[PATCH 1/1] IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

[PATCH 1/1] IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>


Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
---
 drivers/staging/iio/dac/Kconfig  |   10 +
 drivers/staging/iio/dac/Makefile |    1 +
 drivers/staging/iio/dac/ad5791.c |  418 ++++++++++++++++++++++++++++++++++++++
 drivers/staging/iio/dac/ad5791.h |  109 ++++++++++
 4 files changed, 538 insertions(+), 0 deletions(-)
 create mode 100644 drivers/staging/iio/dac/ad5791.c
 create mode 100644 drivers/staging/iio/dac/ad5791.h

diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
index 1b0188a..f25468a 100644
--- a/drivers/staging/iio/dac/Kconfig
+++ b/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
diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile
index 020df4a..83196de 100644
--- a/drivers/staging/iio/dac/Makefile
+++ b/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
diff --git a/drivers/staging/iio/dac/ad5791.c b/drivers/staging/iio/dac/ad5791.c
new file mode 100644
index 0000000..545f1a6
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5791.c
@@ -0,0 +1,418 @@
+/*
+ * 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");
diff --git a/drivers/staging/iio/dac/ad5791.h b/drivers/staging/iio/dac/ad5791.h
new file mode 100644
index 0000000..71c7d59
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5791.h
@@ -0,0 +1,109 @@
+/*
+ * 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_ */
-- 
1.6.0.2

Re: [PATCH 1/1] IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

[Jonathan Cameron]

On 04/14/11 13:26, michael.hennerich@analog.com wrote:
> From: Michael Hennerich <michael.hennerich@analog.com>
> 
Yikes. That union stuff for the transfers is ugly. Having
said that I can't immediately see a better way of doing it.
Otherwise another nice clean an easy to read driver. Thanks,
I don't think I've overly broken anything in here with the recent
changes.  The only acception is adding a 0 parameter to iio_allocate_device.

That kind of depends on when Greg picks up the last set I sent him.

The other cleanup that applies here is to set indio_dev->name and
get rid of the explicit name attribute.  Can do that one later
though as it will still work as is.  Just saves a few lines of
code.
> 
> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>

> ---
>  drivers/staging/iio/dac/Kconfig  |   10 +
>  drivers/staging/iio/dac/Makefile |    1 +
>  drivers/staging/iio/dac/ad5791.c |  418 ++++++++++++++++++++++++++++++++++++++
>  drivers/staging/iio/dac/ad5791.h |  109 ++++++++++
>  4 files changed, 538 insertions(+), 0 deletions(-)
>  create mode 100644 drivers/staging/iio/dac/ad5791.c
>  create mode 100644 drivers/staging/iio/dac/ad5791.h
> 
> diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
> index 1b0188a..f25468a 100644
> --- a/drivers/staging/iio/dac/Kconfig
> +++ b/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
> diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile
> index 020df4a..83196de 100644
> --- a/drivers/staging/iio/dac/Makefile
> +++ b/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
> diff --git a/drivers/staging/iio/dac/ad5791.c b/drivers/staging/iio/dac/ad5791.c
> new file mode 100644
> index 0000000..545f1a6
> --- /dev/null
> +++ b/drivers/staging/iio/dac/ad5791.c
> @@ -0,0 +1,418 @@
> +/*
> + * 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");
> diff --git a/drivers/staging/iio/dac/ad5791.h b/drivers/staging/iio/dac/ad5791.h
> new file mode 100644
> index 0000000..71c7d59
> --- /dev/null
> +++ b/drivers/staging/iio/dac/ad5791.h
> @@ -0,0 +1,109 @@
> +/*
> + * 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_ */

RE: [PATCH 1/1] IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

[Hennerich, Michael]

Jonathan Cameron wrote on 2011-04-15:
> On 04/14/11 13:26, michael.hennerich@analog.com wrote:
>> From: Michael Hennerich <michael.hennerich@analog.com>
>>
> Yikes. That union stuff for the transfers is ugly. Having said that I
> can't immediately see a better way of doing it.
> Otherwise another nice clean an easy to read driver. Thanks, I don't
> think I've overly broken anything in here with the recent changes.
> The only acception is adding a 0 parameter to iio_allocate_device.
>
> That kind of depends on when Greg picks up the last set I sent him.
>
> The other cleanup that applies here is to set indio_dev->name and get
> rid of the explicit name attribute.  Can do that one later though as
> it will still work as is.  Just saves a few lines of code.

I've sent Greg the driver.
Hope he gets the ordering right on how this one interferes with your
[PATCH 4/8] set.

