[PATCH v3 3/4] iio: mpl3115: add support for DRDY interrupt

[Antoni Pokusinski <apokusinski01@gmail.com>]

MPL3115 sensor features a "data ready" interrupt which indicates the
presence of new measurements.

Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
---
 drivers/iio/pressure/mpl3115.c | 197 ++++++++++++++++++++++++++++++---
 1 file changed, 184 insertions(+), 13 deletions(-)

diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
index 80af672f65c6..13c8b338a15e 100644
--- a/drivers/iio/pressure/mpl3115.c
+++ b/drivers/iio/pressure/mpl3115.c
@@ -7,49 +7,77 @@
  * (7-bit I2C slave address 0x60)
  *
  * TODO: FIFO buffer, altimeter mode, oversampling, continuous mode,
- * interrupts, user offset correction, raw mode
+ * user offset correction, raw mode
  */
 
 #include <linux/cleanup.h>
 #include <linux/delay.h>
 #include <linux/i2c.h>
 #include <linux/module.h>
+#include <linux/property.h>
 
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/triggered_buffer.h>
+#include <linux/iio/trigger.h>
 
 #define MPL3115_STATUS 0x00
 #define MPL3115_OUT_PRESS 0x01 /* MSB first, 20 bit */
 #define MPL3115_OUT_TEMP 0x04 /* MSB first, 12 bit */
 #define MPL3115_WHO_AM_I 0x0c
+#define MPL3115_INT_SOURCE 0x12
+#define MPL3115_PT_DATA_CFG 0x13
 #define MPL3115_CTRL_REG1 0x26
+#define MPL3115_CTRL_REG3 0x28
+#define MPL3115_CTRL_REG4 0x29
+#define MPL3115_CTRL_REG5 0x2a
 
 #define MPL3115_DEVICE_ID 0xc4
 
 #define MPL3115_STATUS_PRESS_RDY BIT(2)
 #define MPL3115_STATUS_TEMP_RDY BIT(1)
 
-#define MPL3115_CTRL_RESET BIT(2) /* software reset */
-#define MPL3115_CTRL_OST BIT(1) /* initiate measurement */
-#define MPL3115_CTRL_ACTIVE BIT(0) /* continuous measurement */
-#define MPL3115_CTRL_OS_258MS (BIT(5) | BIT(4)) /* 64x oversampling */
+#define MPL3115_INT_SRC_DRDY BIT(7)
+
+#define MPL3115_PT_DATA_EVENT_ALL GENMASK(2, 0)
+
+#define MPL3115_CTRL1_RESET BIT(2) /* software reset */
+#define MPL3115_CTRL1_OST BIT(1) /* initiate measurement */
+#define MPL3115_CTRL1_ACTIVE BIT(0) /* continuous measurement */
+#define MPL3115_CTRL1_OS_258MS GENMASK(5, 4) /* 64x oversampling */
+
+#define MPL3115_CTRL3_IPOL1 BIT(5)
+#define MPL3115_CTRL3_IPOL2 BIT(1)
+
+#define MPL3115_CTRL4_INT_EN_DRDY BIT(7)
+
+#define MPL3115_CTRL5_INT_CFG_DRDY BIT(7)
+
+#define MPL3115_INT2 BIT(2) /* flag that indicates INT2 in use */
 
 struct mpl3115_data {
 	struct i2c_client *client;
+	struct iio_trigger *drdy_trig;
 	struct mutex lock;
 	u8 ctrl_reg1;
 };
 
+enum mpl3115_irq_type {
+	INT2_ACTIVE_LOW  = MPL3115_INT2 | IRQF_TRIGGER_FALLING,
+	INT2_ACTIVE_HIGH = MPL3115_INT2 | IRQF_TRIGGER_RISING,
+	INT1_ACTIVE_LOW  = (!MPL3115_INT2) | IRQF_TRIGGER_FALLING,
+	INT1_ACTIVE_HIGH = (!MPL3115_INT2) | IRQF_TRIGGER_RISING,
+};
+
 static int mpl3115_request(struct mpl3115_data *data)
 {
 	int ret, tries = 15;
 
