[PATCH v2 0/3] iio: adc: ti-ads112c14: continuous mode support

[PATCH v2 0/3] iio: adc: ti-ads112c14: continuous mode support

[David Lechner (TI)]

The TI ADS112C14 ADC has a continuous mode where it can trigger
conversions using its own clock and signals that data is ready using
the /DRDY line. This allows capturing data at higher rates since it
avoids the settling time between conversions. But it is limited to only
being able to sample one channel at a time.

Users will be able to select between continuous and single-shot mode
for buffered reads by selecting the trigger. If the "own" trigger from
the /DRDY interrupt is selected, continuous mode will be used. Or if
some other (software) trigger is selected, single-shot mode will be used
as was already implemented before this series.

Supporting open-drain /DRDY is deferred for future work. In simple cases
we have just done a `drive-open-drain` DT property for this, but on this
chip there is more than one pin (GPIO, FAULT interrupt) that could also
need to be open-drain and not all at the same time.

Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
---
Changes in v2:
- Split out irq and poll code paths into separate functions.
- Split refactoring into separate patch.
- Use iio_validate_scan_mask_onehot().
- Just return immediately on error in buffer_predisable().
- Don't set default trigger.
- Code style improvements.
- Fixed null pointer dereference bug when no trigger.
- Link to v1: https://patch.msgid.link/20260724-iio-adc-ti-ads112c14-continuous-mode-v1-0-9eb0b7a4f020@baylibre.com

---
David Lechner (TI) (3):
      iio: adc: ti-ads112c14: add DRDY interrupt support
      iio: adc: ti-ads112c14: create data read helper functions
      iio: adc: ti-ads112c14: add continuous mode support

 drivers/iio/adc/ti-ads112c14.c | 296 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 267 insertions(+), 29 deletions(-)
---
base-commit: e0484d62e8e1cff75b210938be835ea6221bda59
change-id: 20260724-iio-adc-ti-ads112c14-continuous-mode-dd1580754609
prerequisite-change-id: 20260714-iio-adc-ti-ads112c14-buffered-read-41e5d1ca0dc3:v3
prerequisite-patch-id: ff8860e03c2f50d9502778dc5b62d26792ed6b65
prerequisite-patch-id: 267a53bbe8c25f05cfe1a448b1ad516cdb2c73d5

Best regards,
--  
David Lechner (TI) <dlechner@baylibre.com>

[PATCH v2 1/3] iio: adc: ti-ads112c14: add DRDY interrupt support

[David Lechner (TI)]

Add handling for the DRDY interrupt to wait for data ready events rather
than polling (only when it is wired up).

Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
---

Small note: the hard-coded 100 ms timeout will be replaced in a future
series with a dynamic value, so I didn't bother with a macro or comments
to explain why the value was chosen.

And passing indio_dev instead of data to irq is intentional as it will
be used in the next patch.
---
 drivers/iio/adc/ti-ads112c14.c | 105 +++++++++++++++++++++++++++++++++++++----
 1 file changed, 95 insertions(+), 10 deletions(-)

diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
index 8ad8caee0ff7..177f7064092e 100644
--- a/drivers/iio/adc/ti-ads112c14.c
+++ b/drivers/iio/adc/ti-ads112c14.c
@@ -10,6 +10,7 @@
 
 #include <linux/bitfield.h>
 #include <linux/cleanup.h>
+#include <linux/completion.h>
 #include <linux/crc8.h>
 #include <linux/delay.h>
 #include <linux/dev_printk.h>
@@ -19,6 +20,7 @@
 #include <linux/iio/iio.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
+#include <linux/interrupt.h>
 #include <linux/math64.h>
 #include <linux/minmax.h>
 #include <linux/module.h>
@@ -117,9 +119,15 @@
 #define   ADS112C14_GPIO_CFG_GPIO2_CFG			GENMASK(5, 4)
 #define   ADS112C14_GPIO_CFG_GPIO1_CFG			GENMASK(3, 2)
 #define   ADS112C14_GPIO_CFG_GPIO0_CFG			GENMASK(1, 0)
+#define     ADS112C14_GPIO_CFG_GPIO_CFG_DISABLED	  0
+#define     ADS112C14_GPIO_CFG_GPIO_CFG_INPUT		  1
+#define     ADS112C14_GPIO_CFG_GPIO_CFG_OUTPUT_PUSH_PULL  2
+#define     ADS112C14_GPIO_CFG_GPIO_CFG_OUTPUT_OPEN_DRAIN 3
 
