[PATCH v6] iio: add ad5761 DAC driver

From: Ricardo Ribalda Delgado
Date: Mon Jan 11 2016 - 11:23:14 EST

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@xxxxxxxxx>
---
v6: Do not set val2 when IIO_VAL_INT
Document AD5761_VOLTAGE_RANGE_0V_5V
Thanks to Jonathan Cameron <jic23@xxxxxxxxxx>

v5: CodeStyle and check val2 value
Thanks to Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx> and

v4: Use locking mechanism
Populate errors
Thanks to Lars-Peter Clausen <lars@xxxxxxxxxx>

v3: Move programmable voltage range to pdata
Exit on error instead of using internal voltage reference
Thanks to Jonathan Cameron <jic23@xxxxxxxxxx>

v2: A lot of CodeStyle Fixes
Thanks to Peter Meerwald-Stadler <pmeerw@xxxxxxxxxx> and
Jonathan Cameron <jic23@xxxxxxxxxx>

CREDITS | 1 +
drivers/iio/dac/Kconfig | 10 +
drivers/iio/dac/Makefile | 1 +
drivers/iio/dac/ad5761.c | 430 +++++++++++++++++++++++++++++++++++++++++
include/linux/iio/dac/ad5761.h | 37 ++++
5 files changed, 479 insertions(+)
create mode 100644 drivers/iio/dac/ad5761.c
create mode 100644 include/linux/iio/dac/ad5761.h

