RE: [PATCH 2/2] iio: adc: Add support for TI INA260 power monitors
From: Raviteja Narayanam
Date: Mon Mar 22 2021 - 09:39:42 EST
> -----Original Message-----
> From: Lars-Peter Clausen <lars@xxxxxxxxxx>
> Sent: Monday, March 22, 2021 6:22 PM
> To: Raviteja Narayanam <rna@xxxxxxxxxx>; robh+dt@xxxxxxxxxx;
> jic23@xxxxxxxxxx
> Cc: Michal Simek <michals@xxxxxxxxxx>; pmeerw@xxxxxxxxxx; linux-
> iio@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> kernel@xxxxxxxxxxxxxxx; git <git@xxxxxxxxxx>; Shubhrajyoti Datta
> <shubhraj@xxxxxxxxxx>
> Subject: Re: [PATCH 2/2] iio: adc: Add support for TI INA260 power monitors
>
> On 3/22/21 1:11 PM, Raviteja Narayanam wrote:
> >
> >> -----Original Message-----
> >> From: Lars-Peter Clausen <lars@xxxxxxxxxx>
> >> Sent: Monday, March 22, 2021 5:22 PM
> >> To: Raviteja Narayanam <rna@xxxxxxxxxx>; robh+dt@xxxxxxxxxx;
> >> jic23@xxxxxxxxxx
> >> Cc: Michal Simek <michals@xxxxxxxxxx>; pmeerw@xxxxxxxxxx; linux-
> >> iio@xxxxxxxxxxxxxxx; devicetree@xxxxxxxxxxxxxxx; linux-
> >> kernel@xxxxxxxxxxxxxxx; git <git@xxxxxxxxxx>; Shubhrajyoti Datta
> >> <shubhraj@xxxxxxxxxx>
> >> Subject: Re: [PATCH 2/2] iio: adc: Add support for TI INA260 power
> >> monitors
> >>
> >> On 3/22/21 12:43 PM, Lars-Peter Clausen wrote:
> >>> On 3/22/21 11:50 AM, Raviteja Narayanam wrote:
> >>>> This driver supports software buffer mode and raw reads of ina260
> >>>> iio channels.
> >>>>
> >>>> In software buffer mode, a kthread will capture the active
> >>>> scan_elements periodically using a delay. This can produce a stream
> >>>> of up to 3 channels plus a 64 bits timestamp based on the
> scan_elements.
> >>>>
> >>>> Signed-off-by: Raviteja Narayanam <raviteja.narayanam@xxxxxxxxxx>
> >>>> Signed-off-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> >>> Hi,
> >>>
> >>> Thanks for that patch, it looks really good.
> >>>
> >>> Looking at the datasheet the part seems to be very similar to the
> >>> ina226 from a software interface point of view. Looks like the
> >>> current and calibration register are missing and the scales are a bit
> different.
> >>>
> >>> We already have a driver for the ina226 (adc-ina2xx) and it looks
> >>> like your driver is also inspired by it. Have you considered adding
> >>> support for the ina260 to the existing driver? This will reduce the
> >>> amount of duplicated code.
> >> To add to that this driver has some nice new features and bug fixes
> >> that are not in the ina2xx driver, like debug register access. But
> >> the ina2xx has also seen a fair amount of improvements since this driver
> was branched off of it.
> >> It would be nice to get the best of both in a single driver.
> > Thanks for the review Lars.
> > Yes, using ina2xx driver was the first preference but after this
> > discussion (https://www.spinics.net/lists/devicetree/msg354475.html ),
> we have started a new driver as ina260 was considered to be sufficiently
> different from ina2xx.
>
> Can you elaborate where you see the significant difference? When I look at
> the code the drivers are >90% identical.
>
> I believe pretty much all we need to support the ina260 in the existing driver
> is to add a new iio_chan_spec and ina2xx_config for it. And then some minor
> tweaks to other parts of the driver, e.g. to make calibration optional. I
> believe this can be done in ~50 lines of code without making the structure of
> the driver more cluttered.
