drivers/staging/iio/meter/ade7753.c - arm/linux - Git at Google

 /*
  * ADE7753 Single-Phase Multifunction Metering IC with di/dt Sensor Interface
  *
  * Copyright 2010 Analog Devices Inc.
  *
  * Licensed under the GPL-2 or later.
  */

 #include <linux/delay.h>
 #include <linux/device.h>
 #include <linux/interrupt.h>
 #include <linux/irq.h>
 #include <linux/kernel.h>
 #include <linux/list.h>
 #include <linux/module.h>
 #include <linux/mutex.h>
 #include <linux/slab.h>
 #include <linux/sysfs.h>
 #include <linux/iio/iio.h>
 #include <linux/iio/sysfs.h>
 #include <linux/spi/spi.h>
 #include "meter.h"

 #define ADE7753_WAVEFORM   0x01
 #define ADE7753_AENERGY    0x02
 #define ADE7753_RAENERGY   0x03
 #define ADE7753_LAENERGY   0x04
 #define ADE7753_VAENERGY   0x05
 #define ADE7753_RVAENERGY  0x06
 #define ADE7753_LVAENERGY  0x07
 #define ADE7753_LVARENERGY 0x08
 #define ADE7753_MODE       0x09
 #define ADE7753_IRQEN      0x0A
 #define ADE7753_STATUS     0x0B
 #define ADE7753_RSTSTATUS  0x0C
 #define ADE7753_CH1OS      0x0D
 #define ADE7753_CH2OS      0x0E
 #define ADE7753_GAIN       0x0F
 #define ADE7753_PHCAL      0x10
 #define ADE7753_APOS       0x11
 #define ADE7753_WGAIN      0x12
 #define ADE7753_WDIV       0x13
 #define ADE7753_CFNUM      0x14
 #define ADE7753_CFDEN      0x15
 #define ADE7753_IRMS       0x16
 #define ADE7753_VRMS       0x17
 #define ADE7753_IRMSOS     0x18
 #define ADE7753_VRMSOS     0x19
 #define ADE7753_VAGAIN     0x1A
 #define ADE7753_VADIV      0x1B
 #define ADE7753_LINECYC    0x1C
 #define ADE7753_ZXTOUT     0x1D
 #define ADE7753_SAGCYC     0x1E
 #define ADE7753_SAGLVL     0x1F
 #define ADE7753_IPKLVL     0x20
 #define ADE7753_VPKLVL     0x21
 #define ADE7753_IPEAK      0x22
 #define ADE7753_RSTIPEAK   0x23
 #define ADE7753_VPEAK      0x24
 #define ADE7753_RSTVPEAK   0x25
 #define ADE7753_TEMP       0x26
 #define ADE7753_PERIOD     0x27
 #define ADE7753_TMODE      0x3D
 #define ADE7753_CHKSUM     0x3E
 #define ADE7753_DIEREV     0x3F

 #define ADE7753_READ_REG(a)    a
 #define ADE7753_WRITE_REG(a) ((a) | 0x80)

 #define ADE7753_MAX_TX    4
 #define ADE7753_MAX_RX    4
 #define ADE7753_STARTUP_DELAY 1000

 #define ADE7753_SPI_SLOW    (u32)(300 * 1000)
 #define ADE7753_SPI_BURST   (u32)(1000 * 1000)
 #define ADE7753_SPI_FAST    (u32)(2000 * 1000)

 /**
  * struct ade7753_state - device instance specific data
  * @us:         actual spi_device
  * @tx:         transmit buffer
  * @rx:         receive buffer
  * @buf_lock:       mutex to protect tx and rx
  **/
 struct ade7753_state {
 	struct spi_device   *us;
 	struct mutex        buf_lock;
 	u8          tx[ADE7753_MAX_TX] ____cacheline_aligned;
 	u8          rx[ADE7753_MAX_RX];
 };

 static int ade7753_spi_write_reg_8(struct device *dev,
 				   u8 reg_address,
 				   u8 val)
 {
 	int ret;
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ade7753_state *st = iio_priv(indio_dev);

 	mutex_lock(&st->buf_lock);
 	st->tx[0] = ADE7753_WRITE_REG(reg_address);
 	st->tx[1] = val;

 	ret = spi_write(st->us, st->tx, 2);
 	mutex_unlock(&st->buf_lock);

 	return ret;
 }

 static int ade7753_spi_write_reg_16(struct device *dev, u8 reg_address,
 				    u16 value)
 {
 	int ret;
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ade7753_state *st = iio_priv(indio_dev);

 	mutex_lock(&st->buf_lock);
 	st->tx[0] = ADE7753_WRITE_REG(reg_address);
 	st->tx[1] = (value >> 8) & 0xFF;
 	st->tx[2] = value & 0xFF;
 	ret = spi_write(st->us, st->tx, 3);
 	mutex_unlock(&st->buf_lock);