 #define ADS112C14_REG_GPIO_DATA_OUTPUT			0x0C
 #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC		BIT(7)
+#define     ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC_DAT_OUT  0
+#define     ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC_DRDY	  1
 #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO2_SRC		BIT(6)
 #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO3_DAT_OUT	BIT(3)
 #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO2_DAT_OUT	BIT(2)
@@ -251,6 +259,8 @@ struct ads112c14_data {
 	struct regmap *regmap;
 	/* Synchronizes access to register value fields. */
 	struct mutex lock;
+	int drdy_irq;
+	struct completion drdy_completion;
 	bool i2c_crc_enabled;
 	u32 avdd_uV;
 	u32 ext_ref_uV;
@@ -265,6 +275,16 @@ struct ads112c14_data {
 						 ARRAY_SIZE(ads112c14_sys_mon_channels));
 };
 
+static irqreturn_t ads112c14_drdy_irq_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct ads112c14_data *data = iio_priv(indio_dev);
+
+	complete(&data->drdy_completion);
+
+	return IRQ_HANDLED;
+}
+
 static bool ads112c14_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
@@ -581,12 +601,50 @@ static int ads112c14_prepare_sys_mon_channel(struct ads112c14_data *data,
 	return 0;
 }
 
+static int ads112c14_wait_for_conversion_irq(struct ads112c14_data *data)
+{
+	unsigned long remaining;
+	int ret;
+
+	reinit_completion(&data->drdy_completion);
+	enable_irq(data->drdy_irq);
+
+	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
+			   ADS112C14_CONVERSION_CTRL_START);
+	if (ret)
+		goto out;
+
+	remaining = wait_for_completion_timeout(&data->drdy_completion,
+						msecs_to_jiffies(100));
+	ret = remaining ? 0 : -ETIMEDOUT;
+
+out:
+	disable_irq(data->drdy_irq);
+
+	return ret;
+}
+
+static int ads112c14_wait_for_conversion_poll(struct ads112c14_data *data)
+{
+	u32 reg_val;
+	int ret;
+
+	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
+			   ADS112C14_CONVERSION_CTRL_START);
+	if (ret)
+		return ret;
+
+	return regmap_read_poll_timeout(data->regmap,
+					ADS112C14_REG_STATUS_MSB, reg_val,
+					FIELD_GET(ADS112C14_STATUS_MSB_DRDY, reg_val),
+					1 * USEC_PER_MSEC, 100 * USEC_PER_MSEC);
+}
+
 static int ads112c14_single_conversion(struct ads112c14_data *data,
 				       const struct iio_chan_spec *chan,
 				       u8 *buf, bool for_scan)
 {
 	struct i2c_client *client = to_i2c_client(regmap_get_device(data->regmap));
-	u32 reg_val;
 	int ret;
 
 	guard(mutex)(&data->lock);
@@ -601,15 +659,10 @@ static int ads112c14_single_conversion(struct ads112c14_data *data,
 			return ret;
 	}
 
-	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
-			   ADS112C14_CONVERSION_CTRL_START);
-	if (ret)
-		return ret;
-
-	ret = regmap_read_poll_timeout(data->regmap,
-				       ADS112C14_REG_STATUS_MSB, reg_val,
-				       FIELD_GET(ADS112C14_STATUS_MSB_DRDY, reg_val),
-				       1 * USEC_PER_MSEC, 100 * USEC_PER_MSEC);
+	if (data->drdy_irq)
+		ret = ads112c14_wait_for_conversion_irq(data);
+	else
+		ret = ads112c14_wait_for_conversion_poll(data);
 	if (ret)
 		return ret;
 
@@ -1392,6 +1445,38 @@ static int ads112c14_probe(struct i2c_client *client)
 	if (ret)
 		return ret;
 
+	if (device_property_present(dev, "interrupts")) {
+		data->drdy_irq = fwnode_irq_get_byname(dev_fwnode(dev), "drdy");
+		if (data->drdy_irq < 0)
+			return dev_err_probe(dev, data->drdy_irq,
+					     "failed to get drdy interrupt\n");
+
+		/*
+		 * REVISIT: would probably need to implement a pin controller in
+		 * order to support open drain option here.
+		 */
+		ret = regmap_update_bits(data->regmap, ADS112C14_REG_GPIO_CFG,
+					 ADS112C14_GPIO_CFG_GPIO3_CFG,
+					 FIELD_PREP(ADS112C14_GPIO_CFG_GPIO3_CFG,
+						    ADS112C14_GPIO_CFG_GPIO_CFG_OUTPUT_PUSH_PULL));
+		if (ret)
+			return ret;
+
+		ret = regmap_update_bits(data->regmap, ADS112C14_REG_GPIO_DATA_OUTPUT,
+					 ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC,
+					 FIELD_PREP(ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC,
+						    ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC_DRDY));
+		if (ret)
+			return ret;
+
+		init_completion(&data->drdy_completion);
+
+		ret = devm_request_irq(dev, data->drdy_irq, ads112c14_drdy_irq_handler,
+				       IRQF_NO_AUTOEN, dev_name(dev), indio_dev);
+		if (ret)
+			return ret;
+	}
+
 	ads112c14_populate_tables(data);
 
 	indio_dev->name = info->name;

