[PATCH] iio: add ad5761 DAC driver

Ricardo Ribalda Delgado
2015-12-16T13:27:54Z

ad5761 is a 1-channel DAC with configurable output range.
The driver uses the regulator interface for its voltage ref.

It shares its register layout with ad5761r, ad5721 and ad5721r.

Differences:
ad5761* are 16 bit, ad5721* are 12 bits.
ad57*1r have an internal reference.

Signed-off-by: Ricardo Ribalda Delgado <ricardo.ribalda@gmail.com>
---
CREDITS | 1 +
drivers/iio/dac/Kconfig | 10 ++
drivers/iio/dac/Makefile | 1 +
drivers/iio/dac/ad5761.c | 425 +++++++++++++++++++++++++++++++++++++++++++++++
4 files changed, 437 insertions(+)
create mode 100644 drivers/iio/dac/ad5761.c

diff --git a/CREDITS b/CREDITS
index 8207cc62ee9d..44ea433d70a1 100644
--- a/CREDITS
+++ b/CREDITS
@@ -3035,6 +3035,7 @@ D: PLX USB338x driver
D: PCA9634 driver
D: Option GTM671WFS
D: Fintek F81216A
+D: AD5761 iio driver
D: Various kernel hacks
S: Qtechnology A/S
S: Valby Langgade 142
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index e701e28fb1cd..4caedd671360 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -111,6 +111,16 @@ config AD5755
To compile this driver as a module, choose M here: the
module will be called ad5755.