 	return ret;
 }

 static int ade7753_spi_read_reg_8(struct device *dev,
 				  u8 reg_address,
 				  u8 *val)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ade7753_state *st = iio_priv(indio_dev);
 	ssize_t ret;

 	ret = spi_w8r8(st->us, ADE7753_READ_REG(reg_address));
 	if (ret < 0) {
 		dev_err(&st->us->dev, "problem when reading 8 bit register 0x%02X",
 			reg_address);
 		return ret;
 	}
 	*val = ret;

 	return 0;
 }

 static int ade7753_spi_read_reg_16(struct device *dev,
 				   u8 reg_address,
 				   u16 *val)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ade7753_state *st = iio_priv(indio_dev);
 	ssize_t ret;

 	ret = spi_w8r16be(st->us, ADE7753_READ_REG(reg_address));
 	if (ret < 0) {
 		dev_err(&st->us->dev, "problem when reading 16 bit register 0x%02X",
 			reg_address);
 		return ret;
 	}

 	*val = ret;

 	return 0;
 }

 static int ade7753_spi_read_reg_24(struct device *dev,
 				   u8 reg_address,
 				   u32 *val)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ade7753_state *st = iio_priv(indio_dev);
 	int ret;
 	struct spi_transfer xfers[] = {
 		{
 			.tx_buf = st->tx,
 			.bits_per_word = 8,
 			.len = 1,
 		}, {
 			.rx_buf = st->tx,
 			.bits_per_word = 8,
 			.len = 3,
 		}
 	};

 	mutex_lock(&st->buf_lock);
 	st->tx[0] = ADE7753_READ_REG(reg_address);

 	ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
 	if (ret) {
 		dev_err(&st->us->dev, "problem when reading 24 bit register 0x%02X",
 			reg_address);
 		goto error_ret;
 	}
 	*val = (st->rx[0] << 16) | (st->rx[1] << 8) | st->rx[2];

 error_ret:
 	mutex_unlock(&st->buf_lock);
 	return ret;
 }

 static ssize_t ade7753_read_8bit(struct device *dev,
 				 struct device_attribute *attr,
 				 char *buf)
 {
 	int ret;
 	u8 val;
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

 	ret = ade7753_spi_read_reg_8(dev, this_attr->address, &val);
 	if (ret)
 		return ret;

 	return sprintf(buf, "%u\n", val);
 }

 static ssize_t ade7753_read_16bit(struct device *dev,
 				  struct device_attribute *attr,
 				  char *buf)
 {
 	int ret;
 	u16 val;
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

 	ret = ade7753_spi_read_reg_16(dev, this_attr->address, &val);
 	if (ret)
 		return ret;

 	return sprintf(buf, "%u\n", val);
 }

 static ssize_t ade7753_read_24bit(struct device *dev,
 				  struct device_attribute *attr,
 				  char *buf)
 {
 	int ret;
 	u32 val;
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

 	ret = ade7753_spi_read_reg_24(dev, this_attr->address, &val);
 	if (ret)
 		return ret;

 	return sprintf(buf, "%u\n", val);
 }

 static ssize_t ade7753_write_8bit(struct device *dev,
 				  struct device_attribute *attr,
 				  const char *buf,
 				  size_t len)
 {
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 	int ret;
 	u8 val;

 	ret = kstrtou8(buf, 10, &val);
 	if (ret)
 		goto error_ret;
 	ret = ade7753_spi_write_reg_8(dev, this_attr->address, val);

 error_ret:
 	return ret ? ret : len;
 }

 static ssize_t ade7753_write_16bit(struct device *dev,
 				   struct device_attribute *attr,
 				   const char *buf,
 				   size_t len)
 {
 	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
 	int ret;
 	u16 val;

 	ret = kstrtou16(buf, 10, &val);
 	if (ret)
 		goto error_ret;
 	ret = ade7753_spi_write_reg_16(dev, this_attr->address, val);

 error_ret:
 	return ret ? ret : len;
 }

 static int ade7753_reset(struct device *dev)
 {
 	u16 val;
 	int ret;

