NOTE: For some of the reported defects, checkpatch may be able to
> >        mechanically convert to the typical style using --fix or --fix-inplace.
> > 
> > index.html has style problems, please review.
> > 
> > Please run checkpatch --strict on your patches.
> > Also see Documentation/hwmon/submitting-patches.rst.
> I will take care of these errors in the updated version.
> > 
> > > ---
> > >   drivers/hwmon/pmbus/pmbus.h      |  2 +-
> > >   drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
> > >   2 files changed, 85 insertions(+), 1 deletion(-)
> > > 
> > > 
> > > base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
> > > 
> > > diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> > > index 10fb17879f8e..6b2e6cf93b19 100644
> > > --- a/drivers/hwmon/pmbus/pmbus.h
> > > +++ b/drivers/hwmon/pmbus/pmbus.h
> > > @@ -26,7 +26,7 @@ enum pmbus_regs {
> > >   	PMBUS_CAPABILITY		= 0x19,
> > >   	PMBUS_QUERY			= 0x1A,
> > > -
> > > +	PMBUS_SMBALERT_MASK		= 0x1B,
> > >   	PMBUS_VOUT_MODE			= 0x20,
> > >   	PMBUS_VOUT_COMMAND		= 0x21,
> > >   	PMBUS_VOUT_TRIM			= 0x22,
> > > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> > > index 95e95783972a..244fd2597252 100644
> > > --- a/drivers/hwmon/pmbus/pmbus_core.c
> > > +++ b/drivers/hwmon/pmbus/pmbus_core.c
> > > @@ -3072,11 +3072,89 @@ static int pmbus_regulator_register(struct pmbus_data *data)
> > >   	return 0;
> > >   }
> > > +
> > > +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
> > > +{
> > > +	return pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
> > > +}
> > > +
> > > +static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
> > > +{
> > > +	struct pmbus_data *data = pdata;
> > > +	struct i2c_client *client = to_i2c_client(data->dev);
> > > +	int i, status;
> > > +
> > > +	for (i = 0; i < data->info->pages; i++) {
> > > +
> > > +		mutex_lock(&data->update_lock);
> > > +		status = pmbus_read_status_word(client, i);
> > > +		if (status < 0) {
> > > +			mutex_unlock(&data->update_lock);
> > > +			return status;
> > > +		}
> > > +
> > > +		if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
> > > +			pmbus_clear_fault_page(client, i);
> > > +
> > > +		mutex_unlock(&data->update_lock);
> > > +	}
> > > +
> > > +	return IRQ_HANDLED;
> > > +}
> > > +
> > > +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> > > +{
> > > +	struct device *dev = &client->dev;
> > > +	const struct pmbus_regulator_status_category *cat;
> > > +	const struct pmbus_regulator_status_assoc *bit;
> > > +	int i, j, err, ret, func;
> > > +	u8 mask;
> > > +
> > > +	for (i = 0; i < data->info->pages; i++) {
> > > +		func = data->info->func[i];
> > > +
> > > +		for (j = 0; j < ARRAY_SIZE(pmbus_regulator_flag_map); j++) {
> > > +			cat = &pmbus_regulator_flag_map[j];
> > > +			if (!(func & cat->func))
> > > +				continue;
> > > +			mask = 0;
> > > +			for (bit = cat->bits; bit->pflag; bit++)
> > > +				mask |= bit->pflag;
> > > +
> > > +			err = pmbus_write_smbalert_mask(client, i, cat->reg, ~mask);
> > > +			if (err)
> > > +				dev_err(dev, "Failed to set smbalert for reg 0x%02x\n",	cat->reg);
> > 
> > This concerns me. It might mean that the chip does not support
> > PMBUS_SMBALERT_MASK. If so, there would be lots of error messages.
> After going through the PMBus specification, it appears that this should not
> be an issue unless there is a violation of the specification.

PMBus chips have lots of issues which violate the specification.
Have a look at the various drivers and the workarounds implemented there.
You'll need to check if the command/register is supported before using it.
