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Commit c43a102e authored by Marc Titinger's avatar Marc Titinger Committed by Jonathan Cameron
Browse files

iio: ina2xx: add support for TI INA2xx Power Monitors 

in SOFTWARE buffer mode, a kthread will capture the active scan_elements
into a kfifo, then compute the remaining time until the next capture tick
and do an active wait (udelay).

This will produce a stream of up to fours channels plus a 64bits
timestamps (ns).

Tested with ina226, on BeagleBoneBlack.

Datasheet: http://www.ti.com/lit/gpn/ina226



Signed-off-by: default avatarMarc Titinger <mtitinger@baylibre.com>
Signed-off-by: default avatarJonathan Cameron <jic23@kernel.org>
parent 466df4d0

drivers/iio/adc/Kconfig

+10 −0
Original line number Diff line number Diff line
@@ -194,6 +194,16 @@ config HI8435 
	  This driver can also be built as a module. If so, the module will be

	  called hi8435.



config INA2XX_ADC

	tristate "Texas Instruments INA2xx Power Monitors IIO driver"

	depends on I2C && !SENSORS_INA2XX

	select REGMAP_I2C

	select IIO_BUFFER

	select IIO_KFIFO_BUF

	help

	  Say yes here to build support for TI INA2xx family of Power Monitors.

	  This driver is mutually exclusive with the HWMON version.



config LP8788_ADC

	tristate "LP8788 ADC driver"

	depends on MFD_LP8788

drivers/iio/adc/Makefile

+1 −0
Original line number Diff line number Diff line
@@ -20,6 +20,7 @@ obj-$(CONFIG_CC10001_ADC) += cc10001_adc.o 
obj-$(CONFIG_DA9150_GPADC) += da9150-gpadc.o

obj-$(CONFIG_EXYNOS_ADC) += exynos_adc.o

obj-$(CONFIG_HI8435) += hi8435.o

obj-$(CONFIG_INA2XX_ADC) += ina2xx-adc.o

obj-$(CONFIG_LP8788_ADC) += lp8788_adc.o

obj-$(CONFIG_MAX1027) += max1027.o

obj-$(CONFIG_MAX1363) += max1363.o

drivers/iio/adc/ina2xx-adc.c

0 → 100644
+668 −0
Original line number Diff line number Diff line 
/*

 * 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/module.h>

#include <linux/kthread.h>

#include <linux/delay.h>

#include <linux/iio/kfifo_buf.h>

#include <linux/iio/sysfs.h>

#include <linux/i2c.h>

#include <linux/regmap.h>

#include <linux/platform_data/ina2xx.h>



#include <linux/util_macros.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_ALERT_MASK		0x06

#define INA266_CVRF			BIT(3)



#define INA2XX_MAX_REGISTERS            8



/* settings - depend on use case */

#define INA219_CONFIG_DEFAULT           0x399F	/* PGA=8 */

#define INA226_CONFIG_DEFAULT           0x4327

#define INA226_DEFAULT_AVG              4

#define INA226_DEFAULT_IT		1110



#define INA2XX_RSHUNT_DEFAULT           10000



/*

 * bit mask for reading the averaging setting in the configuration register

 * FIXME: use regmap_fields.

 */

#define INA2XX_MODE_MASK	GENMASK(3, 0)



#define INA226_AVG_MASK		GENMASK(11, 9)

#define INA226_SHIFT_AVG(val)	((val) << 9)



/* Integration time for VBus */

#define INA226_ITB_MASK		GENMASK(8, 6)

#define INA226_SHIFT_ITB(val)	((val) << 6)



/* Integration time for VShunt */

#define INA226_ITS_MASK		GENMASK(5, 3)