 	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
 	if (ret)
 		return ret;

 	val |= BIT(6); /* Software Chip Reset */

 	return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
 }

 static IIO_DEV_ATTR_AENERGY(ade7753_read_24bit, ADE7753_AENERGY);
 static IIO_DEV_ATTR_LAENERGY(ade7753_read_24bit, ADE7753_LAENERGY);
 static IIO_DEV_ATTR_VAENERGY(ade7753_read_24bit, ADE7753_VAENERGY);
 static IIO_DEV_ATTR_LVAENERGY(ade7753_read_24bit, ADE7753_LVAENERGY);
 static IIO_DEV_ATTR_CFDEN(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_CFDEN);
 static IIO_DEV_ATTR_CFNUM(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_CFNUM);
 static IIO_DEV_ATTR_CHKSUM(ade7753_read_8bit, ADE7753_CHKSUM);
 static IIO_DEV_ATTR_PHCAL(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_PHCAL);
 static IIO_DEV_ATTR_APOS(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_APOS);
 static IIO_DEV_ATTR_SAGCYC(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_SAGCYC);
 static IIO_DEV_ATTR_SAGLVL(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_SAGLVL);
 static IIO_DEV_ATTR_LINECYC(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_LINECYC);
 static IIO_DEV_ATTR_WDIV(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_WDIV);
 static IIO_DEV_ATTR_IRMS(0644,
 		ade7753_read_24bit,
 		NULL,
 		ADE7753_IRMS);
 static IIO_DEV_ATTR_VRMS(0444,
 		ade7753_read_24bit,
 		NULL,
 		ADE7753_VRMS);
 static IIO_DEV_ATTR_IRMSOS(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_IRMSOS);
 static IIO_DEV_ATTR_VRMSOS(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_VRMSOS);
 static IIO_DEV_ATTR_WGAIN(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_WGAIN);
 static IIO_DEV_ATTR_VAGAIN(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_VAGAIN);
 static IIO_DEV_ATTR_PGA_GAIN(0644,
 		ade7753_read_16bit,
 		ade7753_write_16bit,
 		ADE7753_GAIN);
 static IIO_DEV_ATTR_IPKLVL(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_IPKLVL);
 static IIO_DEV_ATTR_VPKLVL(0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_VPKLVL);
 static IIO_DEV_ATTR_IPEAK(0444,
 		ade7753_read_24bit,
 		NULL,
 		ADE7753_IPEAK);
 static IIO_DEV_ATTR_VPEAK(0444,
 		ade7753_read_24bit,
 		NULL,
 		ADE7753_VPEAK);
 static IIO_DEV_ATTR_VPERIOD(0444,
 		ade7753_read_16bit,
 		NULL,
 		ADE7753_PERIOD);
 static IIO_DEV_ATTR_CH_OFF(1, 0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_CH1OS);
 static IIO_DEV_ATTR_CH_OFF(2, 0644,
 		ade7753_read_8bit,
 		ade7753_write_8bit,
 		ADE7753_CH2OS);

 static int ade7753_set_irq(struct device *dev, bool enable)
 {
 	int ret;
 	u8 irqen;

 	ret = ade7753_spi_read_reg_8(dev, ADE7753_IRQEN, &irqen);
 	if (ret)
 		goto error_ret;

 	if (enable)
 		irqen |= BIT(3); /* Enables an interrupt when a data is
 				  * present in the waveform register
 				  */
 	else
 		irqen &= ~BIT(3);

 	ret = ade7753_spi_write_reg_8(dev, ADE7753_IRQEN, irqen);

 error_ret:
 	return ret;
 }

 /* Power down the device */
 static int ade7753_stop_device(struct device *dev)
 {
 	u16 val;
 	int ret;

 	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
 	if (ret)
 		return ret;

 	val |= BIT(4);  /* AD converters can be turned off */

 	return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
 }

 static int ade7753_initial_setup(struct iio_dev *indio_dev)
 {
 	int ret;
 	struct device *dev = &indio_dev->dev;
 	struct ade7753_state *st = iio_priv(indio_dev);

 	/* use low spi speed for init */
 	st->us->mode = SPI_MODE_3;
 	spi_setup(st->us);

 	/* Disable IRQ */
 	ret = ade7753_set_irq(dev, false);
 	if (ret) {
 		dev_err(dev, "disable irq failed");
 		goto err_ret;
 	}

 	ade7753_reset(dev);
 	usleep_range(ADE7753_STARTUP_DELAY, ADE7753_STARTUP_DELAY + 100);

 err_ret:
 	return ret;
 }

 static ssize_t ade7753_read_frequency(struct device *dev,
 				      struct device_attribute *attr,
 				      char *buf)
 {
 	int ret;
 	u16 t;
 	int sps;

 	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &t);
 	if (ret)
 		return ret;

 	t = (t >> 11) & 0x3;
 	sps = 27900 / (1 + t);

 	return sprintf(buf, "%d\n", sps);
 }

 static ssize_t ade7753_write_frequency(struct device *dev,
 				       struct device_attribute *attr,
 				       const char *buf,
 				       size_t len)
 {
 	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
 	struct ade7753_state *st = iio_priv(indio_dev);
 	u16 val;
 	int ret;
 	u16 reg, t;

 	ret = kstrtou16(buf, 10, &val);
 	if (ret)
 		return ret;
 	if (!val)
 		return -EINVAL;

 	mutex_lock(&indio_dev->mlock);

 	t = 27900 / val;
 	if (t > 0)
 		t--;

 	if (t > 1)
 		st->us->max_speed_hz = ADE7753_SPI_SLOW;
 	else
 		st->us->max_speed_hz = ADE7753_SPI_FAST;