Also, if you want to keep the error message, make it dev_err_once().

Either case, an error is an error, not to be ignored. An error here
should result in an error abort.

> > 
> > > +		}
> > > +
> > > +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_CML, 0xff);
> > > +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_OTHER, 0xff);
> > > +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_MFR_SPECIFIC, 0xff);
> > 
> > Why check the return value from pmbus_write_smbalert_mask above but not here ?
> Thank you for pointing out the oversight. I will make sure to include an
> error check at this point.
> > 
> > > +		if (data->info->func[i] & PMBUS_HAVE_FAN12)
> > > +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_12, 0xff);
> > > +		if (data->info->func[i] & PMBUS_HAVE_FAN34)
> > > +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_34, 0xff);
> > > +	}
> > > +
> > > +	/* Register notifiers - can fail if IRQ is not given */
> > 
> > The comment does not make sense. pmbus_irq_setup() is not called
> > if the interrupt "is not given".
> Yes. The comment here is not relevant and will be removed.
> > 
> > > +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
> > > +			      0, "pmbus-irq", data);
> > > +	if (ret) {
> > > +		dev_warn(dev, "IRQ disabled %d\n", ret);
> > 
> > This is not a warning, it is an error.
> Thank you for bringing this to my attention. I will make sure to update the
> code to reflect that this is an error.
> > 
> > > +		return ret;
> > > +	}
> > > +
> > > +	return 0;
> > > +}
> > > +
> > >   #else
> > 
> > This is still in regulator code. I said several times that this is not
> > acceptable.
> Thank you for pointing out the mistake. I will make sure to correct this in
> the next revision.
> > 
> > >   static int pmbus_regulator_register(struct pmbus_data *data)
> > >   {
> > >   	return 0;
> > >   }
> > > +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> > > +{
> > > +	return 0;
> > > +}
> > >   #endif
> > >   static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
> > > @@ -3441,6 +3519,12 @@ int pmbus_do_probe(struct i2c_client *client, struct pmbus_driver_info *info)
> > >   	if (ret)
> > >   		return ret;
> > > +	if (client->irq > 0) {
> > > +		ret = pmbus_irq_setup(client, data);
> > > +		if (ret)
> > > +			return ret;
> > > +	}
> > > +
> > >   	ret = pmbus_init_debugfs(client, data);
> > >   	if (ret)
> > >   		dev_warn(dev, "Failed to register debugfs\n");
> 
> Thanks,
> Naresh
  

Hi Guenter

On 03-01-2023 05:56 pm, Guenter Roeck wrote:
> On Tue, Jan 03, 2023 at 12:18:49PM +0530, Naresh Solanki wrote:
>> Hi Guenter,
>>
>> On 29-12-2022 08:10 pm, Guenter Roeck wrote:
>>> On Wed, Dec 14, 2022 at 09:07:11AM +0100, Naresh Solanki wrote:
>>>> From: Patrick Rudolph <patrick.rudolph@9elements.com>
>>>>
>>>> Implement PMBUS irq handler.
>>>>
>>>> Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
>>>> Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
>>>
>>> $ scripts/checkpatch.pl --strict index.html
>>> CHECK: Blank lines aren't necessary after an open brace '{'
>>> #131: FILE: drivers/hwmon/pmbus/pmbus_core.c:3088:
>>> +	for (i = 0; i < data->info->pages; i++) {
>>> +
>>>
>>> CHECK: Alignment should match open parenthesis
>>> #183: FILE: drivers/hwmon/pmbus/pmbus_core.c:3140:
>>> +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
>>> +			      0, "pmbus-irq", data);
>>>
>>> CHECK: Please use a blank line after function/struct/union/enum declarations
>>> #197: FILE: drivers/hwmon/pmbus/pmbus_core.c:3154:
>>>    }
>>> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
>>>
>>> total: 0 errors, 0 warnings, 3 checks, 109 lines checked
>>>
>>> NOTE: For some of the reported defects, checkpatch may be able to
>>>         mechanically convert to the typical style using --fix or --fix-inplace.