-- 
2.43.0

[PATCH v2 2/3] iio: adc: ti-ads112c14: create data read helper functions

[David Lechner (TI)]

Refactor a few bits of code into helper functions. These will be reused
when continuous mode support is added in a later patch.

Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
---
 drivers/iio/adc/ti-ads112c14.c | 51 +++++++++++++++++++++++++-----------------
 1 file changed, 31 insertions(+), 20 deletions(-)

diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
index 177f7064092e..c6d83298c312 100644
--- a/drivers/iio/adc/ti-ads112c14.c
+++ b/drivers/iio/adc/ti-ads112c14.c
@@ -601,6 +601,32 @@ static int ads112c14_prepare_sys_mon_channel(struct ads112c14_data *data,
 	return 0;
 }
 
+static int ads112c14_prepare_channel(struct ads112c14_data *data,
+				     const struct iio_chan_spec *chan)
+{
+	if (chan->channel < ADS112C14_SYS_MON_CHANNEL_BASE)
+		return ads112c14_prepare_measurement_channel(data, chan);
+
+	return ads112c14_prepare_sys_mon_channel(data, chan);
+}
+
+static int ads112c14_scan_read(struct ads112c14_data *data, u8 *buf)
+{
+	struct i2c_client *client = to_i2c_client(regmap_get_device(data->regmap));
+	int ret;
+	u8 len;
+
+	len = BITS_TO_BYTES(data->chip_info->resolution_bits);
+	if (data->i2c_crc_enabled)
+		len += 1;
+
+	ret = i2c_smbus_read_i2c_block_data(client, ADS112C14_CMD_RDATA, len, buf);
+	if (ret < 0)
+		return ret;
+
+	return 0;
+}
+
 static int ads112c14_wait_for_conversion_irq(struct ads112c14_data *data)
 {
 	unsigned long remaining;
@@ -649,15 +675,9 @@ static int ads112c14_single_conversion(struct ads112c14_data *data,
 
 	guard(mutex)(&data->lock);
 
-	if (chan->channel < ADS112C14_SYS_MON_CHANNEL_BASE) {
-		ret = ads112c14_prepare_measurement_channel(data, chan);
-		if (ret)
-			return ret;
-	} else {
-		ret = ads112c14_prepare_sys_mon_channel(data, chan);
-		if (ret)
-			return ret;
-	}
+	ret = ads112c14_prepare_channel(data, chan);
+	if (ret)
+		return ret;
 
 	if (data->drdy_irq)
 		ret = ads112c14_wait_for_conversion_irq(data);
@@ -672,17 +692,8 @@ static int ads112c14_single_conversion(struct ads112c14_data *data,
 	 * with CRC errors, but rather leave it to userspace to decide what to
 	 * do.
 	 */
-	if (for_scan) {
-		u8 len = BITS_TO_BYTES(data->chip_info->resolution_bits) +
-			 (data->i2c_crc_enabled ? 1 : 0);
-
-		ret = i2c_smbus_read_i2c_block_data(client, ADS112C14_CMD_RDATA,
-						    len, buf);
-		if (ret < 0)
-			return ret;
-
-		return 0;
-	}
+	if (for_scan)
+		return ads112c14_scan_read(data, buf);
 
 	return ads112c14_i2c_read_bytes(client, ADS112C14_CMD_RDATA, buf,
 					BITS_TO_BYTES(data->chip_info->resolution_bits),

-- 
2.43.0

[PATCH v2 3/3] iio: adc: ti-ads112c14: add continuous mode support

[David Lechner (TI)]

Add support for continuous mode in the TI ADS112C14 ADC driver. In this
mode the ADC itself is starting each conversion, so we add a trigger
based on the DRDY interrupt to read each sample. This mode is also
limited in that only one channel can be enabled at a time since the
chip does not have a sequencer or simultaneous sampling capability.
Continuous mode will only be used when this new trigger is the current
trigger.

Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
---
 drivers/iio/adc/ti-ads112c14.c | 146 ++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 144 insertions(+), 2 deletions(-)

diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
index c6d83298c312..5147d10785fb 100644
--- a/drivers/iio/adc/ti-ads112c14.c
+++ b/drivers/iio/adc/ti-ads112c14.c
@@ -9,6 +9,7 @@
  */
 
 #include <linux/bitfield.h>
+#include <linux/bitmap.h>
 #include <linux/cleanup.h>
 #include <linux/completion.h>
 #include <linux/crc8.h>
@@ -18,6 +19,7 @@
 #include <linux/i2c.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
+#include <linux/iio/trigger.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/interrupt.h>
@@ -257,6 +259,7 @@ struct ads112c14_measurement {
 struct ads112c14_data {
 	const struct ads112c14_chip_info *chip_info;
 	struct regmap *regmap;
+	struct iio_trigger *drdy_trig;
 	/* Synchronizes access to register value fields. */
 	struct mutex lock;
 	int drdy_irq;
@@ -280,11 +283,32 @@ static irqreturn_t ads112c14_drdy_irq_handler(int irq, void *private)
 	struct iio_dev *indio_dev = private;
 	struct ads112c14_data *data = iio_priv(indio_dev);
 
-	complete(&data->drdy_completion);
+	if (indio_dev->trig && iio_trigger_using_own(indio_dev))
+		iio_trigger_poll(data->drdy_trig);
+	else
+		complete(&data->drdy_completion);
 
 	return IRQ_HANDLED;
 }
 
+static int ads112c14_trigger_set_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct ads112c14_data *data = iio_priv(indio_dev);
+
+	if (state)
+		enable_irq(data->drdy_irq);
+	else
+		disable_irq(data->drdy_irq);
+
+	return 0;
+}
+
+static const struct iio_trigger_ops ads112c14_trigger_ops = {
+	.set_trigger_state = ads112c14_trigger_set_state,
+	.validate_device = iio_trigger_validate_own_device,
+};
+
 static bool ads112c14_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
@@ -962,10 +986,31 @@ static irqreturn_t ads112c14_trigger_handler(int irq, void *private)
 	struct iio_poll_func *pf = private;
 	struct iio_dev *indio_dev = pf->indio_dev;
 	struct ads112c14_data *data = iio_priv(indio_dev);
+	unsigned int scan_mask_len = iio_get_masklength(indio_dev);
 	u32 offset = 0;
 	u32 i;
 	int ret;
 
+	if (iio_trigger_using_own(indio_dev)) {
+		i = find_first_bit(indio_dev->active_scan_mask, scan_mask_len);
+		if (i >= scan_mask_len)
+			goto out;
+
+		ret = ads112c14_scan_read(data, (u8 *)&data->scan[0]);
+		if (ret) {
+			const struct iio_chan_spec *chan = &indio_dev->channels[i];
+
+			dev_err_once(indio_dev->dev.parent,
+				     "failed to read channel %d: %pe; additional errors will be suppressed\n",
+				     chan->channel, ERR_PTR(ret));
+			goto out;
+		}
+
+		iio_push_to_buffers_with_ts(indio_dev, data->scan,
+					    sizeof(data->scan), pf->timestamp);
+		goto out;
+	}
+
 	iio_for_each_active_channel(indio_dev, i) {
 		const struct iio_chan_spec *chan = &indio_dev->channels[i];
 
@@ -997,6 +1042,89 @@ static const struct iio_info ads112c14_info = {
 	.read_label = ads112c14_read_label,
 };
 