We will take a look at it again and get back to you.
>
> >
> > Regards,
> > Raviteja N
> >
> >>> - Lars
> >>>
> >>>> ---
> >>>> MAINTAINERS | 8 +
> >>>> drivers/iio/adc/Kconfig | 12 +
> >>>> drivers/iio/adc/Makefile | 1 +
> >>>> drivers/iio/adc/ina260-adc.c | 556
> >>>> +++++++++++++++++++++++++++++++++++
> >>>> 4 files changed, 577 insertions(+)
> >>>> create mode 100644 drivers/iio/adc/ina260-adc.c
> >>>>
> >>>> diff --git a/MAINTAINERS b/MAINTAINERS index
> >>>> aa84121c5611..768a4b148035 100644
> >>>> --- a/MAINTAINERS
> >>>> +++ b/MAINTAINERS
> >>>> @@ -8760,6 +8760,14 @@ F: Documentation/hwmon/ina2xx.rst
> >>>> F: drivers/hwmon/ina2xx.c
> >>>> F: include/linux/platform_data/ina2xx.h
> >>>> +INA260 POWER MONITOR DRIVER
> >>>> +M: Raviteja Narayanam <raviteja.narayanam@xxxxxxxxxx>
> >>>> +R: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
> >>>> +R: Michal Simek <michal.simek@xxxxxxxxxx>
> >>>> +S: Maintained
> >>>> +F: Documentation/devicetree/bindings/iio/adc/ti,ina260.yaml
> >>>> +F: drivers/iio/adc/ina260-adc.c
> >>>> +
> >>>> INDUSTRY PACK SUBSYSTEM (IPACK)
> >>>> M: Samuel Iglesias Gonsalvez <siglesias@xxxxxxxxxx>
> >>>> M: Jens Taprogge <jens.taprogge@xxxxxxxxxxxx> diff --git
> >>>> a/drivers/iio/adc/Kconfig b/drivers/iio/adc/Kconfig index
> >>>> bf7d22fa4be2..f6f8fd6bd113 100644
> >>>> --- a/drivers/iio/adc/Kconfig
> >>>> +++ b/drivers/iio/adc/Kconfig
> >>>> @@ -497,6 +497,18 @@ config INA2XX_ADC
> >>>> Say yes here to build support for TI INA2xx family of
> >>>> Power Monitors.
> >>>> This driver is mutually exclusive with the HWMON version.
> >>>> +config INA260_ADC
> >>>> + tristate "Texas Instruments INA260 Power Monitors IIO driver"
> >>>> + depends on I2C
> >>>> + select REGMAP_I2C
> >>>> + select IIO_BUFFER
> >>>> + select IIO_KFIFO_BUF
> >>>> + help
> >>>> + Say yes here to build support for TI INA260 power monitor.
> >>>> + This driver can also be built as a module. It supports
> >>>> software buffer
> >>>> + mode and raw reads of ina260 iio channels. Up to 4 channels
> >>>> +are
> >>>> + supported including timestamp.
