iio:st_sensors: align on storagebits boundaries

Ensure triggered buffering memory accesses are properly aligned on per
channel storagebits boundaries.

Signed-off-by: Gregor Boirie <gregor.boirie@parrot.com>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>

diff --git a/drivers/iio/common/st_sensors/st_sensors_buffer.c b/drivers/iio/common/st_sensors/st_sensors_buffer.c
index 2371fc8..d06e728 100644 (file)
--- a/drivers/iio/common/st_sensors/st_sensors_buffer.c
+++ b/drivers/iio/common/st_sensors/st_sensors_buffer.c
@@ -24,30 +24,29 @@
 
 static int st_sensors_get_buffer_element(struct iio_dev *indio_dev, u8 *buf)
 {
-       int i, len;
-       int total = 0;
+       int i;
        struct st_sensor_data *sdata = iio_priv(indio_dev);
        unsigned int num_data_channels = sdata->num_data_channels;
 
-       for (i = 0; i < num_data_channels; i++) {
-               unsigned int bytes_to_read;
-
-               if (test_bit(i, indio_dev->active_scan_mask)) {
-                       bytes_to_read = indio_dev->channels[i].scan_type.storagebits >> 3;
-                       len = sdata->tf->read_multiple_byte(&sdata->tb,
-                               sdata->dev, indio_dev->channels[i].address,
-                               bytes_to_read,
-                               buf + total, sdata->multiread_bit);
-
-                       if (len < bytes_to_read)
-                               return -EIO;
-
-                       /* Advance the buffer pointer */
-                       total += len;
-               }
+       for_each_set_bit(i, indio_dev->active_scan_mask, num_data_channels) {
+               const struct iio_chan_spec *channel = &indio_dev->channels[i];
+               unsigned int bytes_to_read = channel->scan_type.realbits >> 3;
+               unsigned int storage_bytes =
+                       channel->scan_type.storagebits >> 3;
+
+               buf = PTR_ALIGN(buf, storage_bytes);
+               if (sdata->tf->read_multiple_byte(&sdata->tb, sdata->dev,
+                                                 channel->address,
+                                                 bytes_to_read, buf,
+                                                 sdata->multiread_bit) <
+                   bytes_to_read)
+                       return -EIO;
+
+               /* Advance the buffer pointer */
+               buf += storage_bytes;
        }
 
-       return total;
+       return 0;
 }
 
 irqreturn_t st_sensors_trigger_handler(int irq, void *p)

diff --git a/drivers/iio/common/st_sensors/st_sensors_core.c b/drivers/iio/common/st_sensors/st_sensors_core.c
index 26ce325..2d5282e 100644 (file)
--- a/drivers/iio/common/st_sensors/st_sensors_core.c
+++ b/drivers/iio/common/st_sensors/st_sensors_core.c
@@ -490,7 +490,7 @@ static int st_sensors_read_axis_data(struct iio_dev *indio_dev,
        int err;
        u8 *outdata;
        struct st_sensor_data *sdata = iio_priv(indio_dev);
-       unsigned int byte_for_channel = ch->scan_type.storagebits >> 3;
+       unsigned int byte_for_channel = ch->scan_type.realbits >> 3;
 
        outdata = kmalloc(byte_for_channel, GFP_KERNEL);
        if (!outdata)