iio: mma8452: Add support for interrupt driven triggers.

Implement interrupt driven trigger for data ready.
This allows more efficient access to the sample data.

Signed-off-by: Martin Fuzzey <mfuzzey@parkeon.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/accel/mma8452.c b/drivers/iio/accel/mma8452.c
index 51ae751..e8e2077 100644 (file)
--- a/drivers/iio/accel/mma8452.c
+++ b/drivers/iio/accel/mma8452.c
@@ -18,6 +18,8 @@
 #include <linux/iio/sysfs.h>
 #include <linux/iio/trigger_consumer.h>
 #include <linux/iio/buffer.h>
+#include <linux/iio/trigger.h>
+#include <linux/iio/trigger_consumer.h>
 #include <linux/iio/triggered_buffer.h>
 #include <linux/iio/events.h>
 #include <linux/delay.h>
@@ -66,6 +68,7 @@
 #define MMA8452_DATA_CFG_FS_8G 2
 #define MMA8452_DATA_CFG_HPF_MASK BIT(4)
 
+#define MMA8452_INT_DRDY       BIT(0)
 #define MMA8452_INT_TRANS      BIT(5)
 
 #define MMA8452_DEVICE_ID 0x2a
@@ -577,18 +580,24 @@ static irqreturn_t mma8452_interrupt(int irq, void *p)
 {
        struct iio_dev *indio_dev = p;
        struct mma8452_data *data = iio_priv(indio_dev);
+       int ret = IRQ_NONE;
        int src;
 
        src = i2c_smbus_read_byte_data(data->client, MMA8452_INT_SRC);
        if (src < 0)
                return IRQ_NONE;
 
+       if (src & MMA8452_INT_DRDY) {
+               iio_trigger_poll_chained(indio_dev->trig);
+               ret = IRQ_HANDLED;
+       }
+
        if (src & MMA8452_INT_TRANS) {
                mma8452_transient_interrupt(indio_dev);
-               return IRQ_HANDLED;
+               ret = IRQ_HANDLED;
        }
 
-       return IRQ_NONE;
+       return ret;
 }
 
 static irqreturn_t mma8452_trigger_handler(int irq, void *p)
@@ -714,6 +723,72 @@ static const struct iio_info mma8452_info = {
 
 static const unsigned long mma8452_scan_masks[] = {0x7, 0};
 
+static int mma8452_data_rdy_trigger_set_state(struct iio_trigger *trig,
+                                             bool state)
+{
+       struct iio_dev *indio_dev = iio_trigger_get_drvdata(trig);
+       struct mma8452_data *data = iio_priv(indio_dev);
+       int reg;
+
+       reg = i2c_smbus_read_byte_data(data->client, MMA8452_CTRL_REG4);
+       if (reg < 0)
+               return reg;
+
+       if (state)
+               reg |= MMA8452_INT_DRDY;
+       else
+               reg &= ~MMA8452_INT_DRDY;
+
+       return mma8452_change_config(data, MMA8452_CTRL_REG4, reg);
+}
+
+static int mma8452_validate_device(struct iio_trigger *trig,
+                                  struct iio_dev *indio_dev)
+{
+       struct iio_dev *indio = iio_trigger_get_drvdata(trig);
+
+       if (indio != indio_dev)
+               return -EINVAL;
+
+       return 0;
+}
+
+static const struct iio_trigger_ops mma8452_trigger_ops = {
+       .set_trigger_state = mma8452_data_rdy_trigger_set_state,
+       .validate_device = mma8452_validate_device,
+       .owner = THIS_MODULE,
+};
+
+static int mma8452_trigger_setup(struct iio_dev *indio_dev)
+{
+       struct mma8452_data *data = iio_priv(indio_dev);
+       struct iio_trigger *trig;
+       int ret;
+
+       trig = devm_iio_trigger_alloc(&data->client->dev, "%s-dev%d",
+                                     indio_dev->name,
+                                     indio_dev->id);
+       if (!trig)
+               return -ENOMEM;
+
+       trig->dev.parent = &data->client->dev;
+       trig->ops = &mma8452_trigger_ops;
+       iio_trigger_set_drvdata(trig, indio_dev);
+
+       ret = iio_trigger_register(trig);
+       if (ret)
+               return ret;
+
+       indio_dev->trig = trig;
+       return 0;
+}
+
+static void mma8452_trigger_cleanup(struct iio_dev *indio_dev)
+{
+       if (indio_dev->trig)
+               iio_trigger_unregister(indio_dev->trig);
+}
+
 static int mma8452_reset(struct i2c_client *client)
 {
        int i;
@@ -794,7 +869,8 @@ static int mma8452_probe(struct i2c_client *client,
                 * enabled until userspace asks for it by
                 * mma8452_write_event_config()
                 */
-               int supported_interrupts = MMA8452_INT_TRANS;
+               int supported_interrupts = MMA8452_INT_DRDY | MMA8452_INT_TRANS;
+               int enabled_interrupts = MMA8452_INT_TRANS;
 
                /* Assume wired to INT1 pin */
                ret = i2c_smbus_write_byte_data(client,
@@ -805,7 +881,11 @@ static int mma8452_probe(struct i2c_client *client,
 
                ret = i2c_smbus_write_byte_data(client,
                                                MMA8452_CTRL_REG4,
-                                               supported_interrupts);
+                                               enabled_interrupts);
+               if (ret < 0)
+                       return ret;
+
+               ret = mma8452_trigger_setup(indio_dev);
                if (ret < 0)
                        return ret;
        }
@@ -815,12 +895,12 @@ static int mma8452_probe(struct i2c_client *client,
        ret = i2c_smbus_write_byte_data(client, MMA8452_CTRL_REG1,
                                        data->ctrl_reg1);
        if (ret < 0)
-               return ret;
+               goto trigger_cleanup;
 
        ret = iio_triggered_buffer_setup(indio_dev, NULL,
                mma8452_trigger_handler, NULL);
        if (ret < 0)
-               return ret;
+               goto trigger_cleanup;
 
        if (client->irq) {
                ret = devm_request_threaded_irq(&client->dev,
@@ -840,6 +920,10 @@ static int mma8452_probe(struct i2c_client *client,
 
 buffer_cleanup:
        iio_triggered_buffer_cleanup(indio_dev);
+
+trigger_cleanup:
+       mma8452_trigger_cleanup(indio_dev);
+
        return ret;
 }
 
@@ -849,6 +933,7 @@ static int mma8452_remove(struct i2c_client *client)
 
        iio_device_unregister(indio_dev);
        iio_triggered_buffer_cleanup(indio_dev);
+       mma8452_trigger_cleanup(indio_dev);
        mma8452_standby(iio_priv(indio_dev));
 
        return 0;