iio: chemical: ens160: add triggered buffer support

ENS160 supports a data ready interrupt. Use it in combination with
triggered buffer for continuous data readings.
Signed-off-by: Gustavo Silva <gustavograzs@gmail.com>
Link: https://lore.kernel.org/r/20240604225747.7212-5-gustavograzs@gmail.comSigned-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

drivers/iio/chemical/ens160.h

@@ -2,6 +2,6 @@
 #ifndef ENS160_H_
 #define ENS160_H_
 
-int devm_ens160_core_probe(struct device *dev, struct regmap *regmap,
+int devm_ens160_core_probe(struct device *dev, struct regmap *regmap, int irq,
 			   const char *name);
 #endif

drivers/iio/chemical/ens160_core.c

@@ -10,6 +10,9 @@
 
 #include <linux/bitfield.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/module.h>
 #include <linux/regmap.h>
 
@@ -23,6 +26,11 @@
 
 #define ENS160_REG_OPMODE		0x10
 
+#define ENS160_REG_CONFIG		0x11
+#define ENS160_REG_CONFIG_INTEN		BIT(0)
+#define ENS160_REG_CONFIG_INTDAT	BIT(1)
+#define ENS160_REG_CONFIG_INT_CFG	BIT(5)
+
 #define ENS160_REG_MODE_DEEP_SLEEP	0x00
 #define ENS160_REG_MODE_IDLE		0x01
 #define ENS160_REG_MODE_STANDARD	0x02
@@ -48,7 +56,13 @@
 
 struct ens160_data {
 	struct regmap *regmap;
-	u8 fw_version[3] __aligned(IIO_DMA_MINALIGN);
+	/* Protect reads from the sensor */
+	struct mutex mutex;
+	struct {
+		__le16 chans[2];
+		s64 timestamp __aligned(8);
+	} scan __aligned(IIO_DMA_MINALIGN);
+	u8 fw_version[3];
 	__le16 buf;
 };
 
@@ -60,6 +74,13 @@ static const struct iio_chan_spec ens160_channels[] = {
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.address = ENS160_REG_DATA_TVOC,
+		.scan_index = 0,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_LE,
+		},
 	},
 	{
 		.type = IIO_CONCENTRATION,
@@ -68,7 +89,15 @@ static const struct iio_chan_spec ens160_channels[] = {
 		.info_mask_separate = BIT(IIO_CHAN_INFO_RAW) |
 				      BIT(IIO_CHAN_INFO_SCALE),
 		.address = ENS160_REG_DATA_ECO2,
+		.scan_index = 1,
+		.scan_type = {
+			.sign = 'u',
+			.realbits = 16,
+			.storagebits = 16,
+			.endianness = IIO_LE,
+		},
 	},
+	IIO_CHAN_SOFT_TIMESTAMP(2),
 };
 
 static int ens160_read_raw(struct iio_dev *indio_dev,
@@ -80,13 +109,16 @@ static int ens160_read_raw(struct iio_dev *indio_dev,
 
 	switch (mask) {
 	case IIO_CHAN_INFO_RAW:
-		ret = regmap_bulk_read(data->regmap, chan->address,
-				       &data->buf, sizeof(data->buf));
-		if (ret)
-			return ret;
-		*val = le16_to_cpu(data->buf);
-		return IIO_VAL_INT;
-
+		iio_device_claim_direct_scoped(return -EBUSY, indio_dev) {
+			guard(mutex)(&data->mutex);
+			ret = regmap_bulk_read(data->regmap, chan->address,
+					       &data->buf, sizeof(data->buf));
+			if (ret)
+				return ret;
+			*val = le16_to_cpu(data->buf);
+			return IIO_VAL_INT;
+		}
+		unreachable();
 	case IIO_CHAN_INFO_SCALE:
 		switch (chan->channel2) {
 		case IIO_MOD_CO2:
@@ -188,7 +220,83 @@ static const struct iio_info ens160_info = {
 	.read_raw = ens160_read_raw,
 };
 
