linux-kernel - [PATCH] ina3221: correct the update

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Message-ID: <20221108050029.24576-1-nmalwade@nvidia.com>
Date:   Tue, 8 Nov 2022 13:00:29 +0800
From:   Ninad Malwade <nmalwade@...dia.com>
To:     <nmalwade@...dia.com>, <treding@...dia.com>,
        <jonathanh@...dia.com>, <linux@...ck-us.net>, <jdelvare@...e.com>,
        <nicolinc@...dia.com>, <rkasirajan@...dia.com>
CC:     <linux-hwmon@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-pm@...r.kernel.org>
Subject: [PATCH] ina3221: correct the update_interval value

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@...dia.com>
---
 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