 	/* trigger measurement */
 	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
-		data->ctrl_reg1 | MPL3115_CTRL_OST);
+		data->ctrl_reg1 | MPL3115_CTRL1_OST);
 	if (ret < 0)
 		return ret;
 
@@ -58,7 +86,7 @@ static int mpl3115_request(struct mpl3115_data *data)
 		if (ret < 0)
 			return ret;
 		/* wait for data ready, i.e. OST cleared */
-		if (!(ret & MPL3115_CTRL_OST))
+		if (!(ret & MPL3115_CTRL1_OST))
 			break;
 		msleep(20);
 	}
@@ -166,9 +194,11 @@ static irqreturn_t mpl3115_trigger_handler(int irq, void *p)
 	int ret, pos = 0;
 
 	scoped_guard(mutex, &data->lock) {
-		ret = mpl3115_request(data);
-		if (ret < 0)
-			goto done;
+		if (!(data->ctrl_reg1 & MPL3115_CTRL1_ACTIVE)) {
+			ret = mpl3115_request(data);
+			if (ret < 0)
+				goto done;
+		}
 
 		if (test_bit(0, indio_dev->active_scan_mask)) {
 			ret = i2c_smbus_read_i2c_block_data(data->client,
@@ -224,10 +254,147 @@ static const struct iio_chan_spec mpl3115_channels[] = {
 	IIO_CHAN_SOFT_TIMESTAMP(2),
 };
 
+static irqreturn_t mpl3115_interrupt_handler(int irq, void *private)
+{
+	struct iio_dev *indio_dev = private;
+	struct mpl3115_data *data = iio_priv(indio_dev);
+	int ret;
+
+	ret = i2c_smbus_read_byte_data(data->client, MPL3115_INT_SOURCE);
+	if (ret < 0)
+		return IRQ_HANDLED;
+
+	if (!(ret & MPL3115_INT_SRC_DRDY))
+		return IRQ_NONE;
+
+	iio_trigger_poll_nested(data->drdy_trig);
+
+	return IRQ_HANDLED;
+}
+
+static int mpl3115_set_trigger_state(struct iio_trigger *trig, bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct mpl3115_data *data = iio_priv(indio_dev);
+	int ret;
+	u8 ctrl_reg1 = data->ctrl_reg1;
+
+	if (state)
+		ctrl_reg1 |= MPL3115_CTRL1_ACTIVE;
+	else
+		ctrl_reg1 &= ~MPL3115_CTRL1_ACTIVE;
+
+	guard(mutex)(&data->lock);
+
+	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
+					ctrl_reg1);
+	if (ret < 0)
+		return ret;
+
+	ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG4,
+					state ? MPL3115_CTRL4_INT_EN_DRDY : 0);
+	if (ret < 0)
+		goto reg1_cleanup;
+
+	data->ctrl_reg1 = ctrl_reg1;
+
+	return 0;
+
+reg1_cleanup:
+	i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
+				  data->ctrl_reg1);
+	return ret;
+}
+
+static const struct iio_trigger_ops mpl3115_trigger_ops = {
+	.set_trigger_state = mpl3115_set_trigger_state,
+};
+
 static const struct iio_info mpl3115_info = {
 	.read_raw = &mpl3115_read_raw,
 };
 
