Message-ID: <20251205-staging-ad4062-v3-7-8761355f9c66@analog.com>
Date: Fri, 5 Dec 2025 16:12:08 +0100
From: Jorge Marques <jorge.marques@...log.com>
To: Lars-Peter Clausen <lars@...afoo.de>,
        Michael Hennerich
	<Michael.Hennerich@...log.com>,
        Jonathan Cameron <jic23@...nel.org>,
        "David
 Lechner" <dlechner@...libre.com>,
        Nuno Sá
	<nuno.sa@...log.com>,
        Andy Shevchenko <andy@...nel.org>, Rob Herring
	<robh@...nel.org>,
        Krzysztof Kozlowski <krzk+dt@...nel.org>,
        Conor Dooley
	<conor+dt@...nel.org>, Jonathan Corbet <corbet@....net>,
        Linus Walleij
	<linus.walleij@...aro.org>,
        Bartosz Golaszewski <brgl@...ev.pl>
CC: <linux-iio@...r.kernel.org>, <devicetree@...r.kernel.org>,
        <linux-kernel@...r.kernel.org>, <linux-doc@...r.kernel.org>,
        <linux-gpio@...r.kernel.org>, Jorge Marques <jorge.marques@...log.com>
Subject: [PATCH v3 7/9] iio: adc: ad4062: Add IIO Events support

Adds support for IIO Events. Optionally, gp0 is assigned as Threshold
Either signal, if not present, fallback to an I3C IBI with the same
role.

Signed-off-by: Jorge Marques <jorge.marques@...log.com>
---
 drivers/iio/adc/ad4062.c | 376 ++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 372 insertions(+), 4 deletions(-)

diff --git a/drivers/iio/adc/ad4062.c b/drivers/iio/adc/ad4062.c
index 080dc80fd1621..e432aa60a224e 100644
--- a/drivers/iio/adc/ad4062.c
+++ b/drivers/iio/adc/ad4062.c
@@ -14,6 +14,7 @@
 #include <linux/i3c/device.h>
 #include <linux/i3c/master.h>
 #include <linux/iio/buffer.h>
+#include <linux/iio/events.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger.h>
@@ -52,14 +53,22 @@
 #define     AD4062_REG_ADC_CONFIG_SCALE_EN_MSK		BIT(4)
 #define AD4062_REG_AVG_CONFIG				0x23
 #define AD4062_REG_GP_CONF				0x24
+#define     AD4062_REG_GP_CONF_MODE_MSK_0		GENMASK(2, 0)
 #define     AD4062_REG_GP_CONF_MODE_MSK_1		GENMASK(6, 4)
 #define AD4062_REG_INTR_CONF				0x25
+#define     AD4062_REG_INTR_CONF_EN_MSK_0		GENMASK(1, 0)
 #define     AD4062_REG_INTR_CONF_EN_MSK_1		GENMASK(5, 4)
 #define AD4062_REG_TIMER_CONFIG				0x27
 #define     AD4062_REG_TIMER_CONFIG_FS_MASK		GENMASK(7, 4)
+#define AD4062_REG_MAX_LIMIT				0x29
+#define AD4062_REG_MIN_LIMIT				0x2B
+#define AD4062_REG_MAX_HYST				0x2C
+#define AD4062_REG_MIN_HYST				0x2D
 #define AD4062_REG_MON_VAL				0x2F
 #define AD4062_REG_ADC_IBI_EN				0x31
 #define AD4062_REG_ADC_IBI_EN_CONV_TRIGGER		BIT(2)
+#define AD4062_REG_ADC_IBI_EN_MAX			BIT(1)
+#define AD4062_REG_ADC_IBI_EN_MIN			BIT(0)
 #define AD4062_REG_FUSE_CRC				0x40
 #define AD4062_REG_DEVICE_STATUS			0x41
 #define     AD4062_REG_DEVICE_STATUS_DEVICE_RESET	BIT(6)
@@ -78,9 +87,13 @@
 #define AD4060_MAX_AVG		0x7
 #define AD4062_MAX_AVG		0xB
 
+#define AD4062_GP_INTR		0x1
 #define AD4062_GP_DRDY		0x2
 
+#define AD4062_LIMIT_BITS	11
+
 #define AD4062_INTR_EN_NEITHER	0x0
+#define AD4062_INTR_EN_EITHER	0x3
 