> >>>> +
> >>>> config INGENIC_ADC
> >>>> tristate "Ingenic JZ47xx SoCs ADC driver"
> >>>> depends on MIPS || COMPILE_TEST diff --git
> >>>> a/drivers/iio/adc/Makefile b/drivers/iio/adc/Makefile index
> >>>> 5fca90ada0ec..a3bbcad64a41 100644
> >>>> --- a/drivers/iio/adc/Makefile
> >>>> +++ b/drivers/iio/adc/Makefile
> >>>> @@ -47,6 +47,7 @@ obj-$(CONFIG_HI8435) += hi8435.o
> >>>> obj-$(CONFIG_HX711) += hx711.o
> >>>> obj-$(CONFIG_IMX7D_ADC) += imx7d_adc.o
> >>>> obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o
> >>>> +obj-$(CONFIG_INA260_ADC) += ina260-adc.o
> >>>> obj-$(CONFIG_INGENIC_ADC) += ingenic-adc.o
> >>>> obj-$(CONFIG_INTEL_MRFLD_ADC) += intel_mrfld_adc.o
> >>>> obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o diff --git
> >>>> a/drivers/iio/adc/ina260-adc.c b/drivers/iio/adc/ina260-adc.c new
> >>>> file mode 100644 index 000000000000..7f74aa94fd31
> >>>> --- /dev/null
> >>>> +++ b/drivers/iio/adc/ina260-adc.c
> >>>> @@ -0,0 +1,556 @@
> >>>> +// SPDX-License-Identifier: GPL-2.0
> >>>> +/*
> >>>> + * INA260 power monitor driver
> >>>> + * Based on drivers/iio/adc/ina2xx-adc.c
> >>>> + *
> >>>> + * Copyright (C) 2021 Xilinx, Inc.
> >>>> + */
> >>>> +
> >>>> +#include <linux/i2c.h>
> >>>> +#include <linux/iio/iio.h>
> >>>> +#include <linux/iio/buffer.h>
> >>>> +#include <linux/iio/kfifo_buf.h>
> >>>> +#include <linux/iio/sysfs.h>
> >>>> +#include <linux/kthread.h>
> >>>> +#include <linux/module.h>
> >>>> +#include <linux/of_device.h>
> >>>> +#include <linux/regmap.h>
> >>>> +#include <linux/sched/task.h>
> >>>> +#include <linux/util_macros.h>
> >>>> +
> >>>> +/* INA260 registers definition */
> >>>> +#define INA260_CONFIG 0x00
> >>>> +#define INA260_CURRENT 0x01 #define INA260_VOLTAGE
> >>>> +0x02 #define INA260_POWER 0x03 #define
> INA260_MASK_ENABLE
> >>>> +0x06 #define INA260_ALERT_LIMIT 0x07 #define
> INA260_MANF_ID
> >>>> +0xFE #define INA260_DIE_ID 0xFF
> >>>> +
> >>>> +#define INA260_CONFIG_DEFAULT 0x6327
> >>>> +
> >>>> +#define INA260_CURRENT_LSB 1250 #define
> INA260_VOLTAGE_LSB
> >>>> +1250 #define INA260_POWER_LSB 10
> >>>> +
> >>>> +/* Bits */
> >>>> +#define INA260_CVRF BIT(3)
> >>>> +
> >>>> +#define INA260_MODE_MASK GENMASK(2, 0) #define
> >> INA260_VOLT_MASK
> >>>> +GENMASK(8, 6) #define INA260_SHIFT_VOLT(val) ((val) << 6)
> >>>> +#define INA260_CURR_MASK GENMASK(5, 3) #define
> >> INA260_SHIFT_CURR(val)
> >>>> +((val) << 3) #define INA260_AVG_MASK GENMASK(11, 9) #define
> >>>> +INA260_SHIFT_AVG(val) ((val) << 9)
> >>>> +
> >>>> +#define SAMPLING_PERIOD(x) ({ \
> >>>> + typeof(x) _x = (x); \
> >>>> + (_x->config->volt_conv_time \
> >>>> + + _x->config->curr_conv_time) \
> >>>> + * _x->config->avgs; })
> >>>> +
> >>>> +static bool ina260_is_writeable_reg(struct device *dev, unsigned
> >>>> +int
> >>>> reg)
> >>>> +{
> >>>> + return (reg == INA260_CONFIG) || (reg == INA260_MASK_ENABLE)
> >>>> +||
> >>>> + (reg == INA260_ALERT_LIMIT); }
> >>>> +
> >>>> +static bool ina260_is_volatile_reg(struct device *dev, unsigned
> >>>> +int
> >>>> reg)
> >>>> +{
> >>>> + return (reg != INA260_CONFIG); }
> >>>> +
> >>>> +static inline bool is_signed_reg(unsigned int reg) {
