iio: mxc4005: add data ready trigger for mxc4005

Add iio trigger for the data ready interrupt that signals new
measurements for the X, Y and Z axes.
Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

drivers/iio/accel/mxc4005.c

@@ -17,13 +17,16 @@
 #include <linux/i2c.h>
 #include <linux/iio/iio.h>
 #include <linux/acpi.h>
+#include <linux/gpio/consumer.h>
 #include <linux/regmap.h>
 #include <linux/iio/sysfs.h>
+#include <linux/iio/trigger.h>
 #include <linux/iio/buffer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/trigger_consumer.h>
 
 #define MXC4005_DRV_NAME		"mxc4005"
+#define MXC4005_IRQ_NAME		"mxc4005_event"
 #define MXC4005_REGMAP_NAME		"mxc4005_regmap"
 
 #define MXC4005_REG_XOUT_UPPER		0x03
@@ -33,6 +36,12 @@
 #define MXC4005_REG_ZOUT_UPPER		0x07
 #define MXC4005_REG_ZOUT_LOWER		0x08
 
+#define MXC4005_REG_INT_MASK1		0x0B
+#define MXC4005_REG_INT_MASK1_BIT_DRDYE	0x01
+
+#define MXC4005_REG_INT_CLR1		0x01
+#define MXC4005_REG_INT_CLR1_BIT_DRDYC	0x01
+
 #define MXC4005_REG_CONTROL		0x0D
 #define MXC4005_REG_CONTROL_MASK_FSR	GENMASK(6, 5)
 #define MXC4005_CONTROL_FSR_SHIFT	5
@@ -55,7 +64,9 @@ struct mxc4005_data {
 	struct device *dev;
 	struct mutex mutex;
 	struct regmap *regmap;
+	struct iio_trigger *dready_trig;
 	__be16 buffer[8];
+	bool trigger_enabled;
 };
 
 /*
@@ -107,6 +118,8 @@ static bool mxc4005_is_readable_reg(struct device *dev, unsigned int reg)
 static bool mxc4005_is_writeable_reg(struct device *dev, unsigned int reg)
 {
 	switch (reg) {
+	case MXC4005_REG_INT_CLR1:
+	case MXC4005_REG_INT_MASK1:
 	case MXC4005_REG_CONTROL:
 		return true;
 	default:
@@ -307,6 +320,91 @@ static irqreturn_t mxc4005_trigger_handler(int irq, void *private)
 	return IRQ_HANDLED;
 }
 
+static int mxc4005_clr_intr(struct mxc4005_data *data)
+{
+	int ret;
+
+	/* clear interrupt */
+	ret = regmap_write(data->regmap, MXC4005_REG_INT_CLR1,
+			   MXC4005_REG_INT_CLR1_BIT_DRDYC);
+	if (ret < 0) {
+		dev_err(data->dev, "failed to write to reg_int_clr1\n");
+		return ret;
+	}
+
+	return 0;
+}
+
+static int mxc4005_set_trigger_state(struct iio_trigger *trig,
+				     bool state)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct mxc4005_data *data = iio_priv(indio_dev);
+	int ret;
+
+	mutex_lock(&data->mutex);
+	if (state) {
+		ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK1,
+				   MXC4005_REG_INT_MASK1_BIT_DRDYE);
+	} else {
+		ret = regmap_write(data->regmap, MXC4005_REG_INT_MASK1,
+				   ~MXC4005_REG_INT_MASK1_BIT_DRDYE);
+	}
+
+	if (ret < 0) {
+		mutex_unlock(&data->mutex);
+		dev_err(data->dev, "failed to update reg_int_mask1");
+		return ret;
+	}
+
+	data->trigger_enabled = state;
+	mutex_unlock(&data->mutex);
+
+	return 0;
+}
+
+static int mxc4005_trigger_try_reen(struct iio_trigger *trig)
+{
+	struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+	struct mxc4005_data *data = iio_priv(indio_dev);
+
+	if (!data->dready_trig)
+		return 0;
+
+	return mxc4005_clr_intr(data);
+}
+
+static const struct iio_trigger_ops mxc4005_trigger_ops = {
+	.set_trigger_state = mxc4005_set_trigger_state,
+	.try_reenable = mxc4005_trigger_try_reen,
+	.owner = THIS_MODULE,
+};
+
+static int mxc4005_gpio_probe(struct i2c_client *client,
+			      struct mxc4005_data *data)
+{
+	struct device *dev;
+	struct gpio_desc *gpio;
+	int ret;
+
+	if (!client)
+		return -EINVAL;
+
+	dev = &client->dev;
+
+	gpio = devm_gpiod_get_index(dev, "mxc4005_int", 0, GPIOD_IN);
+	if (IS_ERR(gpio)) {
+		dev_err(dev, "failed to get acpi gpio index\n");
+		return PTR_ERR(gpio);
+	}
+
+	ret = gpiod_to_irq(gpio);
+
+	dev_dbg(dev, "GPIO resource, no:%d irq:%d\n", desc_to_gpio(gpio), ret);
+
+	return ret;
+}
+
 static int mxc4005_chip_init(struct mxc4005_data *data)
 {
 	int ret;
@@ -363,7 +461,7 @@ static int mxc4005_probe(struct i2c_client *client,
 	indio_dev->info = &mxc4005_info;
 
