staging: iio: meter: new driver for ADE7754 devices

Signed-off-by: NBarry Song <barry.song@analog.com>
Signed-off-by: NMichael Hennerich <michael.hennerich@analog.com>
Acked-by: NJonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: NMike Frysinger <vapier@gentoo.org>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/meter/Kconfig

@@ -9,3 +9,10 @@ config ADE7753
 	help
 	  Say yes here to build support for Analog Devices ADE7753 Single-Phase Multifunction
 	  Metering IC with di/dt Sensor Interface.
+
+config ADE7754
+	tristate "Analog Devices ADE7754 Polyphase Multifunction Energy Metering IC Driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices ADE7754 Polyphase
+	  Multifunction Energy Metering IC Driver.

drivers/staging/iio/meter/Makefile

@@ -3,3 +3,4 @@
 #
 
 obj-$(CONFIG_ADE7753) += ade7753.o
+obj-$(CONFIG_ADE7754) += ade7754.o

drivers/staging/iio/meter/ade7754.c

+/*
+ * ADE7754 Polyphase Multifunction Energy Metering IC Driver
+ *
+ * Copyright 2010 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2 or later.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/gpio.h>
+#include <linux/delay.h>
+#include <linux/mutex.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/list.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "meter.h"
+#include "ade7754.h"
+
+static int ade7754_spi_write_reg_8(struct device *dev,
+		u8 reg_address,
+		u8 val)
+{
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ade7754_state *st = iio_dev_get_devdata(indio_dev);
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADE7754_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 ade7754_spi_write_reg_16(struct device *dev,
+		u8 reg_address,
+		u16 value)
+{
+	int ret;
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ade7754_state *st = iio_dev_get_devdata(indio_dev);
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.bits_per_word = 8,
+			.len = 3,
+		}
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADE7754_WRITE_REG(reg_address);
+	st->tx[1] = (value >> 8) & 0xFF;
+	st->tx[2] = value & 0xFF;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(xfers, &msg);
+	ret = spi_sync(st->us, &msg);
+	mutex_unlock(&st->buf_lock);
+
+	return ret;
+}
+
+static int ade7754_spi_read_reg_8(struct device *dev,
+		u8 reg_address,
+		u8 *val)
+{
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ade7754_state *st = iio_dev_get_devdata(indio_dev);
+	int ret;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.rx_buf = st->rx,
+			.bits_per_word = 8,
+			.len = 2,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADE7754_READ_REG(reg_address);
+	st->tx[1] = 0;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(xfers, &msg);
+	ret = spi_sync(st->us, &msg);
+	if (ret) {
+		dev_err(&st->us->dev, "problem when reading 8 bit register 0x%02X",
+				reg_address);
+		goto error_ret;
+	}
+	*val = st->rx[1];
+
+error_ret:
+	mutex_unlock(&st->buf_lock);
+	return ret;
+}
+
+static int ade7754_spi_read_reg_16(struct device *dev,
+		u8 reg_address,
+		u16 *val)
+{
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ade7754_state *st = iio_dev_get_devdata(indio_dev);