>>>
>>> index.html has style problems, please review.
>>>
>>> Please run checkpatch --strict on your patches.
>>> Also see Documentation/hwmon/submitting-patches.rst.
>> I will take care of these errors in the updated version.
>>>
>>>> ---
>>>>    drivers/hwmon/pmbus/pmbus.h      |  2 +-
>>>>    drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
>>>>    2 files changed, 85 insertions(+), 1 deletion(-)
>>>>
>>>>
>>>> base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
>>>>
>>>> diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
>>>> index 10fb17879f8e..6b2e6cf93b19 100644
>>>> --- a/drivers/hwmon/pmbus/pmbus.h
>>>> +++ b/drivers/hwmon/pmbus/pmbus.h
>>>> @@ -26,7 +26,7 @@ enum pmbus_regs {
>>>>    	PMBUS_CAPABILITY		= 0x19,
>>>>    	PMBUS_QUERY			= 0x1A,
>>>> -
>>>> +	PMBUS_SMBALERT_MASK		= 0x1B,
>>>>    	PMBUS_VOUT_MODE			= 0x20,
>>>>    	PMBUS_VOUT_COMMAND		= 0x21,
>>>>    	PMBUS_VOUT_TRIM			= 0x22,
>>>> diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
>>>> index 95e95783972a..244fd2597252 100644
>>>> --- a/drivers/hwmon/pmbus/pmbus_core.c
>>>> +++ b/drivers/hwmon/pmbus/pmbus_core.c
>>>> @@ -3072,11 +3072,89 @@ static int pmbus_regulator_register(struct pmbus_data *data)
>>>>    	return 0;
>>>>    }
>>>> +
>>>> +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
>>>> +{
>>>> +	return pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
>>>> +}
>>>> +
>>>> +static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
>>>> +{
>>>> +	struct pmbus_data *data = pdata;
>>>> +	struct i2c_client *client = to_i2c_client(data->dev);
>>>> +	int i, status;
>>>> +
>>>> +	for (i = 0; i < data->info->pages; i++) {
>>>> +
>>>> +		mutex_lock(&data->update_lock);
>>>> +		status = pmbus_read_status_word(client, i);
>>>> +		if (status < 0) {
>>>> +			mutex_unlock(&data->update_lock);
>>>> +			return status;
>>>> +		}
>>>> +
>>>> +		if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
>>>> +			pmbus_clear_fault_page(client, i);
>>>> +
>>>> +		mutex_unlock(&data->update_lock);
>>>> +	}
>>>> +
>>>> +	return IRQ_HANDLED;
>>>> +}
>>>> +
>>>> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
>>>> +{
>>>> +	struct device *dev = &client->dev;
>>>> +	const struct pmbus_regulator_status_category *cat;
>>>> +	const struct pmbus_regulator_status_assoc *bit;
>>>> +	int i, j, err, ret, func;
>>>> +	u8 mask;
>>>> +
>>>> +	for (i = 0; i < data->info->pages; i++) {
>>>> +		func = data->info->func[i];
>>>> +
>>>> +		for (j = 0; j < ARRAY_SIZE(pmbus_regulator_flag_map); j++) {
>>>> +			cat = &pmbus_regulator_flag_map[j];
>>>> +			if (!(func & cat->func))
>>>> +				continue;
>>>> +			mask = 0;
>>>> +			for (bit = cat->bits; bit->pflag; bit++)
>>>> +				mask |= bit->pflag;
>>>> +
>>>> +			err = pmbus_write_smbalert_mask(client, i, cat->reg, ~mask);
>>>> +			if (err)
>>>> +				dev_err(dev, "Failed to set smbalert for reg 0x%02x\n",	cat->reg);
>>>
>>> This concerns me. It might mean that the chip does not support
>>> PMBUS_SMBALERT_MASK. If so, there would be lots of error messages.
>> After going through the PMBus specification, it appears that this should not
>> be an issue unless there is a violation of the specification.
> 
> PMBus chips have lots of issues which violate the specification.
