Commit 6eaf3f60 authored by Uwe Kleine-König's avatar Uwe Kleine-König Committed by Jonathan Cameron
Browse files

iio: adc: ad7124: Implement temperature measurement 



If the maximal count of channels the driver supports isn't fully
utilized, add an attribute providing the internal temperature.

Signed-off-by: default avatarUwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/433211af8ac3f02dee58586ecb51d2e98246a095.1733504533.git.u.kleine-koenig@baylibre.com


Signed-off-by: default avatarJonathan Cameron <Jonathan.Cameron@huawei.com>
parent abc61acd

drivers/iio/adc/ad7124.c

+91 −21
Original line number Diff line number Diff line
@@ -95,6 +95,10 @@ 
#define AD7124_MAX_CONFIGS	8

#define AD7124_MAX_CHANNELS	16



/* AD7124 input sources */

#define AD7124_INPUT_TEMPSENSOR	16

#define AD7124_INPUT_AVSS	17



enum ad7124_ids {

	ID_AD7124_4,

	ID_AD7124_8,
@@ -589,6 +593,8 @@ static int ad7124_read_raw(struct iio_dev *indio_dev, 


		return IIO_VAL_INT;

	case IIO_CHAN_INFO_SCALE:

		switch (chan->type) {

		case IIO_VOLTAGE:

			mutex_lock(&st->cfgs_lock);



			idx = st->channels[chan->address].cfg.pga_bits;
@@ -600,7 +606,28 @@ static int ad7124_read_raw(struct iio_dev *indio_dev, 


			mutex_unlock(&st->cfgs_lock);

			return IIO_VAL_FRACTIONAL_LOG2;



		case IIO_TEMP:

			/*

			 * According to the data sheet

			 *   Temperature (°C)

			 * = ((Conversion − 0x800000)/13584) − 272.5

			 * = (Conversion − 0x800000 - 13584 * 272.5) / 13584

			 * = (Conversion − 12090248) / 13584

			 * So scale with 1000/13584 to yield °mC. Reduce by 8 to

			 * 125/1698.

			 */

			*val = 125;

			*val2 = 1698;

			return IIO_VAL_FRACTIONAL;



		default:

			return -EINVAL;

		}



	case IIO_CHAN_INFO_OFFSET:

		switch (chan->type) {

		case IIO_VOLTAGE:

			mutex_lock(&st->cfgs_lock);

			if (st->channels[chan->address].cfg.bipolar)

				*val = -(1 << (chan->scan_type.realbits - 1));
@@ -609,6 +636,16 @@ static int ad7124_read_raw(struct iio_dev *indio_dev, 


			mutex_unlock(&st->cfgs_lock);

			return IIO_VAL_INT;



		case IIO_TEMP:

			/* see calculation above */

			*val = -12090248;

			return IIO_VAL_INT;



		default:

			return -EINVAL;

		}



	case IIO_CHAN_INFO_SAMP_FREQ:

		mutex_lock(&st->cfgs_lock);

		*val = st->channels[chan->address].cfg.odr;
@@ -826,11 +863,10 @@ static int ad7124_parse_channel_config(struct iio_dev *indio_dev, 
	struct ad7124_channel *channels;

	struct iio_chan_spec *chan;

	unsigned int ain[2], channel = 0, tmp;

	unsigned int num_channels;

	int ret;



	st->num_channels = device_get_child_node_count(dev);

	if (!st->num_channels)

		return dev_err_probe(dev, -ENODEV, "no channel children\n");

	num_channels = device_get_child_node_count(dev);



	/*

	 * The driver assigns each logical channel defined in the device tree
@@ -839,9 +875,12 @@ static int ad7124_parse_channel_config(struct iio_dev *indio_dev, 
	 * CHANNEL_15) as an additional channel register. The driver could be

	 * improved to lift this limitation.

	 */

	if (st->num_channels > AD7124_MAX_CHANNELS)

	if (num_channels > AD7124_MAX_CHANNELS)

		return dev_err_probe(dev, -EINVAL, "Too many channels defined\n");



	/* Add one for temperature */

	st->num_channels = min(num_channels + 1, AD7124_MAX_CHANNELS);



	chan = devm_kcalloc(indio_dev->dev.parent, st->num_channels,

			    sizeof(*chan), GFP_KERNEL);

	if (!chan)
@@ -862,7 +901,7 @@ static int ad7124_parse_channel_config(struct iio_dev *indio_dev, 
			return dev_err_probe(dev, ret,

					     "Failed to parse reg property of %pfwP\n", child);



		if (channel >= indio_dev->num_channels)

		if (channel >= num_channels)

			return dev_err_probe(dev, -EINVAL,

					     "Channel index >= number of channels in %pfwP\n", child);
@@ -902,6 +941,37 @@ static int ad7124_parse_channel_config(struct iio_dev *indio_dev, 
		chan[channel].channel2 = ain[1];

	}



	if (num_channels < AD7124_MAX_CHANNELS) {

		st->channels[num_channels] = (struct ad7124_channel) {

			.nr = num_channels,

			.ain = AD7124_CHANNEL_AINP(AD7124_INPUT_TEMPSENSOR) |

				AD7124_CHANNEL_AINM(AD7124_INPUT_AVSS),

			.cfg = {

				.bipolar = true,

			},

		};



		chan[num_channels] = (struct iio_chan_spec) {

			.type = IIO_TEMP,

			.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |

				BIT(IIO_CHAN_INFO_SCALE) | BIT(IIO_CHAN_INFO_OFFSET) |

				BIT(IIO_CHAN_INFO_SAMP_FREQ),

			.scan_type = {

				/*

				 * You might find it strange that a bipolar

				 * measurement yields an unsigned value, but

				 * this matches the device's manual.

				 */

				.sign = 'u',

				.realbits = 24,

				.storagebits = 32,

				.endianness = IIO_BE,

			},

			.address = num_channels,

			.scan_index = num_channels,

		};

	}



	return 0;

}