Re: [PATCH] staging:iio:accel:adis16240: sign extend function avoiding code duplication

From: Joe Perches
Date: Mon Jun 11 2018 - 19:57:40 EST


On Tue, 2018-06-12 at 01:38 +0200, Karim Eshapa wrote:
> Use sign_extend32 kernel function instead of code duplication.
> Safe also for 16 bit.

Perhaps remove the bits declaration and assignments
and just use 9 directly.

> diff --git a/drivers/staging/iio/accel/adis16240.c b/drivers/staging/iio/accel/adis16240.c
[]
> @@ -292,9 +292,7 @@ static int adis16240_read_raw(struct iio_dev *indio_dev,
> ret = adis_read_reg_16(st, addr, &val16);
> if (ret)
> return ret;
> - val16 &= (1 << bits) - 1;
> - val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
> - *val = val16;
> + *val = sign_extend32(val16, bits - 1);
> return IIO_VAL_INT;
> case IIO_CHAN_INFO_PEAK:
> bits = 10;
> @@ -302,9 +300,7 @@ static int adis16240_read_raw(struct iio_dev *indio_dev,
> ret = adis_read_reg_16(st, addr, &val16);
> if (ret)
> return ret;
> - val16 &= (1 << bits) - 1;
> - val16 = (s16)(val16 << (16 - bits)) >> (16 - bits);
> - *val = val16;
> + *val = sign_extend32(val16, bits - 1);
> return IIO_VAL_INT;
> }
> return -EINVAL;