[PATCH v7 2/2] iio/scmi: Add reading "raw" attribute.

[Andriy Tryshnivskyy <andriy.tryshnivskyy@opensynergy.com>]

Add IIO_CHAN_INFO_RAW to the mask and implement corresponding
reading "raw" attribute in scmi_iio_read_raw.

Signed-off-by: Andriy Tryshnivskyy <andriy.tryshnivskyy@opensynergy.com>
---
Changes comparing v6 -> v7:
* split into two patches: one for changes in core functionality,
  another - for changes in the driver

Changes comparing v5 -> v6:
* revert v5 changes since with scmi_iio_read_raw() the channel
  can't be used by in kernel users (iio-hwmon)
* returned to v3 with direct mode
* introduce new type IIO_VAL_INT_64 to read 64-bit value

Changes comparing v4 -> v5:
* call iio_device_release_direct_mode() on error
* code cleanup, fix typo

Changes comparing v3 -> v4:
* do not use scmi_iio_get_raw() for reading raw attribute due to 32-bit
  return value limitation (actually I reverted the previous v3)
* introduce scmi_iio_read_raw to scmi_iio_ext_info[] which can return
  64-bit value
* enabling/disabling and reading raw attribute is done in direct mode

Changes comparing v2 -> v3:
* adaptation for changes in structure scmi_iio_priv (no member
  named 'handle')

Changes comparing v0 -> v2:
* added an error return when the error happened during config_set
* removed redundant cast for "readings"
* added check if raw value fits 32 bits

 drivers/iio/common/scmi_sensors/scmi_iio.c | 57 +++++++++++++++++++++-
 1 file changed, 56 insertions(+), 1 deletion(-)

diff --git a/drivers/iio/common/scmi_sensors/scmi_iio.c b/drivers/iio/common/scmi_sensors/scmi_iio.c
index 7cf2bf282cef..d538bf3ab1ef 100644
--- a/drivers/iio/common/scmi_sensors/scmi_iio.c
+++ b/drivers/iio/common/scmi_sensors/scmi_iio.c
@@ -279,6 +279,52 @@ static int scmi_iio_get_odr_val(struct iio_dev *iio_dev, int *val, int *val2)
 	return 0;
 }
 
+static int scmi_iio_read_channel_data(struct iio_dev *iio_dev,
+			     struct iio_chan_spec const *ch, int *val, int *val2)
+{
+	struct scmi_iio_priv *sensor = iio_priv(iio_dev);
+	u32 sensor_config;
+	struct scmi_sensor_reading readings[SCMI_IIO_NUM_OF_AXIS];
+	int err;
+
+	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 disabling sensor %s err %d",
+			sensor->sensor_info->name, err);
+		return err;
+	}
+
+	*val = lower_32_bits(readings[ch->scan_index].value);
+	*val2 = upper_32_bits(readings[ch->scan_index].value);
+
+	return IIO_VAL_INT_64;
+}
+
 static int scmi_iio_read_raw(struct iio_dev *iio_dev,
 			     struct iio_chan_spec const *ch, int *val,
 			     int *val2, long mask)
@@ -300,6 +346,14 @@ static int scmi_iio_read_raw(struct iio_dev *iio_dev,
 	case IIO_CHAN_INFO_SAMP_FREQ:
 		ret = scmi_iio_get_odr_val(iio_dev, val, val2);
 		return ret ? ret : IIO_VAL_INT_PLUS_MICRO;
+	case IIO_CHAN_INFO_RAW:
+		ret = iio_device_claim_direct_mode(iio_dev);
+		if (ret)
+			return ret;
+
+		ret = scmi_iio_read_channel_data(iio_dev, ch, val, val2);
+		iio_device_release_direct_mode(iio_dev);
+		return ret;
 	default:
 		return -EINVAL;
 	}
@@ -381,7 +435,8 @@ static void scmi_iio_set_data_channel(struct iio_chan_spec *iio_chan,
 	iio_chan->type = type;
 	iio_chan->modified = 1;
 	iio_chan->channel2 = mod;
-	iio_chan->info_mask_separate = BIT(IIO_CHAN_INFO_SCALE);
+	iio_chan->info_mask_separate =
+		BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_RAW);
 	iio_chan->info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SAMP_FREQ);
 	iio_chan->info_mask_shared_by_type_available =
 		BIT(IIO_CHAN_INFO_SAMP_FREQ);
-- 
2.17.1