[PATCH] iio:dac:ti-dac7612: Add driver for Texas Instruments DAC7612

From: Ricardo Ribalda Delgado
Date: Thu Jan 24 2019 - 16:32:57 EST

It is a driver for Texas Instruments Dual, 12-Bit Serial Input
Digital-to-Analog Converter.

Datasheet of this chip:
http://www.ti.com/lit/ds/sbas106/sbas106.pdf

Signed-off-by: Ricardo Ribalda Delgado <ricardo@xxxxxxxxxxx>
---
MAINTAINERS | 6 ++
drivers/iio/dac/Kconfig | 10 +++
drivers/iio/dac/Makefile | 1 +
drivers/iio/dac/ti-dac7612.c | 170 +++++++++++++++++++++++++++++++++++
4 files changed, 187 insertions(+)
create mode 100644 drivers/iio/dac/ti-dac7612.c

diff --git a/MAINTAINERS b/MAINTAINERS
index d039f66a5cef..30ba5435906b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -14877,6 +14877,12 @@ F: Documentation/devicetree/bindings/clock/ti,sci-clk.txt
F: drivers/clk/keystone/sci-clk.c
F: drivers/reset/reset-ti-sci.c

+Texas Instruments' DAC7612 DAC Driver
+M: Ricardo Ribalda <ricardo@xxxxxxxxxxx>
+L: linux-iio@xxxxxxxxxxxxxxx
+S: Supported
+F: drivers/iio/dac/ti-dac7612.c
+
THANKO'S RAREMONO AM/FM/SW RADIO RECEIVER USB DRIVER
M: Hans Verkuil <hverkuil@xxxxxxxxx>
L: linux-media@xxxxxxxxxxxxxxx
diff --git a/drivers/iio/dac/Kconfig b/drivers/iio/dac/Kconfig
index f28daf67db6a..fbef9107acad 100644
--- a/drivers/iio/dac/Kconfig
+++ b/drivers/iio/dac/Kconfig
@@ -375,6 +375,16 @@ config TI_DAC7311

If compiled as a module, it will be called ti-dac7311.