 #define AD4062_TCONV_NS		270
 
@@ -149,6 +162,7 @@ struct ad4062_state {
 	struct iio_dev *indio_dev;
 	struct i3c_device *i3cdev;
 	struct regmap *regmap;
+	bool wait_event;
 	int vref_uV;
 	unsigned int samp_freqs[ARRAY_SIZE(ad4062_conversion_freqs)];
 	bool gpo_irq[2];
@@ -158,6 +172,7 @@ struct ad4062_state {
 		u8 bytes[4];
 	} buf __aligned(IIO_DMA_MINALIGN);
 	u16 sampling_frequency;
+	u16 events_frequency;
 	u8 oversamp_ratio;
 	u8 reg_addr_conv;
 };
@@ -188,6 +203,26 @@ static const struct regmap_access_table ad4062_regmap_wr_table = {
 	.n_yes_ranges = ARRAY_SIZE(ad4062_regmap_wr_ranges),
 };
 
+static const struct iio_event_spec ad4062_events[] = {
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_EITHER,
+		.mask_shared_by_all = BIT(IIO_EV_INFO_ENABLE),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_RISING,
+		.mask_shared_by_all = BIT(IIO_EV_INFO_VALUE) |
+				      BIT(IIO_EV_INFO_HYSTERESIS),
+	},
+	{
+		.type = IIO_EV_TYPE_THRESH,
+		.dir = IIO_EV_DIR_FALLING,
+		.mask_shared_by_all = BIT(IIO_EV_INFO_VALUE) |
+				      BIT(IIO_EV_INFO_HYSTERESIS),
+	},
+};
+
 static int ad4062_conversion_frequency_set(struct ad4062_state *st, u8 val)
 {
 	return regmap_write(st->regmap, AD4062_REG_TIMER_CONFIG,
@@ -205,6 +240,8 @@ static int ad4062_conversion_frequency_set(struct ad4062_state *st, u8 val)
 	.info_mask_shared_by_all_available = BIT(IIO_CHAN_INFO_SAMP_FREQ),		\
 	.indexed = 1,									\
 	.channel = 0,									\
+	.event_spec = ad4062_events,							\
+	.num_event_specs = ARRAY_SIZE(ad4062_events),					\
 	.has_ext_scan_type = 1,								\
 	.ext_scan_type = ad4062_scan_type_##bits##_s,					\
 	.num_ext_scan_type = ARRAY_SIZE(ad4062_scan_type_##bits##_s),			\
@@ -224,6 +261,68 @@ static const struct ad4062_chip_info ad4062_chip_info = {
 	.max_avg = AD4062_MAX_AVG,
 };
 
+static ssize_t sampling_frequency_show(struct device *dev,
+				       struct device_attribute *attr, char *buf)
+{
+	struct ad4062_state *st = iio_priv(dev_to_iio_dev(dev));
+
+	return sysfs_emit(buf, "%d\n", ad4062_conversion_freqs[st->events_frequency]);
+}
+
+static ssize_t sampling_frequency_store(struct device *dev,
+					struct device_attribute *attr,
+					const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
+	struct ad4062_state *st = iio_priv(indio_dev);
+	int val, ret;
+
+	if (!iio_device_claim_direct(indio_dev))
+		return -EBUSY;
+	if (st->wait_event) {
+		ret = -EBUSY;
+		goto out_release;
+	}
+
+	ret = kstrtoint(buf, 10, &val);
+	if (ret < 0)
+		goto out_release;
+
+	st->events_frequency = find_closest_descending(val, ad4062_conversion_freqs,
+						       ARRAY_SIZE(ad4062_conversion_freqs));
+	ret = 0;
+
+out_release:
+	iio_device_release_direct(indio_dev);
+	return ret ?: len;
+}
+
+static IIO_DEVICE_ATTR_RW(sampling_frequency, 0);
+
+static ssize_t sampling_frequency_available_show(struct device *dev,
+						 struct device_attribute *attr,
+						 char *buf)
+{
+	int ret = 0;
+
+	for (u8 i = 0; i < ARRAY_SIZE(ad4062_conversion_freqs); i++)
+		ret += sysfs_emit_at(buf, ret, "%d%s", ad4062_conversion_freqs[i],
+				     i != (ARRAY_SIZE(ad4062_conversion_freqs) - 1) ? " " : "\n");
+	return ret;
+}
+
+static IIO_DEVICE_ATTR_RO(sampling_frequency_available, 0);
+
+static struct attribute *ad4062_event_attributes[] = {
+	&iio_dev_attr_sampling_frequency.dev_attr.attr,
+	&iio_dev_attr_sampling_frequency_available.dev_attr.attr,
+	NULL
+};
+
+static const struct attribute_group ad4062_event_attribute_group = {
+	.attrs = ad4062_event_attributes,
+};
+
 static int ad4062_set_oversampling_ratio(struct ad4062_state *st, unsigned int val)
 {
 	const u32 _max = GENMASK(st->chip->max_avg, 0)  + 1;
@@ -385,9 +484,12 @@ static int ad4062_setup(struct iio_dev *indio_dev, struct iio_chan_spec const *c
 	if (IS_ERR(scan_type))
 		return PTR_ERR(scan_type);
 