> >>>> + return (reg == INA260_CURRENT); }
> >>>> +
> >>>> +static const struct regmap_config ina260_regmap_config = {
> >>>> + .reg_bits = 8,
> >>>> + .val_bits = 16,
> >>>> + .max_register = 8,
> >>>> + .writeable_reg = ina260_is_writeable_reg,
> >>>> + .volatile_reg = ina260_is_volatile_reg, };
> >>>> +
> >>>> +enum ina260_ids {ina260 = 0};
> >>>> +
> >>>> +/**
> >>>> + * struct ina260_config - For configurable parameters
> >>>> + * @config_default: Default configuration
> >>>> + * @volt_conv_time: Bus voltage conversion time
> >>>> + * @curr_conv_time: Shunt current conversion time
> >>>> + * @avgs: Number of samples collected and averaged */ struct
> >>>> +ina260_config {
> >>>> + u16 config_default;
> >>>> + int volt_conv_time;
> >>>> + int curr_conv_time;
> >>>> + int avgs;
> >>>> +};
> >>>> +
> >>>> +/**
> >>>> + * struct ina260_chip - For device specific data
> >>>> + * @regmap: Regmap pointer to device registers
> >>>> + * @task: Pointer to task created by buffer mode
> >>>> + * @lock: Mutex to enable use of multiple user apps
> >>>> + * @chip_id: Id to determine chip
> >>>> + * @config: Pointer to config structure */ struct ina260_chip {
> >>>> + struct regmap *regmap;
> >>>> + struct task_struct *task;
> >>>> + struct mutex lock; /* Lock for device writes */
> >>>> + enum ina260_ids chip_id;
> >>>> + struct ina260_config *config;
> >>>> +};
> >>>> +
> >>>> +static struct ina260_config ina260_config[] = {
> >>>> + [ina260] = {
> >>>> + .config_default = INA260_CONFIG_DEFAULT,
> >>>> + .volt_conv_time = 1100,
> >>>> + .curr_conv_time = 1100,
> >>>> + .avgs = 4,
> >>>> + },
> >>>> +};
> >>>> +
> >>>> +static int ina260_read_raw(struct iio_dev *indio_dev,
> >>>> + struct iio_chan_spec const *chan,
> >>>> + int *val, int *val2, long mask) {
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> + unsigned int regval;
> >>>> + int ret;
> >>>> +
> >>>> + switch (mask) {
> >>>> + case IIO_CHAN_INFO_RAW:
> >>>> + if (iio_buffer_enabled(indio_dev))
> >>>> + return -EBUSY;
> >>>> +
> >>>> + ret = regmap_read(chip->regmap, chan->address, ®val);
> >>>> + if (ret)
> >>>> + return ret;
> >>>> +
> >>>> + if (is_signed_reg(chan->address))
> >>>> + *val = (s16)regval;
> >>>> + else
> >>>> + *val = regval;
> >>>> + return IIO_VAL_INT;
> >>>> +
> >>>> + case IIO_CHAN_INFO_SCALE:
> >>>> + switch (chan->address) {
> >>>> + case INA260_CURRENT:
> >>>> + *val = INA260_CURRENT_LSB;
> >>>> + *val2 = 1000;
> >>>> + return IIO_VAL_FRACTIONAL;
> >>>> +
> >>>> + case INA260_VOLTAGE:
> >>>> + *val = INA260_VOLTAGE_LSB;
> >>>> + *val2 = 1000;
> >>>> + return IIO_VAL_FRACTIONAL;
> >>>> +
> >>>> + case INA260_POWER:
> >>>> + *val = INA260_POWER_LSB;
> >>>> + return IIO_VAL_INT;
> >>>> + }
> >>>> + return -EINVAL;
> >>>> +
> >>>> + case IIO_CHAN_INFO_INT_TIME:
> >>>> + *val = 0;
> >>>> + if (chan->address == INA260_VOLTAGE)
> >>>> + *val2 = chip->config->volt_conv_time;
> >>>> + else
> >>>> + *val2 = chip->config->curr_conv_time;
> >>>> +
> >>>> + return IIO_VAL_INT_PLUS_MICRO;
> >>>> +
> >>>> + case IIO_CHAN_INFO_SAMP_FREQ:
> >>>> + *val = DIV_ROUND_CLOSEST(1000000, SAMPLING_PERIOD(chip));
