--- /dev/null
+/*
+ * ti-dac082s085.c - Texas Instruments 8/10/12-bit 2/4-channel DAC driver
+ *
+ * Copyright (C) 2017 KUNBUS GmbH
+ *
+ * http://www.ti.com/lit/ds/symlink/dac082s085.pdf
+ * http://www.ti.com/lit/ds/symlink/dac102s085.pdf
+ * http://www.ti.com/lit/ds/symlink/dac122s085.pdf
+ * http://www.ti.com/lit/ds/symlink/dac084s085.pdf
+ * http://www.ti.com/lit/ds/symlink/dac104s085.pdf
+ * http://www.ti.com/lit/ds/symlink/dac124s085.pdf
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License (version 2) as
+ * published by the Free Software Foundation.
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+
+/**
+ * struct ti_dac_chip - TI DAC chip
+ * @lock: protects write sequences
+ * @vref: regulator generating Vref
+ * @mesg: SPI message to perform a write
+ * @xfer: SPI transfer used by @mesg
+ * @val: cached value of each output
+ * @powerdown: whether the chip is powered down
+ * @powerdown_mode: selected by the user
+ * @resolution: resolution of the chip
+ * @buf: buffer for @xfer
+ */
+struct ti_dac_chip {
+ struct mutex lock;
+ struct regulator *vref;
+ struct spi_message mesg;
+ struct spi_transfer xfer;
+ u16 val[4];
+ bool powerdown;
+ u8 powerdown_mode;
+ u8 resolution;
+ u8 buf[2] ____cacheline_aligned;
+};
+
+#define WRITE_NOT_UPDATE(chan) (0x00 | (chan) << 6)
+#define WRITE_AND_UPDATE(chan) (0x10 | (chan) << 6)
+#define WRITE_ALL_UPDATE 0x20
+#define POWERDOWN(mode) (0x30 | ((mode) + 1) << 6)
+
+static int ti_dac_cmd(struct ti_dac_chip *ti_dac, u8 cmd, u16 val)
+{
+ u8 shift = 12 - ti_dac->resolution;
+
+ ti_dac->buf[0] = cmd | (val >> (8 - shift));
+ ti_dac->buf[1] = (val << shift) & 0xff;
+ return spi_sync(ti_dac->mesg.spi, &ti_dac->mesg);
+}
+
+static const char * const ti_dac_powerdown_modes[] = {
+ "2.5kohm_to_gnd", "100kohm_to_gnd", "three_state",
+};
+
+static int ti_dac_get_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan)
+{
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+
+ return ti_dac->powerdown_mode;
+}
+
+static int ti_dac_set_powerdown_mode(struct iio_dev *indio_dev,
+ const struct iio_chan_spec *chan,
+ unsigned int mode)
+{
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+ int ret = 0;
+
+ if (ti_dac->powerdown_mode == mode)
+ return 0;
+
+ mutex_lock(&ti_dac->lock);
+ if (ti_dac->powerdown) {
+ ret = ti_dac_cmd(ti_dac, POWERDOWN(mode), 0);
+ if (ret)
+ goto out;
+ }
+ ti_dac->powerdown_mode = mode;
+
+out:
+ mutex_unlock(&ti_dac->lock);
+ return ret;
+}
+
+static const struct iio_enum ti_dac_powerdown_mode = {
+ .items = ti_dac_powerdown_modes,
+ .num_items = ARRAY_SIZE(ti_dac_powerdown_modes),
+ .get = ti_dac_get_powerdown_mode,
+ .set = ti_dac_set_powerdown_mode,
+};
+
+static ssize_t ti_dac_read_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ char *buf)
+{
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+
+ return sprintf(buf, "%d\n", ti_dac->powerdown);
+}
+
+static ssize_t ti_dac_write_powerdown(struct iio_dev *indio_dev,
+ uintptr_t private,
+ const struct iio_chan_spec *chan,
+ const char *buf, size_t len)
+{
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+ bool powerdown;
+ int ret;
+
+ ret = strtobool(buf, &powerdown);
+ if (ret)
+ return ret;
+
+ if (ti_dac->powerdown == powerdown)
+ return len;
+
+ mutex_lock(&ti_dac->lock);
+ if (powerdown)
+ ret = ti_dac_cmd(ti_dac, POWERDOWN(ti_dac->powerdown_mode), 0);
+ else
+ ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(0), ti_dac->val[0]);
+ if (!ret)
+ ti_dac->powerdown = powerdown;
+ mutex_unlock(&ti_dac->lock);
+
+ return ret ? ret : len;
+}
+
+static const struct iio_chan_spec_ext_info ti_dac_ext_info[] = {
+ {
+ .name = "powerdown",
+ .read = ti_dac_read_powerdown,
+ .write = ti_dac_write_powerdown,
+ .shared = IIO_SHARED_BY_TYPE,
+ },
+ IIO_ENUM("powerdown_mode", IIO_SHARED_BY_TYPE, &ti_dac_powerdown_mode),
+ IIO_ENUM_AVAILABLE("powerdown_mode", &ti_dac_powerdown_mode),
+ { },
+};
+
+#define TI_DAC_CHANNEL(chan) { \
+ .type = IIO_VOLTAGE, \
+ .channel = (chan), \
+ .address = (chan), \
+ .indexed = true, \
+ .output = true, \
+ .datasheet_name = (const char[]){ 'A' + (chan), 0 }, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \
+ .ext_info = ti_dac_ext_info, \
+}
+
+static const struct iio_chan_spec ti_dac_channels[] = {
+ TI_DAC_CHANNEL(0),
+ TI_DAC_CHANNEL(1),
+ TI_DAC_CHANNEL(2),
+ TI_DAC_CHANNEL(3),
+};
+
+static int ti_dac_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int *val, int *val2, long mask)
+{
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ *val = ti_dac->val[chan->channel];
+ ret = IIO_VAL_INT;
+ break;
+
+ case IIO_CHAN_INFO_SCALE:
+ ret = regulator_get_voltage(ti_dac->vref);
+ if (ret < 0)
+ return ret;
+
+ *val = ret / 1000;
+ *val2 = ti_dac->resolution;
+ ret = IIO_VAL_FRACTIONAL_LOG2;
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int ti_dac_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan,
+ int val, int val2, long mask)
+{
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (ti_dac->val[chan->channel] == val)
+ return 0;
+
+ if (val >= (1 << ti_dac->resolution) || val < 0)
+ return -EINVAL;
+
+ if (ti_dac->powerdown)
+ return -EBUSY;
+
+ mutex_lock(&ti_dac->lock);
+ ret = ti_dac_cmd(ti_dac, WRITE_AND_UPDATE(chan->channel), val);
+ if (!ret)
+ ti_dac->val[chan->channel] = val;
+ mutex_unlock(&ti_dac->lock);
+ break;
+
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int ti_dac_write_raw_get_fmt(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, long mask)
+{
+ return IIO_VAL_INT;
+}
+
+static const struct iio_info ti_dac_info = {
+ .read_raw = ti_dac_read_raw,
+ .write_raw = ti_dac_write_raw,
+ .write_raw_get_fmt = ti_dac_write_raw_get_fmt,
+};
+
+static int ti_dac_probe(struct spi_device *spi)
+{
+ struct device *dev = &spi->dev;
+ struct ti_dac_chip *ti_dac;
+ struct iio_dev *indio_dev;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(dev, sizeof(*ti_dac));
+ if (!indio_dev)
+ return -ENOMEM;
+
+ indio_dev->dev.parent = dev;
+ indio_dev->info = &ti_dac_info;
+ indio_dev->name = spi->modalias;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ti_dac_channels;
+ spi_set_drvdata(spi, indio_dev);
+
+ ti_dac = iio_priv(indio_dev);
+ ti_dac->xfer.tx_buf = &ti_dac->buf;
+ ti_dac->xfer.len = sizeof(ti_dac->buf);
+ spi_message_init_with_transfers(&ti_dac->mesg, &ti_dac->xfer, 1);
+ ti_dac->mesg.spi = spi;
+
+ ret = sscanf(spi->modalias, "dac%2hhu%1d",
+ &ti_dac->resolution, &indio_dev->num_channels);
+ WARN_ON(ret != 2);
+
+ ti_dac->vref = devm_regulator_get(dev, "vref");
+ if (IS_ERR(ti_dac->vref))
+ return PTR_ERR(ti_dac->vref);
+
+ ret = regulator_enable(ti_dac->vref);
+ if (ret < 0)
+ return ret;
+
+ mutex_init(&ti_dac->lock);
+
+ ret = ti_dac_cmd(ti_dac, WRITE_ALL_UPDATE, 0);
+ if (ret) {
+ dev_err(dev, "failed to initialize outputs to 0\n");
+ goto err;
+ }
+
+ ret = iio_device_register(indio_dev);
+ if (ret)
+ goto err;
+
+ return 0;
+
+err:
+ mutex_destroy(&ti_dac->lock);
+ regulator_disable(ti_dac->vref);
+ return ret;
+}
+
+static int ti_dac_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ti_dac_chip *ti_dac = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ mutex_destroy(&ti_dac->lock);
+ regulator_disable(ti_dac->vref);
+
+ return 0;
+}
+
+#ifdef CONFIG_OF
+static const struct of_device_id ti_dac_of_id[] = {
+ { .compatible = "ti,dac082s085" },
+ { .compatible = "ti,dac102s085" },
+ { .compatible = "ti,dac122s085" },
+ { .compatible = "ti,dac084s085" },
+ { .compatible = "ti,dac104s085" },
+ { .compatible = "ti,dac124s085" },
+ { }
+};
+MODULE_DEVICE_TABLE(of, ti_dac_of_id);
+#endif
+
+static const struct spi_device_id ti_dac_spi_id[] = {
+ { "dac082s085" },
+ { "dac102s085" },
+ { "dac122s085" },
+ { "dac084s085" },
+ { "dac104s085" },
+ { "dac124s085" },
+ { }
+};
+MODULE_DEVICE_TABLE(spi, ti_dac_spi_id);
+
+static struct spi_driver ti_dac_driver = {
+ .driver = {
+ .name = "ti-dac082s085",
+ .of_match_table = of_match_ptr(ti_dac_of_id),
+ },
+ .probe = ti_dac_probe,
+ .remove = ti_dac_remove,
+ .id_table = ti_dac_spi_id,
+};
+module_spi_driver(ti_dac_driver);
+
+MODULE_AUTHOR("Lukas Wunner <lukas@wunner.de>");
+MODULE_DESCRIPTION("Texas Instruments 8/10/12-bit 2/4-channel DAC driver");
+MODULE_LICENSE("GPL v2");
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