On Fri, 8 Oct 2021 21:28:26 +0300
Andriy Tryshnivskyy <andriy.tryshnivskyy@xxxxxxxxxxxxxxx> wrote:
> Add scmi_iio_get_raw() to read "raw" attribute.
>
> Signed-off-by: Andriy Tryshnivskyy <andriy.tryshnivskyy@xxxxxxxxxxxxxxx>
> ---
For a single patch series, it is better to put a change log in the patch (here)
Whilst I can see why you would use this approach rather than the read_raw callback
there are significant disadvantages in doing so. The channel can't be used
by in kernel users such as iio-hwmon. That may cause you more trouble than
it is worth in the long run.
Note that you could also define a new IIO_VAL type to still use the two
(possibly) 32 bit values and return a 64 bit value. That way, with appropriate
additions in the consumer drivers the channel could still be used.
IIO_VAL_INT_64 perhaps with val as the lower 32 bits and val2 as the upper
with appropriate care around the sign.
> drivers/iio/common/scmi_sensors/scmi_iio.c | 61 ++++++++++++++++++++++
> 1 file changed, 61 insertions(+)
>
> diff --git a/drivers/iio/common/scmi_sensors/scmi_iio.c b/drivers/iio/common/scmi_sensors/scmi_iio.c
> index 7cf2bf282cef..691cbbd61e3a 100644
> --- a/drivers/iio/common/scmi_sensors/scmi_iio.c
> +++ b/drivers/iio/common/scmi_sensors/scmi_iio.c
> @@ -311,6 +311,62 @@ static const struct iio_info scmi_iio_info = {
> .write_raw = scmi_iio_write_raw,
> };
>
> +static ssize_t scmi_iio_get_raw(struct iio_dev *iio_dev, uintptr_t private,
> + const struct iio_chan_spec *chan, char *buf)
> +{
> + struct scmi_iio_priv *sensor = iio_priv(iio_dev);
> + int err;
> + u32 sensor_config;
> + struct scmi_sensor_reading readings[SCMI_IIO_NUM_OF_AXIS];
> + int len = 0;
> +
> + err = iio_device_claim_direct_mode(iio_dev);
> + if (err) {
> + dev_err(&iio_dev->dev,
> + "Error in claiming direct mode for sensor %s err %d",
> + sensor->sensor_info->name, err);
It's not an error, it just means the device is busy, so at most dev_info()
or just rely on userspace correctly interpreting EBUSY.
> + goto err_release;
> + }
> +
> + 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);
> + goto err_release;
> + }
> +
> + 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);
> + goto err_release;
> + }
> +
> + 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 disabling sensor %s err %d",
> + sensor->sensor_info->name, err);
> + goto err_release;
> + }
> +
> + len = scnprintf(buf, PAGE_SIZE, "%lld\n",
> + readings[chan->scan_index].value);
> +
> +err_release:
> + iio_device_release_direct_mode(iio_dev);
> +
> + return len;
> +}
> +
> static ssize_t scmi_iio_get_raw_available(struct iio_dev *iio_dev,
> uintptr_t private,
> const struct iio_chan_spec *chan,
> @@ -355,6 +411,11 @@ static ssize_t scmi_iio_get_raw_available(struct iio_dev *iio_dev,
> }
>
> static const struct iio_chan_spec_ext_info scmi_iio_ext_info[] = {
> + {
> + .name = "raw",
> + .read = scmi_iio_get_raw,
> + .shared = IIO_SEPARATE,
> + },
> {
> .name = "raw_available",
> .read = scmi_iio_get_raw_available,