> Have a look at the various drivers and the workarounds implemented there.
> You'll need to check if the command/register is supported before using it.
> Also, if you want to keep the error message, make it dev_err_once().
> 
> Either case, an error is an error, not to be ignored. An error here
> should result in an error abort.
Yes, I agree that PMBus chips can have issues that violate the 
specification, and that it is important to check whether a command or 
register is supported before using it.
I have noticed that many drivers use the PMBUS_HAVE_* flags to expose 
the presence of specific registers, and I think it would be a good idea 
to add a PMBUS_HAVE_SMBALERT flag as well, so that drivers for supported 
chips can use it to determine whether they should set up an IRQ handler 
or not. If PMBUS_HAVE_SMBALERT is set, then the IRQ handler should be 
set up, otherwise it should be ignored.
Will this approach be right?
> 
>>>
>>>> +		}
>>>> +
>>>> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_CML, 0xff);
>>>> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_OTHER, 0xff);
>>>> +		pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_MFR_SPECIFIC, 0xff);
>>>
>>> Why check the return value from pmbus_write_smbalert_mask above but not here ?
>> Thank you for pointing out the oversight. I will make sure to include an
>> error check at this point.
>>>
>>>> +		if (data->info->func[i] & PMBUS_HAVE_FAN12)
>>>> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_12, 0xff);
>>>> +		if (data->info->func[i] & PMBUS_HAVE_FAN34)
>>>> +			pmbus_write_smbalert_mask(client, i, PMBUS_STATUS_FAN_34, 0xff);
>>>> +	}
>>>> +
>>>> +	/* Register notifiers - can fail if IRQ is not given */
>>>
>>> The comment does not make sense. pmbus_irq_setup() is not called
>>> if the interrupt "is not given".
>> Yes. The comment here is not relevant and will be removed.
>>>
>>>> +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
>>>> +			      0, "pmbus-irq", data);
>>>> +	if (ret) {
>>>> +		dev_warn(dev, "IRQ disabled %d\n", ret);
>>>
>>> This is not a warning, it is an error.
>> Thank you for bringing this to my attention. I will make sure to update the
>> code to reflect that this is an error.
>>>
>>>> +		return ret;
>>>> +	}
>>>> +
>>>> +	return 0;
>>>> +}
>>>> +
>>>>    #else
>>>
>>> This is still in regulator code. I said several times that this is not
>>> acceptable.
>> Thank you for pointing out the mistake. I will make sure to correct this in
>> the next revision.
>>>
>>>>    static int pmbus_regulator_register(struct pmbus_data *data)
>>>>    {
>>>>    	return 0;
>>>>    }
>>>> +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
>>>> +{
>>>> +	return 0;
>>>> +}
>>>>    #endif
>>>>    static struct dentry *pmbus_debugfs_dir;	/* pmbus debugfs directory */
>>>> @@ -3441,6 +3519,12 @@ int pmbus_do_probe(struct i2c_client *client, struct pmbus_driver_info *info)
>>>>    	if (ret)
>>>>    		return ret;
>>>> +	if (client->irq > 0) {
>>>> +		ret = pmbus_irq_setup(client, data);
>>>> +		if (ret)
>>>> +			return ret;
>>>> +	}
>>>> +
>>>>    	ret = pmbus_init_debugfs(client, data);
>>>>    	if (ret)
>>>>    		dev_warn(dev, "Failed to register debugfs\n");
>>
>> Thanks,
>> Naresh
  

On Tue, Jan 03, 2023 at 08:56:59PM +0530, Naresh Solanki wrote:
> Hi Guenter
> 
> On 03-01-2023 05:56 pm, Guenter Roeck wrote:
> > On Tue, Jan 03, 2023 at 12:18:49PM +0530, Naresh Solanki wrote:
> > > Hi Guenter,
> > > 
> > > On 29-12-2022 08:10 pm, Guenter Roeck wrote:
> > > > On Wed, Dec 14, 2022 at 09:07:11AM +0100, Naresh Solanki wrote:
> > > > > From: Patrick Rudolph <patrick.rudolph@9elements.com>
> > > > > 
> > > > > Implement PMBUS irq handler.
