[PATCH] staging:iio:dac: Add AD5360 driver

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This patch adds support for the Analog Devices AD5360, AD5361, AD5362, AD5363,
AD5370, AD5371, AD5372, AD5373 multi-channel digital-to-analog converters.

Signed-off-by: Lars-Peter Clausen <lars@xxxxxxxxxx>

---

I'm not entirly sure about one aspect of this driver. The chip has multiple
reference voltages and each vref is shared between multiple channels. There is
an adjustable offset per vref. For the current implementation I choose to have a
offset attribute for each channel which returns the offset which is used for
that channel. So now if that offset gets written to, the offset for all other
channels which share the same offset gets updated as well.
The alternative would be to register a iio device per vref and have a shared
offset attribute.
---
 drivers/staging/iio/dac/Kconfig  |   10 +
 drivers/staging/iio/dac/Makefile |    1 +
 drivers/staging/iio/dac/ad5360.c |  584 ++++++++++++++++++++++++++++++++++++++
 3 files changed, 595 insertions(+), 0 deletions(-)
 create mode 100644 drivers/staging/iio/dac/ad5360.c

diff --git a/drivers/staging/iio/dac/Kconfig b/drivers/staging/iio/dac/Kconfig
index 3000156..d5c95dc 100644
--- a/drivers/staging/iio/dac/Kconfig
+++ b/drivers/staging/iio/dac/Kconfig
@@ -3,6 +3,16 @@
 #
 menu "Digital to analog convertors"
 
+config AD5360
+	tristate "Analog Devices Analog Devices AD5360/61/62/63/70/71/73 DAC driver"
+	depends on SPI
+	help
+	  Say yes here to build support for Analog Devices AD5360/61/62/63/70/71/73
+	  digital-to-analog convertors (DAC). This driver uses the common SPI interface.
+
+	  To compile this driver as module choose M here: the module will be called
+	  ad5360.
+
 config AD5624R_SPI
 	tristate "Analog Devices AD5624/44/64R DAC spi driver"
 	depends on SPI
diff --git a/drivers/staging/iio/dac/Makefile b/drivers/staging/iio/dac/Makefile
index 7f4f2ed..e0a8c97 100644
--- a/drivers/staging/iio/dac/Makefile
+++ b/drivers/staging/iio/dac/Makefile
@@ -2,6 +2,7 @@
 # Makefile for industrial I/O DAC drivers
 #
 
+obj-$(CONFIG_AD5360) += ad5360.o
 obj-$(CONFIG_AD5624R_SPI) += ad5624r_spi.o
 obj-$(CONFIG_AD5504) += ad5504.o
 obj-$(CONFIG_AD5446) += ad5446.o
diff --git a/drivers/staging/iio/dac/ad5360.c b/drivers/staging/iio/dac/ad5360.c
new file mode 100644
index 0000000..6cdff44
--- /dev/null
+++ b/drivers/staging/iio/dac/ad5360.c
@@ -0,0 +1,584 @@
+/*
+ * AD5360 Digital to analog converters  driver
+ *
+ * Copyright 2011 Analog Devices Inc.
