Re: [PATCH 3/6] hwmon: jc42: use bitops' sign_extend16

From: Guenter Roeck
Date: Mon Dec 15 2014 - 16:30:30 EST


On Mon, Dec 15, 2014 at 05:18:34PM +0100, Martin Kepplinger wrote:
> ---

Some description would be nice. Also, please consider adding
relevant subsystem mailing lists and maintainers to your patches.

> drivers/hwmon/jc42.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/hwmon/jc42.c b/drivers/hwmon/jc42.c
> index 388f8bc..335a2de 100644
> --- a/drivers/hwmon/jc42.c
> +++ b/drivers/hwmon/jc42.c
> @@ -31,6 +31,7 @@
> #include <linux/hwmon-sysfs.h>
> #include <linux/err.h>
> #include <linux/mutex.h>
> +#include <linux/bitops.h>
>
> /* Addresses to scan */
> static const unsigned short normal_i2c[] = {
> @@ -215,9 +216,7 @@ static int jc42_temp_from_reg(s16 reg)
> {
> reg &= 0x1fff;
>
If I understand the code in sign_extend16 correctly, the above mask
should no longer be necessary.

Thanks,
Guenter

> - /* sign extend register */
> - if (reg & 0x1000)
> - reg |= 0xf000;
> + reg = sign_extend16(reg, 12);
>
> /* convert from 0.0625 to 0.001 resolution */
> return reg * 125 / 2;
> --
> 2.1.3
>
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