 	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &reg);
 	if (ret)
 		goto out;

 	reg &= ~(3 << 11);
 	reg |= t << 11;

 	ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);

 out:
 	mutex_unlock(&indio_dev->mlock);

 	return ret ? ret : len;
 }

 static IIO_DEV_ATTR_TEMP_RAW(ade7753_read_8bit);
 static IIO_CONST_ATTR(in_temp_offset, "-25 C");
 static IIO_CONST_ATTR(in_temp_scale, "0.67 C");

 static IIO_DEV_ATTR_SAMP_FREQ(0644,
 		ade7753_read_frequency,
 		ade7753_write_frequency);

 static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("27900 14000 7000 3500");

 static struct attribute *ade7753_attributes[] = {
 	&iio_dev_attr_in_temp_raw.dev_attr.attr,
 	&iio_const_attr_in_temp_offset.dev_attr.attr,
 	&iio_const_attr_in_temp_scale.dev_attr.attr,
 	&iio_dev_attr_sampling_frequency.dev_attr.attr,
 	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
 	&iio_dev_attr_phcal.dev_attr.attr,
 	&iio_dev_attr_cfden.dev_attr.attr,
 	&iio_dev_attr_aenergy.dev_attr.attr,
 	&iio_dev_attr_laenergy.dev_attr.attr,
 	&iio_dev_attr_vaenergy.dev_attr.attr,
 	&iio_dev_attr_lvaenergy.dev_attr.attr,
 	&iio_dev_attr_cfnum.dev_attr.attr,
 	&iio_dev_attr_apos.dev_attr.attr,
 	&iio_dev_attr_sagcyc.dev_attr.attr,
 	&iio_dev_attr_saglvl.dev_attr.attr,
 	&iio_dev_attr_linecyc.dev_attr.attr,
 	&iio_dev_attr_chksum.dev_attr.attr,
 	&iio_dev_attr_pga_gain.dev_attr.attr,
 	&iio_dev_attr_wgain.dev_attr.attr,
 	&iio_dev_attr_choff_1.dev_attr.attr,
 	&iio_dev_attr_choff_2.dev_attr.attr,
 	&iio_dev_attr_wdiv.dev_attr.attr,
 	&iio_dev_attr_irms.dev_attr.attr,
 	&iio_dev_attr_vrms.dev_attr.attr,
 	&iio_dev_attr_irmsos.dev_attr.attr,
 	&iio_dev_attr_vrmsos.dev_attr.attr,
 	&iio_dev_attr_vagain.dev_attr.attr,
 	&iio_dev_attr_ipklvl.dev_attr.attr,
 	&iio_dev_attr_vpklvl.dev_attr.attr,
 	&iio_dev_attr_ipeak.dev_attr.attr,
 	&iio_dev_attr_vpeak.dev_attr.attr,
 	&iio_dev_attr_vperiod.dev_attr.attr,
 	NULL,
 };

 static const struct attribute_group ade7753_attribute_group = {
 	.attrs = ade7753_attributes,
 };

 static const struct iio_info ade7753_info = {
 	.attrs = &ade7753_attribute_group,
 	.driver_module = THIS_MODULE,
 };

 static int ade7753_probe(struct spi_device *spi)
 {
 	int ret;
 	struct ade7753_state *st;
 	struct iio_dev *indio_dev;

 	/* setup the industrialio driver allocated elements */
 	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
 	if (!indio_dev)
 		return -ENOMEM;
 	/* this is only used for removal purposes */
 	spi_set_drvdata(spi, indio_dev);

 	st = iio_priv(indio_dev);
 	st->us = spi;
 	mutex_init(&st->buf_lock);

 	indio_dev->name = spi->dev.driver->name;
 	indio_dev->dev.parent = &spi->dev;
 	indio_dev->info = &ade7753_info;
 	indio_dev->modes = INDIO_DIRECT_MODE;

 	/* Get the device into a sane initial state */
 	ret = ade7753_initial_setup(indio_dev);
 	if (ret)
 		return ret;

 	return iio_device_register(indio_dev);
 }

 static int ade7753_remove(struct spi_device *spi)
 {
 	struct iio_dev *indio_dev = spi_get_drvdata(spi);

 	iio_device_unregister(indio_dev);
 	ade7753_stop_device(&indio_dev->dev);

 	return 0;
 }

 static struct spi_driver ade7753_driver = {
 	.driver = {
 		.name = "ade7753",
 	},
 	.probe = ade7753_probe,
 	.remove = ade7753_remove,
 };
 module_spi_driver(ade7753_driver);

 MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
 MODULE_DESCRIPTION("Analog Devices ADE7753/6 Single-Phase Multifunction Meter");
 MODULE_LICENSE("GPL v2");
 MODULE_ALIAS("spi:ade7753");
	/*
	* ADE7753 Single-Phase Multifunction Metering IC with di/dt Sensor Interface
	*
	* Copyright 2010 Analog Devices Inc.
	*
	* Licensed under the GPL-2 or later.
	*/

	#include <linux/delay.h>
	#include <linux/device.h>
	#include <linux/interrupt.h>
	#include <linux/irq.h>
	#include <linux/kernel.h>
	#include <linux/list.h>
	#include <linux/module.h>
	#include <linux/mutex.h>
	#include <linux/slab.h>
	#include <linux/sysfs.h>
	#include <linux/iio/iio.h>
	#include <linux/iio/sysfs.h>
	#include <linux/spi/spi.h>
	#include "meter.h"

	#define ADE7753_WAVEFORM 0x01
	#define ADE7753_AENERGY 0x02
	#define ADE7753_RAENERGY 0x03
	#define ADE7753_LAENERGY 0x04
	#define ADE7753_VAENERGY 0x05
	#define ADE7753_RVAENERGY 0x06
	#define ADE7753_LVAENERGY 0x07
	#define ADE7753_LVARENERGY 0x08
	#define ADE7753_MODE 0x09
	#define ADE7753_IRQEN 0x0A
	#define ADE7753_STATUS 0x0B
	#define ADE7753_RSTSTATUS 0x0C
	#define ADE7753_CH1OS 0x0D
	#define ADE7753_CH2OS 0x0E
	#define ADE7753_GAIN 0x0F
	#define ADE7753_PHCAL 0x10
	#define ADE7753_APOS 0x11
	#define ADE7753_WGAIN 0x12
	#define ADE7753_WDIV 0x13
	#define ADE7753_CFNUM 0x14
	#define ADE7753_CFDEN 0x15
	#define ADE7753_IRMS 0x16
	#define ADE7753_VRMS 0x17
	#define ADE7753_IRMSOS 0x18
	#define ADE7753_VRMSOS 0x19
	#define ADE7753_VAGAIN 0x1A
	#define ADE7753_VADIV 0x1B
	#define ADE7753_LINECYC 0x1C
	#define ADE7753_ZXTOUT 0x1D
	#define ADE7753_SAGCYC 0x1E
	#define ADE7753_SAGLVL 0x1F
	#define ADE7753_IPKLVL 0x20
	#define ADE7753_VPKLVL 0x21
	#define ADE7753_IPEAK 0x22
	#define ADE7753_RSTIPEAK 0x23
	#define ADE7753_VPEAK 0x24
	#define ADE7753_RSTVPEAK 0x25
	#define ADE7753_TEMP 0x26
	#define ADE7753_PERIOD 0x27
	#define ADE7753_TMODE 0x3D
	#define ADE7753_CHKSUM 0x3E
	#define ADE7753_DIEREV 0x3F

	#define ADE7753_READ_REG(a) a
	#define ADE7753_WRITE_REG(a) ((a) \| 0x80)

	#define ADE7753_MAX_TX 4
	#define ADE7753_MAX_RX 4
	#define ADE7753_STARTUP_DELAY 1000

	#define ADE7753_SPI_SLOW (u32)(300 * 1000)
	#define ADE7753_SPI_BURST (u32)(1000 * 1000)
	#define ADE7753_SPI_FAST (u32)(2000 * 1000)

	/**
	* struct ade7753_state - device instance specific data
	* @us: actual spi_device
	* @tx: transmit buffer
	* @rx: receive buffer
	* @buf_lock: mutex to protect tx and rx
	**/
	struct ade7753_state {
	struct spi_device *us;
	struct mutex buf_lock;
	u8 tx[ADE7753_MAX_TX] ____cacheline_aligned;
	u8 rx[ADE7753_MAX_RX];
	};

	static int ade7753_spi_write_reg_8(struct device *dev,
	u8 reg_address,
	u8 val)
	{
	int ret;
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ade7753_state *st = iio_priv(indio_dev);

	mutex_lock(&st->buf_lock);
	st->tx[0] = ADE7753_WRITE_REG(reg_address);
	st->tx[1] = val;

	ret = spi_write(st->us, st->tx, 2);
	mutex_unlock(&st->buf_lock);

	return ret;
	}

	static int ade7753_spi_write_reg_16(struct device *dev, u8 reg_address,
	u16 value)
	{
	int ret;
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ade7753_state *st = iio_priv(indio_dev);

