Re: [PATCH v2 4/4] hwmon: (adt7470) Use standard update_interval property

[Chris Packham]

On 28/08/21 9:29 am, Guenter Roeck wrote:
> On Thu, Aug 26, 2021 at 02:41:21PM +1200, Chris Packham wrote:
>> Instead of the non-standard auto_update_interval make use of the
>> update_interval property that is supported by the hwmon core.
>>
>> Signed-off-by: Chris Packham <chris.packham@xxxxxxxxxxxxxxxxxxx>
>> ---
>>
>> Notes:
>>      I kind of anticipate a NAK on this because it affects the ABI. But I figured
>>      I'd run it past the ML to see if moving towards the hwmon core is worth the hit
>>      in ABI compatibility.
>>      
> I personally don't mind (most likely no one is using it anyway), but let's
> wait until after the upcoming commit window closes to give people time to
> complain.

I know of one application using this sysfs entry. But it's our in-house 
environmental monitoring code so if this gets merged I'll just update it 
to use the new path.

One thought I had was we could do both. i.e. have an entry that conforms 
to the hwmon core and a backwards compatible entry that just aliases the 
new path.

>
> Guenter
>
>>      Changes in v2:
>>      - none
>>
>>   drivers/hwmon/adt7470.c | 64 +++++++++++++++++++++++++----------------
>>   1 file changed, 39 insertions(+), 25 deletions(-)
>>
>> diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
>> index db19a52b13de..7afbd1e4721e 100644
>> --- a/drivers/hwmon/adt7470.c
>> +++ b/drivers/hwmon/adt7470.c
>> @@ -469,35 +469,37 @@ static struct adt7470_data *adt7470_update_device(struct device *dev)
>>   	return err < 0 ? ERR_PTR(err) : data;
>>   }
>>   
>> -static ssize_t auto_update_interval_show(struct device *dev,
>> -					 struct device_attribute *devattr,
>> -					 char *buf)
>> -{
>> -	struct adt7470_data *data = adt7470_update_device(dev);
>> -
>> -	if (IS_ERR(data))
>> -		return PTR_ERR(data);
>> -
>> -	return sprintf(buf, "%d\n", data->auto_update_interval);
>> -}
>> -
>> -static ssize_t auto_update_interval_store(struct device *dev,
>> -					  struct device_attribute *devattr,
>> -					  const char *buf, size_t count)
>> +static int adt7470_chip_read(struct device *dev, u32 attr, long *val)
>>   {
>>   	struct adt7470_data *data = dev_get_drvdata(dev);
>> -	long temp;
>>   
>> -	if (kstrtol(buf, 10, &temp))
>> -		return -EINVAL;
>> +	switch (attr) {
>> +	case hwmon_chip_update_interval:
>> +		*val = data->auto_update_interval;
>> +		break;
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>>   
>> -	temp = clamp_val(temp, 0, 60000);
>> +	return 0;
>> +}
>>   
>> -	mutex_lock(&data->lock);
>> -	data->auto_update_interval = temp;
>> -	mutex_unlock(&data->lock);
>> +static int adt7470_chip_write(struct device *dev, u32 attr, long val)
>> +{
>> +	struct adt7470_data *data = dev_get_drvdata(dev);
>>   
>> -	return count;
>> +	switch (attr) {
>> +	case hwmon_chip_update_interval:
>> +		val = clamp_val(val, 0, 60000);
>> +		mutex_lock(&data->lock);
>> +		data->auto_update_interval = val;
>> +		mutex_unlock(&data->lock);
>> +		break;
>> +	default:
>> +		return -EOPNOTSUPP;
>> +	}
>> +
>> +	return 0;
>>   }
>>   
>>   static ssize_t num_temp_sensors_show(struct device *dev,
>> @@ -1034,7 +1036,6 @@ static ssize_t pwm_auto_temp_store(struct device *dev,
>>   
>>   static DEVICE_ATTR_RW(alarm_mask);
>>   static DEVICE_ATTR_RW(num_temp_sensors);
>> -static DEVICE_ATTR_RW(auto_update_interval);
>>   
>>   static SENSOR_DEVICE_ATTR_RW(force_pwm_max, force_pwm_max, 0);
>>   
>> @@ -1066,7 +1067,6 @@ static SENSOR_DEVICE_ATTR_RW(pwm4_auto_channels_temp, pwm_auto_temp, 3);
>>   static struct attribute *adt7470_attrs[] = {
>>   	&dev_attr_alarm_mask.attr,
>>   	&dev_attr_num_temp_sensors.attr,
>> -	&dev_attr_auto_update_interval.attr,
>>   	&sensor_dev_attr_force_pwm_max.dev_attr.attr,
>>   	&sensor_dev_attr_pwm1_auto_point1_pwm.dev_attr.attr,
>>   	&sensor_dev_attr_pwm2_auto_point1_pwm.dev_attr.attr,
>> @@ -1097,6 +1097,8 @@ static int adt7470_read(struct device *dev, enum hwmon_sensor_types type, u32 at
>>   			int channel, long *val)
>>   {
>>   	switch (type) {
>> +	case hwmon_chip:
>> +		return adt7470_chip_read(dev, attr, val);
>>   	case hwmon_temp:
>>   		return adt7470_temp_read(dev, attr, channel, val);
>>   	case hwmon_fan:
>> @@ -1112,6 +1114,8 @@ static int adt7470_write(struct device *dev, enum hwmon_sensor_types type, u32 a
>>   			int channel, long val)
>>   {
>>   	switch (type) {
>> +	case hwmon_chip:
>> +		return adt7470_chip_write(dev, attr, val);
>>   	case hwmon_temp:
>>   		return adt7470_temp_write(dev, attr, channel, val);
>>   	case hwmon_fan:
>> @@ -1129,6 +1133,15 @@ static umode_t adt7470_is_visible(const void *_data, enum hwmon_sensor_types typ
>>   	umode_t mode = 0;
>>   
>>   	switch (type) {
>> +	case hwmon_chip:
>> +		switch (attr) {
>> +		case hwmon_chip_update_interval:
>> +			mode = 0644;
>> +			break;
>> +		default:
>> +			break;
>> +		}
>> +		break;
>>   	case hwmon_temp:
>>   		switch (attr) {
>>   		case hwmon_temp:
>> @@ -1187,6 +1200,7 @@ static const struct hwmon_ops adt7470_hwmon_ops = {
>>   };
>>   
>>   static const struct hwmon_channel_info *adt7470_info[] = {
>> +	HWMON_CHANNEL_INFO(chip, HWMON_C_UPDATE_INTERVAL),
>>   	HWMON_CHANNEL_INFO(temp,
>>   			HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | HWMON_T_ALARM,
>>   			HWMON_T_INPUT | HWMON_T_MIN | HWMON_T_MAX | HWMON_T_ALARM,