#define INA226_SHIFT_ITS(val)	((val) << 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 {

	u16 config_default;

	int calibration_factor;

	int shunt_div;

	int bus_voltage_shift;

	int bus_voltage_lsb;	/* uV */

	int power_lsb;		/* uW */

};



struct ina2xx_chip_info {

	struct regmap *regmap;

	struct task_struct *task;

	const struct ina2xx_config *config;

	struct mutex state_lock;

	long rshunt;

	int avg;

	s64 prev_ns;	/* track buffer capture time, check for underruns*/

	int int_time_vbus; /* Bus voltage integration time uS */

	int int_time_vshunt; /* Shunt voltage integration time uS */

};



static const struct ina2xx_config ina2xx_config[] = {

	[ina219] = {

		    .config_default = INA219_CONFIG_DEFAULT,

		    .calibration_factor = 40960000,

		    .shunt_div = 100,

		    .bus_voltage_shift = 3,

		    .bus_voltage_lsb = 4000,

		    .power_lsb = 20000,

		    },

	[ina226] = {

		    .config_default = INA226_CONFIG_DEFAULT,

		    .calibration_factor = 5120000,

		    .shunt_div = 400,

		    .bus_voltage_shift = 0,

		    .bus_voltage_lsb = 1250,

		    .power_lsb = 25000,

		    },

};



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 < 0)

			return ret;



		if (is_signed_reg(chan->address))

			*val = (s16) regval;

		else

			*val  = regval;



		return IIO_VAL_INT;



	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		*val = chip->avg;

		return IIO_VAL_INT;



	case IIO_CHAN_INFO_INT_TIME:

		*val = 0;

		if (chan->address == INA2XX_SHUNT_VOLTAGE)

			*val2 = chip->int_time_vshunt;

		else

			*val2 = chip->int_time_vbus;



		return IIO_VAL_INT_PLUS_MICRO;



	case IIO_CHAN_INFO_SAMP_FREQ:

		/*

		 * Sample freq is read only, it is a consequence of

		 * 1/AVG*(CT_bus+CT_shunt).

		 */

		*val = DIV_ROUND_CLOSEST(1000000, SAMPLING_PERIOD(chip));



		return IIO_VAL_INT;



	case IIO_CHAN_INFO_SCALE:

		switch (chan->address) {

		case INA2XX_SHUNT_VOLTAGE:

			/* processed (mV) = raw*1000/shunt_div */

			*val2 = chip->config->shunt_div;

			*val = 1000;

			return IIO_VAL_FRACTIONAL;



		case INA2XX_BUS_VOLTAGE:

			/* processed (mV) = raw*lsb (uV) / (1000 << shift) */

			*val = chip->config->bus_voltage_lsb;

			*val2 = 1000 << chip->config->bus_voltage_shift;

			return IIO_VAL_FRACTIONAL;



		case INA2XX_POWER:

			/* processed (mW) = raw*lsb (uW) / 1000 */

			*val = chip->config->power_lsb;

			*val2 = 1000;

			return IIO_VAL_FRACTIONAL;



		case INA2XX_CURRENT:

			/* processed (mA) = raw (mA) */

			*val = 1;

			return IIO_VAL_INT;

		}

	}



	return -EINVAL;

}



/*

 * Available averaging rates for ina226. The indices correspond with

 * the bit values expected by the chip (according to the ina226 datasheet,

 * table 3 AVG bit settings, found at

 * http://www.ti.com/lit/ds/symlink/ina226.pdf.

 */

static const int ina226_avg_tab[] = { 1, 4, 16, 64, 128, 256, 512, 1024 };



static int ina226_set_average(struct ina2xx_chip_info *chip, unsigned int val,

			      unsigned int *config)

{

	int bits;



	if (val > 1024 || val < 1)

		return -EINVAL;



	bits = find_closest(val, ina226_avg_tab,

			    ARRAY_SIZE(ina226_avg_tab));



	chip->avg = ina226_avg_tab[bits];



	*config &= ~INA226_AVG_MASK;

	*config |= INA226_SHIFT_AVG(bits) & INA226_AVG_MASK;



	return 0;

}



/* Conversion times in uS */

static const int ina226_conv_time_tab[] = { 140, 204, 332, 588, 1100,

					    2116, 4156, 8244 };



static int ina226_set_int_time_vbus(struct ina2xx_chip_info *chip,

				    unsigned int val_us, unsigned int *config)