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include <linux/device.h>
+#include <linux/err.h>
+#include <linux/module.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"
+
+#define AD5360_CMD(x)				((x) << 22)
+#define AD5360_ADDR(x)				((x) << 16)
+
+#define AD5360_READBACK_TYPE(x)			((x) << 13)
+#define AD5360_READBACK_ADDR(x)			((x) << 7)
+
+#define AD5360_CHAN_ADDR(chan)			((chan) + 0x8)
+
+#define AD5360_CMD_WRITE_DATA			0x3
+#define AD5360_CMD_WRITE_OFFSET			0x2
+#define AD5360_CMD_WRITE_GAIN			0x1
+#define AD5360_CMD_SPECIAL_FUNCTION		0x0
+
+/* Special function register addresses */
+#define AD5360_REG_SF_NOP			0x0
+#define AD5360_REG_SF_CTRL			0x1
+#define AD5360_REG_SF_OFS(x)			(0x2 + (x))
+#define AD5360_REG_SF_READBACK			0x5
+
+#define AD5360_SF_CTRL_PWR_DOWN			BIT(0)
+
+#define AD5360_READBACK_X1A			0x0
+#define AD5360_READBACK_X1B			0x1
+#define AD5360_READBACK_OFFSET			0x2
+#define AD5360_READBACK_GAIN			0x3
+#define AD5360_READBACK_SF			0x4
+
+
+/**
+ * struct ad5360_chip_info - chip specific information
+ * @channel_template:	channel specification template
+ * @num_channels:	number of channels
+ * @channels_per_group:	number of channels per group
+ * @num_vrefs:		number of vref supplies for the chip
+*/
+
+struct ad5360_chip_info {
+	struct iio_chan_spec	channel_template;
+	unsigned int		num_channels;
+	unsigned int		channels_per_group;
+	unsigned int		num_vrefs;
+};
+
+/**
+ * struct ad5360_state - driver instance specific data
+ * @spi:		spi_device
+ * @chip_info:		chip model specific constants, available modes etc
+ * @vref_reg:		vref supply regulators
+ * @ctrl:		control register cache
+ * @data:		spi transfer buffers
+ */
+
+struct ad5360_state {
+	struct spi_device		*spi;
+	const struct ad5360_chip_info	*chip_info;
+	struct regulator_bulk_data	vref_reg[3];
+	unsigned int			ctrl;
+
+	/*
+	 * DMA (thus cache coherency maintenance) requires the
+	 * transfer buffers to live in their own cache lines.
+	 */
+	union {
+		__be32 d32;
+		u8 d8[4];
+	} data[2] ____cacheline_aligned;
+};
+
+enum ad5360_type {
+	ID_AD5360,
+	ID_AD5361,
+	ID_AD5362,
+	ID_AD5363,
+	ID_AD5370,
+	ID_AD5371,
+	ID_AD5372,
+	ID_AD5373,
+};
+
+#define AD5360_CHANNEL(bits) {					\
+	.type = IIO_VOLTAGE,					\
+	.indexed = 1,						\
+	.output = 1,						\
+	.info_mask = (1 << IIO_CHAN_INFO_SCALE_SEPARATE) |	\
+		(1 << IIO_CHAN_INFO_OFFSET_SEPARATE) |		\
+		(1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE) |	\
+		(1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE),	\
+	.scan_type = IIO_ST('u', (bits), 16, 16 - (bits))	\
+}
+
+static const struct ad5360_chip_info ad5360_chip_info_tbl[] = {
+	[ID_AD5360] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 16,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5361] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 16,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5362] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 8,
+		.channels_per_group = 4,
+		.num_vrefs = 2,
+	},
+	[ID_AD5363] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 8,
+		.channels_per_group = 4,
+		.num_vrefs = 2,
+	},
+	[ID_AD5370] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 40,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5371] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 40,
+		.channels_per_group = 8,
+		.num_vrefs = 3,
+	},
+	[ID_AD5372] = {
+		.channel_template = AD5360_CHANNEL(16),
+		.num_channels = 32,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+	[ID_AD5373] = {
+		.channel_template = AD5360_CHANNEL(14),
+		.num_channels = 32,
+		.channels_per_group = 8,
+		.num_vrefs = 2,
