staging: IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

drivers/staging/iio/dac/Kconfig

@@ -31,6 +31,16 @@ config AD5504
 	  To compile this driver as a module, choose M here: the
 	  module will be called ad5504.
 
+config AD5791
+	tristate "Analog Devices AD5781/AD5791 DAC SPI driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD5781, AD5791,
+	  High Resolution Voltage Output Digital to Analog Converter.
+
+	  To compile this driver as a module, choose M here: the
+	  module will be called ad5791.
+
 config MAX517
 	tristate "Maxim MAX517/518/519 DAC driver"
 	depends on I2C && EXPERIMENTAL

drivers/staging/iio/dac/Makefile

@@ -5,4 +5,5 @@
 obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
 obj-$(CONFIG_AD5504) += ad5504.o
 obj-$(CONFIG_AD5446) += ad5446.o
+obj-$(CONFIG_AD5791) += ad5791.o
 obj-$(CONFIG_MAX517) += max517.o

drivers/staging/iio/dac/ad5791.c

+/*
+ * AD5791, AD5791 Voltage Output Digital to Analog Converter
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/interrupt.h>
+#include <linux/gpio.h>
+#include <linux/fs.h>
+#include <linux/device.h>
+#include <linux/kernel.h>
+#include <linux/spi/spi.h>
+#include <linux/slab.h>
+#include <linux/sysfs.h>
+#include <linux/regulator/consumer.h>
+
+#include "../iio.h"
+#include "../sysfs.h"
+#include "dac.h"
+#include "ad5791.h"
+
+static int ad5791_spi_write(struct spi_device *spi, u8 addr, u32 val)
+{
+	union {
+		u32 d32;
+		u8 d8[4];
+	} data;
+
+	data.d32 = cpu_to_be32(AD5791_CMD_WRITE |
+			      AD5791_ADDR(addr) |
+			      (val & AD5791_DAC_MASK));
+
+	return spi_write(spi, &data.d8[1], 3);
+}
+
+static int ad5791_spi_read(struct spi_device *spi, u8 addr, u32 *val)
+{
+	union {
+		u32 d32;
+		u8 d8[4];
+	} data[3];
+	int ret;
+	struct spi_message msg;
+	struct spi_transfer xfers[] = {
+		{
+			.tx_buf = &data[0].d8[1],
+			.bits_per_word = 8,
+			.len = 3,
+			.cs_change = 1,
+		}, {
+			.tx_buf = &data[1].d8[1],
+			.rx_buf = &data[2].d8[1],
+			.bits_per_word = 8,
+			.len = 3,
+		},
+	};
+
+	data[0].d32 = cpu_to_be32(AD5791_CMD_READ |
+			      AD5791_ADDR(addr));
+	data[1].d32 = cpu_to_be32(AD5791_ADDR(AD5791_ADDR_NOOP));
+
+	spi_message_init(&msg);
+	spi_message_add_tail(&xfers[0], &msg);
+	spi_message_add_tail(&xfers[1], &msg);
+	ret = spi_sync(spi, &msg);
+
+	*val = be32_to_cpu(data[2].d32);
+
+	return ret;
+}
+
+static ssize_t ad5791_write_dac(struct device *dev,
+				 struct device_attribute *attr,
+				 const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	long readin;
+	int ret;
+
+	ret = strict_strtol(buf, 10, &readin);
+	if (ret)
+		return ret;
+
+	readin += (1 << (st->chip_info->bits - 1));
+	readin &= AD5791_RES_MASK(st->chip_info->bits);
+	readin <<= st->chip_info->left_shift;
+
+	ret = ad5791_spi_write(st->spi, this_attr->address, readin);
+	return ret ? ret : len;
+}
+
+static ssize_t ad5791_read_dac(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+	struct iio_dev_attr *this_attr = to_iio_dev_attr(attr);
+	int ret;
+	int val;
+
+	ret = ad5791_spi_read(st->spi, this_attr->address, &val);
+	if (ret)
+		return ret;
+
+	val &= AD5791_DAC_MASK;
+	val >>= st->chip_info->left_shift;
+	val -= (1 << (st->chip_info->bits - 1));
+
+	return sprintf(buf, "%d\n", val);
+}
+
+static ssize_t ad5791_read_powerdown_mode(struct device *dev,
+				      struct device_attribute *attr, char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+
+	const char mode[][14] = {"6kohm_to_gnd", "three_state"};
+
+	return sprintf(buf, "%s\n", mode[st->pwr_down_mode]);
+}
+
+static ssize_t ad5791_write_powerdown_mode(struct device *dev,
+				       struct device_attribute *attr,