{

	int bits;



	if (val_us > 8244 || val_us < 140)

		return -EINVAL;



	bits = find_closest(val_us, ina226_conv_time_tab,

			ARRAY_SIZE(ina226_conv_time_tab));



	chip->int_time_vbus = ina226_conv_time_tab[bits];



	*config &= ~INA226_ITB_MASK;

	*config |= INA226_SHIFT_ITB(bits) & INA226_ITB_MASK;



	return 0;

}



static int ina226_set_int_time_vshunt(struct ina2xx_chip_info *chip,

				      unsigned int val_us, unsigned int *config)

{

	int bits;



	if (val_us > 8244 || val_us < 140)

		return -EINVAL;



	bits = find_closest(val_us, ina226_conv_time_tab,

			ARRAY_SIZE(ina226_conv_time_tab));



	chip->int_time_vshunt = ina226_conv_time_tab[bits];



	*config &= ~INA226_ITS_MASK;

	*config |= INA226_SHIFT_ITS(bits) & INA226_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)

{

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);

	int ret;

	unsigned int config, tmp;



	if (iio_buffer_enabled(indio_dev))

		return -EBUSY;



	mutex_lock(&chip->state_lock);



	ret = regmap_read(chip->regmap, INA2XX_CONFIG, &config);

	if (ret < 0)

		goto _err;



	tmp = config;



	switch (mask) {

	case IIO_CHAN_INFO_OVERSAMPLING_RATIO:

		ret = ina226_set_average(chip, val, &tmp);

		break;



	case IIO_CHAN_INFO_INT_TIME:

		if (chan->address == INA2XX_SHUNT_VOLTAGE)

			ret = ina226_set_int_time_vshunt(chip, val2, &tmp);

		else

			ret = ina226_set_int_time_vbus(chip, val2, &tmp);

		break;

	default:

		ret = -EINVAL;

	}



	if (!ret && (tmp != config))

		ret = regmap_write(chip->regmap, INA2XX_CONFIG, tmp);

_err:

	mutex_unlock(&chip->state_lock);



	return ret;

}





#define INA2XX_CHAN(_type, _index, _address) { \

	.type = (_type), \

	.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_LE, \

	} \

}



/*

 * Sampling Freq is a consequence of the integration times of

 * the Voltage channels.

 */

#define INA2XX_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), \

	.scan_index = (_index), \

	.scan_type = { \

		.sign = 'u', \

		.realbits = 16, \

		.storagebits = 16, \

		.endianness = IIO_LE, \

	} \

}



static const struct iio_chan_spec ina2xx_channels[] = {

	INA2XX_CHAN_VOLTAGE(0, INA2XX_SHUNT_VOLTAGE),

	INA2XX_CHAN_VOLTAGE(1, INA2XX_BUS_VOLTAGE),

	INA2XX_CHAN(IIO_CURRENT, 2, INA2XX_CURRENT),

	INA2XX_CHAN(IIO_POWER, 3, INA2XX_POWER),

	IIO_CHAN_SOFT_TIMESTAMP(4),

};



static int ina2xx_work_buffer(struct iio_dev *indio_dev)

{

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);

	unsigned short data[8];

	int bit, ret, i = 0;

	unsigned long buffer_us, elapsed_us;

	s64 time_a, time_b;

	unsigned int alert;



	time_a = iio_get_time_ns();



	/*

	 * Because the timer thread and the chip conversion clock

	 * are asynchronous, the period difference will eventually

	 * result in reading V[k-1] again, or skip V[k] at time Tk.

	 * In order to resync the timer with the conversion process

	 * we check the ConVersionReadyFlag.

	 * On hardware that supports using the ALERT pin to toggle a

	 * GPIO a triggered buffer could be used instead.

