Re: [RFC PATCH v2 3/3] hwmon: (adt7475) temperature smoothing

[Chris Packham <Chris.Packham@alliedtelesis.co.nz>]

On 04/05/17 04:30, Guenter Roeck wrote:
> On Wed, May 03, 2017 at 12:40:09PM +1200, Chris Packham wrote:
>> When enabled temperature smoothing allows ramping the fan speed over a
>> configurable period of time instead of jumping to the new speed
>> instantaneously.
>>
>> Signed-off-by: Chris Packham <chris.packham@alliedtelesis.co.nz>
>> ---
>> Changes in v2:
>> - use a single tempN_smoothing attribute
>>
>>  Documentation/hwmon/adt7475 |  4 ++
>>  drivers/hwmon/adt7475.c     | 99 +++++++++++++++++++++++++++++++++++++++++++++
>>  2 files changed, 103 insertions(+)
>>
>> diff --git a/Documentation/hwmon/adt7475 b/Documentation/hwmon/adt7475
>> index 63507402cd4f..dd6433d819d0 100644
>> --- a/Documentation/hwmon/adt7475
>> +++ b/Documentation/hwmon/adt7475
>> @@ -114,6 +114,10 @@ minimum (i.e. auto_point1_pwm). This behaviour be configured using the
>>  pwm[1-*]_stall_dis sysfs attribute. A value of 0 means the fans will shut off.
>>  A value of 1 means the fans will run at auto_point1_pwm.
>>
>> +The responsiveness of the ADT747x to temperature changes can be configured.
>> +This allows smoothing of the fan speed transition. To set the transition time
>> +set the value in ms in the temp[1-*]_smoothing sysfs attribute.
>> +
>>  Notes
>>  -----
>>
>> diff --git a/drivers/hwmon/adt7475.c b/drivers/hwmon/adt7475.c
>> index 85957324cd85..41342de6e20c 100644
>> --- a/drivers/hwmon/adt7475.c
>> +++ b/drivers/hwmon/adt7475.c
>> @@ -526,6 +526,96 @@ static ssize_t set_temp(struct device *dev, struct device_attribute *attr,
>>  	return count;
>>  }
>>
>> +/* Assuming CONFIG6[SLOW] is 0 */
>
> Can you take that into account and calculate a "best fit" based on the
> available options ?

Do you mean check CONFIG6[SLOW] and choose between 1 of 2 possible maps? 
Or have a unified map and choose both the SLOW and ACOU values?

I briefly considered the latter but things soon started to get 
complicated. It would look something like this (please excuse using a 
MUA as a code editor).

static const int ad7475_st_map[] = {
	52200, 37500, 26100, 18800, 17400, 12500, 10400, 7500,
	6500, 4700, 4400, 3100, 2200, 1600, 1100, 800,
};

i = find_closest_descending(val, ad7475_st_map,
			    ARRAY_SIZE(ad7475_st_map));
acou = i / 2;
slow = i % 2;

Going in reverse then gets really fun

slow = !!(i2c_smbus_read_byte_data(client, REG_CONFIG6) & BIT(PWMx))
acou = data->enh_acou[idx];

i = (acou * 2) + slow;

return sprintf(buf, "%d\n", ad7475_st_map[i]);

I could probably make the above work I just wasn't sure it was worth the 
hassle. Only the higher ranges would really be noticeable to anyone.

