On 11/23/2016 03:34 AM, Martin Etnestad wrote:
The ADT7470 driver uses num_temp_sensors to check whether or not it
actually needs to read the temperature registers. However, the check
currently has a broken comparison: "num_temp_sensors >= 0" instead of
"num_temp_sensors == 0".
This causes the driver to only read the temperature registers _once_
because num_temp_sensors gets set to a non-negative number after the
check, in the same function.
Additionally, the check is currently done _after_ the measurement
sequence has been completed. The check should be done before the
measurement sequence is initiated, as it can be skipped altogether if
num_temp_sensors is 0.
The check is there to ensure that num_temp_sensors is calculated only once.
Your change breaks that. After the initial probe, temperature sensor
values are read in adt7470_update_device(), and it is no longer necessary
to do the read from adt7470_read_temperatures().
NACK, sorry.
Guenter
This patch fixes the comparison and moves the check.
Signed-off-by: Martin Etnestad <martin.etnestad@xxxxxxxxxxxx>
---
drivers/hwmon/adt7470.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/drivers/hwmon/adt7470.c b/drivers/hwmon/adt7470.c
index f5da39a..d1f9a54 100644
--- a/drivers/hwmon/adt7470.c
+++ b/drivers/hwmon/adt7470.c
@@ -201,6 +201,10 @@ static int adt7470_read_temperatures(struct i2c_client *client,
int i;
u8 cfg, pwm[4], pwm_cfg[2];
+ /* only read sensors if we have to */
+ if (data->num_temp_sensors == 0)
+ return 0;
+
/* save pwm[1-4] config register */
pwm_cfg[0] = i2c_smbus_read_byte_data(client, ADT7470_REG_PWM_CFG(0));
pwm_cfg[1] = i2c_smbus_read_byte_data(client, ADT7470_REG_PWM_CFG(2));
@@ -243,10 +247,6 @@ static int adt7470_read_temperatures(struct i2c_client *client,
return -EAGAIN;
}
- /* Only count fans if we have to */
- if (data->num_temp_sensors >= 0)
- return 0;
-
for (i = 0; i < ADT7470_TEMP_COUNT; i++) {
data->temp[i] = i2c_smbus_read_byte_data(client,
ADT7470_TEMP_REG(i));
--
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