	 * For now, we pay for that extra read of the ALERT register

	 */

	do {

		ret = regmap_read(chip->regmap, INA226_ALERT_MASK,

				  &alert);

		if (ret < 0)

			return ret;



		alert &= INA266_CVRF;

		trace_printk("Conversion ready: %d\n", !!alert);



	} while (!alert);



	/*

	 * Single register reads: bulk_read will not work with ina226

	 * as there is no auto-increment of the address register for

	 * data length longer than 16bits.

	 */

	for_each_set_bit(bit, indio_dev->active_scan_mask,

			 indio_dev->masklength) {

		unsigned int val;



		ret = regmap_read(chip->regmap,

				  INA2XX_SHUNT_VOLTAGE + bit, &val);

		if (ret < 0)

			return ret;



		data[i++] = val;

	}



	time_b = iio_get_time_ns();



	iio_push_to_buffers_with_timestamp(indio_dev,

					   (unsigned int *)data, time_a);



	buffer_us = (unsigned long)(time_b - time_a) / 1000;

	elapsed_us = (unsigned long)(time_a - chip->prev_ns) / 1000;



	trace_printk("uS: elapsed: %lu, buf: %lu\n", elapsed_us, buffer_us);



	chip->prev_ns = time_a;



	return buffer_us;

};



static int ina2xx_capture_thread(void *data)

{

	struct iio_dev *indio_dev = (struct iio_dev *)data;

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);

	unsigned int sampling_us = SAMPLING_PERIOD(chip);

	int buffer_us;



	/*

	 * Poll a bit faster than the chip internal Fs, in case

	 * we wish to sync with the conversion ready flag.

	 */

	sampling_us -= 200;



	do {

		buffer_us = ina2xx_work_buffer(indio_dev);

		if (buffer_us < 0)

			return buffer_us;



		if (sampling_us > buffer_us)

			udelay(sampling_us - buffer_us);



	} while (!kthread_should_stop());



	return 0;

}



static int ina2xx_buffer_enable(struct iio_dev *indio_dev)

{

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);

	unsigned int sampling_us = SAMPLING_PERIOD(chip);



	trace_printk("Enabling buffer w/ scan_mask %02x, freq = %d, avg =%u\n",

		     (unsigned int)(*indio_dev->active_scan_mask),

		     1000000/sampling_us, chip->avg);



	trace_printk("Expected work period: %u us\n", sampling_us);



	chip->prev_ns = iio_get_time_ns();



	chip->task = kthread_run(ina2xx_capture_thread, (void *)indio_dev,

				 "ina2xx-%uus", sampling_us);



	return PTR_ERR_OR_ZERO(chip->task);

}



static int ina2xx_buffer_disable(struct iio_dev *indio_dev)

{

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);



	if (chip->task) {

		kthread_stop(chip->task);

		chip->task = NULL;

	}



	return 0;

}



static const struct iio_buffer_setup_ops ina2xx_setup_ops = {

	.postenable = &ina2xx_buffer_enable,

	.predisable = &ina2xx_buffer_disable,

};



static int ina2xx_debug_reg(struct iio_dev *indio_dev,

			    unsigned reg, unsigned writeval, unsigned *readval)

{

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);



	if (!readval)

		return regmap_write(chip->regmap, reg, writeval);



	return regmap_read(chip->regmap, reg, readval);

}



/* 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 struct attribute *ina2xx_attributes[] = {

	&iio_const_attr_integration_time_available.dev_attr.attr,

	NULL,

};



static const struct attribute_group ina2xx_attribute_group = {

	.attrs = ina2xx_attributes,

};



static const struct iio_info ina2xx_info = {

	.debugfs_reg_access = &ina2xx_debug_reg,

	.read_raw = &ina2xx_read_raw,

	.write_raw = &ina2xx_write_raw,

	.attrs = &ina2xx_attribute_group,

	.driver_module = THIS_MODULE,

};



/* Initialize the configuration and calibration registers. */

static int ina2xx_init(struct ina2xx_chip_info *chip, unsigned int config)

{

	u16 regval;

	int ret = regmap_write(chip->regmap, INA2XX_CONFIG, config);



	if (ret < 0)

		return ret;

	/*

	 * Set current LSB to 1mA, shunt is in uOhms

	 * (equation 13 in datasheet). We hardcode a Current_LSB

	 * of 1.0 x10-6. The only remaining parameter is RShunt.

