[PATCH v2 3/3] iio: adc: ad7192: Add fast settling support

From: alisadariana
Date: Tue Sep 19 2023 - 20:34:37 EST

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From: Alisa-Dariana Roman <alisadariana@xxxxxxxxx>

Add fast settling mode support for AD7193.

Add fast_settling_average_factor attribute. Expose to user the current
value of the fast settling average factor. User can change the value by
writing a new one.

Add fast_settling_average_factor_available attribute. Expose to user
possible values for the fast settling average factor.

Signed-off-by: Alisa-Dariana Roman <alisa.roman@xxxxxxxxxx>
---
.../ABI/testing/sysfs-bus-iio-adc-ad7192 | 18 +++
drivers/iio/adc/ad7192.c | 128 ++++++++++++++++--
2 files changed, 134 insertions(+), 12 deletions(-)

diff --git a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192 b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192
index f8315202c8f0..5790adbb1cc1 100644
--- a/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192
+++ b/Documentation/ABI/testing/sysfs-bus-iio-adc-ad7192
@@ -19,6 +19,24 @@ Description:
the bridge can be disconnected (when it is not being used
using the bridge_switch_en attribute.

+What: /sys/bus/iio/devices/iio:deviceX/fast_settling_average_factor
+KernelVersion:
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ This attribute, if available, is used to activate or deactivate
+ fast settling mode and set the value of the average factor to
+ 1, 2, 8 or 16. If the average factor is set to 1, the fast
+ settling mode is disabled. The data from the sinc filter is
+ averaged by chosen value. The averaging reduces the output data
+ rate for a given FS word, however, the rms noise improves.
+
+What: /sys/bus/iio/devices/iio:deviceX/fast_settling_average_factor_available
+KernelVersion:
+Contact: linux-iio@xxxxxxxxxxxxxxx
+Description:
+ Reading returns a list with the possible values for the fast
+ settling average factor: 1, 2, 8, 16.
+
What: /sys/bus/iio/devices/iio:deviceX/in_voltagex_sys_calibration
KernelVersion:
Contact: linux-iio@xxxxxxxxxxxxxxx
diff --git a/drivers/iio/adc/ad7192.c b/drivers/iio/adc/ad7192.c
index eed3de02c26d..8987b78865f3 100644
--- a/drivers/iio/adc/ad7192.c
+++ b/drivers/iio/adc/ad7192.c
@@ -60,6 +60,8 @@
#define AD7192_MODE_SEL_MASK GENMASK(23, 21) /* Operation Mode Select Mask */
#define AD7192_MODE_STA_MASK BIT(20) /* Status Register transmission Mask */
#define AD7192_MODE_CLKSRC_MASK GENMASK(19, 18) /* Clock Source Select Mask */
+#define AD7192_MODE_AVG_MASK GENMASK(17, 16)
+ /* Fast Settling Filter Average Select Mask (AD7193 only) */
#define AD7192_MODE_SINC3 BIT(15) /* SINC3 Filter Select */
#define AD7192_MODE_ENPAR BIT(13) /* Parity Enable */
#define AD7192_MODE_CLKDIV BIT(12) /* Clock divide by 2 (AD7190/2 only)*/
@@ -182,6 +184,7 @@ struct ad7192_state {
u32 mode;
u32 conf;
u32 scale_avail[8][2];
+ u8 avg_avail[4];
u8 gpocon;
u8 clock_sel;
struct mutex lock; /* protect sensor state */
@@ -459,6 +462,13 @@ static int ad7192_setup(struct iio_dev *indio_dev, struct device_node *np)
st->scale_avail[i][0] = scale_uv;
}

+ if (st->chip_info->chip_id == CHIPID_AD7193) {
+ st->avg_avail[0] = 1;
+ st->avg_avail[1] = 2;
+ st->avg_avail[2] = 8;
+ st->avg_avail[3] = 16;
+ }
+
return 0;
}

@@ -483,6 +493,18 @@ static ssize_t ad7192_show_bridge_switch(struct device *dev,
!!FIELD_GET(AD7192_GPOCON_BPDSW, st->gpocon));
}

