iio: dac: Add support for the AD5592R/AD5593R ADCs/DACs

This patch adds support for the AD5592R (spi) and AD5593R (i2c)
ADC/DAC/GPIO devices.

Signed-off-by: Paul Cercueil <paul.cercueil@analog.com>
Signed-off-by: Michael Hennerich <michael.hennerich@analog.com>
Reviewed-by: Linus Walleij <linus.walleij@linaro.org>
Acked-by: Rob Herring <robh@kernel.org>
Signed-off-by: Jonathan Cameron <jic23@kernel.org>
diff --git a/drivers/iio/dac/ad5593r.c b/drivers/iio/dac/ad5593r.c
new file mode 100644
index 0000000..dca158a
--- /dev/null
+++ b/drivers/iio/dac/ad5593r.c
@@ -0,0 +1,131 @@
+/*
+ * AD5593R Digital <-> Analog converters driver
+ *
+ * Copyright 2015-2016 Analog Devices Inc.
+ * Author: Paul Cercueil <paul.cercueil@analog.com>
+ *
+ * Licensed under the GPL-2.
+ */
+
+#include "ad5592r-base.h"
+
+#include <linux/bitops.h>
+#include <linux/i2c.h>
+#include <linux/module.h>
+#include <linux/of.h>
+
+#define AD5593R_MODE_CONF		(0 << 4)
+#define AD5593R_MODE_DAC_WRITE		(1 << 4)
+#define AD5593R_MODE_ADC_READBACK	(4 << 4)
+#define AD5593R_MODE_DAC_READBACK	(5 << 4)
+#define AD5593R_MODE_GPIO_READBACK	(6 << 4)
+#define AD5593R_MODE_REG_READBACK	(7 << 4)
+
+static int ad5593r_write_dac(struct ad5592r_state *st, unsigned chan, u16 value)
+{
+	struct i2c_client *i2c = to_i2c_client(st->dev);
+
+	return i2c_smbus_write_word_swapped(i2c,
+			AD5593R_MODE_DAC_WRITE | chan, value);
+}
+
+static int ad5593r_read_adc(struct ad5592r_state *st, unsigned chan, u16 *value)
+{
+	struct i2c_client *i2c = to_i2c_client(st->dev);
+	s32 val;
+
+	val = i2c_smbus_write_word_swapped(i2c,
+			AD5593R_MODE_CONF | AD5592R_REG_ADC_SEQ, BIT(chan));
+	if (val < 0)
+		return (int) val;
+
+	val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_ADC_READBACK);
+	if (val < 0)
+		return (int) val;
+
+	*value = (u16) val;
+
+	return 0;
+}
+
+static int ad5593r_reg_write(struct ad5592r_state *st, u8 reg, u16 value)
+{
+	struct i2c_client *i2c = to_i2c_client(st->dev);
+
+	return i2c_smbus_write_word_swapped(i2c,
+			AD5593R_MODE_CONF | reg, value);
+}
+
+static int ad5593r_reg_read(struct ad5592r_state *st, u8 reg, u16 *value)
+{
+	struct i2c_client *i2c = to_i2c_client(st->dev);
+	s32 val;
+
+	val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_REG_READBACK | reg);
+	if (val < 0)
+		return (int) val;
+
+	*value = (u16) val;
+
+	return 0;
+}
+
+static int ad5593r_gpio_read(struct ad5592r_state *st, u8 *value)
+{
+	struct i2c_client *i2c = to_i2c_client(st->dev);
+	s32 val;
+
+	val = i2c_smbus_read_word_swapped(i2c, AD5593R_MODE_GPIO_READBACK);
+	if (val < 0)
+		return (int) val;
+
+	*value = (u8) val;
+
+	return 0;
+}
+
+static const struct ad5592r_rw_ops ad5593r_rw_ops = {
+	.write_dac = ad5593r_write_dac,
+	.read_adc = ad5593r_read_adc,
+	.reg_write = ad5593r_reg_write,
+	.reg_read = ad5593r_reg_read,
+	.gpio_read = ad5593r_gpio_read,
+};
+
+static int ad5593r_i2c_probe(struct i2c_client *i2c,
+		const struct i2c_device_id *id)
+{
+	return ad5592r_probe(&i2c->dev, id->name, &ad5593r_rw_ops);
+}
+
+static int ad5593r_i2c_remove(struct i2c_client *i2c)
+{
+	return ad5592r_remove(&i2c->dev);
+}
+
+static const struct i2c_device_id ad5593r_i2c_ids[] = {
+	{ .name = "ad5593r", },
+	{},
+};
+MODULE_DEVICE_TABLE(i2c, ad5593r_i2c_ids);
+
+static const struct of_device_id ad5593r_of_match[] = {
+	{ .compatible = "adi,ad5593r", },
+	{},
+};
+MODULE_DEVICE_TABLE(of, ad5593r_of_match);
+
+static struct i2c_driver ad5593r_driver = {
+	.driver = {
+		.name = "ad5593r",
+		.of_match_table = of_match_ptr(ad5593r_of_match),
+	},
+	.probe = ad5593r_i2c_probe,
+	.remove = ad5593r_i2c_remove,
+	.id_table = ad5593r_i2c_ids,
+};
+module_i2c_driver(ad5593r_driver);
+
+MODULE_AUTHOR("Paul Cercueil <paul.cercueil@analog.com>");
+MODULE_DESCRIPTION("Analog Devices AD5592R multi-channel converters");
+MODULE_LICENSE("GPL v2");