+	int ret;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.rx_buf = st->rx,
+			.bits_per_word = 8,
+			.len = 3,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADE7754_READ_REG(reg_address);
+	st->tx[1] = 0;
+	st->tx[2] = 0;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(xfers, &msg);
+	ret = spi_sync(st->us, &msg);
+	if (ret) {
+		dev_err(&st->us->dev, "problem when reading 16 bit register 0x%02X",
+				reg_address);
+		goto error_ret;
+	}
+	*val = (st->rx[1] << 8) | st->rx[2];
+
+error_ret:
+	mutex_unlock(&st->buf_lock);
+	return ret;
+}
+
+static int ade7754_spi_read_reg_24(struct device *dev,
+		u8 reg_address,
+		u32 *val)
+{
+	struct spi_message msg;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ade7754_state *st = iio_dev_get_devdata(indio_dev);
+	int ret;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = st->tx,
+			.rx_buf = st->rx,
+			.bits_per_word = 8,
+			.len = 4,
+		},
+	};
+
+	mutex_lock(&st->buf_lock);
+	st->tx[0] = ADE7754_READ_REG(reg_address);
+	st->tx[1] = 0;
+	st->tx[2] = 0;
+	st->tx[3] = 0;
+
+	spi_message_init(&msg);
+	spi_message_add_tail(xfers, &msg);
+	ret = spi_sync(st->us, &msg);
+	if (ret) {
+		dev_err(&st->us->dev, "problem when reading 24 bit register 0x%02X",
+				reg_address);
+		goto error_ret;
+	}
+	*val = (st->rx[1] << 16) | (st->rx[2] << 8) | st->rx[3];
+
+error_ret:
+	mutex_unlock(&st->buf_lock);
+	return ret;
+}
+
+static ssize_t ade7754_read_8bit(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret;
+	u8 val = 0;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = ade7754_spi_read_reg_8(dev, this_attr->address, &val);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t ade7754_read_16bit(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret;
+	u16 val = 0;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = ade7754_spi_read_reg_16(dev, this_attr->address, &val);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u\n", val);
+}
+
+static ssize_t ade7754_read_24bit(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret;
+	u32 val = 0;
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+
+	ret = ade7754_spi_read_reg_24(dev, this_attr->address, &val);
+	if (ret)
+		return ret;
+
+	return sprintf(buf, "%u\n", val & 0xFFFFFF);
+}
+
+static ssize_t ade7754_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;
+	long val;
+
+	ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		goto error_ret;
+	ret = ade7754_spi_write_reg_8(dev, this_attr->address, val);
+
+error_ret:
+	return ret ? ret : len;
+}
+
+static ssize_t ade7754_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;
+	long val;
+
+	ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		goto error_ret;
+	ret = ade7754_spi_write_reg_16(dev, this_attr->address, val);
+
+error_ret:
+	return ret ? ret : len;
+}
+
+static int ade7754_reset(struct device *dev)
+{
+	int ret;
+	u8 val;
+	ade7754_spi_read_reg_8(dev,
+			ADE7754_OPMODE,
+			&val);
+	val |= 1 << 6; /* Software Chip Reset */
+	ret = ade7754_spi_write_reg_8(dev,
+			ADE7754_OPMODE,
+			val);
+
+	return ret;
+}
+
+
+static ssize_t ade7754_write_reset(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf, size_t len)
