[PATCH] ina3221: correct the update_interval value

From: Ninad Malwade
Date: Tue Nov 08 2022 - 00:01:10 EST


As per the INA3221 datasheet the samples value should not be
considered while calculating the update_interval value.
Section 8.4.2.2 from datasheet says - "The conversion-time
settings, along with the programmable-averaging mode, enable
the INA3221 to optimize available timing requirements in a given
application. For example, if a system requires data to be read
every 2 ms with all three channels monitored, configure the INA3221
with the conversion times for the shunt- and bus-voltage
measurements set to 332 μs"

As per above only conversion time and number of channels are
required to set the update_interval value. Correcting the same in
the driver.

Signed-off-by: Ninad Malwade <nmalwade@xxxxxxxxxx>
---
Documentation/hwmon/ina3221.rst | 3 +--
drivers/hwmon/ina3221.c | 4 +---
2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/Documentation/hwmon/ina3221.rst b/Documentation/hwmon/ina3221.rst
index 8c12c54d2c24..a4f107d1e489 100644
--- a/Documentation/hwmon/ina3221.rst
+++ b/Documentation/hwmon/ina3221.rst
@@ -61,10 +61,9 @@ samples Number of samples using in the averaging mode.

update_interval Data conversion time in millisecond, following:

- update_interval = C x S x (BC + SC)
+ update_interval = C x (BC + SC)

* C: number of enabled channels
- * S: number of samples
* BC: bus-voltage conversion time in millisecond
* SC: shunt-voltage conversion time in millisecond

diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index 2a57f4b60c29..e3aa57e3b039 100644
--- a/drivers/hwmon/ina3221.c
+++ b/drivers/hwmon/ina3221.c
@@ -183,11 +183,9 @@ static const int ina3221_avg_samples[] = {
static inline u32 ina3221_interval_ms_to_conv_time(u16 config, int interval)
{
u32 channels = hweight16(config & INA3221_CONFIG_CHs_EN_MASK);
- u32 samples_idx = INA3221_CONFIG_AVG(config);
- u32 samples = ina3221_avg_samples[samples_idx];

/* Bisect the result to Bus and Shunt conversion times */
- return DIV_ROUND_CLOSEST(interval * 1000 / 2, channels * samples);
+ return DIV_ROUND_CLOSEST(interval / 2, channels);
}

/* Converting CONFIG register value to update_interval in usec */
--
2.17.1