+				       const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+	int ret;
+
+	if (sysfs_streq(buf, "6kohm_to_gnd"))
+		st->pwr_down_mode = AD5791_DAC_PWRDN_6K;
+	else if (sysfs_streq(buf, "three_state"))
+		st->pwr_down_mode = AD5791_DAC_PWRDN_3STATE;
+	else
+		ret = -EINVAL;
+
+	return ret ? ret : len;
+}
+
+static ssize_t ad5791_read_dac_powerdown(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+
+	return sprintf(buf, "%d\n", st->pwr_down);
+}
+
+static ssize_t ad5791_write_dac_powerdown(struct device *dev,
+					    struct device_attribute *attr,
+					    const char *buf, size_t len)
+{
+	long readin;
+	int ret;
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+
+	ret = strict_strtol(buf, 10, &readin);
+	if (ret)
+		return ret;
+
+	if (readin == 0) {
+		st->pwr_down = false;
+		st->ctrl &= ~(AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
+	} else if (readin == 1) {
+		st->pwr_down = true;
+		if (st->pwr_down_mode == AD5791_DAC_PWRDN_6K)
+			st->ctrl |= AD5791_CTRL_OPGND;
+		else if (st->pwr_down_mode == AD5791_DAC_PWRDN_3STATE)
+			st->ctrl |= AD5791_CTRL_DACTRI;
+	} else
+		ret = -EINVAL;
+
+	ret = ad5791_spi_write(st->spi, AD5791_ADDR_CTRL, st->ctrl);
+
+	return ret ? ret : len;
+}
+
+static ssize_t ad5791_show_scale(struct device *dev,
+				struct device_attribute *attr,
+				char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+	/* Corresponds to Vref / 2^(bits) */
+	unsigned int scale_uv = (st->vref_mv * 1000) >> st->chip_info->bits;
+
+	return sprintf(buf, "%d.%03d\n", scale_uv / 1000, scale_uv % 1000);
+}
+static IIO_DEVICE_ATTR(out_scale, S_IRUGO, ad5791_show_scale, NULL, 0);
+
+static ssize_t ad5791_show_name(struct device *dev,
+				 struct device_attribute *attr,
+				 char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5791_state *st = iio_dev_get_devdata(indio_dev);
+
+	return sprintf(buf, "%s\n", spi_get_device_id(st->spi)->name);
+}
+static IIO_DEVICE_ATTR(name, S_IRUGO, ad5791_show_name, NULL, 0);
+
+#define IIO_DEV_ATTR_OUT_RW_RAW(_num, _show, _store, _addr)		\
+	IIO_DEVICE_ATTR(out##_num##_raw,				\
+			S_IRUGO | S_IWUSR, _show, _store, _addr)
+
+static IIO_DEV_ATTR_OUT_RW_RAW(0, ad5791_read_dac,
+	ad5791_write_dac, AD5791_ADDR_DAC0);
+
+static IIO_DEVICE_ATTR(out_powerdown_mode, S_IRUGO |
+			S_IWUSR, ad5791_read_powerdown_mode,
+			ad5791_write_powerdown_mode, 0);
+
+static IIO_CONST_ATTR(out_powerdown_mode_available,
+			"6kohm_to_gnd three_state");
+
+#define IIO_DEV_ATTR_DAC_POWERDOWN(_num, _show, _store, _addr)		\
+	IIO_DEVICE_ATTR(out##_num##_powerdown,				\
+			S_IRUGO | S_IWUSR, _show, _store, _addr)
+
+static IIO_DEV_ATTR_DAC_POWERDOWN(0, ad5791_read_dac_powerdown,
+				   ad5791_write_dac_powerdown, 0);
+
+static struct attribute *ad5791_attributes[] = {
+	&iio_dev_attr_out0_raw.dev_attr.attr,
+	&iio_dev_attr_out0_powerdown.dev_attr.attr,
+	&iio_dev_attr_out_powerdown_mode.dev_attr.attr,
+	&iio_const_attr_out_powerdown_mode_available.dev_attr.attr,
+	&iio_dev_attr_out_scale.dev_attr.attr,
+	&iio_dev_attr_name.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad5791_attribute_group = {
+	.attrs = ad5791_attributes,
+};
+
+static const struct ad5791_chip_info ad5791_chip_info_tbl[] = {
+	[ID_AD5791] = {
+		.bits = 20,
+		.left_shift = 0,
+	},
+	[ID_AD5781] = {
+		.bits = 18,
+		.left_shift = 2,
+	},
+};
+
+static int ad5791_get_lin_comp(unsigned int span)
+{
+	if (span <= 10000)
+		return AD5791_LINCOMP_0_10;
+	else if (span <= 12000)
+		return AD5791_LINCOMP_10_12;
+	else if (span <= 16000)
+		return AD5791_LINCOMP_12_16;
+	else if (span <= 19000)
+		return AD5791_LINCOMP_16_19;
