iio: mxc4005: add triggered buffer mode for mxc4005

This patch adds support for buffered readings for the 3-axis
accelerometer mxc4005.

Signed-off-by: Teodora Baluta <teodora.baluta@intel.com>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

2 files changed, 78 insertions, 3 deletions

diff --git a/drivers/iio/accel/Kconfig b/drivers/iio/accel/Kconfig
index 69302bed2860..cd5cd246792d 100644
--- a/drivers/iio/accel/Kconfig
+++ b/drivers/iio/accel/Kconfig
@@ -140,6 +140,8 @@ config MMA9553
 config MXC4005
         tristate "Memsic MXC4005XC 3-Axis Accelerometer Driver"
         depends on I2C
+        select IIO_BUFFER
+        select IIO_TRIGGERED_BUFFER
         select REGMAP_I2C
         help
           Say yes here to build support for the Memsic MXC4005XC 3-axis
diff --git a/drivers/iio/accel/mxc4005.c b/drivers/iio/accel/mxc4005.c
index e15c1bd26bd1..390eaf8cb2f8 100644
--- a/drivers/iio/accel/mxc4005.c
+++ b/drivers/iio/accel/mxc4005.c
@@ -19,6 +19,9 @@
 #include <linux/acpi.h>
 #include <linux/regmap.h>
 #include <linux/iio/sysfs.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_REGMAP_NAME             "mxc4005_regmap"
@@ -52,6 +55,7 @@ struct mxc4005_data {
         struct device *dev;
         struct mutex mutex;
         struct regmap *regmap;
+        __be16 buffer[8];
 };
 
 /*
@@ -122,6 +126,20 @@ static const struct regmap_config mxc4005_regmap_config = {
         .writeable_reg = mxc4005_is_writeable_reg,
 };
 
+static int mxc4005_read_xyz(struct mxc4005_data *data)
+{
+        int ret;
+
+        ret = regmap_bulk_read(data->regmap, MXC4005_REG_XOUT_UPPER,
+                               (u8 *) data->buffer, sizeof(data->buffer));
+        if (ret < 0) {
+                dev_err(data->dev, "failed to read axes\n");
+                return ret;
+        }
+
+        return 0;
+}
+
 static int mxc4005_read_axis(struct mxc4005_data *data,
                              unsigned int addr)
 {
@@ -197,7 +215,8 @@ static int mxc4005_read_raw(struct iio_dev *indio_dev,
                         ret = mxc4005_read_axis(data, chan->address);
                         if (ret < 0)
                                 return ret;
-                        *val = sign_extend32(ret >> 4, 11);
+                        *val = sign_extend32(ret >> chan->scan_type.shift,
+                                             chan->scan_type.realbits - 1);
                         return IIO_VAL_INT;
                 default:
                         return -EINVAL;
@@ -239,6 +258,11 @@ static const struct iio_info mxc4005_info = {
         .attrs          = &mxc4005_attrs_group,
 };
 
+static const unsigned long mxc4005_scan_masks[] = {
+        BIT(AXIS_X) | BIT(AXIS_Y) | BIT(AXIS_Z),
+        0
+};
+
 #define MXC4005_CHANNEL(_axis, _addr) {                         \
         .type = IIO_ACCEL,                                      \
         .modified = 1,                                          \
@@ -246,14 +270,43 @@ static const struct iio_info mxc4005_info = {
         .address = _addr,                                       \
         .info_mask_separate = BIT(IIO_CHAN_INFO_RAW),           \
         .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),   \
+        .scan_index = AXIS_##_axis,                             \
+        .scan_type = {                                          \
+                .sign = 's',                                    \
+                .realbits = 12,                                 \
+                .storagebits = 16,                              \
+                .shift = 4,                                     \
+                .endianness = IIO_BE,                           \
+        },                                                      \
 }
 
 static const struct iio_chan_spec mxc4005_channels[] = {
         MXC4005_CHANNEL(X, MXC4005_REG_XOUT_UPPER),
         MXC4005_CHANNEL(Y, MXC4005_REG_YOUT_UPPER),
         MXC4005_CHANNEL(Z, MXC4005_REG_ZOUT_UPPER),
+        IIO_CHAN_SOFT_TIMESTAMP(3),
 };
 
+static irqreturn_t mxc4005_trigger_handler(int irq, void *private)
+{
+        struct iio_poll_func *pf = private;
+        struct iio_dev *indio_dev = pf->indio_dev;
+        struct mxc4005_data *data = iio_priv(indio_dev);
+        int ret;
+
+        ret = mxc4005_read_xyz(data);
+        if (ret < 0)
+                goto err;
+
+        iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+                                           pf->timestamp);
+
+err:
+        iio_trigger_notify_done(indio_dev->trig);
+
+        return IRQ_HANDLED;
+}
+
 static int mxc4005_chip_init(struct mxc4005_data *data)
 {
         int ret;
@@ -304,23 +357,43 @@ static int mxc4005_probe(struct i2c_client *client,
         indio_dev->dev.parent = &client->dev;
         indio_dev->channels = mxc4005_channels;
         indio_dev->num_channels = ARRAY_SIZE(mxc4005_channels);
+        indio_dev->available_scan_masks = mxc4005_scan_masks;
         indio_dev->name = MXC4005_DRV_NAME;
         indio_dev->modes = INDIO_DIRECT_MODE;
         indio_dev->info = &mxc4005_info;
 
+        ret = iio_triggered_buffer_setup(indio_dev,
+                                         &iio_pollfunc_store_time,
+                                         mxc4005_trigger_handler,
+                                         NULL);
+        if (ret < 0) {
+                dev_err(&client->dev,
+                        "failed to setup iio triggered buffer\n");
+                return ret;
+        }
+
         ret = iio_device_register(indio_dev);
         if (ret < 0) {
                 dev_err(&client->dev,
                         "unable to register iio device %d\n", ret);
-                return ret;
+                goto err_buffer_cleanup;
         }
 
         return 0;
+
+err_buffer_cleanup:
+        iio_triggered_buffer_cleanup(indio_dev);
+
+        return ret;
 }
 
 static int mxc4005_remove(struct i2c_client *client)
 {
-        iio_device_unregister(i2c_get_clientdata(client));
+        struct iio_dev *indio_dev = i2c_get_clientdata(client);
+
+        iio_device_unregister(indio_dev);
+
+        iio_triggered_buffer_cleanup(indio_dev);
 
         return 0;
 }