+static bool ads112c14_using_drdy_trigger(struct iio_dev *indio_dev)
+{
+	struct ads112c14_data *data = iio_priv(indio_dev);
+
+	return data->drdy_trig && indio_dev->trig == data->drdy_trig;
+}
+
+static bool ads112c14_validate_scan_mask(struct iio_dev *indio_dev,
+					 const unsigned long *mask)
+{
+	if (!ads112c14_using_drdy_trigger(indio_dev))
+		return true;
+
+	return iio_validate_scan_mask_onehot(indio_dev, mask);
+}
+
+static int ads112c14_buffer_postenable(struct iio_dev *indio_dev)
+{
+	unsigned int scan_mask_len = iio_get_masklength(indio_dev);
+	struct ads112c14_data *data = iio_priv(indio_dev);
+	const struct iio_chan_spec *chan;
+	unsigned int i;
+	int ret;
+
+	if (!ads112c14_using_drdy_trigger(indio_dev))
+		return 0;
+
+	i = find_first_bit(indio_dev->active_scan_mask, scan_mask_len);
+	if (i >= scan_mask_len)
+		return -EINVAL;
+
+	chan = &indio_dev->channels[i];
+
+	guard(mutex)(&data->lock);
+
+	ret = ads112c14_prepare_channel(data, chan);
+	if (ret)
+		return ret;
+
+	ret = regmap_assign_bits(data->regmap, ADS112C14_REG_DEVICE_CFG,
+				 ADS112C14_DEVICE_CFG_CONV_MODE,
+				 ADS112C14_DEVICE_CFG_CONV_MODE_CONTINUOUS);
+	if (ret)
+		return ret;
+
+	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
+			   ADS112C14_CONVERSION_CTRL_START);
+	if (ret) {
+		regmap_assign_bits(data->regmap, ADS112C14_REG_DEVICE_CFG,
+				   ADS112C14_DEVICE_CFG_CONV_MODE,
+				   ADS112C14_DEVICE_CFG_CONV_MODE_SINGLE_SHOT);
+		return ret;
+	}
+
+	return 0;
+}
+
+static int ads112c14_buffer_predisable(struct iio_dev *indio_dev)
+{
+	struct ads112c14_data *data = iio_priv(indio_dev);
+	int ret;
+
+	if (!ads112c14_using_drdy_trigger(indio_dev))
+		return 0;
+
+	guard(mutex)(&data->lock);
+
+	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
+			   ADS112C14_CONVERSION_CTRL_STOP);
+	if (ret)
+		return ret;
+
+	return regmap_assign_bits(data->regmap, ADS112C14_REG_DEVICE_CFG,
+				  ADS112C14_DEVICE_CFG_CONV_MODE,
+				  ADS112C14_DEVICE_CFG_CONV_MODE_SINGLE_SHOT);
+}
+
+static const struct iio_buffer_setup_ops ads112c14_buffer_setup_ops = {
+	.postenable = ads112c14_buffer_postenable,
+	.predisable = ads112c14_buffer_predisable,
+	.validate_scan_mask = ads112c14_validate_scan_mask,
+};
+
 static int ads112c14_populate_idac_mag(u32 current_nA, u8 *idac_mag)
 {
 	u32 current_uA = current_nA / (NANO / MICRO);
@@ -1486,6 +1614,19 @@ static int ads112c14_probe(struct i2c_client *client)
 				       IRQF_NO_AUTOEN, dev_name(dev), indio_dev);
 		if (ret)
 			return ret;
+
+		data->drdy_trig = devm_iio_trigger_alloc(dev, "%s-dev%d-drdy",
+							 info->name,
+							 iio_device_id(indio_dev));
+		if (!data->drdy_trig)
+			return -ENOMEM;
+
+		data->drdy_trig->ops = &ads112c14_trigger_ops;
+		iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
+
+		ret = devm_iio_trigger_register(dev, data->drdy_trig);
+		if (ret)
+			return ret;
 	}
 
 	ads112c14_populate_tables(data);
@@ -1496,7 +1637,8 @@ static int ads112c14_probe(struct i2c_client *client)
 
 	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
 					      iio_pollfunc_store_time,
-					      ads112c14_trigger_handler, NULL);
+					      ads112c14_trigger_handler,
+					      &ads112c14_buffer_setup_ops);
 	if (ret)
 		return ret;
 

-- 
2.43.0

Re: [PATCH v2 1/3] iio: adc: ti-ads112c14: add DRDY interrupt support

[Jonathan Cameron]

On Fri, 31 Jul 2026 18:48:10 -0500
"David Lechner (TI)" <dlechner@baylibre.com> wrote:

> Add handling for the DRDY interrupt to wait for data ready events rather
> than polling (only when it is wired up).
> 
> Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>

Repeating discussion from other thread a bit just so people can find it.