 	ret = iio_triggered_buffer_setup(indio_dev,
-					 &iio_pollfunc_store_time,
+					 iio_pollfunc_store_time,
 					 mxc4005_trigger_handler,
 					 NULL);
 	if (ret < 0) {
@@ -372,6 +470,43 @@ static int mxc4005_probe(struct i2c_client *client,
 		return ret;
 	}
 
+	if (client->irq < 0)
+		client->irq = mxc4005_gpio_probe(client, data);
+
+	if (client->irq > 0) {
+		data->dready_trig = devm_iio_trigger_alloc(&client->dev,
+							   "%s-dev%d",
+							   indio_dev->name,
+							   indio_dev->id);
+		if (!data->dready_trig)
+			return -ENOMEM;
+
+		ret = devm_request_threaded_irq(&client->dev, client->irq,
+						iio_trigger_generic_data_rdy_poll,
+						NULL,
+						IRQF_TRIGGER_FALLING |
+						IRQF_ONESHOT,
+						MXC4005_IRQ_NAME,
+						data->dready_trig);
+		if (ret) {
+			dev_err(&client->dev,
+				"failed to init threaded irq\n");
+			goto err_buffer_cleanup;
+		}
+
+		data->dready_trig->dev.parent = &client->dev;
+		data->dready_trig->ops = &mxc4005_trigger_ops;
+		iio_trigger_set_drvdata(data->dready_trig, indio_dev);
+		indio_dev->trig = data->dready_trig;
+		iio_trigger_get(indio_dev->trig);
+		ret = iio_trigger_register(data->dready_trig);
+		if (ret) {
+			dev_err(&client->dev,
+				"failed to register trigger\n");
+			goto err_trigger_unregister;
+		}
+	}
+
 	ret = iio_device_register(indio_dev);
 	if (ret < 0) {
 		dev_err(&client->dev,
@@ -381,6 +516,8 @@ static int mxc4005_probe(struct i2c_client *client,
 
 	return 0;
 
+err_trigger_unregister:
+	iio_trigger_unregister(data->dready_trig);
 err_buffer_cleanup:
 	iio_triggered_buffer_cleanup(indio_dev);
 
@@ -390,10 +527,13 @@ static int mxc4005_probe(struct i2c_client *client,
 static int mxc4005_remove(struct i2c_client *client)
 {
 	struct iio_dev *indio_dev = i2c_get_clientdata(client);
+	struct mxc4005_data *data = iio_priv(indio_dev);
 
 	iio_device_unregister(indio_dev);
 
 	iio_triggered_buffer_cleanup(indio_dev);
+	if (data->dready_trig)
+		iio_trigger_unregister(data->dready_trig);
 
 	return 0;
 }