+{
+	if (len < 1)
+		return -1;
+	switch (buf[0]) {
+	case '1':
+	case 'y':
+	case 'Y':
+		return ade7754_reset(dev);
+	}
+	return -1;
+}
+
+static IIO_DEV_ATTR_AENERGY(ade7754_read_24bit, ADE7754_AENERGY);
+static IIO_DEV_ATTR_LAENERGY(ade7754_read_24bit, ADE7754_LAENERGY);
+static IIO_DEV_ATTR_VAENERGY(ade7754_read_24bit, ADE7754_VAENERGY);
+static IIO_DEV_ATTR_LVAENERGY(ade7754_read_24bit, ADE7754_LVAENERGY);
+static IIO_DEV_ATTR_VPEAK(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_VPEAK);
+static IIO_DEV_ATTR_IPEAK(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_VPEAK);
+static IIO_DEV_ATTR_APHCAL(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_APHCAL);
+static IIO_DEV_ATTR_BPHCAL(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_BPHCAL);
+static IIO_DEV_ATTR_CPHCAL(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_CPHCAL);
+static IIO_DEV_ATTR_AAPOS(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_AAPOS);
+static IIO_DEV_ATTR_BAPOS(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_BAPOS);
+static IIO_DEV_ATTR_CAPOS(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_CAPOS);
+static IIO_DEV_ATTR_WDIV(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_WDIV);
+static IIO_DEV_ATTR_VADIV(S_IWUSR | S_IRUGO,
+		ade7754_read_8bit,
+		ade7754_write_8bit,
+		ADE7754_VADIV);
+static IIO_DEV_ATTR_CFNUM(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_CFNUM);
+static IIO_DEV_ATTR_CFDEN(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_CFDEN);
+static IIO_DEV_ATTR_ACTIVE_POWER_A_GAIN(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_AAPGAIN);
+static IIO_DEV_ATTR_ACTIVE_POWER_B_GAIN(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_BAPGAIN);
+static IIO_DEV_ATTR_ACTIVE_POWER_C_GAIN(S_IWUSR | S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_CAPGAIN);
+static IIO_DEV_ATTR_AIRMS(S_IRUGO,
+		ade7754_read_24bit,
+		NULL,
+		ADE7754_AIRMS);
+static IIO_DEV_ATTR_BIRMS(S_IRUGO,
+		ade7754_read_24bit,
+		NULL,
+		ADE7754_BIRMS);
+static IIO_DEV_ATTR_CIRMS(S_IRUGO,
+		ade7754_read_24bit,
+		NULL,
+		ADE7754_CIRMS);
+static IIO_DEV_ATTR_AVRMS(S_IRUGO,
+		ade7754_read_24bit,
+		NULL,
+		ADE7754_AVRMS);
+static IIO_DEV_ATTR_BVRMS(S_IRUGO,
+		ade7754_read_24bit,
+		NULL,
+		ADE7754_BVRMS);
+static IIO_DEV_ATTR_CVRMS(S_IRUGO,
+		ade7754_read_24bit,
+		NULL,
+		ADE7754_CVRMS);
+static IIO_DEV_ATTR_AIRMSOS(S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_AIRMSOS);
+static IIO_DEV_ATTR_BIRMSOS(S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_BIRMSOS);
+static IIO_DEV_ATTR_CIRMSOS(S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_CIRMSOS);
+static IIO_DEV_ATTR_AVRMSOS(S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_AVRMSOS);
+static IIO_DEV_ATTR_BVRMSOS(S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_BVRMSOS);
+static IIO_DEV_ATTR_CVRMSOS(S_IRUGO,
+		ade7754_read_16bit,
+		ade7754_write_16bit,
+		ADE7754_CVRMSOS);
+
+static int ade7754_set_irq(struct device *dev, bool enable)
+{
+	int ret;
+	u16 irqen;
+	ret = ade7754_spi_read_reg_16(dev, ADE7754_IRQEN, &irqen);
+	if (ret)
+		goto error_ret;
+
+	if (enable)
