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Date: Wed, 26 Apr 2017 07:10:55 +0100
From: Jonathan Cameron <jic23@...nel.org>
To: Stefan Bruens <stefan.bruens@...h-aachen.de>
Cc: linux-iio@...r.kernel.org, linux-kernel@...r.kernel.org,
Hartmut Knaack <knaack.h@....de>,
Lars-Peter Clausen <lars@...afoo.de>,
Peter Meerwald-Stadler <pmeerw@...erw.net>
Subject: Re: [PATCH 1/2] iio: adc: Fix integration time/averaging for
INA219/220
On 17/04/17 13:41, Stefan Bruens wrote:
> On Freitag, 14. April 2017 17:02:33 CEST Jonathan Cameron wrote:
>> On 12/04/17 04:01, Stefan Brüns wrote:
>>> INA226/230/231 has integration times per voltage channel and common
>>> averaging setting for both channels, while the INA219/220 only has a
>>> combined integration time/averaging setting per channel.
>>> Only expose the averaging attribute for the INA226, and expose the correct
>>> integration times for the INA219.
>>>
>>> Signed-off-by: Stefan Brüns <stefan.bruens@...h-aachen.de>
>>
>> A few bits inline.
>>
>> The info_mask_shared_by_dir isn't right in the driver currently.
>> Those elements should be list for every channel in that direction. This
>> moves where they are rather than fixing that.
>>
>> Please sort that mess out whilst you are here.
>>
>> Thanks,
>>
>> Jonathan
>>
>>> ---
>>>
>>> drivers/iio/adc/ina2xx-adc.c | 179
>>> ++++++++++++++++++++++++++++++++++++++----- 1 file changed, 158
>>> insertions(+), 21 deletions(-)
>>>
>>> diff --git a/drivers/iio/adc/ina2xx-adc.c b/drivers/iio/adc/ina2xx-adc.c
>>> index 3263231276ca..d1678f886297 100644
>>> --- a/drivers/iio/adc/ina2xx-adc.c
>>> +++ b/drivers/iio/adc/ina2xx-adc.c
>>> @@ -48,6 +48,7 @@
>>>
>>> /* settings - depend on use case */
>>> #define INA219_CONFIG_DEFAULT 0x399F /* PGA=8 */
>>>
>>> +#define INA219_DEFAULT_IT 532
>>>
>>> #define INA226_CONFIG_DEFAULT 0x4327
>>> #define INA226_DEFAULT_AVG 4
>>> #define INA226_DEFAULT_IT 1110
>>>
>>> @@ -55,19 +56,24 @@
>>>
>>> #define INA2XX_RSHUNT_DEFAULT 10000
>>>
>>> /*
>>>
>>> - * bit mask for reading the averaging setting in the configuration
>>> register + * bit masks for reading the settings in the configuration
>>> register>
>>> * FIXME: use regmap_fields.
>>
>> Either fix this or drop the fixme. It's fine to regmap fields if you
>> like, but it it's not broken if it doesn't use them.
>
> The FIXME was not added nor changed by me. I see no reason to drop it.
oops., My mistake.
