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Subject[PATCH v2 2/2] hwmon: (ina3221) Add voltage conversion time settings
Date
The CONFIG register has two 3-bit fields for conversion time
settings of Bus-voltage and Shunt-voltage, respectively. The
conversion settings, along with averaging mode, allow users
to optimize available timing requirement.

This patch adds an 'update_interval' sysfs node through the
hwmon_chip_info of hwmon core. It reflects a total hardware
conversion time:
samples * channels * (Bus + Shunt conversion times)

Though INA3221 supports different conversion time setups for
Bus and Shunt voltages, this patch only adds the support of
a unified setting for both conversion times, by dividing the
conversion time into two equal values.

Signed-off-by: Nicolin Chen <nicoleotsuka@gmail.com>
---
Changelog
v1->v2:
* Merged two adjacent calls of regmap_update_bits().
* Replaced CONFIG register read-back with tmp variable

Documentation/hwmon/ina3221 | 9 ++++++
drivers/hwmon/ina3221.c | 58 ++++++++++++++++++++++++++++++++-----
2 files changed, 59 insertions(+), 8 deletions(-)

diff --git a/Documentation/hwmon/ina3221 b/Documentation/hwmon/ina3221
index ed3f22769d4b..3b05170112f0 100644
--- a/Documentation/hwmon/ina3221
+++ b/Documentation/hwmon/ina3221
@@ -38,3 +38,12 @@ in[456]_input Shunt voltage(uV) for channels 1, 2, and 3 respectively
samples Number of samples using in the averaging mode.
Supports the list of number of samples:
1, 4, 16, 64, 128, 256, 512, 1024
+update_interval Data conversion time in millisecond, following:
+ update_interval = C x S 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
+ Affects both Bus- and Shunt-voltage conversion time.
+ Note that setting update_interval to 0ms sets both BC
+ and SC to 140 us (minimum conversion time).
diff --git a/drivers/hwmon/ina3221.c b/drivers/hwmon/ina3221.c
index 62040aac653c..e0637fed9585 100644
--- a/drivers/hwmon/ina3221.c
+++ b/drivers/hwmon/ina3221.c
@@ -144,19 +144,37 @@ static const int ina3221_avg_samples[] = {
1, 4, 16, 64, 128, 256, 512, 1024,
};

-static inline int ina3221_wait_for_data(struct ina3221_data *ina)
+/* Converting update_interval in msec to conversion time in usec */
+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);
+}
+
+/* Converting CONFIG register value to update_interval in usec */
+static inline u32 ina3221_reg_to_interval_us(u16 config)
{
- u32 channels = hweight16(ina->reg_config & INA3221_CONFIG_CHs_EN_MASK);
- u32 vbus_ct_idx = INA3221_CONFIG_VBUS_CT(ina->reg_config);
- u32 vsh_ct_idx = INA3221_CONFIG_VSH_CT(ina->reg_config);
- u32 samples_idx = INA3221_CONFIG_AVG(ina->reg_config);
+ u32 channels = hweight16(config & INA3221_CONFIG_CHs_EN_MASK);
+ u32 vbus_ct_idx = INA3221_CONFIG_VBUS_CT(config);
+ u32 vsh_ct_idx = INA3221_CONFIG_VSH_CT(config);
+ u32 samples_idx = INA3221_CONFIG_AVG(config);
u32 samples = ina3221_avg_samples[samples_idx];
u32 vbus_ct = ina3221_conv_time[vbus_ct_idx];
u32 vsh_ct = ina3221_conv_time[vsh_ct_idx];
- u32 wait, cvrf;

/* Calculate total conversion time */
- wait = channels * (vbus_ct + vsh_ct) * samples;
+ return channels * (vbus_ct + vsh_ct) * samples;
+}
+
+static inline int ina3221_wait_for_data(struct ina3221_data *ina)
+{
+ u32 wait, cvrf;
+
+ wait = ina3221_reg_to_interval_us(ina->reg_config);

/* Polling the CVRF bit to make sure read data is ready */
return regmap_field_read_poll_timeout(ina->fields[F_CVRF],
@@ -197,6 +215,11 @@ static int ina3221_read_chip(struct device *dev, u32 attr, long *val)
regval = INA3221_CONFIG_AVG(ina->reg_config);
*val = ina3221_avg_samples[regval];
return 0;
+ case hwmon_chip_update_interval:
+ /* Return in msec */
+ *val = ina3221_reg_to_interval_us(ina->reg_config);
+ *val = DIV_ROUND_CLOSEST(*val, 1000);
+ return 0;
default:
return -EOPNOTSUPP;
}
@@ -322,6 +345,23 @@ static int ina3221_write_chip(struct device *dev, u32 attr, long val)
if (ret)
return ret;

+ /* Update reg_config accordingly */
+ ina->reg_config = tmp;
+ return 0;
+ case hwmon_chip_update_interval:
+ tmp = ina3221_interval_ms_to_conv_time(ina->reg_config, val);
+ idx = find_closest(tmp, ina3221_conv_time,
+ ARRAY_SIZE(ina3221_conv_time));
+
+ /* Update Bus and Shunt voltage conversion times */
+ tmp = INA3221_CONFIG_VBUS_CT_MASK | INA3221_CONFIG_VSH_CT_MASK;
+ tmp = (ina->reg_config & ~tmp) |
+ (idx << INA3221_CONFIG_VBUS_CT_SHIFT) |
+ (idx << INA3221_CONFIG_VSH_CT_SHIFT);
+ ret = regmap_write(ina->regmap, INA3221_CONFIG, tmp);
+ if (ret)
+ return ret;
+
/* Update reg_config accordingly */
ina->reg_config = tmp;
return 0;
@@ -483,6 +523,7 @@ static umode_t ina3221_is_visible(const void *drvdata,
case hwmon_chip:
switch (attr) {
case hwmon_chip_samples:
+ case hwmon_chip_update_interval:
return 0644;
default:
return 0;
@@ -528,7 +569,8 @@ static umode_t ina3221_is_visible(const void *drvdata,

static const struct hwmon_channel_info *ina3221_info[] = {
HWMON_CHANNEL_INFO(chip,
- HWMON_C_SAMPLES),
+ HWMON_C_SAMPLES,
+ HWMON_C_UPDATE_INTERVAL),
HWMON_CHANNEL_INFO(in,
/* 0: dummy, skipped in is_visible */
HWMON_I_INPUT,
--
2.17.1
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