> ---
> 
> Small note: the hard-coded 100 ms timeout will be replaced in a future
> series with a dynamic value, so I didn't bother with a macro or comments
> to explain why the value was chosen.
> 
> And passing indio_dev instead of data to irq is intentional as it will
> be used in the next patch.
> ---
>  drivers/iio/adc/ti-ads112c14.c | 105 +++++++++++++++++++++++++++++++++++++----
>  1 file changed, 95 insertions(+), 10 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
> index 8ad8caee0ff7..177f7064092e 100644
> --- a/drivers/iio/adc/ti-ads112c14.c
> +++ b/drivers/iio/adc/ti-ads112c14.c
> @@ -10,6 +10,7 @@
>  
>  #include <linux/bitfield.h>
>  #include <linux/cleanup.h>
> +#include <linux/completion.h>
>  #include <linux/crc8.h>
>  #include <linux/delay.h>
>  #include <linux/dev_printk.h>
> @@ -19,6 +20,7 @@
>  #include <linux/iio/iio.h>
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/triggered_buffer.h>
> +#include <linux/interrupt.h>
>  #include <linux/math64.h>
>  #include <linux/minmax.h>
>  #include <linux/module.h>
> @@ -117,9 +119,15 @@
>  #define   ADS112C14_GPIO_CFG_GPIO2_CFG			GENMASK(5, 4)
>  #define   ADS112C14_GPIO_CFG_GPIO1_CFG			GENMASK(3, 2)
>  #define   ADS112C14_GPIO_CFG_GPIO0_CFG			GENMASK(1, 0)
> +#define     ADS112C14_GPIO_CFG_GPIO_CFG_DISABLED	  0
> +#define     ADS112C14_GPIO_CFG_GPIO_CFG_INPUT		  1
> +#define     ADS112C14_GPIO_CFG_GPIO_CFG_OUTPUT_PUSH_PULL  2
> +#define     ADS112C14_GPIO_CFG_GPIO_CFG_OUTPUT_OPEN_DRAIN 3
>  
>  #define ADS112C14_REG_GPIO_DATA_OUTPUT			0x0C
>  #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC		BIT(7)
> +#define     ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC_DAT_OUT  0
> +#define     ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC_DRDY	  1
>  #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO2_SRC		BIT(6)
>  #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO3_DAT_OUT	BIT(3)
>  #define   ADS112C14_GPIO_DATA_OUTPUT_GPIO2_DAT_OUT	BIT(2)
> @@ -251,6 +259,8 @@ struct ads112c14_data {
>  	struct regmap *regmap;
>  	/* Synchronizes access to register value fields. */
>  	struct mutex lock;
> +	int drdy_irq;
> +	struct completion drdy_completion;
>  	bool i2c_crc_enabled;
>  	u32 avdd_uV;
>  	u32 ext_ref_uV;
> @@ -265,6 +275,16 @@ struct ads112c14_data {
>  						 ARRAY_SIZE(ads112c14_sys_mon_channels));
>  };
>  
> +static irqreturn_t ads112c14_drdy_irq_handler(int irq, void *private)
> +{
> +	struct iio_dev *indio_dev = private;
> +	struct ads112c14_data *data = iio_priv(indio_dev);

This should probably be defending against spurious interrupts by checking
the status register.  Ideally that would be in a threaded handler to avoid
a retry loop and race conditions around the completion.

i.e. we should know it is our interrupt for sure before complete()


The interrupt lets us skip polling (unless we do get a spurious) in favour
of just checking the status once after the interrupt gives us a strong
indication it should be set.

> +
> +	complete(&data->drdy_completion);
> +
> +	return IRQ_HANDLED;
> +}
> +
>  static bool ads112c14_writeable_reg(struct device *dev, unsigned int reg)
>  {
>  	switch (reg) {
> @@ -581,12 +601,50 @@ static int ads112c14_prepare_sys_mon_channel(struct ads112c14_data *data,
>  	return 0;
>  }
>  
> +static int ads112c14_wait_for_conversion_irq(struct ads112c14_data *data)
> +{
> +	unsigned long remaining;
> +	int ret;
> +
> +	reinit_completion(&data->drdy_completion);
> +	enable_irq(data->drdy_irq);

With the status register check I don't think we need to be doing this fine
grained host side control of the interrupt enable.  They tend to be
a bit unpredictable.  So if we had seen an interrupt when it was disabled
you might immediately see it fire upon enabling here before you call
the start.

> +
> +	ret = regmap_write(data->regmap, ADS112C14_REG_CONVERSION_CTRL,
> +			   ADS112C14_CONVERSION_CTRL_START);
> +	if (ret)
> +		goto out;

Plus side of getting rid of the enable disable dance, is you can return directly
here giving us simpler code flow.

