On 6/21/24 11:22, Sean Anderson wrote:
> On 6/21/24 11:08, Guenter Roeck wrote:
>> On 6/20/24 14:13, Sean Anderson wrote:
>>> Add labels from IIO channels to our channels. This allows userspace to
>>> display more meaningful names instead of "in0" or "temp5".
>>>
>>> Signed-off-by: Sean Anderson <sean.anderson@xxxxxxxxx>
>>> ---
>>>
>>> drivers/hwmon/iio_hwmon.c | 33 ++++++++++++++++++++++++++++++---
>>> 1 file changed, 30 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/hwmon/iio_hwmon.c b/drivers/hwmon/iio_hwmon.c
>>> index 4c8a80847891..588b64c18e63 100644
>>> --- a/drivers/hwmon/iio_hwmon.c
>>> +++ b/drivers/hwmon/iio_hwmon.c
>>> @@ -33,6 +33,17 @@ struct iio_hwmon_state {
>>> struct attribute **attrs;
>>> };
>>> +static ssize_t iio_hwmon_read_label(struct device *dev,
>>> + struct device_attribute *attr,
>>> + char *buf)
>>> +{
>>> + struct sensor_device_attribute *sattr = to_sensor_dev_attr(attr);
>>> + struct iio_hwmon_state *state = dev_get_drvdata(dev);
>>> + struct iio_channel *chan = &state->channels[sattr->index];
>>> +
>>> + return iio_read_channel_label(chan, buf);
>>
>> This can return -EINVAL if there is no label. Since the label attribute
>> is created unconditionally, every affected system would end up with
>> lots of error messages when running the "sensors" command.
>> This is not acceptable.
>
> The sensors command gracefully handles this. There are no errors, and the label is unused.
For example, without IIO labels I get:
$ sensors hwmon_ams_ps-isa-0000
hwmon_ams_ps-isa-0000
Adapter: ISA adapter
in1: 825.00 mV
in2: 826.00 mV
in3: 1.81 V
in4: 1.18 V
in5: 1.80 V
in6: 1.80 V
in7: 3.27 V
in8: 1.81 V
in9: 825.00 mV
in10: 1.81 V
in11: 1.80 V
temp1: +79.8 C
temp2: +80.9 C
and with labels I get
$ sensors hwmon_ams_ps-isa-0000
hwmon_ams_ps-isa-0000
Adapter: ISA adapter
VCC_PSINTLP: 824.00 mV
VCC_PSINTFP: 822.00 mV
VCC_PSAUX: 1.81 V
VCC_PSDDR: 1.18 V
VCC_PSIO3: 1.80 V
VCC_PSIO0: 1.80 V
VCC_PSIO1: 3.27 V
VCC_PSIO2: 1.80 V
PS_MGTRAVCC: 822.00 mV
PS_MGTRAVTT: 1.81 V
VCC_PSADC: 1.80 V
Temp_LPD: +79.5 C
Temp_FPD: +80.2 C
I also was concerned about the same thing, but lm-sensors handles things
gracefully, allowing us to simplify the implementation.
--Sean
