On Sun, 11 Nov 2018 23:28:28 +0100
Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx> wrote:
> Generalize st_lsm6dsx_shub_read_oneshot in order to not use a fixed
> read length and take into account iio channel realbits for single
> read operations
>
> Signed-off-by: Lorenzo Bianconi <lorenzo.bianconi@xxxxxxxxxx>
> ---
> drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c | 31 +++++++++++++-------
> 1 file changed, 20 insertions(+), 11 deletions(-)
>
> diff --git a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> index ee59b0cac84f..b908df0380b3 100644
> --- a/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> +++ b/drivers/iio/imu/st_lsm6dsx/st_lsm6dsx_shub.c
> @@ -27,6 +27,7 @@
> #include <linux/iio/iio.h>
> #include <linux/iio/sysfs.h>
> #include <linux/bitfield.h>
> +#include <linux/slab.h>
>
> #include "st_lsm6dsx.h"
>
> @@ -432,31 +433,39 @@ st_lsm6dsx_shub_read_oneshot(struct st_lsm6dsx_sensor *sensor,
> struct iio_chan_spec const *ch,
> int *val)
> {
> - int err, delay, len = ch->scan_type.realbits >> 3;
> - __le16 data;
> + int ret, delay, len = ch->scan_type.realbits >> 3;
> + u8 *data;
>
> - err = st_lsm6dsx_shub_set_enable(sensor, true);
> - if (err < 0)
> - return err;
> + ret = st_lsm6dsx_shub_set_enable(sensor, true);
> + if (ret < 0)
> + return ret;
> +
> + data = kmalloc(len, GFP_KERNEL);
> + if (!data)
> + return -ENOMEM;
Do we not want to disable should this fail?
Easier might be to just do the allocation before the set_enable
call.
I'd also be tempted to just put a big enough buffer on the stack, or
into the sensor structure.
Also, I haven't checked but is there potential for DMA into this
buffer?
>
> delay = 1000000 / sensor->odr;
> usleep_range(delay, 2 * delay);
>
> - err = st_lsm6dsx_shub_read(sensor, ch->address, (u8 *)&data, len);
> - if (err < 0)
> - return err;
> + ret = st_lsm6dsx_shub_read(sensor, ch->address, data, len);
> + if (ret < 0)
> + goto out;
>
> st_lsm6dsx_shub_set_enable(sensor, false);
>
> switch (len) {
> case 2:
> - *val = (s16)le16_to_cpu(data);
> + *val = (s16)le16_to_cpu(*((__le16 *)data));
> + ret = IIO_VAL_INT;
> break;
> default:
> - return -EINVAL;
> + ret = -EINVAL;
> + break;
> }
>
> - return IIO_VAL_INT;
> +out:
> + kfree(data);
> + return ret;
> }
>
> static int