+	else
+		return AD5791_LINCOMP_19_20;
+}
+
+static int __devinit ad5791_probe(struct spi_device *spi)
+{
+	struct ad5791_platform_data *pdata = spi->dev.platform_data;
+	struct ad5791_state *st;
+	int ret, pos_voltage_uv = 0, neg_voltage_uv = 0;
+
+	st = kzalloc(sizeof(*st), GFP_KERNEL);
+	if (st == NULL) {
+		ret = -ENOMEM;
+		goto error_ret;
+	}
+
+	spi_set_drvdata(spi, st);
+
+	st->reg_vdd = regulator_get(&spi->dev, "vdd");
+	if (!IS_ERR(st->reg_vdd)) {
+		ret = regulator_enable(st->reg_vdd);
+		if (ret)
+			goto error_put_reg_pos;
+
+		pos_voltage_uv = regulator_get_voltage(st->reg_vdd);
+	}
+
+	st->reg_vss = regulator_get(&spi->dev, "vss");
+	if (!IS_ERR(st->reg_vss)) {
+		ret = regulator_enable(st->reg_vss);
+		if (ret)
+			goto error_put_reg_neg;
+
+		neg_voltage_uv = regulator_get_voltage(st->reg_vss);
+	}
+
+	if (!IS_ERR(st->reg_vss) && !IS_ERR(st->reg_vdd))
+		st->vref_mv = (pos_voltage_uv - neg_voltage_uv) / 1000;
+	else if (pdata)
+		st->vref_mv = pdata->vref_pos_mv - pdata->vref_neg_mv;
+	else
+		dev_warn(&spi->dev, "reference voltage unspecified\n");
+
+	ret = ad5791_spi_write(spi, AD5791_ADDR_SW_CTRL, AD5791_SWCTRL_RESET);
+	if (ret)
+		goto error_disable_reg_neg;
+
+	st->chip_info =
+		&ad5791_chip_info_tbl[spi_get_device_id(spi)->driver_data];
+
+
+	st->ctrl = AD5761_CTRL_LINCOMP(ad5791_get_lin_comp(st->vref_mv)) |
+		  ((pdata && pdata->use_rbuf_gain2) ? 0 : AD5791_CTRL_RBUF) |
+		  AD5791_CTRL_BIN2SC;
+
+	ret = ad5791_spi_write(spi, AD5791_ADDR_CTRL, st->ctrl |
+		AD5791_CTRL_OPGND | AD5791_CTRL_DACTRI);
+	if (ret)
+		goto error_disable_reg_neg;
+
+	st->pwr_down = true;
+
+	st->spi = spi;
+	st->indio_dev = iio_allocate_device();
+	if (st->indio_dev == NULL) {
+		ret = -ENOMEM;
+		goto error_disable_reg_neg;
+	}
+	st->indio_dev->dev.parent = &spi->dev;
+	st->indio_dev->dev_data = (void *)(st);
+	st->indio_dev->attrs = &ad5791_attribute_group;
+	st->indio_dev->driver_module = THIS_MODULE;
+	st->indio_dev->modes = INDIO_DIRECT_MODE;
+
+	ret = iio_device_register(st->indio_dev);
+	if (ret)
+		goto error_free_dev;
+
+	return 0;
+
+error_free_dev:
+	iio_free_device(st->indio_dev);
+
+error_disable_reg_neg:
+	if (!IS_ERR(st->reg_vss))
+		regulator_disable(st->reg_vss);
+error_put_reg_neg:
+	if (!IS_ERR(st->reg_vss))
+		regulator_put(st->reg_vss);
+
+	if (!IS_ERR(st->reg_vdd))
+		regulator_disable(st->reg_vdd);
+error_put_reg_pos:
+	if (!IS_ERR(st->reg_vdd))
+		regulator_put(st->reg_vdd);
+
+	kfree(st);
+error_ret:
+	return ret;
+}
+
+static int __devexit ad5791_remove(struct spi_device *spi)
+{
+	struct ad5791_state *st = spi_get_drvdata(spi);
+
+	iio_device_unregister(st->indio_dev);
+
+	if (!IS_ERR(st->reg_vdd)) {
+		regulator_disable(st->reg_vdd);
+		regulator_put(st->reg_vdd);
+	}
+
+	if (!IS_ERR(st->reg_vss)) {
+		regulator_disable(st->reg_vss);
+		regulator_put(st->reg_vss);
+	}
+
+	kfree(st);
+
+	return 0;
+}
+
+static const struct spi_device_id ad5791_id[] = {
+	{"ad5791", ID_AD5791},
+	{"ad5781", ID_AD5781},
+	{}
+};
+
+static struct spi_driver ad5791_driver = {
+	.driver = {
+		   .name = "ad5791",
+		   .owner = THIS_MODULE,
+		   },
+	.probe = ad5791_probe,
+	.remove = __devexit_p(ad5791_remove),
+	.id_table = ad5791_id,
+};
+
+static __init int ad5791_spi_init(void)
+{
+	return spi_register_driver(&ad5791_driver);
+}
+module_init(ad5791_spi_init);
+
+static __exit void ad5791_spi_exit(void)
+{
+	spi_unregister_driver(&ad5791_driver);
+}
+module_exit(ad5791_spi_exit);
+
+MODULE_AUTHOR("Michael Hennerich <hennerich@blackfin.uclinux.org>");
+MODULE_DESCRIPTION("Analog Devices AD5791/AD5781 DAC");
+MODULE_LICENSE("GPL v2");