> >>>> + return IIO_VAL_INT;
> >>>> +
> >>>> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> >>>> + *val = chip->config->avgs;
> >>>> + return IIO_VAL_INT;
> >>>> + }
> >>>> +
> >>>> + return -EINVAL;
> >>>> +}
> >>>> +
> >>>> +static const int ina260_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512,
> >>>> 1024 };
> >>>> +
> >>>> +/* Conversion times in uS */
> >>>> +static const int ina260_conv_time_tab[] = { 140, 204, 332, 588,
> >>>> 1100, 2116, 4156, 8244 };
> >>>> +
> >>>> +static int ina260_write_raw(struct iio_dev *indio_dev,
> >>>> + struct iio_chan_spec const *chan,
> >>>> + int val, int val2, long mask) {
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> + unsigned int config;
> >>>> + int ret, bits;
> >>>> +
> >>>> + if (iio_buffer_enabled(indio_dev))
> >>>> + return -EBUSY;
> >>>> +
> >>>> + mutex_lock(&chip->lock);
> >>>> +
> >>>> + ret = regmap_read(chip->regmap, INA260_CONFIG, &config);
> >>>> + if (ret)
> >>>> + goto err;
> >>>> +
> >>>> + switch (mask) {
> >>>> + case IIO_CHAN_INFO_INT_TIME:
> >>>> + if (val2 > 8244 || val2 < 140) {
> >>>> + ret = -EINVAL;
> >>>> + goto err;
> >>>> + }
> >>>> +
> >>>> + bits = find_closest(val2, ina260_conv_time_tab,
> >>>> + ARRAY_SIZE(ina260_conv_time_tab));
> >>>> +
> >>>> + if (chan->address == INA260_VOLTAGE) {
> >>>> + chip->config->volt_conv_time =
> >>>> +ina260_conv_time_tab[bits];
> >>>> + config &= ~INA260_VOLT_MASK;
> >>>> + config |= INA260_SHIFT_VOLT(bits) & INA260_VOLT_MASK;
> >>>> + } else {
> >>>> + chip->config->curr_conv_time =
> >>>> +ina260_conv_time_tab[bits];
> >>>> + config &= ~INA260_CURR_MASK;
> >>>> + config |= INA260_SHIFT_CURR(bits) & INA260_CURR_MASK;
> >>>> + }
> >>>> + break;
> >>>> +
> >>>> + case IIO_CHAN_INFO_OVERSAMPLING_RATIO:
> >>>> + bits = find_closest(val, ina260_avg_tab,
> >>>> ARRAY_SIZE(ina260_avg_tab));
> >>>> + chip->config->avgs = ina260_avg_tab[bits];
> >>>> + config &= ~INA260_AVG_MASK;
> >>>> + config |= INA260_SHIFT_AVG(bits) & INA260_AVG_MASK;
> >>>> + break;
> >>>> +
> >>>> + default:
> >>>> + ret = -EINVAL;
> >>>> + }
> >>>> + if (!ret)
> >>>> + ret = regmap_write(chip->regmap, INA260_CONFIG, config);
> >>>> +err:
> >>>> + mutex_unlock(&chip->lock);
> >>>> +
> >>>> + return ret;
> >>>> +}
> >>>> +
> >>>> +static int ina260_debug_reg(struct iio_dev *indio_dev,
> >>>> + unsigned int reg, unsigned int writeval, unsigned
> >>>> int *readval)
> >>>> +{
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> +
> >>>> + if (!readval)
> >>>> + return regmap_write(chip->regmap, reg, writeval);
> >>>> +
> >>>> + return regmap_read(chip->regmap, reg, readval); }
> >>>> +
> >>>> +#define INA260_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_CPU, \
> >>>> + } \
> >>>> +}
> >>>> +
> >>>> +#define INA260_CHAN_CURRENT(_index, _address) { \
> >>>> + .type = IIO_CURRENT, \
> >>>> + .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 = 's', \
> >>>> + .realbits = 16, \
> >>>> + .storagebits = 16, \
> >>>> + .endianness = IIO_CPU, \
> >>>> + } \
> >>>> +}
> >>>> +
> >>>> +#define INA260_CHAN_POWER(_index, _address) { \
> >>>> + .type = IIO_POWER, \
