lkml.org 
[lkml]   [2021]   [Oct]   [5]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
Date
SubjectRe: [PATCH v3 0/1] iio/scmi: Add reading "raw" attribute.
From
Hi, Jyoti,

> In the code below, why is the logic of enabling and disabling the
> sensor in this function? Generally the function to read the sensor
> value is just used for the code to read the sensor values ? and not
> enable/disable the sensor

But to read sensor value we have to enable it first. Other way to enable
sensor we found is, for example:

echo 1 > /sys/bus/iio/devices/.../scan_elements/in_anglvel_x_en

But, this command is related to IIO buffers use.

Other sensors drivers enable/disable sensor in read raw too, for
example, drivers/iio/accel/kxcjk-1013.c has:

case IIO_CHAN_INFO_RAW:
mutex_lock(&data->mutex);
if (iio_buffer_enabled(indio_dev))
ret = -EBUSY;
else {
ret = kxcjk1013_set_power_state(data, true);
... reading ...
ret = kxcjk1013_set_power_state(data, false);
}
mutex_unlock(&data->mutex);

But, after looking on this code I have some questions:

1. Should we block reading raw attribute and IIO buffer enabled, for for
SCMI sensor it can coexist?
2. Should we wrap reading raw attribute implementation in iio_dev->mlock
mutex?

>> case IIO_CHAN_INFO_RAW:
>> + sensor_config = FIELD_PREP(SCMI_SENS_CFG_SENSOR_ENABLED_MASK,
>> + SCMI_SENS_CFG_SENSOR_ENABLE);
>> + err = sensor->sensor_ops->config_set(
>> + sensor->ph, sensor->sensor_info->id, sensor_config);
>> + if (err) {
>> + dev_err(&iio_dev->dev,
>> + "Error in enabling sensor %s err %d",
>> + sensor->sensor_info->name, err);
>> + return err;
>> + }
>> +
>> + err = sensor->sensor_ops->reading_get_timestamped(
>> + sensor->ph, sensor->sensor_info->id,
>> + sensor->sensor_info->num_axis, readings);
>> + if (err) {
>> + dev_err(&iio_dev->dev,
>> + "Error in reading raw attribute for sensor %s err %d",
>> + sensor->sensor_info->name, err);
>> + return err;
>> + }
>> +
>> + sensor_config = FIELD_PREP(SCMI_SENS_CFG_SENSOR_ENABLED_MASK,
>> + SCMI_SENS_CFG_SENSOR_DISABLE);
>> + err = sensor->sensor_ops->config_set(
>> + sensor->ph, sensor->sensor_info->id, sensor_config);
>> + if (err) {
>> + dev_err(&iio_dev->dev,
>> + "Error in enabling sensor %s err %d",
>> + sensor->sensor_info->name, err);
>> + return err;
>> + }
>> + /* Check if raw value fits 32 bits */
>> + if (readings[ch->scan_index].value < INT_MIN ||
>> + readings[ch->scan_index].value > INT_MAX)
>> + return -ERANGE;
>> + /* Use 32-bit value, since practically there is no need in 64 bits */
>> + *val = (int)readings[ch->scan_index].value;
>>
>> + return IIO_VAL_INT;

\
 
 \ /
  Last update: 2021-10-05 14:52    [W:0.385 / U:0.512 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site