-	val = FIELD_PREP(AD4062_REG_GP_CONF_MODE_MSK_1, AD4062_GP_DRDY);
+	val = FIELD_PREP(AD4062_REG_GP_CONF_MODE_MSK_0, AD4062_GP_INTR) |
+	      FIELD_PREP(AD4062_REG_GP_CONF_MODE_MSK_1, AD4062_GP_DRDY);
+
 	ret = regmap_update_bits(st->regmap, AD4062_REG_GP_CONF,
-				 AD4062_REG_GP_CONF_MODE_MSK_1, val);
+				 AD4062_REG_GP_CONF_MODE_MSK_1 | AD4062_REG_GP_CONF_MODE_MSK_0,
+				 val);
 	if (ret)
 		return ret;
 
@@ -403,9 +505,11 @@ static int ad4062_setup(struct iio_dev *indio_dev, struct iio_chan_spec const *c
 	if (ret)
 		return ret;
 
-	val = FIELD_PREP(AD4062_REG_INTR_CONF_EN_MSK_1, AD4062_INTR_EN_NEITHER);
+	val = FIELD_PREP(AD4062_REG_INTR_CONF_EN_MSK_0, AD4062_INTR_EN_EITHER) |
+	      FIELD_PREP(AD4062_REG_INTR_CONF_EN_MSK_1, AD4062_INTR_EN_NEITHER);
 	ret = regmap_update_bits(st->regmap, AD4062_REG_INTR_CONF,
-				 AD4062_REG_INTR_CONF_EN_MSK_1, val);
+				 AD4062_REG_INTR_CONF_EN_MSK_0 | AD4062_REG_INTR_CONF_EN_MSK_1,
+				 val);
 	if (ret)
 		return ret;
 
@@ -414,6 +518,19 @@ static int ad4062_setup(struct iio_dev *indio_dev, struct iio_chan_spec const *c
 				 &st->buf.be16, sizeof(st->buf.be16));
 }
 
+static irqreturn_t ad4062_irq_handler_thresh(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+
+	iio_push_event(indio_dev,
+		       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, 0,
+					    IIO_EV_TYPE_THRESH,
+					    IIO_EV_DIR_EITHER),
+		       iio_get_time_ns(indio_dev));
+
+	return IRQ_HANDLED;
+}
+
 static irqreturn_t ad4062_irq_handler_drdy(int irq, void *private)
 {
 	struct iio_dev *indio_dev = private;
@@ -432,6 +549,14 @@ static void ad4062_ibi_handler(struct i3c_device *i3cdev,
 {
 	struct ad4062_state *st = i3cdev_get_drvdata(i3cdev);
 
+	if (st->wait_event) {
+		iio_push_event(st->indio_dev,
+			       IIO_UNMOD_EVENT_CODE(IIO_VOLTAGE, 0,
+						    IIO_EV_TYPE_THRESH,
+						    IIO_EV_DIR_EITHER),
+			       iio_get_time_ns(st->indio_dev));
+		return;
+	}
 	if (iio_buffer_enabled(st->indio_dev))
 		iio_trigger_poll_nested(st->trigger);
 	else
@@ -523,6 +648,24 @@ static int ad4062_request_irq(struct iio_dev *indio_dev)
 	struct device *dev = &st->i3cdev->dev;
 	int ret;
 