>
>>> */
>>>
>>> #define INA2XX_MODE_MASK GENMASK(3, 0)
>>>
>>> +/* Averaging for VBus/VShunt/Power */
>>>
>>> #define INA226_AVG_MASK GENMASK(11, 9)
>>> #define INA226_SHIFT_AVG(val) ((val) << 9)
>>>
>>> /* Integration time for VBus */
>>>
>>> +#define INA219_ITB_MASK GENMASK(10, 7)
>>> +#define INA219_SHIFT_ITB(val) ((val) << 7)
>>>
>>> #define INA226_ITB_MASK GENMASK(8, 6)
>>> #define INA226_SHIFT_ITB(val) ((val) << 6)
>>>
>>> /* Integration time for VShunt */
>>>
>>> +#define INA219_ITS_MASK GENMASK(6, 3)
>>> +#define INA219_SHIFT_ITS(val) ((val) << 3)
>>>
>>> #define INA226_ITS_MASK GENMASK(5, 3)
>>> #define INA226_SHIFT_ITS(val) ((val) << 3)
>>>
>>> @@ -107,6 +113,7 @@ struct ina2xx_config {
>>>
>>> int bus_voltage_shift;
>>> int bus_voltage_lsb; /* uV */
>>> int power_lsb; /* uW */
>>>
>>> + enum ina2xx_ids chip_id;
>>>
>>> };
>>>
>>> struct ina2xx_chip_info {
>>>
>>> @@ -129,6 +136,7 @@ static const struct ina2xx_config ina2xx_config[] = {
>>>
>>> .bus_voltage_shift = 3,
>>> .bus_voltage_lsb = 4000,
>>> .power_lsb = 20000,
>>>
>>> + .chip_id = ina219,
>>>
>>> },
>>> [ina226] = {
>>>
>>> .config_default = INA226_CONFIG_DEFAULT,
>>>
>>> @@ -137,6 +145,7 @@ static const struct ina2xx_config ina2xx_config[] = {
>>>
>>> .bus_voltage_shift = 0,
>>> .bus_voltage_lsb = 1250,
>>> .power_lsb = 25000,
>>>
>>> + .chip_id = ina226,
>>>
>>> },
>>>
>>> };
>>>
>>> @@ -282,6 +291,66 @@ static int ina226_set_int_time_vshunt(struct
>>> ina2xx_chip_info *chip,>
>>> return 0;
>>>
>>> }
>>>
>>> +/* Conversion times in uS. */
>>> +static const int ina219_conv_time_tab_subsample[] = { 84, 148, 276, 532
>>> };
>>> +static const int ina219_conv_time_tab_average[] = { 532, 1060, 2130,
>>> 4260,
>>> + 8510, 17020, 34050, 68100};
>>> +
>>> +static int ina219_lookup_int_time(unsigned int *val_us, int *bits)
>>> +{
>>> + if (*val_us > 68100 || *val_us < 84)
>>> + return -EINVAL;
>>> +
>>> + if (*val_us <= 532) {
>>> + *bits = find_closest(*val_us, ina219_conv_time_tab_subsample,
>>> + ARRAY_SIZE(ina219_conv_time_tab_subsample));
>>> + *val_us = ina219_conv_time_tab_subsample[*bits];
>>> + } else {
>>> + *bits = find_closest(*val_us, ina219_conv_time_tab_average,
>>> + ARRAY_SIZE(ina219_conv_time_tab_average));
>>> + *val_us = ina219_conv_time_tab_average[*bits];
>>> + *bits |= 0x8;
>>> + }
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int ina219_set_int_time_vbus(struct ina2xx_chip_info *chip,
>>> + unsigned int val_us, unsigned int *config)
>>> +{
>>> + int bits, ret;
>>> + unsigned int val_us_best = val_us;
>>> +
>>> + ret = ina219_lookup_int_time(&val_us_best, &bits);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + chip->int_time_vbus = val_us_best;
>>> +
>>> + *config &= ~INA219_ITB_MASK;
>>> + *config |= INA219_SHIFT_ITB(bits) & INA219_ITB_MASK;
>>> +
>>> + return 0;
>>> +}
>>> +
>>> +static int ina219_set_int_time_vshunt(struct ina2xx_chip_info *chip,
>>> + unsigned int val_us, unsigned int *config)
>>> +{
>>> + int bits, ret;
>>> + unsigned int val_us_best = val_us;
>>> +
>>> + ret = ina219_lookup_int_time(&val_us_best, &bits);
>>> + if (ret)
>>> + return ret;
>>> +
>>> + chip->int_time_vshunt = val_us_best;
>>> +
>>> + *config &= ~INA219_ITS_MASK;
>>> + *config |= INA219_SHIFT_ITS(bits) & INA219_ITS_MASK;
>>> +
>>> + return 0;
>>> +}
>>> +
>>>
>>> static int ina2xx_write_raw(struct iio_dev *indio_dev,
>>>
>>> struct iio_chan_spec const *chan,
>>> int val, int val2, long mask)
>>>
>>> @@ -307,10 +376,15 @@ static int ina2xx_write_raw(struct iio_dev
>>> *indio_dev,>
>>> break;
>>>
>>> case IIO_CHAN_INFO_INT_TIME:
>>> - if (chan->address == INA2XX_SHUNT_VOLTAGE)
>>> + if ((chip->config->chip_id == ina226) &&
>>> + (chan->address == INA2XX_SHUNT_VOLTAGE))
>>>
>>> ret = ina226_set_int_time_vshunt(chip, val2, &tmp);
>>>
>>> - else
>>> + else if (chip->config->chip_id == ina226)
>>>
>>> ret = ina226_set_int_time_vbus(chip, val2, &tmp);
>>>
>>> + else if (chan->address == INA2XX_SHUNT_VOLTAGE)
>>> + ret = ina219_set_int_time_vshunt(chip, val2, &tmp);
>>> + else
>>> + ret = ina219_set_int_time_vbus(chip, val2, &tmp);
>>
>> This new ordering of the if statement is convoluted and difficult to follow.
