[PATCH v1 3/4] hwmon: (acpi_power_meter) Remove redundant 'sensors_valid' variable

[Huisong Li <lihuisong@huawei.com>]

The 'sensors_valid' in acpi_power_meter_resource structure is always one
after querying power once. The default value of this variable is zero which
just ensure user can query power successfully without any time requirement
at first time. We can get power and fill the 'sensors_last_updated' field
at probing phase to make sure that a valid value is returned to user at
first query within the sampling interval. Then this redundant variable can
be safely removed.

Signed-off-by: Huisong Li <lihuisong@huawei.com>
---
 drivers/hwmon/acpi_power_meter.c | 18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

diff --git a/drivers/hwmon/acpi_power_meter.c b/drivers/hwmon/acpi_power_meter.c
index 95da73858a0b..3500859ff0bf 100644
--- a/drivers/hwmon/acpi_power_meter.c
+++ b/drivers/hwmon/acpi_power_meter.c
@@ -84,7 +84,6 @@ struct acpi_power_meter_resource {
 	u64		power;
 	u64		cap;
 	u64		avg_interval;
-	int			sensors_valid;
 	unsigned long		sensors_last_updated;
 	struct sensor_device_attribute	sensors[NUM_SENSORS];
 	int			num_sensors;
@@ -316,15 +315,14 @@ static ssize_t set_trip(struct device *dev, struct device_attribute *devattr,
 }
 
 /* Power meter */
-static int update_meter(struct acpi_power_meter_resource *resource)
+static int update_meter(struct acpi_power_meter_resource *resource, bool check)
 {
 	unsigned long long data;
 	acpi_status status;
 	unsigned long local_jiffies = jiffies;
 
-	if (time_before(local_jiffies, resource->sensors_last_updated +
-			msecs_to_jiffies(resource->caps.sampling_time)) &&
-			resource->sensors_valid)
+	if (check && time_before(local_jiffies, resource->sensors_last_updated +
+			msecs_to_jiffies(resource->caps.sampling_time)))
 		return 0;
 
 	status = acpi_evaluate_integer(resource->acpi_dev->handle, "_PMM",
@@ -336,7 +334,6 @@ static int update_meter(struct acpi_power_meter_resource *resource)
 	}
 
 	resource->power = data;
-	resource->sensors_valid = 1;
 	resource->sensors_last_updated = jiffies;
 	return 0;
 }
@@ -349,7 +346,7 @@ static ssize_t show_power(struct device *dev,
 	struct acpi_power_meter_resource *resource = acpi_dev->driver_data;
 
 	mutex_lock(&resource->lock);
-	update_meter(resource);
+	update_meter(resource, true);
 	mutex_unlock(&resource->lock);
 
 	if (resource->power == UNKNOWN_POWER)
@@ -429,7 +426,7 @@ static ssize_t show_val(struct device *dev,
 			val = 0;
 		break;
 	case 6:
-		ret = update_meter(resource);
+		ret = update_meter(resource, true);
 		if (ret)
 			return ret;
 		ret = update_cap(resource);
@@ -699,6 +696,10 @@ static int setup_attrs(struct acpi_power_meter_resource *resource)
 		return res;
 
 	if (resource->caps.flags & POWER_METER_CAN_MEASURE) {
+		res = update_meter(resource, false);
+		if (res)
+			goto error;
+
 		res = register_attrs(resource, meter_attrs);
 		if (res)
 			goto error;
@@ -890,7 +891,6 @@ static int acpi_power_meter_add(struct acpi_device *device)
 	if (!resource)
 		return -ENOMEM;
 
-	resource->sensors_valid = 0;
 	resource->acpi_dev = device;
 	mutex_init(&resource->lock);
 	strcpy(acpi_device_name(device), ACPI_POWER_METER_DEVICE_NAME);
-- 
2.22.0