+	},
+};
+
+static unsigned int ad5360_get_channel_vref_index(struct ad5360_state *st,
+	unsigned int channel)
+{
+	unsigned int i;
+
+	/* The first groups have their own vref, while the remaining groups
+	 * share the last vref */
+	i = channel / st->chip_info->channels_per_group;
+	if (i >= st->chip_info->num_vrefs)
+		i = st->chip_info->num_vrefs - 1;
+
+	return i;
+}
+
+static int ad5360_get_channel_vref(struct ad5360_state *st,
+	unsigned int channel)
+{
+	unsigned int i = ad5360_get_channel_vref_index(st, channel);
+
+	return regulator_get_voltage(st->vref_reg[i].consumer);
+}
+
+
+static int ad5360_write_unlocked(struct iio_dev *indio_dev,
+	unsigned int cmd, unsigned int addr, unsigned int val,
+	unsigned int shift)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+
+	val <<= shift;
+	val |= AD5360_CMD(cmd) | AD5360_ADDR(addr);
+	st->data[0].d32 = cpu_to_be32(val);
+
+	return spi_write(st->spi, &st->data[0].d8[1], 3);
+}
+
+static int ad5360_write(struct iio_dev *indio_dev, unsigned int cmd,
+	unsigned int addr, unsigned int val, unsigned int shift)
+{
+	int ret;
+
+	mutex_lock(&indio_dev->mlock);
+	ret = ad5360_write_unlocked(indio_dev, cmd, addr, val, shift);
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static int ad5360_read(struct iio_dev *indio_dev, unsigned int type,
+	unsigned int addr)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	struct spi_message m;
+	int ret;
+	struct spi_transfer t[] = {
+		{
+			.tx_buf = &st->data[0].d8[1],
+			.len = 3,
+			.cs_change = 1,
+		}, {
+			.rx_buf = &st->data[1].d8[1],
+			.len = 3,
+		},
+	};
+
+	spi_message_init(&m);
+	spi_message_add_tail(&t[0], &m);
+	spi_message_add_tail(&t[1], &m);
+
+	mutex_lock(&indio_dev->mlock);
+
+	st->data[0].d32 = cpu_to_be32(AD5360_CMD(AD5360_CMD_SPECIAL_FUNCTION) |
+		AD5360_ADDR(AD5360_REG_SF_READBACK) |
+		AD5360_READBACK_TYPE(type) |
+		AD5360_READBACK_ADDR(addr));
+
+	ret = spi_sync(st->spi, &m);
+	if (ret >= 0)
+		ret = be32_to_cpu(st->data[1].d32) & 0xffff;
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t ad5360_read_dac_powerdown(struct device *dev,
+					   struct device_attribute *attr,
+					   char *buf)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	struct ad5360_state *st = iio_priv(indio_dev);
+
+	return sprintf(buf, "%d\n", (bool)(st->ctrl & AD5360_SF_CTRL_PWR_DOWN));
+}
+
+static int ad5360_update_ctrl(struct iio_dev *indio_dev, unsigned int set,
+	unsigned int clr)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	unsigned int ret;
+
+	mutex_lock(&indio_dev->mlock);
+
+	st->ctrl |= set;
+	st->ctrl &= ~clr;
+
+	ret = ad5360_write_unlocked(indio_dev, AD5360_CMD_SPECIAL_FUNCTION,
+			AD5360_REG_SF_CTRL, st->ctrl, 0);
+
+	mutex_unlock(&indio_dev->mlock);
+
+	return ret;
+}
+
+static ssize_t ad5360_write_dac_powerdown(struct device *dev,
+	struct device_attribute *attr, const char *buf, size_t len)
+{
+	struct iio_dev *indio_dev = dev_get_drvdata(dev);
+	bool pwr_down;
+	int ret;
+
+	ret = strtobool(buf, &pwr_down);
+	if (ret)
+		return ret;
+
+	if (pwr_down)
+		ret = ad5360_update_ctrl(indio_dev, AD5360_SF_CTRL_PWR_DOWN, 0);
+	else
+		ret = ad5360_update_ctrl(indio_dev, 0, AD5360_SF_CTRL_PWR_DOWN);
+
+	return ret ? ret : len;
+}
+
+static IIO_DEVICE_ATTR(out_voltage_powerdown,
+			S_IRUGO | S_IWUSR,
+			ad5360_read_dac_powerdown,
+			ad5360_write_dac_powerdown, 0);
+
+static struct attribute *ad5360_attributes[] = {
+	&iio_dev_attr_out_voltage_powerdown.dev_attr.attr,
+	NULL,
+};
+
+static const struct attribute_group ad5360_attribute_group = {
+	.attrs = ad5360_attributes,
+};
+
+static int ad5360_write_raw(struct iio_dev *indio_dev,
