Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings
On Wed, Apr 17, 2019 at 01:12:34PM -0700, Guenter Roeck wrote:
> On Wed, Apr 17, 2019 at 12:48:18PM -0700, Nicolin Chen wrote:
> > On Wed, Apr 17, 2019 at 11:39:49AM -0700, Nicolin Chen wrote:
> >
> > > > Thinking about it ... does it even make sense to cache reg_config twice,
> > > > or would it be better to just update the local copy and use
> > > > regmap_write()
> > > > to send it to the chip ?
> > >
> > > I remember the reason of adding the read-back was to prevent race
> > > condition. But now we have mutex protections for all sysfs nodes,
> > > maybe it's not necessary anymore. I will read the code carefully
> > > and see if it's safe to remove it -- will do in a separate patch.
> >
> > I just recalled a second thought for the reason why I left them
> > there as it'd logically require a copy to restore upon failure
> > of regmap_write, that might not look so neat as the read-back:
> >
> > old_config = reg_config;
> > reg_config &= mask;
> > reg_config |= val;
> > ret = regmap_write(reg_config);
> > if (ret) {
> > reg_config = old_config;
> > return ret;
> > }
>
> reg = (reg_config & mask) | val;
> ret = regmap_write(reg);
> if (ret)
> return ret;
> reg_config = reg;
>
> doesn't look that bad to me, and is much less costly.
Okay. Will submit a change. Thanks
Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings
On Wed, Apr 17, 2019 at 12:48:18PM -0700, Nicolin Chen wrote:
> On Wed, Apr 17, 2019 at 11:39:49AM -0700, Nicolin Chen wrote:
>
> > > Thinking about it ... does it even make sense to cache reg_config twice,
> > > or would it be better to just update the local copy and use regmap_write()
> > > to send it to the chip ?
> >
> > I remember the reason of adding the read-back was to prevent race
> > condition. But now we have mutex protections for all sysfs nodes,
> > maybe it's not necessary anymore. I will read the code carefully
> > and see if it's safe to remove it -- will do in a separate patch.
>
> I just recalled a second thought for the reason why I left them
> there as it'd logically require a copy to restore upon failure
> of regmap_write, that might not look so neat as the read-back:
>
> old_config = reg_config;
> reg_config &= mask;
> reg_config |= val;
> ret = regmap_write(reg_config);
> if (ret) {
> reg_config = old_config;
> return ret;
> }
reg = (reg_config & mask) | val;
ret = regmap_write(reg);
if (ret)
return ret;
reg_config = reg;
doesn't look that bad to me, and is much less costly.
Guenter
Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings
On Wed, Apr 17, 2019 at 11:39:49AM -0700, Nicolin Chen wrote:
> > Thinking about it ... does it even make sense to cache reg_config twice,
> > or would it be better to just update the local copy and use regmap_write()
> > to send it to the chip ?
>
> I remember the reason of adding the read-back was to prevent race
> condition. But now we have mutex protections for all sysfs nodes,
> maybe it's not necessary anymore. I will read the code carefully
> and see if it's safe to remove it -- will do in a separate patch.
I just recalled a second thought for the reason why I left them
there as it'd logically require a copy to restore upon failure
of regmap_write, that might not look so neat as the read-back:
old_config = reg_config;
reg_config &= mask;
reg_config |= val;
ret = regmap_write(reg_config);
if (ret) {
reg_config = old_config;
return ret;
}
Would you prefer this?
Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings
On Wed, Apr 17, 2019 at 07:04:09AM -0700, Guenter Roeck wrote: > > > 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. OK. I will go ahead with this approach then. > > > + /* 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. Will merge them. > Thinking about it ... does it even make sense to cache reg_config twice, > or would it be better to just update the local copy and use regmap_write() > to send it to the chip ? I remember the reason of adding the read-back was to prevent race condition. But now we have mutex protections for all sysfs nodes, maybe it's not necessary anymore. I will read the code carefully and see if it's safe to remove it -- will do in a separate patch. Thanks Nicolin
Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings
On 4/17/19 6:46 AM, Guenter Roeck wrote:
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
---
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..af4ab8ce 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 =
Re: [PATCH] hwmon: (ina3221) Add voltage conversion time settings
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
---
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..af4ab8ce 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 =
[PATCH] 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
---
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?
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..af4ab8ce 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