+config AD5761
+ tristate "Analog Devices AD5761/61R/21/21R DAC driver"
+ depends on SPI_MASTER
+ help
+ Say yes here to build support for Analog Devices AD5761, AD5761R, AD5721,
+ AD5721R Digital to Analog Converter.
+
+ To compile this driver as a module, choose M here: the
+ module will be called ad5761.
+
config AD5764
tristate "Analog Devices AD5764/64R/44/44R DAC driver"
depends on SPI_MASTER
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index 63ae05633e0c..cb525b53fc7b 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_AD5504) += ad5504.o
obj-$(CONFIG_AD5446) += ad5446.o
obj-$(CONFIG_AD5449) += ad5449.o
obj-$(CONFIG_AD5755) += ad5755.o
+obj-$(CONFIG_AD5761) += ad5761.o
obj-$(CONFIG_AD5764) += ad5764.o
obj-$(CONFIG_AD5791) += ad5791.o
obj-$(CONFIG_AD5686) += ad5686.o
diff --git a/drivers/iio/dac/ad5761.c b/drivers/iio/dac/ad5761.c
new file mode 100644
index 000000000000..b4eac59ef81f
--- /dev/null
+++ b/drivers/iio/dac/ad5761.c
@@ -0,0 +1,425 @@
+/*
+ * AD5721, AD5721R, AD5761, AD5761R, Voltage Output Digital to Analog Converter
+ *
+ * Copyright 2015 Qtechnology A/S
+ *
+ * Licensed under the GPL-2.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/bitops.h>
+#include <linux/iio/iio.h>
+#include <linux/iio/sysfs.h>
+#include <linux/regulator/consumer.h>
+
+#define AD5761_ADDR(addr) ((addr&0xf) << 16)
+#define AD5761_ADDR_NOOP 0x0
+#define AD5761_ADDR_DAC_WRITE 0x3
+#define AD5761_ADDR_CTRL_WRITE_REG 0x4
+#define AD5761_ADDR_SW_DATA_RESET 0x7
+#define AD5761_ADDR_DAC_READ 0xb
+#define AD5761_ADDR_CTRL_READ_REG 0xc
+#define AD5761_ADDR_SW_FULL_RESET 0xf
+
+#define AD5761_CTRL_USE_INTVREF BIT(5)
+#define AD5761_CTRL_ETS BIT(6)
+
+/**
+ * struct ad5761_chip_info - chip specific information
+ * @int_vref: Value of the internal reference voltage in mV - 0 if external
+ * reference voltage is used
+ * @channel channel specification
+*/
+
+struct ad5761_chip_info {
+ unsigned long int_vref;
+ const struct iio_chan_spec channel;
+};
+
+struct ad5761_range_params {
+ int m;
+ int c;
+};
+
+/**
+ * ad5761_supported_device_ids:
+ */
+
+enum ad5761_supported_device_ids {
+ ID_AD5721,
+ ID_AD5721R,
+ ID_AD5761,
+ ID_AD5761R,
+};
+
+/**
+ * struct ad5761_state - driver instance specific data
+ * @spi: spi_device
+ * @chip_info: chip model specific constants
+ * @vref_mv: actual reference voltage used
+ */
+struct ad5761_state {
+ struct spi_device *spi;
+ struct regulator *vref_reg;
+
+ bool use_intref;
+ int vref;
+ int range;
+
+ /*
+ * DMA (thus cache coherency maintenance) requires the
+ * transfer buffers to live in their own cache lines.
+ */
+ union {
+ __be32 d32;
+ u8 d8[4];
+ } data[3] ____cacheline_aligned;
+};
+
+enum ad5761_range_ids {
+ MODE_M10V_10V,
+ MODE_0V_10V,
+ MODE_M5V_5V,
+ MODE_0V_5V,
+ MODE_M2V5_7V5,
+ MODE_M3V_3V,
+ MODE_0V_16V,
+ MODE_0V_20V,
+};
+
+static const struct ad5761_range_params ad5761_range_params[] = {
+ [MODE_M10V_10V] = {
+ .m = 80,
+ .c = 40,
+ },
+ [MODE_0V_10V] = {
+ .m = 40,
+ .c = 0,
+ },
+ [MODE_M5V_5V] = {
+ .m = 40,
+ .c = 20,
+ },
+ [MODE_0V_5V] = {
+ .m = 20,
+ .c = 0,
+ },
+ [MODE_M2V5_7V5] = {
+ .m = 40,
+ .c = 10,
+ },
+ [MODE_M3V_3V] = {
+ .m = 24,
+ .c = 12,
+ },
+ [MODE_0V_16V] = {
+ .m = 64,
+ .c = 0,
+ },
+ [MODE_0V_20V] = {
+ .m = 80,
+ .c = 0,
+ },
+};
+
+static const char * const ad5761_ranges[] = {
+ [MODE_M10V_10V] = "-10V_10V",
