Messages in this thread Patch in this message | | | Subject | Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings | From | Guenter Roeck <> | Date | Wed, 17 Apr 2019 06:46:50 -0700 |
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On 4/16/19 4:55 PM, Nicolin Chen wrote: > 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> > --- > > Hi Guenter, > > I am not quite sure if this update_interval is the best way to > implement the conversion time settings but I can't find another > common approach. This implementation certainly has drawbacks: > 1) It can't configure Bus and Shunt conversion times separately > (Not crucial for me at this point as I set them equally) > 2) Users need to calculate for the settings of conversion time > 3) The ABI defines update_interval in msec while the hardware > and datasheet does in usec, and that generates rounding diff > 4) The update_interval value would be spontaneously modified > everytime number of samples or number of enabled channels > gets changed. This might confuses users who tries to have > a fixed update_interval other than really merely setting > conversion time. > > I see IIO subsystem have something like IIO_CHAN_INFO_INT_TIME > for conversion time setting exclusively. Do we have something > similar under hwmon? >
No. I think what you have should be good enough for now. Please see comments below.
Thanks, Guenter
> Thanks > > Documentation/hwmon/ina3221 | 9 +++++ > drivers/hwmon/ina3221.c | 65 ++++++++++++++++++++++++++++++++----- > 2 files changed, 65 insertions(+), 9 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 74d39d212931..af4ab8ddddce 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(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; > } > @@ -308,7 +331,7 @@ static int ina3221_read_curr(struct device *dev, u32 attr, > static int ina3221_write_chip(struct device *dev, u32 attr, long val) > { > struct ina3221_data *ina = dev_get_drvdata(dev); > - int ret, idx; > + int ret, idx, tmp; > > switch (attr) { > case hwmon_chip_samples: > @@ -321,6 +344,28 @@ static int ina3221_write_chip(struct device *dev, u32 attr, long val) > if (ret) > return ret; > > + /* Update reg_config accordingly */ > + return regmap_read(ina->regmap, INA3221_CONFIG, > + &ina->reg_config); > + 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-voltage conversion time */ > + ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, > + INA3221_CONFIG_VBUS_CT_MASK, > + idx << INA3221_CONFIG_VBUS_CT_SHIFT); > + if (ret) > + return ret; > + > + /* Update Shunt-voltage conversion time */ > + ret = regmap_update_bits(ina->regmap, INA3221_CONFIG, > + INA3221_CONFIG_VSH_CT_MASK, > + idx << INA3221_CONFIG_VSH_CT_SHIFT); > + if (ret) > + return ret;
It should be possible to update both conversion times with a single call, since both calls touch only one register. Something like
ret = regmap_update_bits(ina->regmap, INA3221_CONFIG INA3221_CONFIG_VBUS_CT_MASK | INA3221_CONFIG_VSH_CT_MASK, (idx << INA3221_CONFIG_VBUS_CT_SHIFT) | (idx << INA3221_CONFIG_VSH_CT_SHIFT));
Granted, that is a bit long, but it saves an extra i2c write operation.
> + > /* Update reg_config accordingly */ > return regmap_read(ina->regmap, INA3221_CONFIG, > &ina->reg_config); > @@ -482,6 +527,7 @@ 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; > @@ -527,7 +573,8 @@ 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, >
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