[PATCH v6 8/8] iio: adc: ad7606: add support for AD7606C-{16,18} parts
From: Alexandru Ardelean
Date: Fri Sep 13 2024 - 10:03:29 EST
The AD7606C-16 and AD7606C-18 are pretty similar with the AD7606B.
The main difference between AD7606C-16 & AD7606C-18 is the precision in
bits (16 vs 18).
Because of that, some scales need to be defined for the 18-bit variants, as
they need to be computed against 2**18 (vs 2**16 for the 16 bit-variants).
Because the AD7606C-16,18 also supports bipolar & differential channels,
for SW-mode, the default range of 10 V or ±10V should be set at probe.
On reset, the default range (in the registers) is set to value 0x3 which
corresponds to '±10 V single-ended range', regardless of bipolar or
differential configuration.
Aside from the scale/ranges, the AD7606C-16 is similar to the AD7606B.
The AD7606C-18 variant offers 18-bit precision. Because of this, the
requirement to use this chip is that the SPI controller supports padding
of 18-bit sequences to 32-bit arrays.
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7606c-16.pdf
Datasheet: https://www.analog.com/media/en/technical-documentation/data-sheets/ad7606c-18.pdf
Signed-off-by: Alexandru Ardelean <aardelean@xxxxxxxxxxxx>
---
drivers/iio/adc/ad7606.c | 253 +++++++++++++++++++++++++++++++++--
drivers/iio/adc/ad7606.h | 16 ++-
drivers/iio/adc/ad7606_spi.c | 55 ++++++++
3 files changed, 312 insertions(+), 12 deletions(-)
diff --git a/drivers/iio/adc/ad7606.c b/drivers/iio/adc/ad7606.c
index b909ee14fd81..c29512029bfb 100644
--- a/drivers/iio/adc/ad7606.c
+++ b/drivers/iio/adc/ad7606.c
@@ -36,6 +36,33 @@ static const unsigned int ad7606_16bit_hw_scale_avail[2] = {
152588, 305176
};
+static const unsigned int ad7606_18bit_hw_scale_avail[2] = {
+ 38147, 76294
+};
+
+static const unsigned int ad7606c_16bit_single_ended_unipolar_scale_avail[3] = {
+ 76294, 152588, 190735,
+};
+
+static const unsigned int ad7606c_16bit_single_ended_bipolar_scale_avail[5] = {
+ 76294, 152588, 190735, 305176, 381470
+};
+
+static const unsigned int ad7606c_16bit_differential_bipolar_scale_avail[4] = {
+ 152588, 305176, 381470, 610352
+};
+
+static const unsigned int ad7606c_18bit_single_ended_unipolar_scale_avail[3] = {
+ 19073, 38147, 47684
+};
+
+static const unsigned int ad7606c_18bit_single_ended_bipolar_scale_avail[5] = {
+ 19073, 38147, 47684, 76294, 95367
+};
+
+static const unsigned int ad7606c_18bit_differential_bipolar_scale_avail[4] = {
+ 38147, 76294, 95367, 152588
+};
static const unsigned int ad7606_16bit_sw_scale_avail[3] = {
76293, 152588, 305176
@@ -62,7 +89,8 @@ int ad7606_reset(struct ad7606_state *st)
}
EXPORT_SYMBOL_NS_GPL(ad7606_reset, IIO_AD7606);
-static int ad7606_16bit_chan_scale_setup(struct ad7606_state *st, int ch)
+static int ad7606_16bit_chan_scale_setup(struct ad7606_state *st,
+ struct iio_chan_spec *chan, int ch)
{
struct ad7606_chan_scale *cs = &st->chan_scales[ch];
@@ -83,6 +111,163 @@ static int ad7606_16bit_chan_scale_setup(struct ad7606_state *st, int ch)
return 0;
}
+static int ad7606_get_chan_config(struct ad7606_state *st, int ch,