> > > > > 
> > > > > Signed-off-by: Patrick Rudolph <patrick.rudolph@9elements.com>
> > > > > Signed-off-by: Naresh Solanki <Naresh.Solanki@9elements.com>
> > > > 
> > > > $ scripts/checkpatch.pl --strict index.html
> > > > CHECK: Blank lines aren't necessary after an open brace '{'
> > > > #131: FILE: drivers/hwmon/pmbus/pmbus_core.c:3088:
> > > > +	for (i = 0; i < data->info->pages; i++) {
> > > > +
> > > > 
> > > > CHECK: Alignment should match open parenthesis
> > > > #183: FILE: drivers/hwmon/pmbus/pmbus_core.c:3140:
> > > > +	ret = devm_request_threaded_irq(dev, client->irq, NULL, pmbus_fault_handler,
> > > > +			      0, "pmbus-irq", data);
> > > > 
> > > > CHECK: Please use a blank line after function/struct/union/enum declarations
> > > > #197: FILE: drivers/hwmon/pmbus/pmbus_core.c:3154:
> > > >    }
> > > > +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> > > > 
> > > > total: 0 errors, 0 warnings, 3 checks, 109 lines checked
> > > > 
> > > > NOTE: For some of the reported defects, checkpatch may be able to
> > > >         mechanically convert to the typical style using --fix or --fix-inplace.
> > > > 
> > > > index.html has style problems, please review.
> > > > 
> > > > Please run checkpatch --strict on your patches.
> > > > Also see Documentation/hwmon/submitting-patches.rst.
> > > I will take care of these errors in the updated version.
> > > > 
> > > > > ---
> > > > >    drivers/hwmon/pmbus/pmbus.h      |  2 +-
> > > > >    drivers/hwmon/pmbus/pmbus_core.c | 84 ++++++++++++++++++++++++++++++++
> > > > >    2 files changed, 85 insertions(+), 1 deletion(-)
> > > > > 
> > > > > 
> > > > > base-commit: 364ffd2537c44cb6914ff5669153f4a86fffad29
> > > > > 
> > > > > diff --git a/drivers/hwmon/pmbus/pmbus.h b/drivers/hwmon/pmbus/pmbus.h
> > > > > index 10fb17879f8e..6b2e6cf93b19 100644
> > > > > --- a/drivers/hwmon/pmbus/pmbus.h
> > > > > +++ b/drivers/hwmon/pmbus/pmbus.h
> > > > > @@ -26,7 +26,7 @@ enum pmbus_regs {
> > > > >    	PMBUS_CAPABILITY		= 0x19,
> > > > >    	PMBUS_QUERY			= 0x1A,
> > > > > -
> > > > > +	PMBUS_SMBALERT_MASK		= 0x1B,
> > > > >    	PMBUS_VOUT_MODE			= 0x20,
> > > > >    	PMBUS_VOUT_COMMAND		= 0x21,
> > > > >    	PMBUS_VOUT_TRIM			= 0x22,
> > > > > diff --git a/drivers/hwmon/pmbus/pmbus_core.c b/drivers/hwmon/pmbus/pmbus_core.c
> > > > > index 95e95783972a..244fd2597252 100644
> > > > > --- a/drivers/hwmon/pmbus/pmbus_core.c
> > > > > +++ b/drivers/hwmon/pmbus/pmbus_core.c
> > > > > @@ -3072,11 +3072,89 @@ static int pmbus_regulator_register(struct pmbus_data *data)
> > > > >    	return 0;
> > > > >    }
> > > > > +
> > > > > +static int pmbus_write_smbalert_mask(struct i2c_client *client, u8 page, u8 reg, u8 val)
> > > > > +{
> > > > > +	return pmbus_write_word_data(client, page, PMBUS_SMBALERT_MASK, reg | (val << 8));
> > > > > +}
> > > > > +
> > > > > +static irqreturn_t pmbus_fault_handler(int irq, void *pdata)
> > > > > +{
> > > > > +	struct pmbus_data *data = pdata;
> > > > > +	struct i2c_client *client = to_i2c_client(data->dev);
> > > > > +	int i, status;
> > > > > +
> > > > > +	for (i = 0; i < data->info->pages; i++) {
> > > > > +
> > > > > +		mutex_lock(&data->update_lock);
> > > > > +		status = pmbus_read_status_word(client, i);
> > > > > +		if (status < 0) {