+ [MODE_0V_10V] = "0V_10V",
+ [MODE_M5V_5V] = "-5V_5V",
+ [MODE_0V_5V] = "0V_5V",
+ [MODE_M2V5_7V5] = "-2V5_7V5",
+ [MODE_M3V_3V] = "-3V_3V",
+ [MODE_0V_16V] = "0V_16V",
+ [MODE_0V_20V] = "0V_20V",
+};
+
+static int ad5761_spi_write(struct ad5761_state *st, u8 addr, u16 val)
+{
+ st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr) | val);
+
+ return spi_write(st->spi, &st->data[0].d8[1], 3);
+}
+
+static int ad5761_spi_read(struct ad5761_state *st, u8 addr, u16 *val)
+{
+ int ret;
+ struct spi_transfer xfers[] = {
+ {
+ .tx_buf = &st->data[0].d8[1],
+ .bits_per_word = 8,
+ .len = 3,
+ .cs_change = true,
+ }, {
+ .tx_buf = &st->data[1].d8[1],
+ .rx_buf = &st->data[2].d8[1],
+ .bits_per_word = 8,
+ .len = 3,
+ },
+ };
+
+ st->data[0].d32 = cpu_to_be32(AD5761_ADDR(addr));
+ st->data[1].d32 = cpu_to_be32(AD5761_ADDR(AD5761_ADDR_NOOP));
+
+ ret = spi_sync_transfer(st->spi, xfers, ARRAY_SIZE(xfers));
+
+ *val = be32_to_cpu(st->data[2].d32);
+
+ return ret;
+}
+
+static int ad5761_spi_set_range(struct ad5761_state *st, int range)
+{
+ u16 aux;
+ int ret;
+
+ aux = range;
+ aux |= AD5761_CTRL_ETS;
+ if (st->use_intref)
+ aux |= AD5761_CTRL_USE_INTVREF;
+ ret = ad5761_spi_write(st, AD5761_ADDR_CTRL_WRITE_REG, aux);
+ if (ret)
+ return ret;
+ ret = ad5761_spi_write(st, AD5761_ADDR_SW_DATA_RESET, 0);
+ if (ret)
+ return ret;
+
+ st->range = range;
+ return 0;
+}
+
+static int ad5761_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val,
+ int *val2,
+ long m)
+{
+ struct ad5761_state *st = iio_priv(indio_dev);
+ int ret;
+ u16 aux;
+
+ switch (m) {
+ case IIO_CHAN_INFO_RAW:
+ ret = ad5761_spi_read(st, AD5761_ADDR_DAC_READ, &aux);
+ if (ret)
+ return ret;
+ *val = aux >> chan->scan_type.shift;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = st->vref * ad5761_range_params[st->range].m;
+ *val /= 10;
+ *val2 = chan->scan_type.realbits;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_OFFSET:
+ *val = -(1<<chan->scan_type.realbits);
+ *val *= ad5761_range_params[st->range].c;
+ *val /= ad5761_range_params[st->range].m;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+
+}
+
+static int ad5761_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val,
+ int val2,
+ long mask)
+{
+ struct ad5761_state *st = iio_priv(indio_dev);
+ u16 aux;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ aux = val << chan->scan_type.shift;
+ return ad5761_spi_write(st, AD5761_ADDR_DAC_WRITE, aux);
+ default:
+ return -EINVAL;
+ }
+}
+
+static int ad5761_set_range(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan, unsigned int range)
+{
+ struct ad5761_state *st = iio_priv(indio_dev);
+
+ return ad5761_spi_set_range(st, range);
+}
+
+static int ad5761_get_range(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct ad5761_state *st = iio_priv(indio_dev);
+ u16 aux;
+ int ret;
+
+ ret = ad5761_spi_read(st, AD5761_ADDR_CTRL_READ_REG, &aux);
+ if (ret)
+ return ret;
+
+ return aux & 0x7;
+}
+
+static const struct iio_info ad5761_info = {
+ .read_raw = &ad5761_read_raw,
+ .write_raw = &ad5761_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+static const struct iio_enum ad5761_range_enum = {
+ .items = ad5761_ranges,
+ .num_items = ARRAY_SIZE(ad5761_ranges),
+ .get = ad5761_get_range,
+ .set = ad5761_set_range,
+};
+
+static struct iio_chan_spec_ext_info ad5761_ext_info[] = {
+ IIO_ENUM("range", IIO_SHARED_BY_TYPE,