+static int mpl3115_trigger_probe(struct mpl3115_data *data,
+				 struct iio_dev *indio_dev)
+{
+	struct fwnode_handle *fwnode = dev_fwnode(&data->client->dev);
+	int ret, irq, irq_type, irq_cfg_flags = 0;
+
+	irq = fwnode_irq_get_byname(fwnode, "INT1");
+	if (irq < 0) {
+		irq = fwnode_irq_get_byname(fwnode, "INT2");
+		if (irq < 0)
+			return 0;
+
+		irq_cfg_flags |= MPL3115_INT2;
+	}
+
+	irq_type = irq_get_trigger_type(irq);
+	if (irq_type != IRQF_TRIGGER_RISING && irq_type != IRQF_TRIGGER_FALLING)
+		return -EINVAL;
+
+	irq_cfg_flags |= irq_type;
+
+	ret = i2c_smbus_write_byte_data(data->client, MPL3115_PT_DATA_CFG,
+					MPL3115_PT_DATA_EVENT_ALL);
+	if (ret < 0)
+		return ret;
+
+	switch (irq_cfg_flags) {
+	case INT2_ACTIVE_HIGH:
+		ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG3,
+						MPL3115_CTRL3_IPOL2);
+		if (ret)
+			return ret;
+
+		break;
+	case INT2_ACTIVE_LOW:
+		break;
+	case INT1_ACTIVE_HIGH:
+		ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG5,
+						MPL3115_CTRL5_INT_CFG_DRDY);
+		if (ret)
+			return ret;
+
+		ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG3,
+						MPL3115_CTRL3_IPOL1);
+		if (ret)
+			return ret;
+
+		break;
+	case INT1_ACTIVE_LOW:
+		ret = i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG5,
+						MPL3115_CTRL5_INT_CFG_DRDY);
+		if (ret)
+			return ret;
+		break;
+	default:
+		return -EINVAL;
+	}
+
+	data->drdy_trig = devm_iio_trigger_alloc(&data->client->dev,
+						 "%s-dev%d",
+						 indio_dev->name,
+						 iio_device_id(indio_dev));
+	if (!data->drdy_trig)
+		return -ENOMEM;
+
+	data->drdy_trig->ops = &mpl3115_trigger_ops;
+	iio_trigger_set_drvdata(data->drdy_trig, indio_dev);
+	ret = devm_iio_trigger_register(&data->client->dev, data->drdy_trig);
+	if (ret)
+		return ret;
+
+	indio_dev->trig = iio_trigger_get(data->drdy_trig);
+
+	return devm_request_threaded_irq(&data->client->dev, irq,
+					 NULL,
+					 mpl3115_interrupt_handler,
+					 IRQF_ONESHOT,
+					 "mpl3115_irq",
+					 indio_dev);
+}
+
 static int mpl3115_probe(struct i2c_client *client)
 {
 	const struct i2c_device_id *id = i2c_client_get_device_id(client);
@@ -258,15 +425,19 @@ static int mpl3115_probe(struct i2c_client *client)
 
 	/* software reset, I2C transfer is aborted (fails) */
 	i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
-		MPL3115_CTRL_RESET);
+		MPL3115_CTRL1_RESET);
 	msleep(50);
 
-	data->ctrl_reg1 = MPL3115_CTRL_OS_258MS;
+	data->ctrl_reg1 = MPL3115_CTRL1_OS_258MS;
 	ret = i2c_smbus_write_byte_data(client, MPL3115_CTRL_REG1,
 		data->ctrl_reg1);
 	if (ret < 0)
 		return ret;
 
+	ret = mpl3115_trigger_probe(data, indio_dev);
+	if (ret)
+		return ret;
+
 	ret = iio_triggered_buffer_setup(indio_dev, NULL,
 		mpl3115_trigger_handler, NULL);
 	if (ret < 0)
@@ -285,7 +456,7 @@ static int mpl3115_probe(struct i2c_client *client)
 static int mpl3115_standby(struct mpl3115_data *data)
 {
 	return i2c_smbus_write_byte_data(data->client, MPL3115_CTRL_REG1,
-		data->ctrl_reg1 & ~MPL3115_CTRL_ACTIVE);
+		data->ctrl_reg1 & ~MPL3115_CTRL1_ACTIVE);
 }
 
 static void mpl3115_remove(struct i2c_client *client)
-- 
2.25.1