> >>>> + .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), \
> >>>> + .scan_index = (_index), \
> >>>> + .scan_type = { \
> >>>> + .sign = 'u', \
> >>>> + .realbits = 16, \
> >>>> + .storagebits = 16, \
> >>>> + .endianness = IIO_CPU, \
> >>>> + } \
> >>>> +}
> >>>> +
> >>>> +static const struct iio_chan_spec ina260_channels[] = {
> >>>> + INA260_CHAN_CURRENT(0, INA260_CURRENT),
> >>>> + INA260_CHAN_VOLTAGE(1, INA260_VOLTAGE),
> >>>> + INA260_CHAN_POWER(2, INA260_POWER),
> >>>> + IIO_CHAN_SOFT_TIMESTAMP(3),
> >>>> +};
> >>>> +
> >>>> +/* Possible integration times for current and voltage */ static
> >>>> +IIO_CONST_ATTR_NAMED(ina260_integration_time_available,
> >>>> + integration_time_available,
> >>>> + "0.000140 0.000204 0.000332 0.000588 0.001100
> >>>> 0.002116 0.004156 0.008244");
> >>>> +
> >>>> +static struct attribute *ina260_attributes[] = {
> >>>> +&iio_const_attr_ina260_integration_time_available.dev_attr.attr,
> >>>> + NULL,
> >>>> +};
> >>>> +
> >>>> +static const struct attribute_group ina260_attribute_group = {
> >>>> + .attrs = ina260_attributes,
> >>>> +};
> >>>> +
> >>>> +static const struct iio_info ina260_info = {
> >>>> + .attrs = &ina260_attribute_group,
> >>>> + .read_raw = ina260_read_raw,
> >>>> + .write_raw = ina260_write_raw,
> >>>> + .debugfs_reg_access = ina260_debug_reg, };
> >>>> +
> >>>> +static int ina260_conversion_ready(struct iio_dev *indio_dev) {
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> + unsigned int alert;
> >>>> + int ret;
> >>>> +
> >>>> + ret = regmap_read(chip->regmap, INA260_MASK_ENABLE, &alert);
> >>>> + if (ret < 0)
> >>>> + return ret;
> >>>> +
> >>>> + return (alert & INA260_CVRF);
> >>>> +}
> >>>> +
> >>>> +static int ina260_work_buffer(struct iio_dev *indio_dev) {
> >>>> + /* data buffer needs space for channel data and timestap */
> >>>> + unsigned short data[3 + sizeof(s64) / sizeof(short)];
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> + int bit, ret, i = 0;
> >>>> + s64 time;
> >>>> +
> >>>> + time = iio_get_time_ns(indio_dev);
> >>>> +
> >>>> + /*
> >>>> + * Read current, voltage and power from device
> >>>> + */
> >>>> + for_each_set_bit(bit, indio_dev->active_scan_mask,
> >>>> + indio_dev->masklength) {
> >>>> + unsigned int val;
> >>>> +
> >>>> + ret = regmap_read(chip->regmap, INA260_CURRENT + bit,
> >>>> +&val);
> >>>> + if (ret < 0)
> >>>> + return ret;
> >>>> +
> >>>> + data[i++] = val;
> >>>> + }
> >>>> +
> >>>> + iio_push_to_buffers_with_timestamp(indio_dev, data, time);
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static int ina260_capture_thread(void *data) {
> >>>> + struct iio_dev *indio_dev = data;
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> + int sampling_us = SAMPLING_PERIOD(chip);
> >>>> + struct timespec64 next, now, delta;
> >>>> + s64 delay_us;
> >>>> + int ret;
> >>>> +
> >>>> + ktime_get_ts64(&next);
> >>>> +
> >>>> + do {
> >>>> + while (1) {
> >>>> + /* Check if conversion is ready */
> >>>> + ret = ina260_conversion_ready(indio_dev);
> >>>> + if (ret < 0)
> >>>> + return ret;
> >>>> +
> >>>> + /*
> >>>> + * If the conversion was not yet finished,
> >>>> + * reset the reference timestamp.