drivers/staging/iio/dac/ad5791.h

+/*
+ * AD5791 SPI DAC driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#ifndef SPI_AD5791_H_
+#define SPI_AD5791_H_
+
+#define AD5791_RES_MASK(x)		((1 << (x)) - 1)
+#define AD5791_DAC_MASK			AD5791_RES_MASK(20)
+#define AD5791_DAC_MSB			(1 << 19)
+
+#define AD5791_CMD_READ			(1 << 23)
+#define AD5791_CMD_WRITE		(0 << 23)
+#define AD5791_ADDR(addr)		((addr) << 20)
+
+/* Registers */
+#define AD5791_ADDR_NOOP		0
+#define AD5791_ADDR_DAC0		1
+#define AD5791_ADDR_CTRL		2
+#define AD5791_ADDR_CLRCODE		3
+#define AD5791_ADDR_SW_CTRL		4
+
+/* Control Register */
+#define AD5791_CTRL_RBUF		(1 << 1)
+#define AD5791_CTRL_OPGND		(1 << 2)
+#define AD5791_CTRL_DACTRI		(1 << 3)
+#define AD5791_CTRL_BIN2SC		(1 << 4)
+#define AD5791_CTRL_SDODIS		(1 << 5)
+#define AD5761_CTRL_LINCOMP(x)		((x) << 6)
+
+#define AD5791_LINCOMP_0_10		0
+#define AD5791_LINCOMP_10_12		1
+#define AD5791_LINCOMP_12_16		2
+#define AD5791_LINCOMP_16_19		3
+#define AD5791_LINCOMP_19_20		12
+
+/* Software Control Register */
+#define AD5791_SWCTRL_LDAC		(1 << 0)
+#define AD5791_SWCTRL_CLR		(1 << 1)
+#define AD5791_SWCTRL_RESET		(1 << 2)
+
+#define AD5791_DAC_PWRDN_6K		0
+#define AD5791_DAC_PWRDN_3STATE		1
+
+/*
+ * TODO: struct ad5791_platform_data needs to go into include/linux/iio
+ */
+
+/**
+ * struct ad5791_platform_data - platform specific information
+ * @vref_pos_mv:	Vdd Positive Analog Supply Volatge (mV)
+ * @vref_neg_mv:	Vdd Negative Analog Supply Volatge (mV)
+ * @use_rbuf_gain2:	ext. amplifier connected in gain of two configuration
+ */
+
+struct ad5791_platform_data {
+	u16				vref_pos_mv;
+	u16				vref_neg_mv;
+	bool				use_rbuf_gain2;
+};
+
+/**
+ * struct ad5791_chip_info - chip specific information
+ * @bits:		accuracy of the DAC in bits
+ * @left_shift:		number of bits the datum must be shifted
+ */
+
+struct ad5791_chip_info {
+	u8			bits;
+	u8			left_shift;
+};
+
+/**
+ * struct ad5791_state - driver instance specific data
+ * @indio_dev:		the industrial I/O device
+ * @us:			spi_device
+ * @reg_vdd:		positive supply regulator
+ * @reg_vss:		negative supply regulator
+ * @chip_info:		chip model specific constants
+ * @vref_mv:		actual reference voltage used
+ * @pwr_down_mode	current power down mode
+ */
+
+struct ad5791_state {
+	struct iio_dev			*indio_dev;
+	struct spi_device		*spi;
+	struct regulator		*reg_vdd;
+	struct regulator		*reg_vss;
+	const struct ad5791_chip_info	*chip_info;
+	unsigned short			vref_mv;
+	unsigned			ctrl;
+	unsigned			pwr_down_mode;
+	bool				pwr_down;
+};
+
+/**
+ * ad5791_supported_device_ids:
+ */
+
+enum ad5791_supported_device_ids {
+	ID_AD5791,
+	ID_AD5781,
+};
+
+#endif /* SPI_AD5791_H_ */