[PATCH 2/2] iio: adc: Add support for TI INA260 power monitors

From: Raviteja Narayanam
Date: Mon Mar 22 2021 - 06:53:09 EST

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>
---
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, &regval);
+ 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");
--
2.17.1