On 01/31/2013 09:43 PM, Guenter Roeck wrote:
> For chips with more than 8 bit ADC resolution, received data was always
> masked against 0xfff, ie with a 12 bit mask. This can result in bad data
> for chips with 10 bit resolution if those chips have higher bits set
> (seen with MAX1139).
>
> The receive buffer was defined as char array. This could result in
> unintentional sign extensions if the upper bit in a received byte
> was set. Since the chip is configured for unipolar mode, we never
> have to handle negative values, and sign extensions are never needed.
>
> Signed-off-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Applied to togreg branch of iio.git
> ---
> drivers/iio/adc/max1363.c | 5 +++--
> 1 file changed, 3 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/iio/adc/max1363.c b/drivers/iio/adc/max1363.c
> index 2c773b4..fdc8be9 100644
> --- a/drivers/iio/adc/max1363.c
> +++ b/drivers/iio/adc/max1363.c
> @@ -334,7 +334,7 @@ static int max1363_read_single_chan(struct iio_dev *indio_dev,
> {
> int ret = 0;
> s32 data;
> - char rxbuf[2];
> + u8 rxbuf[2];
> struct max1363_state *st = iio_priv(indio_dev);
> struct i2c_client *client = st->client;
>
> @@ -366,7 +366,8 @@ static int max1363_read_single_chan(struct iio_dev *indio_dev,
> ret = data;
> goto error_ret;
> }
> - data = (s32)(rxbuf[1]) | ((s32)(rxbuf[0] & 0x0F)) << 8;
> + data = (rxbuf[1] | rxbuf[0] << 8) &
> + ((1 << st->chip_info->bits) - 1);
> } else {
> /* Get reading */
> data = i2c_master_recv(client, rxbuf, 1);
>
--
To unsubscribe from this list: send the line "unsubscribe linux-iio" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
