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hwmon: (ina3221) Add voltage conversion time settings 

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>
[groeck: .rst related formatting changes in documentation]
Signed-off-by: Guenter Roeck <linux@roeck-us.net>
hifive-unleashed-5.2
Nicolin Chen 2019-04-17 16:12:10 -07:00 committed by Guenter Roeck
parent 521c0b6116
commit 023912dbb8
2 changed files with 63 additions and 8 deletions
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13
Documentation/hwmon/ina3221.rst
View File

@ -46,4 +46,17 @@ 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).
======================= =======================================================

58
drivers/hwmon/ina3221.c
View File

@ -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(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 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(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,