+ bool *bipolar, bool *differential)
+{
+ unsigned int num_channels = st->chip_info->num_channels - 1;
+ struct device *dev = st->dev;
+ int ret;
+
+ *bipolar = false;
+ *differential = false;
+
+ device_for_each_child_node_scoped(dev, child) {
+ u32 pins[2];
+ int reg;
+
+ ret = fwnode_property_read_u32(child, "reg", ®);
+ if (ret)
+ continue;
+
+ /* channel number (here) is from 1 to num_channels */
+ if (reg == 0 || reg > num_channels) {
+ dev_warn(dev,
+ "Invalid channel number (ignoring): %d\n", reg);
+ continue;
+ }
+
+ if (reg != (ch + 1))
+ continue;
+
+ *bipolar = fwnode_property_read_bool(child, "bipolar");
+
+ ret = fwnode_property_read_u32_array(child, "diff-channels",
+ pins, ARRAY_SIZE(pins));
+ /* Channel is differential, if pins are the same as 'reg' */
+ if (ret == 0 && (pins[0] != reg || pins[1] != reg)) {
+ dev_err(dev,
+ "Differential pins must be the same as 'reg'");
+ return -EINVAL;
+ }
+
+ *differential = (ret == 0);
+
+ if (*differential && !*bipolar) {
+ dev_err(dev,
+ "'bipolar' must be added for diff channel %d\n",
+ reg);
+ return -EINVAL;
+ }
+
+ return 0;
+ }
+
+ return 0;
+}
+
+static int ad7606c_18bit_chan_scale_setup(struct ad7606_state *st,
+ struct iio_chan_spec *chan, int ch)
+{
+ struct ad7606_chan_scale *cs;
+ bool bipolar, differential;
+ int ret;
+
+ ret = ad7606_get_chan_config(st, ch, &bipolar, &differential);
+ if (ret)
+ return ret;
+
+ cs = &st->chan_scales[ch];
+
+ if (differential) {
+ cs->scale_avail = ad7606c_18bit_differential_bipolar_scale_avail;
+ cs->num_scales =
+ ARRAY_SIZE(ad7606c_18bit_differential_bipolar_scale_avail);
+ /* Bipolar differential ranges start at 8 (b1000) */
+ cs->reg_offset = 8;
+ cs->range = 1;
+ chan->differential = 1;
+ chan->channel2 = chan->channel;
+
+ return 0;
+ }
+
+ chan->differential = 0;
+
+ if (bipolar) {
+ cs->scale_avail = ad7606c_18bit_single_ended_bipolar_scale_avail;
+ cs->num_scales =
+ ARRAY_SIZE(ad7606c_18bit_single_ended_bipolar_scale_avail);
+ /* Bipolar single-ended ranges start at 0 (b0000) */
+ cs->reg_offset = 0;
+ cs->range = 3;
+ chan->scan_type.sign = 's';
+
+ return 0;
+ }
+
+ cs->scale_avail = ad7606c_18bit_single_ended_unipolar_scale_avail;
+ cs->num_scales =
+ ARRAY_SIZE(ad7606c_18bit_single_ended_unipolar_scale_avail);
+ /* Unipolar single-ended ranges start at 5 (b0101) */
+ cs->reg_offset = 5;
+ cs->range = 1;
+ chan->scan_type.sign = 'u';
+
+ return 0;
+}
+
+static int ad7606c_16bit_chan_scale_setup(struct ad7606_state *st,
+ struct iio_chan_spec *chan, int ch)
+{
+ struct ad7606_chan_scale *cs;
+ bool bipolar, differential;
+ int ret;
+
+ ret = ad7606_get_chan_config(st, ch, &bipolar, &differential);
+ if (ret)
+ return ret;
+
+ cs = &st->chan_scales[ch];
+
+ if (differential) {
+ cs->scale_avail = ad7606c_16bit_differential_bipolar_scale_avail;
+ cs->num_scales =
+ ARRAY_SIZE(ad7606c_16bit_differential_bipolar_scale_avail);
+ /* Bipolar differential ranges start at 8 (b1000) */
+ cs->reg_offset = 8;
+ cs->range = 1;
+ chan->differential = 1;
+ chan->channel2 = chan->channel;
+ chan->scan_type.sign = 's';
+
+ return 0;
+ }
+
+ chan->differential = 0;