> >>>> + */
> >>>> + if (ret == 0)
> >>>> + ktime_get_ts64(&next);
> >>>> + else
> >>>> + break;
> >>>> + }
> >>>> + /* Read the data from sensor and push it to buffers */
> >>>> + ret = ina260_work_buffer(indio_dev);
> >>>> + if (ret < 0)
> >>>> + return ret;
> >>>> +
> >>>> + ktime_get_ts64(&now);
> >>>> + /*
> >>>> + * Advance the timestamp for the next poll by one sampling
> >>>> + * interval, and sleep for the remainder (next - now)
> >>>> + * In case "next" has already passed, the interval is
> >>>> +added
> >>>> + * multiple times, i.e. samples are dropped.
> >>>> + */
> >>>> + do {
> >>>> + timespec64_add_ns(&next, 1000 * sampling_us);
> >>>> + delta = timespec64_sub(next, now);
> >>>> + delay_us = div_s64(timespec64_to_ns(&delta), 1000);
> >>>> + } while (delay_us <= 0);
> >>>> +
> >>>> + usleep_range(delay_us, (delay_us * 3) >> 1);
> >>>> +
> >>>> + } while (!kthread_should_stop());
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static int ina260_buffer_enable(struct iio_dev *indio_dev) {
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> + unsigned int sampling_us = SAMPLING_PERIOD(chip);
> >>>> + struct task_struct *task;
> >>>> +
> >>>> + task = kthread_create(ina260_capture_thread, (void
> >>>> +*)indio_dev,
> >>>> + "%s:%d-%uus", indio_dev->name, indio_dev->id,
> >>>> + sampling_us);
> >>>> +
> >>>> + if (IS_ERR(task))
> >>>> + return PTR_ERR(task);
> >>>> +
> >>>> + get_task_struct(task);
> >>>> + wake_up_process(task);
> >>>> + chip->task = task;
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static int ina260_buffer_disable(struct iio_dev *indio_dev) {
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> +
> >>>> + if (chip->task) {
> >>>> + kthread_stop(chip->task);
> >>>> + put_task_struct(chip->task);
> >>>> + chip->task = NULL;
> >>>> + }
> >>>> +
> >>>> + return 0;
> >>>> +}
> >>>> +
> >>>> +static const struct iio_buffer_setup_ops ina260_setup_ops = {
> >>>> + .postenable = &ina260_buffer_enable,
> >>>> + .predisable = &ina260_buffer_disable, };
> >>>> +
> >>>> +static int ina260_probe(struct i2c_client *client, const struct
> >>>> i2c_device_id *id)
> >>>> +{
> >>>> + struct iio_dev *indio_dev;
> >>>> + struct iio_buffer *buffer;
> >>>> + struct ina260_chip *chip;
> >>>> + enum ina260_ids type = 0;
> >>>> + int ret;
> >>>> +
> >>>> + indio_dev = devm_iio_device_alloc(&client->dev,
> >>>> +sizeof(*chip));
> >>>> + if (!indio_dev)
> >>>> + return -ENOMEM;
> >>>> +
> >>>> + chip = iio_priv(indio_dev);
> >>>> + i2c_set_clientdata(client, indio_dev);