+static ssize_t ad7192_show_average_factor(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ad7192_state *st = iio_priv(indio_dev);
+ u8 avg_factor_index;
+
+ avg_factor_index = FIELD_GET(AD7192_MODE_AVG_MASK, st->mode);
+ return sysfs_emit(buf, "%d\n", st->avg_avail[avg_factor_index]);
+}
+
static ssize_t ad7192_set(struct device *dev,
struct device_attribute *attr,
const char *buf,
@@ -491,12 +513,10 @@ static ssize_t ad7192_set(struct device *dev,
struct iio_dev *indio_dev = dev_to_iio_dev(dev);
struct ad7192_state *st = iio_priv(indio_dev);
struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+ bool val, ret_einval;
+ u8 val_avg_factor;
+ unsigned int i;
int ret;
- bool val;
-
- ret = kstrtobool(buf, &val);
- if (ret < 0)
- return ret;

ret = iio_device_claim_direct_mode(indio_dev);
if (ret)
@@ -504,6 +524,10 @@ static ssize_t ad7192_set(struct device *dev,

switch ((u32)this_attr->address) {
case AD7192_REG_GPOCON:
+ ret = kstrtobool(buf, &val);
+ if (ret < 0)
+ return ret;
+
if (val)
st->gpocon |= AD7192_GPOCON_BPDSW;
else
@@ -512,6 +536,10 @@ static ssize_t ad7192_set(struct device *dev,
ad_sd_write_reg(&st->sd, AD7192_REG_GPOCON, 1, st->gpocon);
break;
case AD7192_REG_CONF:
+ ret = kstrtobool(buf, &val);
+ if (ret < 0)
+ return ret;
+
if (val)
st->conf |= AD7192_CONF_ACX;
else
@@ -519,6 +547,27 @@ static ssize_t ad7192_set(struct device *dev,

ad_sd_write_reg(&st->sd, AD7192_REG_CONF, 3, st->conf);
break;
+ case AD7192_REG_MODE:
+ ret = kstrtou8(buf, 10, &val_avg_factor);
+ if (ret < 0)
+ return ret;
+
+ ret_einval = true;
+ for (i = 0; i < ARRAY_SIZE(st->avg_avail); i++) {
+ if (val_avg_factor == st->avg_avail[i]) {
+ st->mode &= ~AD7192_MODE_AVG_MASK;
+ st->mode |= FIELD_PREP(AD7192_MODE_AVG_MASK, i);
+ ret_einval = false;
+ }
+ }
+
+ if (ret_einval)
+ return -EINVAL;
+
+ ret = ad_sd_write_reg(&st->sd, AD7192_REG_MODE, 3, st->mode);
+ if (ret)
+ return ret;
+ break;
default:
ret = -EINVAL;
}
@@ -528,15 +577,22 @@ static ssize_t ad7192_set(struct device *dev,
return ret ? ret : len;
}

-static int ad7192_compute_f_order(bool sinc3_en, bool chop_en)
+static int ad7192_compute_f_order(struct ad7192_state *st, bool sinc3_en, bool chop_en)
{
- if (!chop_en)
+ u8 avg_factor;
+ u8 avg_factor_selected;
+
+ avg_factor_selected = FIELD_GET(AD7192_MODE_AVG_MASK, st->mode);
+
+ if (!avg_factor_selected && !chop_en)
return 1;

+ avg_factor = st->avg_avail[avg_factor_selected];
+
if (sinc3_en)
- return AD7192_SYNC3_FILTER;
+ return AD7192_SYNC3_FILTER + avg_factor - 1;

- return AD7192_SYNC4_FILTER;
+ return AD7192_SYNC4_FILTER + avg_factor - 1;
}

static int ad7192_get_f_order(struct ad7192_state *st)
@@ -546,13 +602,13 @@ static int ad7192_get_f_order(struct ad7192_state *st)
sinc3_en = FIELD_GET(AD7192_MODE_SINC3, st->mode);
chop_en = FIELD_GET(AD7192_CONF_CHOP, st->conf);

- return ad7192_compute_f_order(sinc3_en, chop_en);
+ return ad7192_compute_f_order(st, sinc3_en, chop_en);
}

static int ad7192_compute_f_adc(struct ad7192_state *st, bool sinc3_en,
bool chop_en)
{
- unsigned int f_order = ad7192_compute_f_order(sinc3_en, chop_en);
+ unsigned int f_order = ad7192_compute_f_order(st, sinc3_en, chop_en);

return DIV_ROUND_CLOSEST(st->fclk,
f_order * FIELD_PREP(AD7192_MODE_RATE_MASK, st->mode));
@@ -605,9 +661,29 @@ static ssize_t ad7192_show_filter_avail(struct device *dev,
return len;
}