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..069d3bfc6b1e
--- /dev/null
+++ b/drivers/iio/dac/ad5761.c
@@ -0,0 +1,430 @@
+/*
+ * AD5721, AD5721R, AD5761, AD5761R, Voltage Output Digital to Analog Converter
+ *
+ * Copyright 2016 Qtechnology A/S
+ * 2016 Ricardo Ribalda <ricardo.ribalda@xxxxxxxxx>
+ *
+ * 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>
+#include <linux/iio/dac/ad5761.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;
+};
+
+enum ad5761_supported_device_ids {
+ ID_AD5721,
+ ID_AD5721R,
+ ID_AD5761,
+ ID_AD5761R,
+};
+
+/**
+ * struct ad5761_state - driver instance specific data
+ * @spi: spi_device
+ * @vref_reg: reference voltage regulator
+ * @use_intref: true when the internal voltage reference is used
+ * @vref: actual voltage reference in mVolts
+ * @range: output range mode used
+ * @data: cache aligned spi buffer
+ */
+struct ad5761_state {
+ struct spi_device *spi;
+ struct regulator *vref_reg;
+
+ bool use_intref;
+ int vref;
+ enum ad5761_voltage_range 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;
+};
+
+static const struct ad5761_range_params ad5761_range_params[] = {
+ [AD5761_VOLTAGE_RANGE_M10V_10V] = {
+ .m = 80,
+ .c = 40,
+ },
+ [AD5761_VOLTAGE_RANGE_0V_10V] = {
+ .m = 40,
+ .c = 0,
+ },
+ [AD5761_VOLTAGE_RANGE_M5V_5V] = {
+ .m = 40,
+ .c = 20,
+ },
+ [AD5761_VOLTAGE_RANGE_0V_5V] = {
+ .m = 20,
+ .c = 0,
+ },
+ [AD5761_VOLTAGE_RANGE_M2V5_7V5] = {
+ .m = 40,
+ .c = 10,
+ },
+ [AD5761_VOLTAGE_RANGE_M3V_3V] = {
+ .m = 24,
+ .c = 12,
+ },
+ [AD5761_VOLTAGE_RANGE_0V_16V] = {
+ .m = 64,
+ .c = 0,
+ },
+ [AD5761_VOLTAGE_RANGE_0V_20V] = {
+ .m = 80,
+ .c = 0,
+ },
+};
+
+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_write(struct iio_dev *indio_dev, u8 addr, u16 val)
+{
+ struct ad5761_state *st = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&indio_dev->mlock);
+ ret = _ad5761_spi_write(st, addr, val);
+ mutex_unlock(&indio_dev->mlock);
+
+ return ret;
+}
+
+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_read(struct iio_dev *indio_dev, u8 addr, u16 *val)
+{
+ struct ad5761_state *st = iio_priv(indio_dev);
+ int ret;
+
+ mutex_lock(&indio_dev->mlock);
+ ret = _ad5761_spi_read(st, addr, val);
+ mutex_unlock(&indio_dev->mlock);
+
+ return ret;
+}
+
+static int ad5761_spi_set_range(struct ad5761_state *st,
+ enum ad5761_voltage_range range)
+{
+ u16 aux;
+ int ret;
+
+ aux = (range & 0x7) | AD5761_CTRL_ETS;
+
+ if (st->use_intref)
+ aux |= AD5761_CTRL_USE_INTVREF;
+
+ ret = _ad5761_spi_write(st, AD5761_ADDR_SW_FULL_RESET, 0);
+ if (ret)
+ return ret;
+
+ ret = _ad5761_spi_write(st, AD5761_ADDR_CTRL_WRITE_REG, aux);
+ 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 mask)
+{
+ struct ad5761_state *st;
+ int ret;
+ u16 aux;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ ret = ad5761_spi_read(indio_dev, AD5761_ADDR_DAC_READ, &aux);
+ if (ret)
+ return ret;
+ *val = aux >> chan->scan_type.shift;
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ st = iio_priv(indio_dev);
+ *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:
+ st = iio_priv(indio_dev);
+ *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)
+{
+ u16 aux;
+
+ if (mask != IIO_CHAN_INFO_RAW)
+ return -EINVAL;
+
+ if (val2 || (val << chan->scan_type.shift) > 0xffff || val < 0)
+ return -EINVAL;
+
+ aux = val << chan->scan_type.shift;
+
+ return ad5761_spi_write(indio_dev, AD5761_ADDR_DAC_WRITE, aux);
+}
+
+static const struct iio_info ad5761_info = {
+ .read_raw = &ad5761_read_raw,
+ .write_raw = &ad5761_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+#define AD5761_CHAN(_bits) { \
+ .type = IIO_VOLTAGE, \
+ .output = 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), \
+ }, \
+}
+
+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 int ad5761_get_vref(struct ad5761_state *st,
+ const struct ad5761_chip_info *chip_info)
+{
+ int ret;
+
+ st->vref_reg = devm_regulator_get_optional(&st->spi->dev, "vref");
+ if (!st->vref_reg || PTR_ERR(st->vref_reg) == -ENODEV) {
+ /* Use Internal regulator */
+ if (!chip_info->int_vref) {
+ dev_err(&st->spi->dev,
+ "Voltage reference not found\n");
+ return -EIO;
+ }
+
+ st->use_intref = true;
+ st->vref = chip_info->int_vref;
+ return 0;
+ }
+
+ if (IS_ERR(st->vref_reg)) {
+ dev_err(&st->spi->dev,
+ "Error getting voltage reference regulator\n");
+ return PTR_ERR(st->vref_reg);
+ }
+
+ ret = regulator_enable(st->vref_reg);
+ if (ret) {
+ dev_err(&st->spi->dev,
+ "Failed to enable voltage reference\n");
+ return ret;
+ }
+
+ ret = regulator_get_voltage(st->vref_reg);
+ if (ret < 0) {
+ dev_err(&st->spi->dev,
+ "Failed to get voltage reference value\n");
+ goto disable_regulator_vref;
+ }
+
+ if (ret < 2000000 || ret > 3000000) {
+ dev_warn(&st->spi->dev,
+ "Invalid external voltage ref. value %d uV\n", ret);
+ ret = -EIO;
+ goto disable_regulator_vref;
+ }
+
+ st->vref = ret / 1000;
+ st->use_intref = false;
+
+ return 0;
+
+disable_regulator_vref:
+ regulator_disable(st->vref_reg);
+ st->vref_reg = NULL;
+ return ret;
+}
+
+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];
+ enum ad5761_voltage_range voltage_range = AD5761_VOLTAGE_RANGE_0V_5V;
+ struct ad5761_platform_data *pdata = dev_get_platdata(&spi->dev);
+
+ 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);
+
+ ret = ad5761_get_vref(st, chip_info);
+ if (ret)
+ return ret;
+
+ if (pdata)
+ voltage_range = pdata->voltage_range;
+
+ ret = ad5761_spi_set_range(st, voltage_range);
+ if (ret)
+ goto disable_regulator_err;
+
+ 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)
+ goto disable_regulator_err;
+
+ return 0;
+
+disable_regulator_err:
+ if (!IS_ERR_OR_NULL(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);
+
+ iio_device_unregister(iio_dev);
+
+ if (!IS_ERR_OR_NULL(st->vref_reg))
+ regulator_disable(st->vref_reg);
+
+ 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",
+ },
+ .probe = ad5761_probe,
+ .remove = ad5761_remove,
+ .id_table = ad5761_id,
+};
+module_spi_driver(ad5761_driver);
+
+MODULE_AUTHOR("Ricardo Ribalda <ricardo.ribalda@xxxxxxxxx>");
+MODULE_DESCRIPTION("Analog Devices AD5721, AD5721R, AD5761, AD5761R driver");
+MODULE_LICENSE("GPL v2");
diff --git a/include/linux/iio/dac/ad5761.h b/include/linux/iio/dac/ad5761.h
new file mode 100644
index 000000000000..2f3702309d61
--- /dev/null
+++ b/include/linux/iio/dac/ad5761.h
@@ -0,0 +1,37 @@
+#ifndef __IIO_DAC_AD5761_H__
+#define __IIO_DAC_AD5761_H__
+
+/**
+ * enum ad5761_voltage_range - Voltage range the AD5761 is configured for.
+ * @AD5761_VOLTAGE_RANGE_M10V_10V: -10V to 10V
+ * @AD5761_VOLTAGE_RANGE_0V_10V: 0V to 10V
+ * @AD5761_VOLTAGE_RANGE_M5V_5V: -5V to 5V
+ * @AD5761_VOLTAGE_RANGE_0V_5V: 0V to 5V
+ * @AD5761_VOLTAGE_RANGE_M2V5_7V5: -2.5V to 7.5V
+ * @AD5761_VOLTAGE_RANGE_M3V_3V: -3V to 3V
+ * @AD5761_VOLTAGE_RANGE_0V_16V: 0V to 16V
+ * @AD5761_VOLTAGE_RANGE_0V_20V: 0V to 20V
+ */
+
+enum ad5761_voltage_range {
+ AD5761_VOLTAGE_RANGE_M10V_10V,
+ AD5761_VOLTAGE_RANGE_0V_10V,
+ AD5761_VOLTAGE_RANGE_M5V_5V,
+ AD5761_VOLTAGE_RANGE_0V_5V,
+ AD5761_VOLTAGE_RANGE_M2V5_7V5,
+ AD5761_VOLTAGE_RANGE_M3V_3V,
+ AD5761_VOLTAGE_RANGE_0V_16V,
+ AD5761_VOLTAGE_RANGE_0V_20V,
+};
+
+/**
+ * struct ad5761_platform_data - AD5761 DAC driver platform data
+ * @voltage_range: Voltage range the AD5761 is configured for
+ */
+
+struct ad5761_platform_data {
+ enum ad5761_voltage_range voltage_range;
+};
+
+
+#endif
--
2.6.4