+	ret = fwnode_irq_get_byname(dev_fwnode(&st->i3cdev->dev), "gp0");
+	if (ret == -EPROBE_DEFER) {
+		return ret;
+	} else if (ret < 0) {
+		ret = regmap_update_bits(st->regmap, AD4062_REG_ADC_IBI_EN,
+					 AD4062_REG_ADC_IBI_EN_MAX | AD4062_REG_ADC_IBI_EN_MIN,
+					 AD4062_REG_ADC_IBI_EN_MAX | AD4062_REG_ADC_IBI_EN_MIN);
+		if (ret)
+			return ret;
+	} else {
+		ret = devm_request_threaded_irq(dev, ret, NULL,
+						ad4062_irq_handler_thresh,
+						IRQF_ONESHOT, indio_dev->name,
+						indio_dev);
+		if (ret)
+			return ret;
+	}
+
 	ret = fwnode_irq_get_byname(dev_fwnode(&st->i3cdev->dev), "gp1");
 	if (ret == -EPROBE_DEFER) {
 		return ret;
@@ -741,9 +884,14 @@ static int ad4062_read_raw(struct iio_dev *indio_dev,
 
 	if (!iio_device_claim_direct(indio_dev))
 		return -EBUSY;
+	if (st->wait_event) {
+		ret = -EBUSY;
+		goto out_release;
+	}
 
 	ret = ad4062_read_raw_dispatch(st, val, val2, info);
 
+out_release:
 	iio_device_release_direct(indio_dev);
 	return ret ?: IIO_VAL_INT;
 }
@@ -775,9 +923,219 @@ static int ad4062_write_raw(struct iio_dev *indio_dev,
 
 	if (!iio_device_claim_direct(indio_dev))
 		return -EBUSY;
+	if (st->wait_event) {
+		ret = -EBUSY;
+		goto out_release;
+	}
 
 	ret = ad4062_write_raw_dispatch(st, val, val2, info);
 
