On Wed, Apr 17, 2019 at 04:12:10PM -0700, 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 <[email protected]>

Applied to -next. I had to update the documentation for the .rst formatting
changes. Hope I got it right.

Thanks,
Guenter

> ---
> 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,

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