-int devm_ens160_core_probe(struct device *dev, struct regmap *regmap,
+static irqreturn_t ens160_trigger_handler(int irq, void *p)
+{
+	struct iio_poll_func *pf = p;
+	struct iio_dev *indio_dev = pf->indio_dev;
+	struct ens160_data *data = iio_priv(indio_dev);
+	int ret;
+
+	guard(mutex)(&data->mutex);
+
+	ret = regmap_bulk_read(data->regmap, ENS160_REG_DATA_TVOC,
+			       data->scan.chans, sizeof(data->scan.chans));
+	if (ret)
+		goto err;
+
+	iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
+					   pf->timestamp);
+err:
+	iio_trigger_notify_done(indio_dev->trig);
+
+	return IRQ_HANDLED;
+}
+
+static int ens160_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct ens160_data *data = iio_priv(indio_dev);
+	unsigned int int_bits = ENS160_REG_CONFIG_INTEN |
+				ENS160_REG_CONFIG_INTDAT |
+				ENS160_REG_CONFIG_INT_CFG;
+
+	if (state)
+		return regmap_set_bits(data->regmap, ENS160_REG_CONFIG,
+				       int_bits);
+	else
+		return regmap_clear_bits(data->regmap, ENS160_REG_CONFIG,
+					 int_bits);
+}
+
+static const struct iio_trigger_ops ens160_trigger_ops = {
+	.set_trigger_state = ens160_set_trigger_state,
+	.validate_device = iio_trigger_validate_own_device,
+};
+
+static int ens160_setup_trigger(struct iio_dev *indio_dev, int irq)
+{
+	struct device *dev = indio_dev->dev.parent;
+	struct iio_trigger *trig;
+	int ret;
+
+	trig = devm_iio_trigger_alloc(dev, "%s-dev%d", indio_dev->name,
+				      iio_device_id(indio_dev));
+	if (!trig)
+		return dev_err_probe(dev, -ENOMEM,
+				     "failed to allocate trigger\n");
+
+	trig->ops = &ens160_trigger_ops;
+	iio_trigger_set_drvdata(trig, indio_dev);
+
+	ret = devm_iio_trigger_register(dev, trig);
+	if (ret)
+		return ret;
+
+	indio_dev->trig = iio_trigger_get(trig);
+
+	ret = devm_request_threaded_irq(dev, irq,
+					iio_trigger_generic_data_rdy_poll,
+					NULL,
+					IRQF_ONESHOT,
+					indio_dev->name,
+					indio_dev->trig);
+	if (ret)
+		return dev_err_probe(dev, ret, "failed to request irq\n");
+
+	return 0;
+}
+
+int devm_ens160_core_probe(struct device *dev, struct regmap *regmap, int irq,
 			   const char *name)
 {
 	struct ens160_data *data;
@@ -208,10 +316,25 @@ int devm_ens160_core_probe(struct device *dev, struct regmap *regmap,
 	indio_dev->channels = ens160_channels;
 	indio_dev->num_channels = ARRAY_SIZE(ens160_channels);
 
+	if (irq > 0) {
+		ret = ens160_setup_trigger(indio_dev, irq);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "failed to setup trigger\n");
+	}
+
 	ret = ens160_chip_init(data);
 	if (ret)
 		return dev_err_probe(dev, ret, "chip initialization failed\n");
 
+	mutex_init(&data->mutex);
+
+	ret = devm_iio_triggered_buffer_setup(dev, indio_dev,
+					      iio_pollfunc_store_time,
+					      ens160_trigger_handler, NULL);
+	if (ret)
+		return ret;
+
 	return devm_iio_device_register(dev, indio_dev);
 }
 EXPORT_SYMBOL_NS(devm_ens160_core_probe, IIO_ENS160);

drivers/iio/chemical/ens160_i2c.c

@@ -29,7 +29,8 @@ static int ens160_i2c_probe(struct i2c_client *client)
 		return dev_err_probe(&client->dev, PTR_ERR(regmap),
 				     "Failed to register i2c regmap\n");
 
-	return devm_ens160_core_probe(&client->dev, regmap, "ens160");
+	return devm_ens160_core_probe(&client->dev, regmap, client->irq,
+				      "ens160");
 }
 
 static const struct i2c_device_id ens160_i2c_id[] = {

drivers/iio/chemical/ens160_spi.c

@@ -29,7 +29,7 @@ static int ens160_spi_probe(struct spi_device *spi)
 		return dev_err_probe(&spi->dev, PTR_ERR(regmap),
 				     "Failed to register spi regmap\n");
 
-	return devm_ens160_core_probe(&spi->dev, regmap, "ens160");
+	return devm_ens160_core_probe(&spi->dev, regmap, spi->irq, "ens160");
 }
 
 static const struct of_device_id ens160_spi_of_match[] = {