+static ssize_t ad7192_show_avg_factor_avail(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+ struct ad7192_state *st = iio_priv(indio_dev);
+ unsigned int i;
+ size_t len = 0;
+
+ for (i = 0; i < ARRAY_SIZE(st->avg_avail); i++)
+ len += sysfs_emit_at(buf, len, "%d ", st->avg_avail[i]);
+
+ buf[len - 1] = '\n';
+
+ return len;
+}
+
static IIO_DEVICE_ATTR(filter_low_pass_3db_frequency_available,
0444, ad7192_show_filter_avail, NULL, 0);

+static IIO_DEVICE_ATTR(fast_settling_average_factor_available,
+ 0444, ad7192_show_avg_factor_avail, NULL, 0);
+
static IIO_DEVICE_ATTR(bridge_switch_en, 0644,
ad7192_show_bridge_switch, ad7192_set,
AD7192_REG_GPOCON);
@@ -616,6 +692,10 @@ static IIO_DEVICE_ATTR(ac_excitation_en, 0644,
ad7192_show_ac_excitation, ad7192_set,
AD7192_REG_CONF);

+static IIO_DEVICE_ATTR(fast_settling_average_factor, 0644,
+ ad7192_show_average_factor, ad7192_set,
+ AD7192_REG_MODE);
+
static struct attribute *ad7192_attributes[] = {
&iio_dev_attr_filter_low_pass_3db_frequency_available.dev_attr.attr,
&iio_dev_attr_bridge_switch_en.dev_attr.attr,
@@ -626,6 +706,18 @@ static const struct attribute_group ad7192_attribute_group = {
.attrs = ad7192_attributes,
};

+static struct attribute *ad7193_attributes[] = {
+ &iio_dev_attr_filter_low_pass_3db_frequency_available.dev_attr.attr,
+ &iio_dev_attr_bridge_switch_en.dev_attr.attr,
+ &iio_dev_attr_fast_settling_average_factor.dev_attr.attr,
+ &iio_dev_attr_fast_settling_average_factor_available.dev_attr.attr,
+ NULL
+};
+
+static const struct attribute_group ad7193_attribute_group = {
+ .attrs = ad7193_attributes,
+};
+
static struct attribute *ad7195_attributes[] = {
&iio_dev_attr_filter_low_pass_3db_frequency_available.dev_attr.attr,
&iio_dev_attr_bridge_switch_en.dev_attr.attr,
@@ -882,6 +974,16 @@ static const struct iio_info ad7192_info = {
.update_scan_mode = ad7192_update_scan_mode,
};

+static const struct iio_info ad7193_info = {
+ .read_raw = ad7192_read_raw,
+ .write_raw = ad7192_write_raw,
+ .write_raw_get_fmt = ad7192_write_raw_get_fmt,
+ .read_avail = ad7192_read_avail,
+ .attrs = &ad7193_attribute_group,
+ .validate_trigger = ad_sd_validate_trigger,
+ .update_scan_mode = ad7192_update_scan_mode,
+};
+
static const struct iio_info ad7195_info = {
.read_raw = ad7192_read_raw,
.write_raw = ad7192_write_raw,
@@ -1056,7 +1158,9 @@ static int ad7192_probe(struct spi_device *spi)
if (ret < 0)
return ret;

- if (st->chip_info->chip_id == CHIPID_AD7195)
+ if (st->chip_info->chip_id == CHIPID_AD7193)
+ indio_dev->info = &ad7193_info;
+ else if (st->chip_info->chip_id == CHIPID_AD7195)
indio_dev->info = &ad7195_info;
else
indio_dev->info = &ad7192_info;
--
2.34.1

Next message: Kent Overstreet: "Re: [PATCH] bcachefs: Use snprintf() instead of scnprintf() when appropriate"
Previous message: alisadariana: "[PATCH v2 2/3] iio: adc: ad7192: Improve f_order computation"
In reply to: alisadariana: "[PATCH v2 2/3] iio: adc: ad7192: Improve f_order computation"
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