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iio: adc: ad7124: Implement temperature measurement

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

Signed-off-by: Uwe Kleine-König <u.kleine-koenig@baylibre.com>
Link: https://patch.msgid.link/433211af8ac3f02dee58586ecb51d2e98246a095.1733504533.git.u.kleine-koenig@baylibre.com
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
This commit is contained in:
Uwe Kleine-König
2024-12-06 18:28:42 +01:00
committed by Jonathan Cameron
parent abc61acde1
commit 6eaf3f60ab
1 changed files with 91 additions and 21 deletions
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112
drivers/iio/adc/ad7124.c
View File

@@ -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,
@@ -589,26 +593,59 @@ static int ad7124_read_raw(struct iio_dev *indio_dev,
return IIO_VAL_INT;
case IIO_CHAN_INFO_SCALE:
mutex_lock(&st->cfgs_lock);
switch (chan->type) {
case IIO_VOLTAGE:
mutex_lock(&st->cfgs_lock);
idx = st->channels[chan->address].cfg.pga_bits;
*val = st->channels[chan->address].cfg.vref_mv;
if (st->channels[chan->address].cfg.bipolar)
*val2 = chan->scan_type.realbits - 1 + idx;
else
*val2 = chan->scan_type.realbits + idx;
idx = st->channels[chan->address].cfg.pga_bits;
*val = st->channels[chan->address].cfg.vref_mv;
if (st->channels[chan->address].cfg.bipolar)
*val2 = chan->scan_type.realbits - 1 + idx;
else
*val2 = chan->scan_type.realbits + idx;
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;
}
mutex_unlock(&st->cfgs_lock);
return IIO_VAL_FRACTIONAL_LOG2;
case IIO_CHAN_INFO_OFFSET:
mutex_lock(&st->cfgs_lock);
if (st->channels[chan->address].cfg.bipolar)
*val = -(1 << (chan->scan_type.realbits - 1));
else
*val = 0;
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));
else
*val = 0;
mutex_unlock(&st->cfgs_lock);
return IIO_VAL_INT;
case IIO_TEMP:
/* see calculation above */
*val = -12090248;
return IIO_VAL_INT;
default:
return -EINVAL;
}
mutex_unlock(&st->cfgs_lock);
return IIO_VAL_INT;
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;
}