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 <[email protected]>
---
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
On Tue, Nov 08, 2022 at 01:00:29PM +0800, Ninad Malwade wrote:
> 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 <[email protected]>
> ---
> 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);
Why do you drop the * 1000 multiplication factor? That seems to be there
to account for the input "interval" being specified in ms whereas the
values in ina3221_conv_time[] are in us. Isn't this new code going to
give us values that are in the wrong unit?
Thierry
On Tue, Nov 08, 2022 at 01:00:29PM +0800, Ninad Malwade wrote:
> 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 <[email protected]>
As a bug fix, this patch should come before any functional changes.
> ---
> 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);
Same question as Thierry: Why drop the multiplication ?
Guenter
> }
>
> /* Converting CONFIG register value to update_interval in usec */