>> Just use a nested if and I think it'll be easier to read.
>
> I can change this, but the extra indentation level will force a line break to
> not exceed the 78 character limit.
I think readability will still be improved so go for it.
>
>>> break;
>>>
>>> default:
>>> @@ -416,10 +490,8 @@ static ssize_t ina2xx_shunt_resistor_store(struct
>>> device *dev,>
>>> .address = (_address), \
>>> .indexed = 1, \
>>> .channel = (_index), \
>>>
>>> - .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) \
>>> - | BIT(IIO_CHAN_INFO_SCALE), \
>>> - .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
>>> - BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>>> + BIT(IIO_CHAN_INFO_SCALE), \
>>
>> Sometimes it just feels like diff is trying to make it really hard
>> to see what has changed.
>>
>> Firstly the new info_mask_separate is just a reformat. Fine, but not
>> in this patch. Should be in it's own patch.
>>
>> The dropping of the shared_by_dir however makes me wonder what is going
>> on. Shared_by_dir elements should be present in every single channel
>> of that direction. This already isn't true in the driver and should be
>> fixed to maintain consistency. This makes it worse.
>
> Unfortunately there is no documentation how the *_shared_by_* fields have to
> be used. It seems to work if a bit is only set on some channels of a group.
It will work just fine but the intent is to have them set for all relevant
channels. Agreed, our documentation could do with improving on this.
>
> This patch makes is neither better nor worse. Previously, e.g.
> IIO_CHAN_INFO_SAMP_FREQ was set on both the power and current channels, now it
> is set on the bus and shunt voltage channels. Both variants create a single
> in_sample_frequency attribute.
If we can clean this up whilst you were here it would be great. If not fair
enough - we'll get to it one day!
>
>>> .scan_index = (_index), \
>>> .scan_type = { \
>>>
>>> .sign = 'u', \
>>>
>>> @@ -433,7 +505,26 @@ static ssize_t ina2xx_shunt_resistor_store(struct
>>> device *dev,>
>>> * Sampling Freq is a consequence of the integration times of
>>> * the Voltage channels.
>>> */
>>>
>>> -#define INA2XX_CHAN_VOLTAGE(_index, _address) { \
>>> +#define INA226_CHAN_VOLTAGE(_index, _address) { \
>>> + .type = IIO_VOLTAGE, \
>>> + .address = (_address), \
>>> + .indexed = 1, \
>>> + .channel = (_index), \
>>> + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>>> + BIT(IIO_CHAN_INFO_SCALE) | \
>>> + BIT(IIO_CHAN_INFO_INT_TIME), \
>>> + .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ) | \
>>> + BIT(IIO_CHAN_INFO_OVERSAMPLING_RATIO), \
>>> + .scan_index = (_index), \
>>> + .scan_type = { \
>>> + .sign = 'u', \
>>> + .realbits = 16, \
>>> + .storagebits = 16, \
>>> + .endianness = IIO_LE, \
>>> + } \
>>> +}
>>> +
>>> +#define INA219_CHAN_VOLTAGE(_index, _address) { \
>>>
>>> .type = IIO_VOLTAGE, \
>>> .address = (_address), \
>>> .indexed = 1, \
>>>
>>> @@ -441,6 +532,7 @@ static ssize_t ina2xx_shunt_resistor_store(struct
>>> device *dev,>
>>> .info_mask_separate = BIT(IIO_CHAN_INFO_RAW) | \
>>>
>>> BIT(IIO_CHAN_INFO_SCALE) | \
>>> BIT(IIO_CHAN_INFO_INT_TIME), \
>>>
>>> + .info_mask_shared_by_dir = BIT(IIO_CHAN_INFO_SAMP_FREQ), \
>>
>> This looks sort of like a bug fix. As it is just shared_by_dir it will
>> apply to all input channels so should have been specified for them all in
>> the first place. However, if so, the oversampling ratio should be the
>> same.