+config TI_DAC7612
+ tristate "Texas Instruments 12-bit 2-channel DAC driver"
+ depends on SPI_MASTER && GPIOLIB
+ help
+ Driver for the Texas Instruments DAC7612, DAC7612U, DAC7612UB
+ The driver hand drive the load pin automatically, otherwise
+ it needs to be toggled manually.
+
+ If compiled as a module, it will be called ti-dac7612.
+
config VF610_DAC
tristate "Vybrid vf610 DAC driver"
depends on OF
diff --git a/drivers/iio/dac/Makefile b/drivers/iio/dac/Makefile
index f0a37c93de8e..1369fa1d2f0e 100644
--- a/drivers/iio/dac/Makefile
+++ b/drivers/iio/dac/Makefile
@@ -41,4 +41,5 @@ obj-$(CONFIG_STM32_DAC) += stm32-dac.o
obj-$(CONFIG_TI_DAC082S085) += ti-dac082s085.o
obj-$(CONFIG_TI_DAC5571) += ti-dac5571.o
obj-$(CONFIG_TI_DAC7311) += ti-dac7311.o
+obj-$(CONFIG_TI_DAC7612) += ti-dac7612.o
obj-$(CONFIG_VF610_DAC) += vf610_dac.o
diff --git a/drivers/iio/dac/ti-dac7612.c b/drivers/iio/dac/ti-dac7612.c
new file mode 100644
index 000000000000..5b374aa287c7
--- /dev/null
+++ b/drivers/iio/dac/ti-dac7612.c
@@ -0,0 +1,170 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * DAC7612 Dual, 12-Bit Serial input Digital-to-Analog Converter
+ *
+ * Copyright 2019 Qtechnology A/S
+ * 2019 Ricardo Ribalda <ricardo@xxxxxxxxxxx>
+ *
+ * Licensed under the GPL-2.
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/spi/spi.h>
+#include <linux/gpio/consumer.h>
+#include <linux/iio/iio.h>
+
+#define NUM_CHANS 2
+#define RESOLUTION 12
+
+struct dac7612 {
+ struct spi_device *spi;
+ struct gpio_desc *nld;
+ uint16_t cache[NUM_CHANS];
+};
+
+static int dac7612_cmd_single(struct dac7612 *priv, int channel, u16 val)
+{
+ uint8_t buffer[2];
+ int ret;
+
+ if (channel >= NUM_CHANS)
+ return -EINVAL;
+
+ buffer[0] = BIT(5) | (channel << 4) | (val >> 8);
+ buffer[1] = val & 0xff;
+
+ priv->cache[channel] = val;
+
+ ret = spi_write(priv->spi, buffer, sizeof(buffer));
+ if (ret)
+ return ret;
+
+ gpiod_set_value(priv->nld, 0);
+ gpiod_set_value(priv->nld, 1);
+
+ return 0;
+}
+
+#define dac7612_CHANNEL(chan, name) { \
+ .type = IIO_VOLTAGE, \
+ .channel = (chan), \
+ .address = (chan), \
+ .indexed = true, \
+ .output = true, \
+ .datasheet_name = name, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .scan_type = { \
+ .sign = 'u', \
+ .realbits = RESOLUTION, \
+ .storagebits = RESOLUTION, \
+ }, \
+}
+
+static const struct iio_chan_spec dac7612_channels[] = {
+ dac7612_CHANNEL(0, "OUTA"),
+ dac7612_CHANNEL(1, "OUTB"),
+};
+
+static int dac7612_read_raw(struct iio_dev *iio_dev,
+ const struct iio_chan_spec *chan,
+ int *val, int *val2, long mask)
+{
+ struct dac7612 *priv;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ priv = iio_priv(iio_dev);
+ *val = priv->cache[chan->channel];
+ return IIO_VAL_INT;
+
+ case IIO_CHAN_INFO_SCALE:
+ *val = 1;
+ *val2 = 1000;
+ return IIO_VAL_FRACTIONAL;
+
+ default:
+ return -EINVAL;
+ }
+}
+
+static int dac7612_write_raw(struct iio_dev *iio_dev,
+ const struct iio_chan_spec *chan,
+ int val, int val2, long mask)
+{
+ struct dac7612 *priv;
+ int ret;
+
+ if (mask != IIO_CHAN_INFO_RAW)
+ return -EINVAL;
+
+ if ((val >= BIT(RESOLUTION)) || val < 0)
+ return -EINVAL;
+
+ priv = iio_priv(iio_dev);
+ if (val == priv->cache[chan->channel])
+ return 0;
+
+ mutex_lock(&iio_dev->mlock);
+ ret = dac7612_cmd_single(priv, chan->channel, val);
+ mutex_unlock(&iio_dev->mlock);
+
+ return ret;
+}
+
+static const struct iio_info dac7612_info = {
+ .read_raw = dac7612_read_raw,
+ .write_raw = dac7612_write_raw,
+};
+
+static int dac7612_probe(struct spi_device *spi)
+{
+ struct iio_dev *iio_dev;
+ struct dac7612 *priv;
+ int i;
+ int ret;
+
+ iio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv));
+ if (!iio_dev)
+ return -ENOMEM;
+
+ priv = iio_priv(iio_dev);
+ priv->nld = devm_gpiod_get_optional(&spi->dev, "nLD", GPIOD_OUT_HIGH);
+ if (IS_ERR(priv->nld))
+ return PTR_ERR(priv->nld);
+ priv->spi = spi;
+ spi_set_drvdata(spi, iio_dev);
+ iio_dev->dev.parent = &spi->dev;
+ iio_dev->info = &dac7612_info;
+ iio_dev->modes = INDIO_DIRECT_MODE;
+ iio_dev->channels = dac7612_channels;
+ iio_dev->num_channels = NUM_CHANS;
+ iio_dev->name = spi_get_device_id(spi)->name;
+
+ for (i = 0; i < NUM_CHANS; i++) {
+ ret = dac7612_cmd_single(priv, i, 0);
+ if (ret)
+ return ret;
+ }
+
+ return devm_iio_device_register(&spi->dev, iio_dev);
+}
+
+static const struct spi_device_id dac7612_id[] = {
+ {"ti-dac7612"},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, dac7612_id);
+
+static struct spi_driver dac7612_driver = {
+ .driver = {
+ .name = "ti-dac7612",
+ },
+ .probe = dac7612_probe,
+ .id_table = dac7612_id,
+};
+module_spi_driver(dac7612_driver);
+
+MODULE_AUTHOR("Ricardo Ribalda <ricardo@xxxxxxxxxxx>");
+MODULE_DESCRIPTION("Texas Instruments DAC7612 DAC driver");
+MODULE_LICENSE("GPL v2");
--
2.20.1