> +
> +	remaining = wait_for_completion_timeout(&data->drdy_completion,
> +						msecs_to_jiffies(100));
> +	ret = remaining ? 0 : -ETIMEDOUT;
> +
> +out:
> +	disable_irq(data->drdy_irq);
> +
> +	return ret;
> +}



> @@ -1392,6 +1445,38 @@ static int ads112c14_probe(struct i2c_client *client)
>  	if (ret)
>  		return ret;
>  
> +	if (device_property_present(dev, "interrupts")) {
> +		data->drdy_irq = fwnode_irq_get_byname(dev_fwnode(dev), "drdy");
> +		if (data->drdy_irq < 0)
> +			return dev_err_probe(dev, data->drdy_irq,
> +					     "failed to get drdy interrupt\n");
> +
> +		/*
> +		 * REVISIT: would probably need to implement a pin controller in
> +		 * order to support open drain option here.
> +		 */
> +		ret = regmap_update_bits(data->regmap, ADS112C14_REG_GPIO_CFG,
> +					 ADS112C14_GPIO_CFG_GPIO3_CFG,
> +					 FIELD_PREP(ADS112C14_GPIO_CFG_GPIO3_CFG,
> +						    ADS112C14_GPIO_CFG_GPIO_CFG_OUTPUT_PUSH_PULL));
> +		if (ret)
> +			return ret;
> +
> +		ret = regmap_update_bits(data->regmap, ADS112C14_REG_GPIO_DATA_OUTPUT,
> +					 ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC,
> +					 FIELD_PREP(ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC,
> +						    ADS112C14_GPIO_DATA_OUTPUT_GPIO3_SRC_DRDY));
> +		if (ret)
> +			return ret;
> +
> +		init_completion(&data->drdy_completion);
> +
> +		ret = devm_request_irq(dev, data->drdy_irq, ads112c14_drdy_irq_handler,
> +				       IRQF_NO_AUTOEN, dev_name(dev), indio_dev);
As above (and you pointed out in that other thread) IRQF_NO_AUTOEN is probably
not appropriate here as we aren't supposed to see interrupts until we ask the device
to do something.

> +		if (ret)
> +			return ret;
> +	}
> +
>  	ads112c14_populate_tables(data);
>  
>  	indio_dev->name = info->name;
> 

Re: [PATCH v2 3/3] iio: adc: ti-ads112c14: add continuous mode support

[Jonathan Cameron]

On Fri, 31 Jul 2026 18:48:12 -0500
"David Lechner (TI)" <dlechner@baylibre.com> wrote:

> Add support for continuous mode in the TI ADS112C14 ADC driver. In this
> mode the ADC itself is starting each conversion, so we add a trigger
> based on the DRDY interrupt to read each sample. This mode is also
> limited in that only one channel can be enabled at a time since the
> chip does not have a sequencer or simultaneous sampling capability.
> Continuous mode will only be used when this new trigger is the current
> trigger.
> 
> Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
There is some follow on stuff in here from the earlier suggestion to
check the status register even when datardy involved

> ---
>  drivers/iio/adc/ti-ads112c14.c | 146 ++++++++++++++++++++++++++++++++++++++++-
>  1 file changed, 144 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
> index c6d83298c312..5147d10785fb 100644
> --- a/drivers/iio/adc/ti-ads112c14.c
> +++ b/drivers/iio/adc/ti-ads112c14.c
> @@ -9,6 +9,7 @@
>   */
>  
>  #include <linux/bitfield.h>
> +#include <linux/bitmap.h>
>  #include <linux/cleanup.h>
>  #include <linux/completion.h>
>  #include <linux/crc8.h>
> @@ -18,6 +19,7 @@
>  #include <linux/i2c.h>
>  #include <linux/iio/buffer.h>
>  #include <linux/iio/iio.h>
> +#include <linux/iio/trigger.h>
>  #include <linux/iio/trigger_consumer.h>
>  #include <linux/iio/triggered_buffer.h>
>  #include <linux/interrupt.h>
> @@ -257,6 +259,7 @@ struct ads112c14_measurement {
>  struct ads112c14_data {
>  	const struct ads112c14_chip_info *chip_info;
>  	struct regmap *regmap;
> +	struct iio_trigger *drdy_trig;
>  	/* Synchronizes access to register value fields. */
>  	struct mutex lock;
>  	int drdy_irq;
> @@ -280,11 +283,32 @@ static irqreturn_t ads112c14_drdy_irq_handler(int irq, void *private)
>  	struct iio_dev *indio_dev = private;
>  	struct ads112c14_data *data = iio_priv(indio_dev);
>  
> -	complete(&data->drdy_completion);
> +	if (indio_dev->trig && iio_trigger_using_own(indio_dev))
> +		iio_trigger_poll(data->drdy_trig);

Even for this path we should be checking it wasn't a spurious interrupt.
If that's happening in a threaded interrupt we'll then call iio_trigger_poll_nested()
and the handler will happen in the interrupt thread.   So the overhead
of that check should just be the check.

