Re: [PATCH v4 1/2] firmware: arm_scmi: Fetch and store sensor scale

[Guenter Roeck]

On Wed, May 08, 2019 at 10:00:34AM -0700, Florian Fainelli wrote:
> In preparation for dealing with scales within the SCMI HWMON driver,
> fetch and store the sensor unit scale into the scmi_sensor_info
> structure. In order to simplify computations for upper layer, take care
> of sign extending the scale to a full 8-bit signed value.
> 
> Signed-off-by: Florian Fainelli <f.fainelli@xxxxxxxxx>

Reviewed-by: Guenter Roeck <linux@xxxxxxxxxxxx>

> ---
>  drivers/firmware/arm_scmi/sensors.c | 6 ++++++
>  include/linux/scmi_protocol.h       | 1 +
>  2 files changed, 7 insertions(+)
> 
> diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
> index b53d5cc9c9f6..21353470a740 100644
> --- a/drivers/firmware/arm_scmi/sensors.c
> +++ b/drivers/firmware/arm_scmi/sensors.c
> @@ -34,6 +34,8 @@ struct scmi_msg_resp_sensor_description {
>  		__le32 attributes_high;
>  #define SENSOR_TYPE(x)		((x) & 0xff)
>  #define SENSOR_SCALE(x)		(((x) >> 11) & 0x3f)
> +#define SENSOR_SCALE_SIGN	BIT(5)
> +#define SENSOR_SCALE_EXTEND	GENMASK(7, 6)
>  #define SENSOR_UPDATE_SCALE(x)	(((x) >> 22) & 0x1f)
>  #define SENSOR_UPDATE_BASE(x)	(((x) >> 27) & 0x1f)
>  		    u8 name[SCMI_MAX_STR_SIZE];
> @@ -140,6 +142,10 @@ static int scmi_sensor_description_get(const struct scmi_handle *handle,
>  			s = &si->sensors[desc_index + cnt];
>  			s->id = le32_to_cpu(buf->desc[cnt].id);
>  			s->type = SENSOR_TYPE(attrh);
> +			s->scale = SENSOR_SCALE(attrh);
> +			/* Sign extend to a full s8 */
> +			if (s->scale & SENSOR_SCALE_SIGN)
> +				s->scale |= SENSOR_SCALE_EXTEND;
>  			strlcpy(s->name, buf->desc[cnt].name, SCMI_MAX_STR_SIZE);
>  		}
>  
> diff --git a/include/linux/scmi_protocol.h b/include/linux/scmi_protocol.h
> index 3105055c00a7..9ff2e9357e9a 100644
> --- a/include/linux/scmi_protocol.h
> +++ b/include/linux/scmi_protocol.h
> @@ -144,6 +144,7 @@ struct scmi_power_ops {
>  struct scmi_sensor_info {
>  	u32 id;
>  	u8 type;
> +	s8 scale;
>  	char name[SCMI_MAX_STR_SIZE];
>  };
>  
> -- 
> 2.17.1
>