iio: mpl3115: use get_unaligned_be24() to retrieve pressure data

The pressure measurement result is arranged as 20-bit unsigned value
residing in three 8-bit registers. Hence, it can be retrieved using
get_unaligned_be24() and by applying 4-bit shift.

Reviewed-by: Marcelo Schmitt <marcelo.schmitt1@gmail.com>
Signed-off-by: Antoni Pokusinski <apokusinski01@gmail.com>
Signed-off-by: Jonathan Cameron <Jonathan.Cameron@huawei.com>

diff --git a/drivers/iio/pressure/mpl3115.c b/drivers/iio/pressure/mpl3115.c
index c212dfdf59ffa188e0d43fcc997d942f7d96892c..5594256fffbd46e542e97b570d9c4ea725231d32 100644 (file)
--- a/drivers/iio/pressure/mpl3115.c
+++ b/drivers/iio/pressure/mpl3115.c
@@ -16,6 +16,7 @@
 #include <linux/i2c.h>
 #include <linux/module.h>
 #include <linux/property.h>
+#include <linux/unaligned.h>
 
 #include <linux/iio/buffer.h>
 #include <linux/iio/iio.h>
@@ -125,7 +126,7 @@ static int mpl3115_read_info_raw(struct mpl3115_data *data,
 
        switch (chan->type) {
        case IIO_PRESSURE: { /* in 0.25 pascal / LSB */
-               __be32 tmp = 0;
+               u8 press_be24[3];
 
                guard(mutex)(&data->lock);
                ret = mpl3115_request(data);
@@ -134,11 +135,17 @@ static int mpl3115_read_info_raw(struct mpl3115_data *data,
 
                ret = i2c_smbus_read_i2c_block_data(data->client,
                                                    MPL3115_OUT_PRESS,
-                                                   3, (u8 *) &tmp);
+                                                   sizeof(press_be24),
+                                                   press_be24);
                if (ret < 0)
                        return ret;
 
-               *val = be32_to_cpu(tmp) >> chan->scan_type.shift;
+               /*
+                * The pressure channel shift is applied in the case where the
+                * data (24-bit big endian) is read into a 32-bit buffer. Here
+                * the data is stored in a 24-bit buffer, so the shift is 4.
+                */
+               *val = get_unaligned_be24(press_be24) >> 4;
                return IIO_VAL_INT;
        }
        case IIO_TEMP: { /* in 0.0625 celsius / LSB */