+
+ if (bipolar) {
+ cs->scale_avail = ad7606c_16bit_single_ended_bipolar_scale_avail;
+ cs->num_scales =
+ ARRAY_SIZE(ad7606c_16bit_single_ended_bipolar_scale_avail);
+ /* Bipolar single-ended ranges start at 0 (b0000) */
+ cs->reg_offset = 0;
+ cs->range = 3;
+ chan->scan_type.sign = 's';
+
+ return 0;
+ }
+
+ cs->scale_avail = ad7606c_16bit_single_ended_unipolar_scale_avail;
+ cs->num_scales =
+ ARRAY_SIZE(ad7606c_16bit_single_ended_unipolar_scale_avail);
+ /* Unipolar single-ended ranges start at 5 (b0101) */
+ cs->reg_offset = 5;
+ cs->range = 1;
+ chan->scan_type.sign = 'u';
+
+ return 0;
+}
+
static int ad7606_reg_access(struct iio_dev *indio_dev,
unsigned int reg,
unsigned int writeval,
@@ -107,9 +292,8 @@ static int ad7606_reg_access(struct iio_dev *indio_dev,
static int ad7606_read_samples(struct ad7606_state *st)
{
unsigned int num = st->chip_info->num_channels - 1;
- u16 *data = st->data;
- return st->bops->read_block(st->dev, num, data);
+ return st->bops->read_block(st->dev, num, &st->data);
}
static irqreturn_t ad7606_trigger_handler(int irq, void *p)
@@ -125,7 +309,7 @@ static irqreturn_t ad7606_trigger_handler(int irq, void *p)
if (ret)
goto error_ret;
- iio_push_to_buffers_with_timestamp(indio_dev, st->data,
+ iio_push_to_buffers_with_timestamp(indio_dev, &st->data,
iio_get_time_ns(indio_dev));
error_ret:
iio_trigger_notify_done(indio_dev->trig);
@@ -139,6 +323,8 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch,
int *val)
{
struct ad7606_state *st = iio_priv(indio_dev);
+ unsigned int storagebits = st->chip_info->channels[1].scan_type.storagebits;
+ const struct iio_chan_spec *chan;
int ret;
gpiod_set_value(st->gpio_convst, 1);
@@ -153,7 +339,19 @@ static int ad7606_scan_direct(struct iio_dev *indio_dev, unsigned int ch,
if (ret)
goto error_ret;
- *val = sign_extend32(st->data[ch], 15);
+ chan = &indio_dev->channels[ch + 1];
+ if (chan->scan_type.sign == 'u') {
+ if (storagebits > 16)
+ *val = st->data.buf32[ch];
+ else
+ *val = st->data.buf16[ch];
+ return 0;
+ }
+
+ if (storagebits > 16)
+ *val = sign_extend32(st->data.buf32[ch], 17);
+ else
+ *val = sign_extend32(st->data.buf16[ch], 15);
error_ret:
gpiod_set_value(st->gpio_convst, 0);
@@ -266,7 +464,7 @@ static int ad7606_write_raw(struct iio_dev *indio_dev,
ch = chan->address;
cs = &st->chan_scales[ch];
i = find_closest(val2, cs->scale_avail, cs->num_scales);
- ret = st->write_scale(indio_dev, ch, i);
+ ret = st->write_scale(indio_dev, ch, i + cs->reg_offset);
if (ret < 0)
return ret;
cs->range = i;
@@ -349,6 +547,18 @@ static const struct iio_chan_spec ad7606_channels_16bit[] = {
AD7606_CHANNEL(7, 16),
};
+static const struct iio_chan_spec ad7606_channels_18bit[] = {
+ IIO_CHAN_SOFT_TIMESTAMP(8),
+ AD7606_CHANNEL(0, 18),
+ AD7606_CHANNEL(1, 18),
+ AD7606_CHANNEL(2, 18),
+ AD7606_CHANNEL(3, 18),
+ AD7606_CHANNEL(4, 18),
+ AD7606_CHANNEL(5, 18),
+ AD7606_CHANNEL(6, 18),
+ AD7606_CHANNEL(7, 18),
+};
+
/*
* The current assumption that this driver makes for AD7616, is that it's
* working in Hardware Mode with Serial, Burst and Sequencer modes activated.