>
>> +static const int ad7475_st_map[] = {
>> +	37500, 18800, 12500, 7500, 4700, 3100, 1600, 800,
>> +};
>> +
>> +static ssize_t show_temp_st(struct device *dev, struct device_attribute *attr,
>> +				  char *buf)
>> +{
>> +	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
>> +	struct i2c_client *client = to_i2c_client(dev);
>> +	struct adt7475_data *data = i2c_get_clientdata(client);
>> +	int shift, idx;
>> +	long val;
>> +
>> +	switch (sattr->index) {
>> +	case 0:
>> +		shift = 0;
>> +		idx = 0;
>> +		break;
>> +	case 1:
>> +		shift = 4;
>> +		idx = 1;
>> +		break;
>> +	case 2:
>> +		shift = 0;
>> +		idx = 1;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	val = data->enh_acou[idx] >> shift;
>> +	if (val & 0x8) {
>> +		return sprintf(buf, "%d\n", ad7475_st_map[val & 0x7]);
>> +	} else {
>> +		return sprintf(buf, "0\n");
>> +	}
>> +}
>> +
>> +static ssize_t set_temp_st(struct device *dev, struct device_attribute *attr,
>> +				 const char *buf, size_t count)
>> +{
>> +	struct sensor_device_attribute_2 *sattr = to_sensor_dev_attr_2(attr);
>> +	struct i2c_client *client = to_i2c_client(dev);
>> +	struct adt7475_data *data = i2c_get_clientdata(client);
>> +	unsigned char reg;
>> +	int shift, idx;
>> +	ulong val;
>> +
>> +	if (kstrtoul(buf, 10, &val))
>> +		return -EINVAL;
>> +
>> +	switch (sattr->index) {
>> +	case 0:
>> +		reg = REG_ENHANCE_ACOUSTICS1;
>> +		shift = 0;
>> +		idx = 0;
>> +		break;
>> +	case 1:
>> +		reg = REG_ENHANCE_ACOUSTICS2;
>> +		shift = 4;
>> +		idx = 1;
>> +		break;
>> +	case 2:
>> +		reg = REG_ENHANCE_ACOUSTICS2;
>> +		shift = 0;
>> +		idx = 1;
>> +		break;
>> +	default:
>> +		return -EINVAL;
>> +	}
>> +
>> +	if (val > 0) {
>> +		val = find_closest_descending(val, ad7475_st_map,
>> +					      ARRAY_SIZE(ad7475_st_map));
>> +		val |= 0x8;
>> +	}
>> +
>> +	mutex_lock(&data->lock);
>> +
>> +	data->enh_acou[idx] &= ~(0xf << shift);
>> +	data->enh_acou[idx] |= (val << shift);
>> +
>> +	i2c_smbus_write_byte_data(client, reg, data->enh_acou[idx]);
>> +
>> +	mutex_unlock(&data->lock);
>> +
>> +	return count;
>> +}
>> +
>>  /*
>>   * Table of autorange values - the user will write the value in millidegrees,
>>   * and we'll convert it
>> @@ -1008,6 +1098,8 @@ static SENSOR_DEVICE_ATTR_2(temp1_crit, S_IRUGO | S_IWUSR, show_temp, set_temp,
>>  			    THERM, 0);
>>  static SENSOR_DEVICE_ATTR_2(temp1_crit_hyst, S_IRUGO | S_IWUSR, show_temp,
>>  			    set_temp, HYSTERSIS, 0);
>> +static SENSOR_DEVICE_ATTR_2(temp1_smoothing, S_IRUGO | S_IWUSR, show_temp_st,
>> +			    set_temp_st, 0, 0);
>>  static SENSOR_DEVICE_ATTR_2(temp2_input, S_IRUGO, show_temp, NULL, INPUT, 1);
>>  static SENSOR_DEVICE_ATTR_2(temp2_alarm, S_IRUGO, show_temp, NULL, ALARM, 1);
>>  static SENSOR_DEVICE_ATTR_2(temp2_max, S_IRUGO | S_IWUSR, show_temp, set_temp,
>> @@ -1024,6 +1116,8 @@ static SENSOR_DEVICE_ATTR_2(temp2_crit, S_IRUGO | S_IWUSR, show_temp, set_temp,
>>  			    THERM, 1);
>>  static SENSOR_DEVICE_ATTR_2(temp2_crit_hyst, S_IRUGO | S_IWUSR, show_temp,
>>  			    set_temp, HYSTERSIS, 1);
>> +static SENSOR_DEVICE_ATTR_2(temp2_smoothing, S_IRUGO | S_IWUSR, show_temp_st,
>> +			    set_temp_st, 0, 1);
>>  static SENSOR_DEVICE_ATTR_2(temp3_input, S_IRUGO, show_temp, NULL, INPUT, 2);
>>  static SENSOR_DEVICE_ATTR_2(temp3_alarm, S_IRUGO, show_temp, NULL, ALARM, 2);
>>  static SENSOR_DEVICE_ATTR_2(temp3_fault, S_IRUGO, show_temp, NULL, FAULT, 2);
>> @@ -1041,6 +1135,8 @@ static SENSOR_DEVICE_ATTR_2(temp3_crit, S_IRUGO | S_IWUSR, show_temp, set_temp,
>>  			    THERM, 2);
>>  static SENSOR_DEVICE_ATTR_2(temp3_crit_hyst, S_IRUGO | S_IWUSR, show_temp,
>>  			    set_temp, HYSTERSIS, 2);
>> +static SENSOR_DEVICE_ATTR_2(temp3_smoothing, S_IRUGO | S_IWUSR, show_temp_st,
>> +			    set_temp_st, 0, 2);
>>  static SENSOR_DEVICE_ATTR_2(fan1_input, S_IRUGO, show_tach, NULL, INPUT, 0);
>>  static SENSOR_DEVICE_ATTR_2(fan1_min, S_IRUGO | S_IWUSR, show_tach, set_tach,
>>  			    MIN, 0);
>> @@ -1125,6 +1221,7 @@ static struct attribute *adt7475_attrs[] = {
>>  	&sensor_dev_attr_temp1_auto_point2_temp.dev_attr.attr,
>>  	&sensor_dev_attr_temp1_crit.dev_attr.attr,
>>  	&sensor_dev_attr_temp1_crit_hyst.dev_attr.attr,
>> +	&sensor_dev_attr_temp1_smoothing.dev_attr.attr,
>>  	&sensor_dev_attr_temp2_input.dev_attr.attr,
>>  	&sensor_dev_attr_temp2_alarm.dev_attr.attr,
>>  	&sensor_dev_attr_temp2_max.dev_attr.attr,
>> @@ -1134,6 +1231,7 @@ static struct attribute *adt7475_attrs[] = {
>>  	&sensor_dev_attr_temp2_auto_point2_temp.dev_attr.attr,
>>  	&sensor_dev_attr_temp2_crit.dev_attr.attr,
>>  	&sensor_dev_attr_temp2_crit_hyst.dev_attr.attr,
>> +	&sensor_dev_attr_temp2_smoothing.dev_attr.attr,
>>  	&sensor_dev_attr_temp3_input.dev_attr.attr,
>>  	&sensor_dev_attr_temp3_fault.dev_attr.attr,
>>  	&sensor_dev_attr_temp3_alarm.dev_attr.attr,
>> @@ -1144,6 +1242,7 @@ static struct attribute *adt7475_attrs[] = {
>>  	&sensor_dev_attr_temp3_auto_point2_temp.dev_attr.attr,
>>  	&sensor_dev_attr_temp3_crit.dev_attr.attr,
>>  	&sensor_dev_attr_temp3_crit_hyst.dev_attr.attr,
>> +	&sensor_dev_attr_temp3_smoothing.dev_attr.attr,
>>  	&sensor_dev_attr_fan1_input.dev_attr.attr,
>>  	&sensor_dev_attr_fan1_min.dev_attr.attr,
>>  	&sensor_dev_attr_fan1_alarm.dev_attr.attr,
>> --
>> 2.11.0.24.ge6920cf
>>
>