+		irqen |= 1 << 14; /* Enables an interrupt when a data is
+				     present in the waveform register */
+	else
+		irqen &= ~(1 << 14);
+
+	ret = ade7754_spi_write_reg_16(dev, ADE7754_IRQEN, irqen);
+	if (ret)
+		goto error_ret;
+
+error_ret:
+	return ret;
+}
+
+/* Power down the device */
+static int ade7754_stop_device(struct device *dev)
+{
+	int ret;
+	u8 val;
+	ade7754_spi_read_reg_8(dev,
+			ADE7754_OPMODE,
+			&val);
+	val |= 7 << 3;  /* ADE7754 powered down */
+	ret = ade7754_spi_write_reg_8(dev,
+			ADE7754_OPMODE,
+			val);
+
+	return ret;
+}
+
+static int ade7754_initial_setup(struct ade7754_state *st)
+{
+	int ret;
+	struct device *dev = &st->indio_dev->dev;
+
+	/* use low spi speed for init */
+	st->us->mode = SPI_MODE_3;
+	spi_setup(st->us);
+
+	/* Disable IRQ */
+	ret = ade7754_set_irq(dev, false);
+	if (ret) {
+		dev_err(dev, "disable irq failed");
+		goto err_ret;
+	}
+
+	ade7754_reset(dev);
+	msleep(ADE7754_STARTUP_DELAY);
+
+err_ret:
+	return ret;
+}
+
+static ssize_t ade7754_read_frequency(struct device *dev,
+		struct device_attribute *attr,
+		char *buf)
+{
+	int ret, len = 0;
+	u8 t;
+	int sps;
+	ret = ade7754_spi_read_reg_8(dev,
+			ADE7754_WAVMODE,
+			&t);
+	if (ret)
+		return ret;
+
+	t = (t >> 3) & 0x3;
+	sps = 26000 / (1 + t);
+
+	len = sprintf(buf, "%d SPS\n", sps);
+	return len;
+}
+
+static ssize_t ade7754_write_frequency(struct device *dev,
+		struct device_attribute *attr,
+		const char *buf,
+		size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ade7754_state *st = iio_dev_get_devdata(indio_dev);
+	unsigned long val;
+	int ret;
+	u8 reg, t;
+
+	ret = strict_strtol(buf, 10, &val);
+	if (ret)
+		return ret;
+
+	mutex_lock(&indio_dev->mlock);
+
+	t = (26000 / val);
+	if (t > 0)
+		t--;
+
+	if (t > 1)
+		st->us->max_speed_hz = ADE7754_SPI_SLOW;
+	else
+		st->us->max_speed_hz = ADE7754_SPI_FAST;
+
+	ret = ade7754_spi_read_reg_8(dev,
+			ADE7754_WAVMODE,
+			&reg);
+	if (ret)
+		goto out;
+
+	reg &= ~(3 << 3);
+	reg |= t << 3;
+
+	ret = ade7754_spi_write_reg_8(dev,
+			ADE7754_WAVMODE,
+			reg);
+
+out:
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret ? ret : len;
+}
+static IIO_DEV_ATTR_TEMP_RAW(ade7754_read_8bit);
+static IIO_CONST_ATTR(temp_offset, "129 C");
+static IIO_CONST_ATTR(temp_scale, "4 C");
+
+static IIO_DEV_ATTR_SAMP_FREQ(S_IWUSR | S_IRUGO,
+		ade7754_read_frequency,
+		ade7754_write_frequency);
+
+static IIO_DEV_ATTR_RESET(ade7754_write_reset);
+
+static IIO_CONST_ATTR_SAMP_FREQ_AVAIL("26000 13000 65000 33000");
+
+static IIO_CONST_ATTR(name, "ade7754");
+
+static struct attribute *ade7754_event_attributes[] = {
+	NULL
+};
+
+static struct attribute_group ade7754_event_attribute_group = {
+	.attrs = ade7754_event_attributes,
+};
+
+static struct attribute *ade7754_attributes[] = {
+	&iio_dev_attr_temp_raw.dev_attr.attr,
+	&iio_const_attr_temp_offset.dev_attr.attr,
+	&iio_const_attr_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_reset.dev_attr.attr,
+	&iio_const_attr_name.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_vpeak.dev_attr.attr,
+	&iio_dev_attr_ipeak.dev_attr.attr,
+	&iio_dev_attr_aphcal.dev_attr.attr,