> +	else
> +		complete(&data->drdy_completion);

For this single shot read we are probably less bothered by overhead so
moving this to a thread should be fine I think.

>  
>  	return IRQ_HANDLED;
>  }
>  
> +static int ads112c14_trigger_set_state(struct iio_trigger *trig, bool state)
> +{
> +	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
> +	struct ads112c14_data *data = iio_priv(indio_dev);
> +
> +	if (state)
> +		enable_irq(data->drdy_irq);
> +	else
> +		disable_irq(data->drdy_irq);
> +

So do we need to do this to avoid some condition, or is this the defensive
stuff you pointed out in that other thread?

I'd normally expect a dataready trigger to be controlling if the interrupt
is generated at all rather than masking host end.

> +	return 0;
> +}
> +
> +static const struct iio_trigger_ops ads112c14_trigger_ops = {
> +	.set_trigger_state = ads112c14_trigger_set_state,
> +	.validate_device = iio_trigger_validate_own_device,
> +};
> +

Re: [PATCH v2 3/3] iio: adc: ti-ads112c14: add continuous mode support

[David Lechner]

On 8/2/26 1:17 PM, Jonathan Cameron wrote:
> On Fri, 31 Jul 2026 18:48:12 -0500
> "David Lechner (TI)" <dlechner@baylibre.com> wrote:
> 
>> Add support for continuous mode in the TI ADS112C14 ADC driver. In this
>> mode the ADC itself is starting each conversion, so we add a trigger
>> based on the DRDY interrupt to read each sample. This mode is also
>> limited in that only one channel can be enabled at a time since the
>> chip does not have a sequencer or simultaneous sampling capability.
>> Continuous mode will only be used when this new trigger is the current
>> trigger.
>>
>> Signed-off-by: David Lechner (TI) <dlechner@baylibre.com>
> There is some follow on stuff in here from the earlier suggestion to
> check the status register even when datardy involved
> 
>> ---
>>  drivers/iio/adc/ti-ads112c14.c | 146 ++++++++++++++++++++++++++++++++++++++++-
>>  1 file changed, 144 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/iio/adc/ti-ads112c14.c b/drivers/iio/adc/ti-ads112c14.c
>> index c6d83298c312..5147d10785fb 100644
>> --- a/drivers/iio/adc/ti-ads112c14.c
>> +++ b/drivers/iio/adc/ti-ads112c14.c
>> @@ -9,6 +9,7 @@
>>   */
>>  
>>  #include <linux/bitfield.h>
>> +#include <linux/bitmap.h>
>>  #include <linux/cleanup.h>
>>  #include <linux/completion.h>
>>  #include <linux/crc8.h>
>> @@ -18,6 +19,7 @@
>>  #include <linux/i2c.h>
>>  #include <linux/iio/buffer.h>
>>  #include <linux/iio/iio.h>
>> +#include <linux/iio/trigger.h>
>>  #include <linux/iio/trigger_consumer.h>
>>  #include <linux/iio/triggered_buffer.h>
>>  #include <linux/interrupt.h>
>> @@ -257,6 +259,7 @@ struct ads112c14_measurement {
>>  struct ads112c14_data {
>>  	const struct ads112c14_chip_info *chip_info;
>>  	struct regmap *regmap;
>> +	struct iio_trigger *drdy_trig;
>>  	/* Synchronizes access to register value fields. */
>>  	struct mutex lock;
>>  	int drdy_irq;
>> @@ -280,11 +283,32 @@ static irqreturn_t ads112c14_drdy_irq_handler(int irq, void *private)
>>  	struct iio_dev *indio_dev = private;
>>  	struct ads112c14_data *data = iio_priv(indio_dev);
>>  
>> -	complete(&data->drdy_completion);
>> +	if (indio_dev->trig && iio_trigger_using_own(indio_dev))
>> +		iio_trigger_poll(data->drdy_trig);
> 
> Even for this path we should be checking it wasn't a spurious interrupt.
> If that's happening in a threaded interrupt we'll then call iio_trigger_poll_nested()
> and the handler will happen in the interrupt thread.   So the overhead
> of that check should just be the check.
> 
For now, I think we'll not bother with checking for spurious interrupts.
The only reason it should happen is electrical noise (or disconnecting
wires on a live system). And we can add it in a follow up patch if we
decide we need it. The overhead of an extra read for each sample might be
a bit much at the higher sample rates. So we'll want to implement the
higher sample rates first anyway.

We can read the status along with the data in a single transfer, so that
might be a more efficient way to do it too.