	mutex_lock(&st->buf_lock);
	st->tx[0] = ADE7753_WRITE_REG(reg_address);
	st->tx[1] = (value >> 8) & 0xFF;
	st->tx[2] = value & 0xFF;
	ret = spi_write(st->us, st->tx, 3);
	mutex_unlock(&st->buf_lock);

	return ret;
	}

	static int ade7753_spi_read_reg_8(struct device *dev,
	u8 reg_address,
	u8 *val)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ade7753_state *st = iio_priv(indio_dev);
	ssize_t ret;

	ret = spi_w8r8(st->us, ADE7753_READ_REG(reg_address));
	if (ret < 0) {
	dev_err(&st->us->dev, "problem when reading 8 bit register 0x%02X",
	reg_address);
	return ret;
	}
	*val = ret;

	return 0;
	}

	static int ade7753_spi_read_reg_16(struct device *dev,
	u8 reg_address,
	u16 *val)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ade7753_state *st = iio_priv(indio_dev);
	ssize_t ret;

	ret = spi_w8r16be(st->us, ADE7753_READ_REG(reg_address));
	if (ret < 0) {
	dev_err(&st->us->dev, "problem when reading 16 bit register 0x%02X",
	reg_address);
	return ret;
	}

	*val = ret;

	return 0;
	}

	static int ade7753_spi_read_reg_24(struct device *dev,
	u8 reg_address,
	u32 *val)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ade7753_state *st = iio_priv(indio_dev);
	int ret;
	struct spi_transfer xfers[] = {
	{
	.tx_buf = st->tx,
	.bits_per_word = 8,
	.len = 1,
	}, {
	.rx_buf = st->tx,
	.bits_per_word = 8,
	.len = 3,
	}
	};

	mutex_lock(&st->buf_lock);
	st->tx[0] = ADE7753_READ_REG(reg_address);

	ret = spi_sync_transfer(st->us, xfers, ARRAY_SIZE(xfers));
	if (ret) {
	dev_err(&st->us->dev, "problem when reading 24 bit register 0x%02X",
	reg_address);
	goto error_ret;
	}
	*val = (st->rx[0] << 16) \| (st->rx[1] << 8) \| st->rx[2];

	error_ret:
	mutex_unlock(&st->buf_lock);
	return ret;
	}

	static ssize_t ade7753_read_8bit(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	int ret;
	u8 val;
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

	ret = ade7753_spi_read_reg_8(dev, this_attr->address, &val);
	if (ret)
	return ret;

	return sprintf(buf, "%u\n", val);
	}

	static ssize_t ade7753_read_16bit(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	int ret;
	u16 val;
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

	ret = ade7753_spi_read_reg_16(dev, this_attr->address, &val);
	if (ret)
	return ret;

	return sprintf(buf, "%u\n", val);
	}

	static ssize_t ade7753_read_24bit(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	int ret;
	u32 val;
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);

	ret = ade7753_spi_read_reg_24(dev, this_attr->address, &val);
	if (ret)
	return ret;

	return sprintf(buf, "%u\n", val);
	}

	static ssize_t ade7753_write_8bit(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int ret;
	u8 val;

	ret = kstrtou8(buf, 10, &val);
	if (ret)
	goto error_ret;
	ret = ade7753_spi_write_reg_8(dev, this_attr->address, val);

	error_ret:
	return ret ? ret : len;
	}

	static ssize_t ade7753_write_16bit(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
	int ret;
	u16 val;

	ret = kstrtou16(buf, 10, &val);
	if (ret)
	goto error_ret;
	ret = ade7753_spi_write_reg_16(dev, this_attr->address, val);

	error_ret:
	return ret ? ret : len;
	}

	static int ade7753_reset(struct device *dev)
	{
	u16 val;
	int ret;

	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
	if (ret)
	return ret;