>
> No. TI226 has one oversampling ("averaging" in the DS) setting applying to all
> channels. TI219 has no explicit averaging.
>
> Apparently, on the TI226, all 4 channels (current, power, bus voltage, shunt)
> should have the IIO_CHAN_INFO_SAMP_FREQ and IIO_CHAN_INFO_OVERSAMPLING bits
> set in the info_mask_shared_by_dir, while the TI219 should have set only the
> IIO_CHAN_INFO_SAMP_FREQ bit.
Sounds right to me.
>
>>> .scan_index = (_index), \
>>> .scan_type = { \
>>>
>>> .sign = 'u', \
>>>
>>> @@ -450,9 +542,18 @@ static ssize_t ina2xx_shunt_resistor_store(struct
>>> device *dev,>
>>> } \
>>>
>>> }
>>>
>>> -static const struct iio_chan_spec ina2xx_channels[] = {
>>> - INA2XX_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
>>> - INA2XX_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
>>> +
>>> +static const struct iio_chan_spec ina226_channels[] = {
>>> + INA226_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
>>> + INA226_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
>>> + INA2XX_CHAN(IIO_POWER, 2, INA2XX_POWER),
>>> + INA2XX_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
>>> + IIO_CHAN_SOFT_TIMESTAMP(4),
>>> +};
>>> +
>>> +static const struct iio_chan_spec ina219_channels[] = {
>>> + INA219_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),
>>> + INA219_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),
>>>
>>> INA2XX_CHAN(IIO_POWER, 2, INA2XX_POWER),
>>> INA2XX_CHAN(IIO_CURRENT, 3, INA2XX_CURRENT),
>>> IIO_CHAN_SOFT_TIMESTAMP(4),
>>>
>>> @@ -589,7 +690,14 @@ static int ina2xx_debug_reg(struct iio_dev
>>> *indio_dev,
>>>
>>> }
>>>
>>>
>>> /* Possible integration times for vshunt and vbus */
>>>
>>> -static IIO_CONST_ATTR_INT_TIME_AVAIL("0.000140 0.000204 0.000332 0.000588
>>> 0.001100 0.002116 0.004156 0.008244"); +static
>>> IIO_CONST_ATTR_NAMED(ina219_integration_time_available,
>>> + integration_time_available,
>>> + "0.000084 0.000148 0.000276 0.000532 0.001060 0.002130
> 0.004260
>>> 0.008510 0.017020 0.034050 0.068100"); +
>>> +static IIO_CONST_ATTR_NAMED(ina226_integration_time_available,
>>> + integration_time_available,
>>> + "0.000140 0.000204 0.000332 0.000588 0.001100 0.002116
> 0.004156
>>> 0.008244"); +
>>>
>>> static IIO_DEVICE_ATTR(in_allow_async_readout, S_IRUGO | S_IWUSR,
>>>
>>> ina2xx_allow_async_readout_show,
>>>
>>> @@ -599,20 +707,39 @@ static IIO_DEVICE_ATTR(in_shunt_resistor, S_IRUGO |
>>> S_IWUSR,>
>>> ina2xx_shunt_resistor_show,
>>> ina2xx_shunt_resistor_store, 0);
>>>
>>> -static struct attribute *ina2xx_attributes[] = {
>>> +static struct attribute *ina219_attributes[] = {
>>> + &iio_dev_attr_in_allow_async_readout.dev_attr.attr,
>>> + &iio_const_attr_ina219_integration_time_available.dev_attr.attr,