+ &ad5761_range_enum),
+ IIO_ENUM_AVAILABLE("range", &ad5761_range_enum),
+ { },
+};
+
+#define AD5761_CHAN(_bits) { \
+ .type = IIO_VOLTAGE, \
+ .output = 1, \
+ .indexed = 1, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_OFFSET), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = (_bits), \
+ .storagebits = 16, \
+ .shift = 16 - (_bits), \
+ }, \
+ .ext_info = ad5761_ext_info, \
+}
+
+static const struct ad5761_chip_info ad5761_chip_infos[] = {
+ [ID_AD5721] = {
+ .int_vref = 0,
+ .channel = AD5761_CHAN(12),
+ },
+ [ID_AD5721R] = {
+ .int_vref = 2500,
+ .channel = AD5761_CHAN(12),
+ },
+ [ID_AD5761] = {
+ .int_vref = 0,
+ .channel = AD5761_CHAN(16),
+ },
+ [ID_AD5761R] = {
+ .int_vref = 2500,
+ .channel = AD5761_CHAN(16),
+ },
+};
+
+static void ad5761_get_vref(struct ad5761_state *st)
+{
+ int ret;
+
+
+ st->vref_reg = devm_regulator_get(&st->spi->dev, "vref");
+ if (IS_ERR(st->vref_reg))
+ return;
+
+ ret = regulator_enable(st->vref_reg);
+ if (ret) {
+ dev_warn(&st->spi->dev, "Failed to enable vref. Using internal");
+ return;
+ }
+
+ ret = regulator_get_voltage(st->vref_reg);
+ if (ret < 0) {
+ regulator_disable(st->vref_reg);
+ dev_warn(&st->spi->dev,
+ "Failed to get vref value. Using internal");
+ return;
+ }
+
+ if (ret < 2000000 || ret > 3000000) {
+ regulator_disable(st->vref_reg);
+ dev_warn(&st->spi->dev,
+ "Invalid external vref value. Using internal");
+ return;
+ }
+
+ st->vref = ret / 1000;
+ st->use_intref = false;
+}
+
+static int ad5761_probe(struct spi_device *spi)
+{
+ struct iio_dev *iio_dev;
+ struct ad5761_state *st;
+ int ret;
+ const struct ad5761_chip_info *chip_info =
+ &ad5761_chip_infos[spi_get_device_id(spi)->driver_data];
+
+ iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*st));
+ if (!iio_dev)
+ return -ENOMEM;
+ st = iio_priv(iio_dev);
+
+ st->spi = spi;
+ spi_set_drvdata(spi, iio_dev);
+
+ st->use_intref = true;
+ st->vref = chip_info->int_vref;
+ ad5761_get_vref(st);
+ if (st->use_intref && !chip_info->int_vref) {
+ dev_err(&spi->dev, "Missing vref, cannot continue");
+ return -EIO;
+ }
+
+ ad5761_spi_set_range(st, MODE_0V_5V);
+
+ iio_dev->dev.parent = &spi->dev;
+ iio_dev->info = &ad5761_info;
+ iio_dev->modes = INDIO_DIRECT_MODE;
+ iio_dev->channels = &chip_info->channel;
+ iio_dev->num_channels = 1;
+ iio_dev->name = spi_get_device_id(st->spi)->name;
+ ret = iio_device_register(iio_dev);
+ if (ret && !IS_ERR(st->vref_reg))
+ regulator_disable(st->vref_reg);
+
+ return ret;
+}
+
+static int ad5761_remove(struct spi_device *spi)
+{
+ struct iio_dev *iio_dev = spi_get_drvdata(spi);
+ struct ad5761_state *st = iio_priv(iio_dev);
+
+ if (!IS_ERR(st->vref_reg))
+ regulator_disable(st->vref_reg);
+ iio_device_unregister(iio_dev);
+ return 0;
+}
+
+static const struct spi_device_id ad5761_id[] = {
+ {"ad5721", ID_AD5721},
+ {"ad5721r", ID_AD5721R},
+ {"ad5761", ID_AD5761},
+ {"ad5761r", ID_AD5761R},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad5761_id);
+
+static struct spi_driver ad5761_driver = {
+ .driver = {
+ .name = "ad5761",
+ .owner = THIS_MODULE,
+ },
+ .probe = ad5761_probe,
+ .remove = ad5761_remove,
+ .id_table = ad5761_id,
+};
+module_spi_driver(ad5761_driver);
+
+MODULE_AUTHOR("Ricardo Ribalda <ricardo.ribalda@gmail.com>");
+MODULE_DESCRIPTION("Analog Devices AD5721, AD5721R, AD5761, AD5761R driver");
+MODULE_LICENSE("GPL v2");
--
2.6.2