	 * There is no need to expose the CALIBRATION register

	 * to the user for now.

	 */

	regval = DIV_ROUND_CLOSEST(chip->config->calibration_factor,

			    chip->rshunt);



	return regmap_write(chip->regmap, INA2XX_CALIBRATION, regval);

}



static int ina2xx_probe(struct i2c_client *client,

			const struct i2c_device_id *id)

{

	struct ina2xx_chip_info *chip;

	struct iio_dev *indio_dev;

	struct iio_buffer *buffer;

	int ret;

	unsigned int val;



	indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*chip));

	if (!indio_dev)

		return -ENOMEM;



	chip = iio_priv(indio_dev);



	chip->config = &ina2xx_config[id->driver_data];



	if (of_property_read_u32(client->dev.of_node,

				 "shunt-resistor", &val) < 0) {

		struct ina2xx_platform_data *pdata =

		    dev_get_platdata(&client->dev);



		if (pdata)

			val = pdata->shunt_uohms;

		else

			val = INA2XX_RSHUNT_DEFAULT;

	}



	if (val <= 0 || val > chip->config->calibration_factor)

		return -ENODEV;



	chip->rshunt = val;



	mutex_init(&chip->state_lock);



	/* This is only used for device removal purposes. */

	i2c_set_clientdata(client, indio_dev);



	indio_dev->name = id->name;

	indio_dev->channels = ina2xx_channels;

	indio_dev->num_channels = ARRAY_SIZE(ina2xx_channels);



	indio_dev->dev.parent = &client->dev;

	indio_dev->info = &ina2xx_info;

	indio_dev->modes = INDIO_DIRECT_MODE | INDIO_BUFFER_SOFTWARE;



	chip->regmap = devm_regmap_init_i2c(client, &ina2xx_regmap_config);

	if (IS_ERR(chip->regmap)) {

		dev_err(&client->dev, "failed to allocate register map\n");

		return PTR_ERR(chip->regmap);

	}



	/* Patch the current config register with default. */

	val = chip->config->config_default;



	if (id->driver_data == ina226) {

		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);

	}



	ret = ina2xx_init(chip, val);

	if (ret < 0) {

		dev_err(&client->dev, "error configuring the device: %d\n",

			ret);

		return -ENODEV;

	}



	buffer = devm_iio_kfifo_allocate(&indio_dev->dev);

	if (!buffer)

		return -ENOMEM;



	indio_dev->setup_ops = &ina2xx_setup_ops;



	iio_device_attach_buffer(indio_dev, buffer);



	return iio_device_register(indio_dev);

}





static int ina2xx_remove(struct i2c_client *client)

{

	struct iio_dev *indio_dev = i2c_get_clientdata(client);

	struct ina2xx_chip_info *chip = iio_priv(indio_dev);



	iio_device_unregister(indio_dev);



	/* Powerdown */

	return regmap_update_bits(chip->regmap, INA2XX_CONFIG,

				  INA2XX_MODE_MASK, 0);

}





static const struct i2c_device_id ina2xx_id[] = {

	{"ina219", ina219},

	{"ina220", ina219},

	{"ina226", ina226},

	{"ina230", ina226},

	{"ina231", ina226},

	{}

};



MODULE_DEVICE_TABLE(i2c, ina2xx_id);



static struct i2c_driver ina2xx_driver = {

	.driver = {

		   .name = KBUILD_MODNAME,

	},

	.probe = ina2xx_probe,

	.remove = ina2xx_remove,

	.id_table = ina2xx_id,

};



module_i2c_driver(ina2xx_driver);



MODULE_AUTHOR("Marc Titinger <marc.titinger@baylibre.com>");

MODULE_DESCRIPTION("Texas Instruments INA2XX ADC driver");

MODULE_LICENSE("GPL v2");