+			       struct iio_chan_spec const *chan,
+			       int val,
+			       int val2,
+			       long mask)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	int max_val = (1 << chan->scan_type.realbits);
+	unsigned int ofs_index;
+	int ret;
+
+	switch (mask) {
+	case 0:
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+
+		ret = ad5360_write(indio_dev, AD5360_CMD_WRITE_DATA,
+				 chan->address, val,
+				 chan->scan_type.shift);
+		break;
+	case (1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE):
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+
+		ret = ad5360_write(indio_dev, AD5360_CMD_WRITE_OFFSET,
+				 chan->address, val,
+				 chan->scan_type.shift);
+		break;
+	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
+		if (val >= max_val || val < 0)
+			return -EINVAL;
+
+		ret = ad5360_write(indio_dev, AD5360_CMD_WRITE_GAIN,
+				 chan->address, val,
+				 chan->scan_type.shift);
+		break;
+	case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
+		if (val <= -max_val || val > 0)
+			return -EINVAL;
+
+		val = -val;
+
+		/* offset is supposed to have the same scale as raw, but it
+		 * is always 14bits wide, so on a chip where the raw value has
+		 * more bits, we need to shift offset. */
+		val >>= (chan->scan_type.realbits - 14);
+
+		/* There is one DAC offset register per vref. Changing one
+		 * channels offset will also change the offset for all other
+		 * channels which share the same vref supply. */
+		ofs_index = ad5360_get_channel_vref_index(st, chan->channel);
+		ret = ad5360_write(indio_dev, AD5360_CMD_SPECIAL_FUNCTION,
+				 AD5360_REG_SF_OFS(ofs_index), val, 0);
+		break;
+	default:
+		ret = -EINVAL;
+	}
+
+	return ret;
+}
+
+static int ad5360_read_raw(struct iio_dev *indio_dev,
+			   struct iio_chan_spec const *chan,
+			   int *val,
+			   int *val2,
+			   long m)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	unsigned long scale_uv;
+	unsigned int ofs_index;
+	int ret;
+
+	switch (m) {
+	case 0:
+		ret = ad5360_read(indio_dev, AD5360_READBACK_X1A,
+			chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret >> chan->scan_type.shift;
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_SCALE_SEPARATE):
+		/* vout = 4 * vref * dac_code */
+		scale_uv = ad5360_get_channel_vref(st, chan->channel) * 4 * 100;
+		if (scale_uv < 0)
+			return scale_uv;
+
+		scale_uv >>= (chan->scan_type.realbits);
+		*val =  scale_uv / 100000;
+		*val2 = (scale_uv % 100000) * 10;
+		return IIO_VAL_INT_PLUS_MICRO;
+	case (1 << IIO_CHAN_INFO_CALIBBIAS_SEPARATE):
+		ret = ad5360_read(indio_dev, AD5360_READBACK_OFFSET,
+			chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_CALIBSCALE_SEPARATE):
+		ret = ad5360_read(indio_dev, AD5360_READBACK_GAIN,
+			chan->address);
+		if (ret < 0)
+			return ret;
+		*val = ret;
+		return IIO_VAL_INT;
+	case (1 << IIO_CHAN_INFO_OFFSET_SEPARATE):
+		ofs_index = ad5360_get_channel_vref_index(st, chan->channel);
+		ret = ad5360_read(indio_dev, AD5360_READBACK_SF,
+			AD5360_REG_SF_OFS(ofs_index));
+		if (ret < 0)
+			return ret;
+
+		ret <<= (chan->scan_type.realbits - 14);
+		*val = -ret;
+		return IIO_VAL_INT;
+	}
+
+	return -EINVAL;
+}
+
+static const struct iio_info ad5360_info = {
+	.read_raw = ad5360_read_raw,
+	.write_raw = ad5360_write_raw,
+	.attrs = &ad5360_attribute_group,
+	.driver_module = THIS_MODULE,
+};
+
+static const char * const ad5360_vref_name[] = {
+	 "vref0", "vref1", "vref2"
+};
+
+static int __devinit ad5360_alloc_channels(struct iio_dev *indio_dev)
+{
+	struct ad5360_state *st = iio_priv(indio_dev);
+	struct iio_chan_spec *channels;