As for you your [PATCH x/70] set feel free to add my Acked-by on the
relevant patches. How do you want to handle these?
When do you want to send it on to Greg?

In case you want to wait for a few days, I test a few devices and
send you some patches, that moves the missing ones over to the new
channel registration method.
I'll do that on top of your todays iio-onwards.

>>
>> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
> Acked-by: Jonathan Cameron <jic23@cam.ac.uk>

Greetings,
Michael

--
Analog Devices GmbH      Wilhelm-Wagenfeld-Str. 6      80807 Muenchen
Sitz der Gesellschaft: Muenchen; Registergericht: Muenchen HRB 40368; Gesch=
aeftsfuehrer:Dr.Carsten Suckrow, Thomas Wessel, William A. Martin, Margaret=
 Seif

Re: [PATCH 1/1] IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

[Jonathan Cameron]

On 04/18/11 09:27, Hennerich, Michael wrote:
> Jonathan Cameron wrote on 2011-04-15:
>> On 04/14/11 13:26, michael.hennerich@analog.com wrote:
>>> From: Michael Hennerich <michael.hennerich@analog.com>
>>>
>> Yikes. That union stuff for the transfers is ugly. Having said that I
>> can't immediately see a better way of doing it.
>> Otherwise another nice clean an easy to read driver. Thanks, I don't
>> think I've overly broken anything in here with the recent changes.
>> The only acception is adding a 0 parameter to iio_allocate_device.
>>
>> That kind of depends on when Greg picks up the last set I sent him.
>>
>> The other cleanup that applies here is to set indio_dev->name and get
>> rid of the explicit name attribute.  Can do that one later though as
>> it will still work as is.  Just saves a few lines of code.
> 
> I've sent Greg the driver.
> Hope he gets the ordering right on how this one interferes with your
> [PATCH 4/8] set.
Fingers crossed.
> 
> As for you your [PATCH x/70] set feel free to add my Acked-by on the
> relevant patches. How do you want to handle these?
> When do you want to send it on to Greg?
Not for a few days. Need to do some work on the day job :)
> 
> In case you want to wait for a few days, I test a few devices and
> send you some patches, that moves the missing ones over to the new
> channel registration method.
That would be excellent.
> I'll do that on top of your todays iio-onwards.
Cool. I'll slot those into the series in the appropriate places, so it'll
be rebased from time to time.

I have another small series that cleans up the buffer allocation and handling
code, but I'll hold adding that to the tree for now as it involves some
minor interfaces changes in some of the drivers you'll be adding the chan_spec
stuff to.

Thanks

Jonathan
> 
>>>
>>> Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
>> Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
> 
> Greetings,
> Michael
> 
> --
> Analog Devices GmbH      Wilhelm-Wagenfeld-Str. 6      80807 Muenchen
> Sitz der Gesellschaft: Muenchen; Registergericht: Muenchen HRB 40368; Geschaeftsfuehrer:Dr.Carsten Suckrow, Thomas Wessel, William A. Martin, Margaret Seif
> 
> 
> 

[PATCH 1/1] IIO: DAC: New driver for AD5791/AD5781 High Resolution Voltage Output DACs

[michael.hennerich]

From: Michael Hennerich <michael.hennerich@analog.com>


Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Acked-by: Jonathan Cameron <jic23@cam.ac.uk>
---
 drivers/staging/iio/dac/Kconfig  |   10 +
 drivers/staging/iio/dac/Makefile |    1 +
 drivers/staging/iio/dac/ad5791.c |  418 ++++++++++++++++++++++++++++++++++++++
 drivers/staging/iio/dac/ad5791.h |  109 ++++++++++
 4 files changed, 538 insertions(+), 0 deletions(-)
 create mode 100644 drivers/staging/iio/dac/ad5791.c
 create mode 100644 drivers/staging/iio/dac/ad5791.h

diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
index 1b0188a..f25468a 100644
--- a/drivers/staging/iio/dac/Kconfig
+++ b/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
diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile
index 020df4a..83196de 100644
--- a/drivers/staging/iio/dac/Makefile
+++ b/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
diff --git a/drivers/staging/iio/dac/ad5791.c b/drivers/staging/iio/dac/ad5791.c
new file mode 100644
index 0000000..545f1a6
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5791.c
@@ -0,0 +1,418 @@
+/*
+ * 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");
diff --git a/drivers/staging/iio/dac/ad5791.h b/drivers/staging/iio/dac/ad5791.h
new file mode 100644
index 0000000..71c7d59
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5791.h
@@ -0,0 +1,109 @@
+/*
+ * 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_ */
--
1.6.0.2