@@ -414,6 +624,20 @@ static const struct ad7606_chip_info ad7606_chip_info_tbl[] = {
.oversampling_avail = ad7606_oversampling_avail,
.oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
},
+ [ID_AD7606C_16] = {
+ .channels = ad7606_channels_16bit,
+ .num_channels = 9,
+ .scale_setup_cb = ad7606c_16bit_chan_scale_setup,
+ .oversampling_avail = ad7606_oversampling_avail,
+ .oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
+ },
+ [ID_AD7606C_18] = {
+ .channels = ad7606_channels_18bit,
+ .num_channels = 9,
+ .scale_setup_cb = ad7606c_18bit_chan_scale_setup,
+ .oversampling_avail = ad7606_oversampling_avail,
+ .oversampling_num = ARRAY_SIZE(ad7606_oversampling_avail),
+ },
[ID_AD7616] = {
.channels = ad7616_channels,
.num_channels = 17,
@@ -586,7 +810,7 @@ static const struct iio_trigger_ops ad7606_trigger_ops = {
.validate_device = iio_trigger_validate_own_device,
};
-static int ad7606_sw_mode_setup(struct iio_dev *indio_dev)
+static int ad7606_sw_mode_setup(struct iio_dev *indio_dev, unsigned int id)
{
struct ad7606_state *st = iio_priv(indio_dev);
@@ -604,13 +828,24 @@ static int ad7606_chan_scales_setup(struct iio_dev *indio_dev)
{
unsigned int num_channels = indio_dev->num_channels - 1;
struct ad7606_state *st = iio_priv(indio_dev);
+ struct iio_chan_spec *chans;
+ size_t size;
int ch, ret;
+ /* Clone IIO channels, since some may be differential */
+ size = indio_dev->num_channels * sizeof(*indio_dev->channels);
+ chans = devm_kzalloc(st->dev, size, GFP_KERNEL);
+ if (!chans)
+ return -ENOMEM;
+
+ memcpy(chans, indio_dev->channels, size);
+ indio_dev->channels = chans;
+
for (ch = 0; ch < num_channels; ch++) {
struct ad7606_chan_scale *cs;
int i;
- ret = st->chip_info->scale_setup_cb(st, ch);
+ ret = st->chip_info->scale_setup_cb(st, &chans[ch + 1], ch);
if (ret)
return ret;
@@ -698,7 +933,7 @@ int ad7606_probe(struct device *dev, int irq, void __iomem *base_address,
st->write_scale = ad7606_write_scale_hw;
st->write_os = ad7606_write_os_hw;
- ret = ad7606_sw_mode_setup(indio_dev);
+ ret = ad7606_sw_mode_setup(indio_dev, id);
if (ret)
return ret;
diff --git a/drivers/iio/adc/ad7606.h b/drivers/iio/adc/ad7606.h
index 25e84efd15c3..14ee75aa225b 100644
--- a/drivers/iio/adc/ad7606.h
+++ b/drivers/iio/adc/ad7606.h
@@ -63,7 +63,8 @@
struct ad7606_state;
-typedef int (*ad7606_scale_setup_cb_t)(struct ad7606_state *st, int ch);
+typedef int (*ad7606_scale_setup_cb_t)(struct ad7606_state *st,
+ struct iio_chan_spec *chan, int ch);
/**
* struct ad7606_chip_info - chip specific information
@@ -94,6 +95,8 @@ struct ad7606_chip_info {
* such that it can be read via the 'read_avail' hook
* @num_scales number of elements stored in the scale_avail array
* @range voltage range selection, selects which scale to apply
+ * @reg_offset offset for the register value, to be applied when
+ * writing the value of 'range' to the register value
*/
struct ad7606_chan_scale {
#define AD760X_MAX_SCALES 16
@@ -102,6 +105,7 @@ struct ad7606_chan_scale {
int scale_avail_show[AD760X_MAX_SCALE_SHOW];
unsigned int num_scales;
unsigned int range;
+ unsigned int reg_offset;
};
/**
@@ -158,9 +162,13 @@ struct ad7606_state {
/*
* DMA (thus cache coherency maintenance) may require the
* transfer buffers to live in their own cache lines.
