path: root/drivers/iio/adc/ina2xx-adc.c

/*
 * INA2XX Current and Power Monitors
 *
 * Copyright 2015 Baylibre SAS.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 *
 * Based on linux/drivers/iio/adc/ad7291.c
 * Copyright 2010-2011 Analog Devices Inc.
 *
 * Based on linux/drivers/hwmon/ina2xx.c
 * Copyright 2012 Lothar Felten <l-felten@ti.com>
 *
 * Licensed under the GPL-2 or later.
 *
 * IIO driver for INA219-220-226-230-231
 *
 * Configurable 7-bit I2C slave address from 0x40 to 0x4F
 */

#include <linux/delay.h>
#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>

#include <linux/platform_data/ina2xx.h>

/* INA2XX registers definition */
#define INA2XX_CONFIG                   0x00
#define INA2XX_SHUNT_VOLTAGE            0x01	/* readonly */
#define INA2XX_BUS_VOLTAGE              0x02	/* readonly */
#define INA2XX_POWER                    0x03	/* readonly */
#define INA2XX_CURRENT                  0x04	/* readonly */
#define INA2XX_CALIBRATION              0x05

#define INA226_MASK_ENABLE		0x06
#define INA226_CVRF			BIT(3)

#define INA2XX_MAX_REGISTERS            8

/* settings - depend on use case */
#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=1/8, BRNG=32V */
#define INA219_DEFAULT_IT		532
#define INA219_DEFAULT_BRNG             1   /* 32V */
#define INA219_DEFAULT_PGA              125 /* 1000/8 */
#define INA226_CONFIG_DEFAULT           0x4327
#define INA226_DEFAULT_AVG              4
#define INA226_DEFAULT_IT		1110

#define INA2XX_RSHUNT_DEFAULT           10000

/*
 * bit masks for reading the settings in the configuration register
 * FIXME: use regmap_fields.
 */
#define INA2XX_MODE_MASK	GENMASK(3, 0)

/* Gain for VShunt: 1/8 (default), 1/4, 1/2, 1 */
#define INA219_PGA_MASK		GENMASK(12, 11)
#define INA219_SHIFT_PGA(val)	((val) << 11)

/* VBus range: 32V (default), 16V */
#define INA219_BRNG_MASK	BIT(13)
#define INA219_SHIFT_BRNG(val)	((val) << 13)

/* 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)

/* INA219 Bus voltage register, low bits are flags */
#define INA219_OVF		BIT(0)
#define INA219_CNVR		BIT(1)
#define INA219_BUS_VOLTAGE_SHIFT	3

/* Cosmetic macro giving the sampling period for a full P=UxI cycle */
#define SAMPLING_PERIOD(c)	((c->int_time_vbus + c->int_time_vshunt) \
				 * c->avg)

static bool ina2xx_is_writeable_reg(struct device *dev, unsigned int reg)
{
	return (reg == INA2XX_CONFIG) || (reg > INA2XX_CURRENT);
}

static bool ina2xx_is_volatile_reg(struct device *dev, unsigned int reg)
{
	return (reg != INA2XX_CONFIG);
}

static inline bool is_signed_reg(unsigned int reg)
{
	return (reg == INA2XX_SHUNT_VOLTAGE) || (reg == INA2XX_CURRENT);
}

static const struct regmap_config ina2xx_regmap_config = {
	.reg_bits = 8,
	.val_bits = 16,
	.max_register = INA2XX_MAX_REGISTERS,
	.writeable_reg = ina2xx_is_writeable_reg,
	.volatile_reg = ina2xx_is_volatile_reg,
};

enum ina2xx_ids { ina219, ina226 };

struct ina2xx_config {
	const char *name;
	u16 config_default;
	int calibration_value;
	int shunt_voltage_lsb;	/* nV */
	int bus_voltage_shift;	/* position of lsb */
	int bus_voltage_lsb;	/* uV */
	/* fixed relation between current and power lsb, uW/uA */
	int power_lsb_factor;
	enum ina2xx_ids chip_id;
};

struct ina2xx_chip_info {
	struct regmap *regmap;
	struct task_struct *task;
	const struct ina2xx_config *config;
	struct mutex state_lock;
	unsigned int shunt_resistor_uohm;
	int avg;
	int int_time_vbus; /* Bus voltage integration time uS */
	int int_time_vshunt; /* Shunt voltage integration time uS */
	int range_vbus; /* Bus voltage maximum in V */
	int pga_gain_vshunt; /* Shunt voltage PGA gain */
	bool allow_async_readout;
	/* data buffer needs space for channel data and timestamp */
	struct {
		u16 chan[4];
		u64 ts __aligned(8);
	} scan;
};

static const struct ina2xx_config ina2xx_config[] = {
	[ina219] = {
		.name = "ina219",
		.config_default = INA219_CONFIG_DEFAULT,
		.calibration_value = 4096,
		.shunt_voltage_lsb = 10000,
		.bus_voltage_shift = INA219_BUS_VOLTAGE_SHIFT,
		.bus_voltage_lsb = 4000,
		.power_lsb_factor = 20,
		.chip_id = ina219,
	},
	[ina226] = {
		.name = "ina226",
		.config_default = INA226_CONFIG_DEFAULT,
		.calibration_value = 2048,
		.shunt_voltage_lsb = 2500,
		.bus_voltage_shift = 0,
		.bus_voltage_lsb = 1250,
		.power_lsb_factor = 25,
		.chip_id = ina226,
	},
};

static int ina2xx_read_raw(struct iio_dev *indio_dev,
			   struct iio_chan_spec const *chan,
			   int *val, int *val2, long mask)
{
	int ret;
	struct ina2xx_chip_info *chip = iio_priv(indio_dev);
	unsigned int regval;

	switch (mask) {
	case IIO_CHAN_INFO_RAW:
		ret = regmap_read(chip->regmap, chan->address, &regval);
		if (ret)
			return ret;

		if (is_signed_reg(chan->address))
			*val = (s16) regval;
		else
			*val  = regval;

		if (chan->address == INA2XX_BUS_VOLTAGE)
			*val >>= chip->config->