+	&iio_dev_attr_bphcal.dev_attr.attr,
+	&iio_dev_attr_cphcal.dev_attr.attr,
+	&iio_dev_attr_aapos.dev_attr.attr,
+	&iio_dev_attr_bapos.dev_attr.attr,
+	&iio_dev_attr_capos.dev_attr.attr,
+	&iio_dev_attr_wdiv.dev_attr.attr,
+	&iio_dev_attr_vadiv.dev_attr.attr,
+	&iio_dev_attr_cfnum.dev_attr.attr,
+	&iio_dev_attr_cfden.dev_attr.attr,
+	&iio_dev_attr_active_power_a_gain.dev_attr.attr,
+	&iio_dev_attr_active_power_b_gain.dev_attr.attr,
+	&iio_dev_attr_active_power_c_gain.dev_attr.attr,
+	&iio_dev_attr_airms.dev_attr.attr,
+	&iio_dev_attr_birms.dev_attr.attr,
+	&iio_dev_attr_cirms.dev_attr.attr,
+	&iio_dev_attr_avrms.dev_attr.attr,
+	&iio_dev_attr_bvrms.dev_attr.attr,
+	&iio_dev_attr_cvrms.dev_attr.attr,
+	&iio_dev_attr_airmsos.dev_attr.attr,
+	&iio_dev_attr_birmsos.dev_attr.attr,
+	&iio_dev_attr_cirmsos.dev_attr.attr,
+	&iio_dev_attr_avrmsos.dev_attr.attr,
+	&iio_dev_attr_bvrmsos.dev_attr.attr,
+	&iio_dev_attr_cvrmsos.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ade7754_attribute_group = {
+	.attrs = ade7754_attributes,
+};
+
+
+
+static int __devinit ade7754_probe(struct spi_device *spi)
+{
+	int ret, regdone = 0;
+	struct ade7754_state *st = kzalloc(sizeof *st, GFP_KERNEL);
+	if (!st) {
+		ret =  -ENOMEM;
+		goto error_ret;
+	}
+	/* this is only used for removal purposes */
+	spi_set_drvdata(spi, st);
+
+	/* Allocate the comms buffers */
+	st->rx = kzalloc(sizeof(*st->rx)*ADE7754_MAX_RX, GFP_KERNEL);
+	if (st->rx == NULL) {
+		ret = -ENOMEM;
+		goto error_free_st;
+	}
+	st->tx = kzalloc(sizeof(*st->tx)*ADE7754_MAX_TX, GFP_KERNEL);
+	if (st->tx == NULL) {
+		ret = -ENOMEM;
+		goto error_free_rx;
+	}
+	st->us = spi;
+	mutex_init(&st->buf_lock);
+	/* setup the industrialio driver allocated elements */
+	st->indio_dev = iio_allocate_device();
+	if (st->indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_free_tx;
+	}
+
+	st->indio_dev->dev.parent = &spi->dev;
+	st->indio_dev->num_interrupt_lines = 1;
+	st->indio_dev->event_attrs = &ade7754_event_attribute_group;
+	st->indio_dev->attrs = &ade7754_attribute_group;
+	st->indio_dev->dev_data = (void *)(st);
+	st->indio_dev->driver_module = THIS_MODULE;
+	st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = ade7754_configure_ring(st->indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	ret = iio_device_register(st->indio_dev);
+	if (ret)
+		goto error_unreg_ring_funcs;
+	regdone = 1;
+
+	ret = ade7754_initialize_ring(st->indio_dev->ring);
+	if (ret) {
+		printk(KERN_ERR "failed to initialize the ring\n");
+		goto error_unreg_ring_funcs;
+	}
+
+	if (spi->irq) {
+		ret = iio_register_interrupt_line(spi->irq,
+				st->indio_dev,
+				0,
+				IRQF_TRIGGER_FALLING,
+				"ade7754");
+		if (ret)
+			goto error_uninitialize_ring;
+
+		ret = ade7754_probe_trigger(st->indio_dev);
+		if (ret)
+			goto error_unregister_line;
+	}
+
+	/* Get the device into a sane initial state */
+	ret = ade7754_initial_setup(st);
+	if (ret)
+		goto error_remove_trigger;
+	return 0;
+
+error_remove_trigger:
+	if (st->indio_dev->modes & INDIO_RING_TRIGGERED)
+		ade7754_remove_trigger(st->indio_dev);
+error_unregister_line:
+	if (st->indio_dev->modes & INDIO_RING_TRIGGERED)
