--- /dev/null
+/*
+ * IIO DAC driver for Analog Devices AD8801 DAC
+ *
+ * Copyright (C) 2016 Gwenhael Goavec-Merou
+ * 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.
+ *
+ * This program is distributed in the hope that it will be useful, but
+ * WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ * General Public License for more details.
+ *
+ */
+
+#include <linux/iio/iio.h>
+#include <linux/module.h>
+#include <linux/regulator/consumer.h>
+#include <linux/spi/spi.h>
+#include <linux/sysfs.h>
+
+#define AD8801_CFG_ADDR_OFFSET 8
+
+enum ad8801_device_ids {
+ ID_AD8801,
+ ID_AD8803,
+};
+
+struct ad8801_state {
+ struct spi_device *spi;
+ unsigned char dac_cache[8]; /* Value write on each channel */
+ unsigned int vrefh_mv;
+ unsigned int vrefl_mv;
+ struct regulator *vrefh_reg;
+ struct regulator *vrefl_reg;
+
+ __be16 data ____cacheline_aligned;
+};
+
+static int ad8801_spi_write(struct ad8801_state *state,
+ u8 channel, unsigned char value)
+{
+ state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value);
+ return spi_write(state->spi, &state->data, sizeof(state->data));
+}
+
+static int ad8801_write_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int val, int val2, long mask)
+{
+ struct ad8801_state *state = iio_priv(indio_dev);
+ int ret;
+
+ switch (mask) {
+ case IIO_CHAN_INFO_RAW:
+ if (val >= 256 || val < 0)
+ return -EINVAL;
+
+ ret = ad8801_spi_write(state, chan->channel, val);
+ if (ret == 0)
+ state->dac_cache[chan->channel] = val;
+ break;
+ default:
+ ret = -EINVAL;
+ }
+
+ return ret;
+}
+
+static int ad8801_read_raw(struct iio_dev *indio_dev,
+ struct iio_chan_spec const *chan, int *val, int *val2, long info)
+{
+ struct ad8801_state *state = iio_priv(indio_dev);
+
+ switch (info) {
+ case IIO_CHAN_INFO_RAW:
+ *val = state->dac_cache[chan->channel];
+ return IIO_VAL_INT;
+ case IIO_CHAN_INFO_SCALE:
+ *val = state->vrefh_mv - state->vrefl_mv;
+ *val2 = 8;
+ return IIO_VAL_FRACTIONAL_LOG2;
+ case IIO_CHAN_INFO_OFFSET:
+ *val = state->vrefl_mv;
+ return IIO_VAL_INT;
+ default:
+ return -EINVAL;
+ }
+
+ return -EINVAL;
+}
+
+static const struct iio_info ad8801_info = {
+ .read_raw = ad8801_read_raw,
+ .write_raw = ad8801_write_raw,
+ .driver_module = THIS_MODULE,
+};
+
+#define AD8801_CHANNEL(chan) { \
+ .type = IIO_VOLTAGE, \
+ .indexed = 1, \
+ .output = 1, \
+ .channel = chan, \
+ .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
+ .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
+ BIT(IIO_CHAN_INFO_OFFSET), \
+}
+
+static const struct iio_chan_spec ad8801_channels[] = {
+ AD8801_CHANNEL(0),
+ AD8801_CHANNEL(1),
+ AD8801_CHANNEL(2),
+ AD8801_CHANNEL(3),
+ AD8801_CHANNEL(4),
+ AD8801_CHANNEL(5),
+ AD8801_CHANNEL(6),
+ AD8801_CHANNEL(7),
+};
+
+static int ad8801_probe(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev;
+ struct ad8801_state *state;
+ const struct spi_device_id *id;
+ int ret;
+
+ indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
+ if (indio_dev == NULL)
+ return -ENOMEM;
+
+ state = iio_priv(indio_dev);
+ state->spi = spi;
+ id = spi_get_device_id(spi);
+
+ state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh");
+ if (IS_ERR(state->vrefh_reg)) {
+ dev_err(&spi->dev, "Vrefh regulator not specified\n");
+ return PTR_ERR(state->vrefh_reg);
+ }
+
+ ret = regulator_enable(state->vrefh_reg);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n",
+ ret);
+ return ret;
+ }
+
+ ret = regulator_get_voltage(state->vrefh_reg);
+ if (ret < 0) {
+ dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n",
+ ret);
+ goto error_disable_vrefh_reg;
+ }
+ state->vrefh_mv = ret / 1000;
+
+ if (id->driver_data == ID_AD8803) {
+ state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl");
+ if (IS_ERR(state->vrefl_reg)) {
+ dev_err(&spi->dev, "Vrefl regulator not specified\n");
+ ret = PTR_ERR(state->vrefl_reg);
+ goto error_disable_vrefh_reg;
+ }
+
+ ret = regulator_enable(state->vrefl_reg);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n",
+ ret);
+ goto error_disable_vrefh_reg;
+ }
+
+ ret = regulator_get_voltage(state->vrefl_reg);
+ if (ret < 0) {
+ dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n",
+ ret);
+ goto error_disable_vrefl_reg;
+ }
+ state->vrefl_mv = ret / 1000;
+ } else {
+ state->vrefl_mv = 0;
+ state->vrefl_reg = NULL;
+ }
+
+ spi_set_drvdata(spi, indio_dev);
+ indio_dev->dev.parent = &spi->dev;
+ indio_dev->info = &ad8801_info;
+ indio_dev->modes = INDIO_DIRECT_MODE;
+ indio_dev->channels = ad8801_channels;
+ indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
+ indio_dev->name = id->name;
+
+ ret = iio_device_register(indio_dev);
+ if (ret) {
+ dev_err(&spi->dev, "Failed to register iio device: %d\n",
+ ret);
+ goto error_disable_vrefl_reg;
+ }
+
+ return 0;
+
+error_disable_vrefl_reg:
+ if (state->vrefl_reg)
+ regulator_disable(state->vrefl_reg);
+error_disable_vrefh_reg:
+ regulator_disable(state->vrefh_reg);
+ return ret;
+}
+
+static int ad8801_remove(struct spi_device *spi)
+{
+ struct iio_dev *indio_dev = spi_get_drvdata(spi);
+ struct ad8801_state *state = iio_priv(indio_dev);
+
+ iio_device_unregister(indio_dev);
+ if (state->vrefl_reg)
+ regulator_disable(state->vrefl_reg);
+ regulator_disable(state->vrefh_reg);
+
+ return 0;
+}
+
+static const struct spi_device_id ad8801_ids[] = {
+ {"ad8801", ID_AD8801},
+ {"ad8803", ID_AD8803},
+ {}
+};
+MODULE_DEVICE_TABLE(spi, ad8801_ids);
+
+static struct spi_driver ad8801_driver = {
+ .driver = {
+ .name = "ad8801",
+ },
+ .probe = ad8801_probe,
+ .remove = ad8801_remove,
+ .id_table = ad8801_ids,
+};
+module_spi_driver(ad8801_driver);
+
+MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>");
+MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
+MODULE_LICENSE("GPL v2");
projects / cascardo / linux.git / commitdiff