Merge tag 'scmi-updates-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux into arm/drivers

ARM SCMI updates/fixes for v5.3

1. Correction to ARM document ID referred in SCMI protocol binding
2. Fix to correct bitfield definitions for SENSOR_DESC attributes which
   otherwise will calculate sensor values on wrong scale
3. Adds the missing rate_discrete flag setting so that discrete clocks
   are handled correctly. Without this fix it assumes continuous range
   which is incorrect
4. Adds support to read and scale the sensor values based on the factor
   read from the firmware

* tag 'scmi-updates-5.3' of git://git.kernel.org/pub/scm/linux/kernel/git/sudeep.holla/linux:
  hwmon: scmi: Scale values to target desired HWMON units
  firmware: arm_scmi: fetch and store sensor scale
  firmware: arm_scmi: update rate_discrete in clock_describe_rates_get
  firmware: arm_scmi: fix bitfield definitions for SENSOR_DESC attributes
  dt-bindings: arm: fix the document ID for SCMI protocol documentation

Signed-off-by: Olof Johansson <olof@lixom.net>

3 files changed, 58 insertions, 2 deletions

diff --git a/drivers/firmware/arm_scmi/clock.c b/drivers/firmware/arm_scmi/clock.c
index 30fc04e28431..0a194af92438 100644
--- a/drivers/firmware/arm_scmi/clock.c
+++ b/drivers/firmware/arm_scmi/clock.c
@@ -185,6 +185,8 @@ scmi_clock_describe_rates_get(const struct scmi_handle *handle, u32 clk_id,
 	if (rate_discrete)
 		clk->list.num_rates = tot_rate_cnt;
 
+	clk->rate_discrete = rate_discrete;
+
 err:
 	scmi_xfer_put(handle, t);
 	return ret;
diff --git a/drivers/firmware/arm_scmi/sensors.c b/drivers/firmware/arm_scmi/sensors.c
index b53d5cc9c9f6..0e94ab56f679 100644
--- a/drivers/firmware/arm_scmi/sensors.c
+++ b/drivers/firmware/arm_scmi/sensors.c
@@ -30,10 +30,12 @@ struct scmi_msg_resp_sensor_description {
 		__le32 id;
 		__le32 attributes_low;
 #define SUPPORTS_ASYNC_READ(x)	((x) & BIT(31))
-#define NUM_TRIP_POINTS(x)	(((x) >> 4) & 0xff)
+#define NUM_TRIP_POINTS(x)	((x) & 0xff)
 		__le32 attributes_high;
 #define SENSOR_TYPE(x)		((x) & 0xff)
-#define SENSOR_SCALE(x)		(((x) >> 11) & 0x3f)
+#define SENSOR_SCALE(x)		(((x) >> 11) & 0x1f)
+#define SENSOR_SCALE_SIGN	BIT(4)
+#define SENSOR_SCALE_EXTEND	GENMASK(7, 5)
 #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/drivers/hwmon/scmi-hwmon.c b/drivers/hwmon/scmi-hwmon.c
index a80183a488c5..0c93fc5ca762 100644
--- a/drivers/hwmon/scmi-hwmon.c
+++ b/drivers/hwmon/scmi-hwmon.c
@@ -18,6 +18,50 @@ struct scmi_sensors {
 	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 @@ static int scmi_hwmon_read(struct device *dev, enum hwmon_sensor_types type,
 
 	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;