	val \|= BIT(6); /* Software Chip Reset */

	return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
	}

	static IIO_DEV_ATTR_AENERGY(ade7753_read_24bit, ADE7753_AENERGY);
	static IIO_DEV_ATTR_LAENERGY(ade7753_read_24bit, ADE7753_LAENERGY);
	static IIO_DEV_ATTR_VAENERGY(ade7753_read_24bit, ADE7753_VAENERGY);
	static IIO_DEV_ATTR_LVAENERGY(ade7753_read_24bit, ADE7753_LVAENERGY);
	static IIO_DEV_ATTR_CFDEN(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_CFDEN);
	static IIO_DEV_ATTR_CFNUM(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_CFNUM);
	static IIO_DEV_ATTR_CHKSUM(ade7753_read_8bit, ADE7753_CHKSUM);
	static IIO_DEV_ATTR_PHCAL(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_PHCAL);
	static IIO_DEV_ATTR_APOS(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_APOS);
	static IIO_DEV_ATTR_SAGCYC(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_SAGCYC);
	static IIO_DEV_ATTR_SAGLVL(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_SAGLVL);
	static IIO_DEV_ATTR_LINECYC(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_LINECYC);
	static IIO_DEV_ATTR_WDIV(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_WDIV);
	static IIO_DEV_ATTR_IRMS(0644,
	ade7753_read_24bit,
	NULL,
	ADE7753_IRMS);
	static IIO_DEV_ATTR_VRMS(0444,
	ade7753_read_24bit,
	NULL,
	ADE7753_VRMS);
	static IIO_DEV_ATTR_IRMSOS(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_IRMSOS);
	static IIO_DEV_ATTR_VRMSOS(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_VRMSOS);
	static IIO_DEV_ATTR_WGAIN(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_WGAIN);
	static IIO_DEV_ATTR_VAGAIN(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_VAGAIN);
	static IIO_DEV_ATTR_PGA_GAIN(0644,
	ade7753_read_16bit,
	ade7753_write_16bit,
	ADE7753_GAIN);
	static IIO_DEV_ATTR_IPKLVL(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_IPKLVL);
	static IIO_DEV_ATTR_VPKLVL(0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_VPKLVL);
	static IIO_DEV_ATTR_IPEAK(0444,
	ade7753_read_24bit,
	NULL,
	ADE7753_IPEAK);
	static IIO_DEV_ATTR_VPEAK(0444,
	ade7753_read_24bit,
	NULL,
	ADE7753_VPEAK);
	static IIO_DEV_ATTR_VPERIOD(0444,
	ade7753_read_16bit,
	NULL,
	ADE7753_PERIOD);
	static IIO_DEV_ATTR_CH_OFF(1, 0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_CH1OS);
	static IIO_DEV_ATTR_CH_OFF(2, 0644,
	ade7753_read_8bit,
	ade7753_write_8bit,
	ADE7753_CH2OS);

	static int ade7753_set_irq(struct device *dev, bool enable)
	{
	int ret;
	u8 irqen;

	ret = ade7753_spi_read_reg_8(dev, ADE7753_IRQEN, &irqen);
	if (ret)
	goto error_ret;

	if (enable)
	irqen \|= BIT(3); /* Enables an interrupt when a data is
	* present in the waveform register
	*/
	else
	irqen &= ~BIT(3);

	ret = ade7753_spi_write_reg_8(dev, ADE7753_IRQEN, irqen);

	error_ret:
	return ret;
	}

	/* Power down the device */
	static int ade7753_stop_device(struct device *dev)
	{
	u16 val;
	int ret;

	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &val);
	if (ret)
	return ret;

	val \|= BIT(4); /* AD converters can be turned off */

	return ade7753_spi_write_reg_16(dev, ADE7753_MODE, val);
	}

	static int ade7753_initial_setup(struct iio_dev *indio_dev)
	{
	int ret;
	struct device *dev = &indio_dev->dev;
	struct ade7753_state *st = iio_priv(indio_dev);

	/* use low spi speed for init */
	st->us->mode = SPI_MODE_3;
	spi_setup(st->us);

	/* Disable IRQ */
	ret = ade7753_set_irq(dev, false);
	if (ret) {
	dev_err(dev, "disable irq failed");
	goto err_ret;
	}

	ade7753_reset(dev);
	usleep_range(ADE7753_STARTUP_DELAY, ADE7753_STARTUP_DELAY + 100);

	err_ret:
	return ret;
	}

	static ssize_t ade7753_read_frequency(struct device *dev,
	struct device_attribute *attr,
	char *buf)
	{
	int ret;
	u16 t;
	int sps;

	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &t);
	if (ret)
	return ret;

	t = (t >> 11) & 0x3;
	sps = 27900 / (1 + t);

	return sprintf(buf, "%d\n", sps);
	}

	static ssize_t ade7753_write_frequency(struct device *dev,
	struct device_attribute *attr,
	const char *buf,
	size_t len)
	{
	struct iio_dev *indio_dev = dev_to_iio_dev(dev);
	struct ade7753_state *st = iio_priv(indio_dev);
	u16 val;
	int ret;
	u16 reg, t;

	ret = kstrtou16(buf, 10, &val);
	if (ret)
	return ret;
	if (!val)
	return -EINVAL;

	mutex_lock(&indio_dev->mlock);

	t = 27900 / val;
	if (t > 0)
	t--;

	if (t > 1)
	st->us->max_speed_hz = ADE7753_SPI_SLOW;
	else
	st->us->max_speed_hz = ADE7753_SPI_FAST;

	ret = ade7753_spi_read_reg_16(dev, ADE7753_MODE, &reg);
	if (ret)
	goto out;

