iio: accel: stk8312: Fix buffer alignment in iio_push_to_buffers_with_timestamp()

To make code more readable, use a structure to express the channel
layout and ensure the timestamp is 8 byte aligned.

Found during an audit of all calls of this function.

Fixes: 95c12bba51c3 ("iio: accel: Add buffer mode for Sensortek STK8312")
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Link: https://lore.kernel.org/r/20210501170121.512209-7-jic23@kernel.org

diff --git a/drivers/iio/accel/stk8312.c b/drivers/iio/accel/stk8312.c
index 34dc9bd78fb85825c830379d9b3e0ccfd2f261ea..43c621d0f11e458fe9d89446dfe8784ee7a48cfe 100644 (file)
--- a/drivers/iio/accel/stk8312.c
+++ b/drivers/iio/accel/stk8312.c
@@ -102,7 +102,11 @@ struct stk8312_data {
        u8 mode;
        struct iio_trigger *dready_trig;
        bool dready_trigger_on;
-       s8 buffer[16]; /* 3x8-bit channels + 5x8 padding + 64-bit timestamp */
+       /* Ensure timestamp is naturally aligned */
+       struct {
+               s8 chans[3];
+               s64 timestamp __aligned(8);
+       } scan;
 };
 
 static IIO_CONST_ATTR(in_accel_scale_available, STK8312_SCALE_AVAIL);
@@ -437,7 +441,7 @@ static irqreturn_t stk8312_trigger_handler(int irq, void *p)
                ret = i2c_smbus_read_i2c_block_data(data->client,
                                                    STK8312_REG_XOUT,
                                                    STK8312_ALL_CHANNEL_SIZE,
-                                                   data->buffer);
+                                                   data->scan.chans);
                if (ret < STK8312_ALL_CHANNEL_SIZE) {
                        dev_err(&data->client->dev, "register read failed\n");
                        mutex_unlock(&data->lock);
@@ -451,12 +455,12 @@ static irqreturn_t stk8312_trigger_handler(int irq, void *p)
                                mutex_unlock(&data->lock);
                                goto err;
                        }
-                       data->buffer[i++] = ret;
+                       data->scan.chans[i++] = ret;
                }
        }
        mutex_unlock(&data->lock);
 
-       iio_push_to_buffers_with_timestamp(indio_dev, data->buffer,
+       iio_push_to_buffers_with_timestamp(indio_dev, &data->scan,
                                           pf->timestamp);
 err:
        iio_trigger_notify_done(indio_dev->trig);