+		iio_unregister_interrupt_line(st->indio_dev, 0);
+error_uninitialize_ring:
+	ade7754_uninitialize_ring(st->indio_dev->ring);
+error_unreg_ring_funcs:
+	ade7754_unconfigure_ring(st->indio_dev);
+error_free_dev:
+	if (regdone)
+		iio_device_unregister(st->indio_dev);
+	else
+		iio_free_device(st->indio_dev);
+error_free_tx:
+	kfree(st->tx);
+error_free_rx:
+	kfree(st->rx);
+error_free_st:
+	kfree(st);
+error_ret:
+	return ret;
+}
+
+/* fixme, confirm ordering in this function */
+static int ade7754_remove(struct spi_device *spi)
+{
+	int ret;
+	struct ade7754_state *st = spi_get_drvdata(spi);
+	struct iio_dev *indio_dev = st->indio_dev;
+
+	ret = ade7754_stop_device(&(indio_dev->dev));
+	if (ret)
+		goto err_ret;
+
+	flush_scheduled_work();
+
+	ade7754_remove_trigger(indio_dev);
+	if (spi->irq)
+		iio_unregister_interrupt_line(indio_dev, 0);
+
+	ade7754_uninitialize_ring(indio_dev->ring);
+	ade7754_unconfigure_ring(indio_dev);
+	iio_device_unregister(indio_dev);
+	kfree(st->tx);
+	kfree(st->rx);
+	kfree(st);
+
+	return 0;
+
+err_ret:
+	return ret;
+}
+
+static struct spi_driver ade7754_driver = {
+	.driver = {
+		.name = "ade7754",
+		.owner = THIS_MODULE,
+	},
+	.probe = ade7754_probe,
+	.remove = __devexit_p(ade7754_remove),
+};
+
+static __init int ade7754_init(void)
+{
+	return spi_register_driver(&ade7754_driver);
+}
+module_init(ade7754_init);
+
+static __exit void ade7754_exit(void)
+{
+	spi_unregister_driver(&ade7754_driver);
+}
+module_exit(ade7754_exit);
+
+MODULE_AUTHOR("Barry Song <21cnbao@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices ADE7754 Polyphase Multifunction Energy Metering IC Driver");
+MODULE_LICENSE("GPL v2");

drivers/staging/iio/meter/ade7754.h

+#ifndef _ADE7754_H
+#define _ADE7754_H
+
+#define ADE7754_AENERGY   0x01
+#define ADE7754_RAENERGY  0x02
+#define ADE7754_LAENERGY  0x03
+#define ADE7754_VAENERGY  0x04
+#define ADE7754_RVAENERGY 0x05
+#define ADE7754_LVAENERGY 0x06
+#define ADE7754_PERIOD    0x07
+#define ADE7754_TEMP      0x08
+#define ADE7754_WFORM     0x09
+#define ADE7754_OPMODE    0x0A
+#define ADE7754_MMODE     0x0B
+#define ADE7754_WAVMODE   0x0C
+#define ADE7754_WATMODE   0x0D
+#define ADE7754_VAMODE    0x0E
+#define ADE7754_IRQEN     0x0F
+#define ADE7754_STATUS    0x10
+#define ADE7754_RSTATUS   0x11
+#define ADE7754_ZXTOUT    0x12
+#define ADE7754_LINCYC    0x13
+#define ADE7754_SAGCYC    0x14
+#define ADE7754_SAGLVL    0x15
+#define ADE7754_VPEAK     0x16
+#define ADE7754_IPEAK     0x17
+#define ADE7754_GAIN      0x18
+#define ADE7754_AWG       0x19
+#define ADE7754_BWG       0x1A
+#define ADE7754_CWG       0x1B
+#define ADE7754_AVAG      0x1C
+#define ADE7754_BVAG      0x1D
+#define ADE7754_CVAG      0x1E
+#define ADE7754_APHCAL    0x1F
+#define ADE7754_BPHCAL    0x20
+#define ADE7754_CPHCAL    0x21
+#define ADE7754_AAPOS     0x22
+#define ADE7754_BAPOS     0x23
+#define ADE7754_CAPOS     0x24
+#define ADE7754_CFNUM     0x25
+#define ADE7754_CFDEN     0x26
+#define ADE7754_WDIV      0x27
+#define ADE7754_VADIV     0x28
+#define ADE7754_AIRMS     0x29
+#define ADE7754_BIRMS     0x2A
+#define ADE7754_CIRMS     0x2B
+#define ADE7754_AVRMS     0x2C