	reg &= ~(3 << 11);
	reg \|= t << 11;

	ret = ade7753_spi_write_reg_16(dev, ADE7753_MODE, reg);

	out:
	mutex_unlock(&indio_dev->mlock);

	return ret ? ret : len;
	}

	static IIO_DEV_ATTR_TEMP_RAW(ade7753_read_8bit);
	static IIO_CONST_ATTR(in_temp_offset, "-25 C");
	static IIO_CONST_ATTR(in_temp_scale, "0.67 C");

	static IIO_DEV_ATTR_SAMP_FREQ(0644,
	ade7753_read_frequency,
	ade7753_write_frequency);

	static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("27900 14000 7000 3500");

	static struct attribute *ade7753_attributes[] = {
	&iio_dev_attr_in_temp_raw.dev_attr.attr,
	&iio_const_attr_in_temp_offset.dev_attr.attr,
	&iio_const_attr_in_temp_scale.dev_attr.attr,
	&iio_dev_attr_sampling_frequency.dev_attr.attr,
	&iio_const_attr_sampling_frequency_available.dev_attr.attr,
	&iio_dev_attr_phcal.dev_attr.attr,
	&iio_dev_attr_cfden.dev_attr.attr,
	&iio_dev_attr_aenergy.dev_attr.attr,
	&iio_dev_attr_laenergy.dev_attr.attr,
	&iio_dev_attr_vaenergy.dev_attr.attr,
	&iio_dev_attr_lvaenergy.dev_attr.attr,
	&iio_dev_attr_cfnum.dev_attr.attr,
	&iio_dev_attr_apos.dev_attr.attr,
	&iio_dev_attr_sagcyc.dev_attr.attr,
	&iio_dev_attr_saglvl.dev_attr.attr,
	&iio_dev_attr_linecyc.dev_attr.attr,
	&iio_dev_attr_chksum.dev_attr.attr,
	&iio_dev_attr_pga_gain.dev_attr.attr,
	&iio_dev_attr_wgain.dev_attr.attr,
	&iio_dev_attr_choff_1.dev_attr.attr,
	&iio_dev_attr_choff_2.dev_attr.attr,
	&iio_dev_attr_wdiv.dev_attr.attr,
	&iio_dev_attr_irms.dev_attr.attr,
	&iio_dev_attr_vrms.dev_attr.attr,
	&iio_dev_attr_irmsos.dev_attr.attr,
	&iio_dev_attr_vrmsos.dev_attr.attr,
	&iio_dev_attr_vagain.dev_attr.attr,
	&iio_dev_attr_ipklvl.dev_attr.attr,
	&iio_dev_attr_vpklvl.dev_attr.attr,
	&iio_dev_attr_ipeak.dev_attr.attr,
	&iio_dev_attr_vpeak.dev_attr.attr,
	&iio_dev_attr_vperiod.dev_attr.attr,
	NULL,
	};

	static const struct attribute_group ade7753_attribute_group = {
	.attrs = ade7753_attributes,
	};

	static const struct iio_info ade7753_info = {
	.attrs = &ade7753_attribute_group,
	.driver_module = THIS_MODULE,
	};

	static int ade7753_probe(struct spi_device *spi)
	{
	int ret;
	struct ade7753_state *st;
	struct iio_dev *indio_dev;

	/* setup the industrialio driver allocated elements */
	indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
	if (!indio_dev)
	return -ENOMEM;
	/* this is only used for removal purposes */
	spi_set_drvdata(spi, indio_dev);

	st = iio_priv(indio_dev);
	st->us = spi;
	mutex_init(&st->buf_lock);

	indio_dev->name = spi->dev.driver->name;
	indio_dev->dev.parent = &spi->dev;
	indio_dev->info = &ade7753_info;
	indio_dev->modes = INDIO_DIRECT_MODE;

	/* Get the device into a sane initial state */
	ret = ade7753_initial_setup(indio_dev);
	if (ret)
	return ret;

	return iio_device_register(indio_dev);
	}

	static int ade7753_remove(struct spi_device *spi)
	{
	struct iio_dev *indio_dev = spi_get_drvdata(spi);

	iio_device_unregister(indio_dev);
	ade7753_stop_device(&indio_dev->dev);

	return 0;
	}

	static struct spi_driver ade7753_driver = {
	.driver = {
	.name = "ade7753",
	},
	.probe = ade7753_probe,
	.remove = ade7753_remove,
	};
	module_spi_driver(ade7753_driver);

	MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
	MODULE_DESCRIPTION("Analog Devices ADE7753/6 Single-Phase Multifunction Meter");
	MODULE_LICENSE("GPL v2");
	MODULE_ALIAS("spi:ade7753");