>>> + &iio_dev_attr_in_shunt_resistor.dev_attr.attr,
>>> + NULL,
>>> +};
>>> +
>>> +static struct attribute *ina226_attributes[] = {
>>>
>>> &iio_dev_attr_in_allow_async_readout.dev_attr.attr,
>>>
>>> - &iio_const_attr_integration_time_available.dev_attr.attr,
>>> + &iio_const_attr_ina226_integration_time_available.dev_attr.attr,
>>>
>>> &iio_dev_attr_in_shunt_resistor.dev_attr.attr,
>>> NULL,
>>>
>>> };
>>>
>>> -static const struct attribute_group ina2xx_attribute_group = {
>>> - .attrs = ina2xx_attributes,
>>> +static const struct attribute_group ina219_attribute_group = {
>>> + .attrs = ina219_attributes,
>>>
>>> };
>>>
>>> -static const struct iio_info ina2xx_info = {
>>> +static const struct attribute_group ina226_attribute_group = {
>>> + .attrs = ina226_attributes,
>>> +};
>>> +
>>> +static const struct iio_info ina219_info = {
>>>
>>> .driver_module = THIS_MODULE,
>>>
>>> - .attrs = &ina2xx_attribute_group,
>>> + .attrs = &ina219_attribute_group,
>>> + .read_raw = ina2xx_read_raw,
>>> + .write_raw = ina2xx_write_raw,
>>> + .debugfs_reg_access = ina2xx_debug_reg,
>>> +};
>>> +
>>> +static const struct iio_info ina226_info = {
>>> + .driver_module = THIS_MODULE,
>>> + .attrs = &ina226_attribute_group,
>>>
>>> .read_raw = ina2xx_read_raw,
>>> .write_raw = ina2xx_write_raw,
>>> .debugfs_reg_access = ina2xx_debug_reg,
>>>
>>> @@ -678,6 +805,10 @@ static int ina2xx_probe(struct i2c_client *client,
>>>
>>> ina226_set_average(chip, INA226_DEFAULT_AVG, &val);
>>> ina226_set_int_time_vbus(chip, INA226_DEFAULT_IT, &val);
>>> ina226_set_int_time_vshunt(chip, INA226_DEFAULT_IT, &val);
>>>
>>> + } else {
>>> + chip->avg = 1;
>>> + ina219_set_int_time_vbus(chip, INA219_DEFAULT_IT, &val);
>>> + ina219_set_int_time_vshunt(chip, INA219_DEFAULT_IT, &val);
>>>
>>> }
>>>
>>> ret = ina2xx_init(chip, val);
>>>
>>> @@ -689,10 +820,16 @@ static int ina2xx_probe(struct i2c_client *client,
>>>
>>> indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;
>>> indio_dev->dev.parent = &client->dev;
>>> indio_dev->dev.of_node = client->dev.of_node;
>>>
>>> - indio_dev->channels = ina2xx_channels;
>>> - indio_dev->num_channels = ARRAY_SIZE(ina2xx_channels);
>>> + if (id->driver_data == ina226) {
>>> + indio_dev->channels = ina226_channels;
>>> + indio_dev->num_channels = ARRAY_SIZE(ina226_channels);
>>> + indio_dev->info = &ina226_info;
>>> + } else {
>>> + indio_dev->channels = ina219_channels;
>>> + indio_dev->num_channels = ARRAY_SIZE(ina219_channels);
>>> + indio_dev->info = &ina219_info;
>>> + }
>>>
>>> indio_dev->name = id->name;
>>>
>>> - indio_dev->info = &ina2xx_info;
>>>
>>> indio_dev->setup_ops = &ina2xx_setup_ops;
>>>
>>> buffer = devm_iio_kfifo_allocate(&indio_dev->dev);
>
>
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