+out_release:
+	iio_device_release_direct(indio_dev);
+	return ret;
+}
+
+static int ad4062_monitor_mode_enable(struct ad4062_state *st)
+{
+	int ret;
+
+	ACQUIRE(pm_runtime_active_try_enabled, pm)(&st->i3cdev->dev);
+	ret = ACQUIRE_ERR(pm_runtime_active_try_enabled, &pm);
+	if (ret)
+		return ret;
+
+	ret = ad4062_conversion_frequency_set(st, st->events_frequency);
+	if (ret)
+		return ret;
+
+	ret = ad4062_set_operation_mode(st, AD4062_MONITOR_MODE);
+	if (ret)
+		return ret;
+
+	pm_runtime_get_noresume(&st->i3cdev->dev);
+	return 0;
+}
+
+static int ad4062_monitor_mode_disable(struct ad4062_state *st)
+{
+	pm_runtime_put_autosuspend(&st->i3cdev->dev);
+	return 0;
+}
+
+static int ad4062_read_event_config(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+
+	return st->wait_event;
+}
+
+static int ad4062_write_event_config(struct iio_dev *indio_dev,
+				     const struct iio_chan_spec *chan,
+				     enum iio_event_type type,
+				     enum iio_event_direction dir,
+				     bool state)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (!iio_device_claim_direct(indio_dev))
+		return -EBUSY;
+	if (st->wait_event == state)
+		ret = 0;
+	else if (state)
+		ret = ad4062_monitor_mode_enable(st);
+	else
+		ret = ad4062_monitor_mode_disable(st);
+	if (ret)
+		goto out_release;
+
+	st->wait_event = state;
+
+out_release:
+	iio_device_release_direct(indio_dev);
+	return ret;
+}
+
+static int __ad4062_read_event_info_value(struct ad4062_state *st,
+					  enum iio_event_direction dir, int *val)
+{
+	int ret;
+	u8 reg;
+
+	if (dir == IIO_EV_DIR_RISING)
+		reg = AD4062_REG_MAX_LIMIT;
+	else
+		reg = AD4062_REG_MIN_LIMIT;
+
+	ret = regmap_bulk_read(st->regmap, reg, &st->buf.be16,
+			       sizeof(st->buf.be16));
+	if (ret)
+		return ret;
+
+	*val = sign_extend32(get_unaligned_be16(st->buf.bytes),
+			     AD4062_LIMIT_BITS - 1);
+
+	return 0;
+}
+
+static int __ad4062_read_event_info_hysteresis(struct ad4062_state *st,
+					       enum iio_event_direction dir, int *val)
+{
+	u8 reg;
+
+	if (dir == IIO_EV_DIR_RISING)
+		reg = AD4062_REG_MAX_HYST;
+	else
+		reg = AD4062_REG_MIN_HYST;
+	return regmap_read(st->regmap, reg, val);
+}
+
+static int ad4062_read_event_value(struct iio_dev *indio_dev,
+				   const struct iio_chan_spec *chan,
+				   enum iio_event_type type,
+				   enum iio_event_direction dir,
+				   enum iio_event_info info, int *val,
+				   int *val2)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (!iio_device_claim_direct(indio_dev))
+		return -EBUSY;
+	if (st->wait_event) {
+		ret = -EBUSY;
+		goto out_release;
+	}
+
+	switch (info) {
+	case IIO_EV_INFO_VALUE:
+		ret = __ad4062_read_event_info_value(st, dir, val);
+		break;
+	case IIO_EV_INFO_HYSTERESIS:
+		ret = __ad4062_read_event_info_hysteresis(st, dir, val);
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+out_release:
+	iio_device_release_direct(indio_dev);
+	return ret ?: IIO_VAL_INT;
+}
+
+static int __ad4062_write_event_info_value(struct ad4062_state *st,
+					   enum iio_event_direction dir, int val)
+{
+	u8 reg;
+
+	if (val != sign_extend32(val, AD4062_LIMIT_BITS - 1))
+		return -EINVAL;
+	if (dir == IIO_EV_DIR_RISING)
+		reg = AD4062_REG_MAX_LIMIT;
+	else
+		reg = AD4062_REG_MIN_LIMIT;
+	put_unaligned_be16(val, st->buf.bytes);
+
+	return regmap_bulk_write(st->regmap, reg, &st->buf.be16,
+				 sizeof(st->buf.be16));
+}
+
+static int __ad4062_write_event_info_hysteresis(struct ad4062_state *st,
+						enum iio_event_direction dir, int val)
+{
+	u8 reg;
+
+	if (val > BIT(7) - 1)
+		return -EINVAL;
+	if (dir == IIO_EV_DIR_RISING)
+		reg = AD4062_REG_MAX_HYST;
+	else
+		reg = AD4062_REG_MIN_HYST;
+
+	return regmap_write(st->regmap, reg, val);
+}
+
+static int ad4062_write_event_value(struct iio_dev *indio_dev,
+				    const struct iio_chan_spec *chan,
+				    enum iio_event_type type,
+				    enum iio_event_direction dir,
+				    enum iio_event_info info, int val,
+				    int val2)
+{
+	struct ad4062_state *st = iio_priv(indio_dev);
+	int ret;
+
+	if (!iio_device_claim_direct(indio_dev))
+		return -EBUSY;
+	if (st->wait_event) {
+		ret = -EBUSY;
+		goto out_release;
+	}
+
+	switch (type) {
+	case IIO_EV_TYPE_THRESH:
+		switch (info) {
+		case IIO_EV_INFO_VALUE:
+			ret = __ad4062_write_event_info_value(st, dir, val);
+			break;
+		case IIO_EV_INFO_HYSTERESIS:
+			ret = __ad4062_write_event_info_hysteresis(st, dir, val);
+			break;
+		default:
+			ret = -EINVAL;
+			break;
+		}
+		break;
+	default:
+		ret = -EINVAL;
+		break;
+	}
+
+out_release:
 	iio_device_release_direct(indio_dev);
 	return ret;
 }
@@ -792,6 +1150,9 @@ static int ad4062_triggered_buffer_postenable(struct iio_dev *indio_dev)
 	if (ret)
 		return ret;
 
+	if (st->wait_event)
+		return -EBUSY;
+
 	ret = ad4062_set_operation_mode(st, st->mode);
 	if (ret)
 		return ret;
@@ -856,6 +1217,11 @@ static const struct iio_info ad4062_info = {
 	.read_raw = ad4062_read_raw,
 	.write_raw = ad4062_write_raw,
 	.read_avail = ad4062_read_avail,
+	.read_event_config = &ad4062_read_event_config,
+	.write_event_config = &ad4062_write_event_config,
+	.read_event_value = &ad4062_read_event_value,
+	.write_event_value = &ad4062_write_event_value,
+	.event_attrs = &ad4062_event_attribute_group,
 	.get_current_scan_type = &ad4062_get_current_scan_type,
 	.debugfs_reg_access = &ad4062_debugfs_reg_access,
 };
@@ -938,8 +1304,10 @@ static int ad4062_probe(struct i3c_device *i3cdev)
 				     "Failed to initialize regmap\n");
 
 	st->mode = AD4062_SAMPLE_MODE;
+	st->wait_event = false;
 	st->chip = chip;
 	st->sampling_frequency = 0;
+	st->events_frequency = 0;
 	st->oversamp_ratio = 0;
 	st->indio_dev = indio_dev;
 

-- 
2.51.1

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