- * 16 * 16-bit samples + 64-bit timestamp
+ * 16 * 16-bit samples + 64-bit timestamp - for AD7616
+ * 8 * 32-bit samples + 64-bit timestamp - for AD7616C-18 (and similar)
*/
- unsigned short data[20] __aligned(IIO_DMA_MINALIGN);
+ union {
+ u16 buf16[20];
+ u32 buf32[10];
+ } data __aligned(IIO_DMA_MINALIGN);
__be16 d16[2];
};
@@ -201,6 +209,8 @@ enum ad7606_supported_device_ids {
ID_AD7606_6,
ID_AD7606_4,
ID_AD7606B,
+ ID_AD7606C_16,
+ ID_AD7606C_18,
ID_AD7616,
};
diff --git a/drivers/iio/adc/ad7606_spi.c b/drivers/iio/adc/ad7606_spi.c
index e00f58a6a0e9..143440e73aab 100644
--- a/drivers/iio/adc/ad7606_spi.c
+++ b/drivers/iio/adc/ad7606_spi.c
@@ -77,6 +77,18 @@ static const struct iio_chan_spec ad7606b_sw_channels[] = {
AD7606_SW_CHANNEL(7, 16),
};
+static const struct iio_chan_spec ad7606c_18_sw_channels[] = {
+ IIO_CHAN_SOFT_TIMESTAMP(8),
+ AD7606_SW_CHANNEL(0, 18),
+ AD7606_SW_CHANNEL(1, 18),
+ AD7606_SW_CHANNEL(2, 18),
+ AD7606_SW_CHANNEL(3, 18),
+ AD7606_SW_CHANNEL(4, 18),
+ AD7606_SW_CHANNEL(5, 18),
+ AD7606_SW_CHANNEL(6, 18),
+ AD7606_SW_CHANNEL(7, 18),
+};
+
static const unsigned int ad7606B_oversampling_avail[9] = {
1, 2, 4, 8, 16, 32, 64, 128, 256
};
@@ -120,6 +132,19 @@ static int ad7606_spi_read_block(struct device *dev,
return 0;
}
+static int ad7606_spi_read_block18to32(struct device *dev,
+ int count, void *buf)
+{
+ struct spi_device *spi = to_spi_device(dev);
+ struct spi_transfer xfer = {
+ .bits_per_word = 18,
+ .len = count * sizeof(u32),
+ .rx_buf = buf,
+ };
+
+ return spi_sync_transfer(spi, &xfer, 1);
+}
+
static int ad7606_spi_reg_read(struct ad7606_state *st, unsigned int addr)
{
struct spi_device *spi = to_spi_device(st->dev);
@@ -283,6 +308,19 @@ static int ad7606B_sw_mode_config(struct iio_dev *indio_dev)
return 0;
}
+static int ad7606c_18_sw_mode_config(struct iio_dev *indio_dev)
+{
+ int ret;
+
+ ret = ad7606B_sw_mode_config(indio_dev);
+ if (ret)
+ return ret;
+
+ indio_dev->channels = ad7606c_18_sw_channels;
+
+ return 0;
+}
+
static const struct ad7606_bus_ops ad7606_spi_bops = {
.read_block = ad7606_spi_read_block,
};
@@ -305,6 +343,15 @@ static const struct ad7606_bus_ops ad7606B_spi_bops = {
.sw_mode_config = ad7606B_sw_mode_config,
};
+static const struct ad7606_bus_ops ad7606c_18_spi_bops = {
+ .read_block = ad7606_spi_read_block18to32,
+ .reg_read = ad7606_spi_reg_read,
+ .reg_write = ad7606_spi_reg_write,
+ .write_mask = ad7606_spi_write_mask,
+ .rd_wr_cmd = ad7606B_spi_rd_wr_cmd,
+ .sw_mode_config = ad7606c_18_sw_mode_config,
+};
+
static int ad7606_spi_probe(struct spi_device *spi)
{
const struct spi_device_id *id = spi_get_device_id(spi);
@@ -315,8 +362,12 @@ static int ad7606_spi_probe(struct spi_device *spi)
bops = &ad7616_spi_bops;
break;
case ID_AD7606B:
+ case ID_AD7606C_16:
bops = &ad7606B_spi_bops;
break;
+ case ID_AD7606C_18:
+ bops = &ad7606c_18_spi_bops;
+ break;
default:
bops = &ad7606_spi_bops;
break;
@@ -333,6 +384,8 @@ static const struct spi_device_id ad7606_id_table[] = {
{ "ad7606-6", ID_AD7606_6 },
{ "ad7606-8", ID_AD7606_8 },
{ "ad7606b", ID_AD7606B },
+ { "ad7606c-16", ID_AD7606C_16 },
+ { "ad7606c-18", ID_AD7606C_18 },
{ "ad7616", ID_AD7616 },
{ }
};
@@ -344,6 +397,8 @@ static const struct of_device_id ad7606_of_match[] = {
{ .compatible = "adi,ad7606-6" },
{ .compatible = "adi,ad7606-8" },
{ .compatible = "adi,ad7606b" },
+ { .compatible = "adi,ad7606c-16" },
+ { .compatible = "adi,ad7606c-18" },
{ .compatible = "adi,ad7616" },
{ }
};
--
2.46.0