> >>>> +
> >>>> + chip->regmap = devm_regmap_init_i2c(client,
> >>>> +&ina260_regmap_config);
> >>>> + if (IS_ERR(chip->regmap)) {
> >>>> + dev_err(&client->dev, "failed to allocate register
> >>>> +map\n");
> >>>> + return PTR_ERR(chip->regmap);
> >>>> + }
> >>>> +
> >>>> + mutex_init(&chip->lock);
> >>>> +
> >>>> + indio_dev->modes = INDIO_DIRECT_MODE |
> >> INDIO_BUFFER_SOFTWARE;
> >>>> + indio_dev->dev.parent = &client->dev;
> >>>> + indio_dev->dev.of_node = client->dev.of_node;
> >>>> +
> >>>> + chip->config = &ina260_config[type];
> >>>> + ret = regmap_write(chip->regmap, INA260_CONFIG,
> >>>> + chip->config->config_default);
> >>>> + if (ret) {
> >>>> + dev_err(&client->dev, "Error configuring the device\n");
> >>>> + return ret;
> >>>> + }
> >>>> + indio_dev->channels = ina260_channels;
> >>>> + indio_dev->num_channels = ARRAY_SIZE(ina260_channels);
> >>>> + indio_dev->info = &ina260_info;
> >>>> + indio_dev->name = id->name;
> >>>> + indio_dev->setup_ops = &ina260_setup_ops;
> >>>> +
> >>>> + buffer = devm_iio_kfifo_allocate(&indio_dev->dev);
> >>>> + if (!buffer)
> >>>> + return -ENOMEM;
> >>>> +
> >>>> + iio_device_attach_buffer(indio_dev, buffer);
> >>>> +
> >>>> + return iio_device_register(indio_dev); }
> >>>> +
> >>>> +static int ina260_remove(struct i2c_client *client) {
> >>>> + struct iio_dev *indio_dev = i2c_get_clientdata(client);
> >>>> + struct ina260_chip *chip = iio_priv(indio_dev);
> >>>> +
> >>>> + iio_device_unregister(indio_dev);
> >>>> + /* Power down */
> >>>> + return regmap_update_bits(chip->regmap, INA260_CONFIG,
> >>>> INA260_MODE_MASK, 0);
> >>>> +}
> >>>> +
> >>>> +static const struct i2c_device_id ina260_id[] = {
> >>>> + {"ina260", ina260},
> >>>> + {}
> >>>> +};
> >>>> +MODULE_DEVICE_TABLE(i2c, ina260_id);
> >>>> +
> >>>> +static const struct of_device_id ina260_of_match[] = {
> >>>> + {
> >>>> + .compatible = "ti,ina260",
> >>>> + .data = (void *)ina260
> >>>> + },
> >>>> + {},
> >>>> +};
> >>>> +MODULE_DEVICE_TABLE(of, ina260_of_match);
> >>>> +
> >>>> +static struct i2c_driver ina260_driver = {
> >>>> + .driver = {
> >>>> + .name = "ina260-adc",
> >>>> + .of_match_table = ina260_of_match,
> >>>> + },
> >>>> + .probe = ina260_probe,
> >>>> + .remove = ina260_remove,
> >>>> + .id_table = ina260_id,
> >>>> +};
> >>>> +module_i2c_driver(ina260_driver);
> >>>> +
> >>>> +MODULE_AUTHOR("Raviteja Narayanam
> >> <raviteja.narayanam@xxxxxxxxxx>");
> >>>> +MODULE_DESCRIPTION("Texas Instruments INA 260 ADC driver");
> >>>> +MODULE_LICENSE("GPL v2");
> >>>