+#define ADE7754_BVRMS     0x2D
+#define ADE7754_CVRMS     0x2E
+#define ADE7754_AIRMSOS   0x2F
+#define ADE7754_BIRMSOS   0x30
+#define ADE7754_CIRMSOS   0x31
+#define ADE7754_AVRMSOS   0x32
+#define ADE7754_BVRMSOS   0x33
+#define ADE7754_CVRMSOS   0x34
+#define ADE7754_AAPGAIN   0x35
+#define ADE7754_BAPGAIN   0x36
+#define ADE7754_CAPGAIN   0x37
+#define ADE7754_AVGAIN    0x38
+#define ADE7754_BVGAIN    0x39
+#define ADE7754_CVGAIN    0x3A
+#define ADE7754_CHKSUM    0x3E
+#define ADE7754_VERSION   0x3F
+
+#define ADE7754_READ_REG(a)    a
+#define ADE7754_WRITE_REG(a) ((a) | 0x80)
+
+#define ADE7754_MAX_TX    4
+#define ADE7754_MAX_RX    4
+#define ADE7754_STARTUP_DELAY 1
+
+#define ADE7754_SPI_SLOW	(u32)(300 * 1000)
+#define ADE7754_SPI_BURST	(u32)(1000 * 1000)
+#define ADE7754_SPI_FAST	(u32)(2000 * 1000)
+
+#define DRIVER_NAME		"ade7754"
+
+/**
+ * struct ade7754_state - device instance specific data
+ * @us:			actual spi_device
+ * @work_trigger_to_ring: bh for triggered event handling
+ * @inter:		used to check if new interrupt has been triggered
+ * @last_timestamp:	passing timestamp from th to bh of interrupt handler
+ * @indio_dev:		industrial I/O device structure
+ * @trig:		data ready trigger registered with iio
+ * @tx:			transmit buffer
+ * @rx:			recieve buffer
+ * @buf_lock:		mutex to protect tx and rx
+ **/
+struct ade7754_state {
+	struct spi_device		*us;
+	struct work_struct		work_trigger_to_ring;
+	s64				last_timestamp;
+	struct iio_dev			*indio_dev;
+	struct iio_trigger		*trig;
+	u8				*tx;
+	u8				*rx;
+	struct mutex			buf_lock;
+};
+#if defined(CONFIG_IIO_RING_BUFFER) && defined(THIS_HAS_RING_BUFFER_SUPPORT)
+/* At the moment triggers are only used for ring buffer
+ * filling. This may change!
+ */
+
+enum ade7754_scan {
+	ADE7754_SCAN_PHA_V,
+	ADE7754_SCAN_PHB_V,
+	ADE7754_SCAN_PHC_V,
+	ADE7754_SCAN_PHA_I,
+	ADE7754_SCAN_PHB_I,
+	ADE7754_SCAN_PHC_I,
+};
+
+void ade7754_remove_trigger(struct iio_dev *indio_dev);
+int ade7754_probe_trigger(struct iio_dev *indio_dev);
+
+ssize_t ade7754_read_data_from_ring(struct device *dev,
+				      struct device_attribute *attr,
+				      char *buf);
+
+
+int ade7754_configure_ring(struct iio_dev *indio_dev);
+void ade7754_unconfigure_ring(struct iio_dev *indio_dev);
+
+int ade7754_initialize_ring(struct iio_ring_buffer *ring);
+void ade7754_uninitialize_ring(struct iio_ring_buffer *ring);
+#else /* CONFIG_IIO_RING_BUFFER */
+
+static inline void ade7754_remove_trigger(struct iio_dev *indio_dev)
+{
+}
+static inline int ade7754_probe_trigger(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+
+static inline ssize_t
+ade7754_read_data_from_ring(struct device *dev,
+			      struct device_attribute *attr,
+			      char *buf)
+{
+	return 0;
+}
+
+static int ade7754_configure_ring(struct iio_dev *indio_dev)
+{
+	return 0;
+}
+static inline void ade7754_unconfigure_ring(struct iio_dev *indio_dev)
+{
+}
+static inline int ade7754_initialize_ring(struct iio_ring_buffer *ring)
+{
+	return 0;
+}
+static inline void ade7754_uninitialize_ring(struct iio_ring_buffer *ring)
+{
+}
+#endif /* CONFIG_IIO_RING_BUFFER */
+
+#endif