hwmon: scmi: Scale values to target desired HWMON units
If the SCMI firmware implementation is reporting values in a scale that
is different from the HWMON units, we need to scale up or down the value
according to how far apart they are.
Reviewed-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
[sudeep.holla: added check of scale = 0 for early exit in scmi_hwmon_scale]
Signed-off-by: Sudeep Holla <sudeep.holla@arm.com>
diff --git a/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
index a80183a..0c93fc5 100644
--- a/drivers/hwmon/scmi-hwmon.c
+++ b/drivers/hwmon/scmi-hwmon.c
@@ -18,6 +18,50 @@
const struct scmi_sensor_info **info[hwmon_max];
};
+static inline u64 __pow10(u8 x)
+{
+ u64 r = 1;
+
+ while (x--)
+ r *= 10;
+
+ return r;
+}
+
+static int scmi_hwmon_scale(const struct scmi_sensor_info *sensor, u64 *value)
+{
+ s8 scale = sensor->scale;
+ u64 f;
+
+ switch (sensor->type) {
+ case TEMPERATURE_C:
+ case VOLTAGE:
+ case CURRENT:
+ scale += 3;
+ break;
+ case POWER:
+ case ENERGY:
+ scale += 6;
+ break;
+ default:
+ break;
+ }
+
+ if (scale == 0)
+ return 0;
+
+ if (abs(scale) > 19)
+ return -E2BIG;
+
+ f = __pow10(abs(scale));
+ if (scale > 0)
+ *value *= f;
+ else
+ *value = div64_u64(*value, f);
+
+ return 0;
+}
+
static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
u32 attr, int channel, long *val)
{
@@ -29,6 +73,10 @@
sensor = *(scmi_sensors->info[type] + channel);
ret = h->sensor_ops->reading_get(h, sensor->id, false, &value);
+ if (ret)
+ return ret;
+
+ ret = scmi_hwmon_scale(sensor, &value);
if (!ret)
*val = value;