+	unsigned int i;
+
+	channels = kcalloc(sizeof(struct iio_chan_spec),
+			st->chip_info->num_channels, GFP_KERNEL);
+
+	if (!channels)
+		return -ENOMEM;
+
+	for (i = 0; i < st->chip_info->num_channels; ++i) {
+		channels[i] = st->chip_info->channel_template;
+		channels[i].channel = i;
+		channels[i].address = AD5360_CHAN_ADDR(i);
+	}
+
+	indio_dev->channels = channels;
+
+	return 0;
+}
+
+static int __devinit ad5360_probe(struct spi_device *spi)
+{
+	enum ad5360_type type = spi_get_device_id(spi)->driver_data;
+	struct iio_dev *indio_dev;
+	struct ad5360_state *st;
+	unsigned int i;
+	int ret;
+
+	indio_dev = iio_allocate_device(sizeof(*st));
+	if (indio_dev == NULL) {
+		dev_err(&spi->dev, "Failed to allocate iio device\n");
+		return  -ENOMEM;
+	}
+
+	st = iio_priv(indio_dev);
+	spi_set_drvdata(spi, indio_dev);
+
+	st->chip_info = &ad5360_chip_info_tbl[type];
+	st->spi = spi;
+
+	indio_dev->dev.parent = &spi->dev;
+	indio_dev->name = spi_get_device_id(spi)->name;
+	indio_dev->info = &ad5360_info;
+	indio_dev->modes = INDIO_DIRECT_MODE;
+	indio_dev->num_channels = st->chip_info->num_channels;
+
+	ret = ad5360_alloc_channels(indio_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to allocate channel spec: %d\n", ret);
+		goto error_free;
+	}
+
+	for (i = 0; i < st->chip_info->num_vrefs; ++i)
+		st->vref_reg[i].supply = ad5360_vref_name[i];
+
+	ret = regulator_bulk_get(&st->spi->dev, st->chip_info->num_vrefs,
+		st->vref_reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to request vref regulators: %d\n", ret);
+		goto error_free_channels;
+	}
+
+	ret = regulator_bulk_enable(st->chip_info->num_vrefs, st->vref_reg);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to enable vref regulators: %d\n", ret);
+		goto error_free_reg;
+	}
+
+	ret = iio_device_register(indio_dev);
+	if (ret) {
+		dev_err(&spi->dev, "Failed to register iio device: %d\n", ret);
+		goto error_disable_reg;
+	}
+
+	return 0;
+
+error_disable_reg:
+	regulator_bulk_disable(st->chip_info->num_vrefs, st->vref_reg);
+error_free_reg:
+	regulator_bulk_free(st->chip_info->num_vrefs, st->vref_reg);
+error_free_channels:
+	kfree(indio_dev->channels);
+error_free:
+	iio_free_device(indio_dev);
+
+	return ret;
+}
+
+static int __devexit ad5360_remove(struct spi_device *spi)
+{
+	struct iio_dev *indio_dev = spi_get_drvdata(spi);
+	struct ad5360_state *st = iio_priv(indio_dev);
+
+	iio_device_unregister(indio_dev);
+
+	kfree(indio_dev->channels);
+
+	regulator_bulk_disable(st->chip_info->num_vrefs, st->vref_reg);
+	regulator_bulk_free(st->chip_info->num_vrefs, st->vref_reg);
+
+	iio_free_device(indio_dev);
+
+	return 0;
+}
+
+static const struct spi_device_id ad5360_ids[] = {
+	{ "ad5360", ID_AD5360 },
+	{ "ad5361", ID_AD5361 },
+	{ "ad5362", ID_AD5362 },
+	{ "ad5363", ID_AD5363 },
+	{ "ad5370", ID_AD5370 },
+	{ "ad5371", ID_AD5371 },
+	{ "ad5372", ID_AD5372 },
+	{ "ad5373", ID_AD5373 },
+	{}
+};
+
+static struct spi_driver ad5360_driver = {
+	.driver = {
+		   .name = "ad5360",
+		   .owner = THIS_MODULE,
+	},
+	.probe = ad5360_probe,
+	.remove = __devexit_p(ad5360_remove),
+	.id_table = ad5360_ids,
+};
+
+static __init int ad5360_spi_init(void)
+{
+	return spi_register_driver(&ad5360_driver);
+}
+module_init(ad5360_spi_init);
+
+static __exit void ad5360_spi_exit(void)
+{
+	spi_unregister_driver(&ad5360_driver);
+}
+module_exit(ad5360_spi_exit);
+
+MODULE_AUTHOR("Lars-Peter Clausen <lars@xxxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Devices AD5360/61/62/63/70/71/72/73 DAC");
+MODULE_LICENSE("GPL v2");
-- 
1.7.6.3


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