> > > > > +			mutex_unlock(&data->update_lock);
> > > > > +			return status;
> > > > > +		}
> > > > > +
> > > > > +		if (status & ~(PB_STATUS_OFF | PB_STATUS_BUSY | PB_STATUS_POWER_GOOD_N))
> > > > > +			pmbus_clear_fault_page(client, i);
> > > > > +
> > > > > +		mutex_unlock(&data->update_lock);
> > > > > +	}
> > > > > +
> > > > > +	return IRQ_HANDLED;
> > > > > +}
> > > > > +
> > > > > +static int pmbus_irq_setup(struct i2c_client *client, struct pmbus_data *data)
> > > > > +{
> > > > > +	struct device *dev = &client->dev;
> > > > > +	const struct pmbus_regulator_status_category *cat;
> > > > > +	const struct pmbus_regulator_status_assoc *bit;
> > > > > +	int i, j, err, ret, func;
> > > > > +	u8 mask;
> > > > > +
> > > > > +	for (i = 0; i < data->info->pages; i++) {
> > > > > +		func = data->info->func[i];
> > > > > +
> > > > > +		for (j = 0; j < ARRAY_SIZE(pmbus_regulator_flag_map); j++) {
> > > > > +			cat = &pmbus_regulator_flag_map[j];
> > > > > +			if (!(func & cat->func))
> > > > > +				continue;
> > > > > +			mask = 0;
> > > > > +			for (bit = cat->bits; bit->pflag; bit++)
> > > > > +				mask |= bit->pflag;
> > > > > +
> > > > > +			err = pmbus_write_smbalert_mask(client, i, cat->reg, ~mask);
> > > > > +			if (err)
> > > > > +				dev_err(dev, "Failed to set smbalert for reg 0x%02x\n",	cat->reg);
> > > > 
> > > > This concerns me. It might mean that the chip does not support
> > > > PMBUS_SMBALERT_MASK. If so, there would be lots of error messages.
> > > After going through the PMBus specification, it appears that this should not
> > > be an issue unless there is a violation of the specification.
> > 
> > PMBus chips have lots of issues which violate the specification.
> > Have a look at the various drivers and the workarounds implemented there.
> > You'll need to check if the command/register is supported before using it.
> > Also, if you want to keep the error message, make it dev_err_once().
> > 
> > Either case, an error is an error, not to be ignored. An error here
> > should result in an error abort.
> Yes, I agree that PMBus chips can have issues that violate the
> specification, and that it is important to check whether a command or
> register is supported before using it.
> I have noticed that many drivers use the PMBUS_HAVE_* flags to expose the
> presence of specific registers, and I think it would be a good idea to add a
> PMBUS_HAVE_SMBALERT flag as well, so that drivers for supported chips can
> use it to determine whether they should set up an IRQ handler or not. If
> PMBUS_HAVE_SMBALERT is set, then the IRQ handler should be set up, otherwise
> it should be ignored.
> Will this approach be right?

Not really. PMBUS_HAVE_ flags are intended to indicate sensor register
support, not to indicate compliance problems. What you'd be looking for
would be the flags in struct pmbus_platform_data. However, those are only
intended to be used if registers/commands can not be auto-detected or if
doing so causes problems. See include/linux/pmbus.h for details.
Unless there is reason to believe that chips are misbehaving when trying
to read from or to set PMBUS_SMBALERT_MASK, we should stick with auto-
detection. After all, that is what pmbus_check_{status,byte,word}_register()
functions are for.

Thanks,
Guenter