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![Gwenhael Goavec-Merou](/assets/img/avatar_default.png)
Add support for Analog Devices AD8801/AD8803, 8 channels 8bits, Digital to Analog converters. Signed-off-by: Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com> Signed-off-by: Jonathan Cameron <jic23@kernel.org>
239 lines
5.7 KiB
C
239 lines
5.7 KiB
C
/*
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* IIO DAC driver for Analog Devices AD8801 DAC
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*
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* Copyright (C) 2016 Gwenhael Goavec-Merou
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License, version 2, as
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* published by the Free Software Foundation.
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*
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* This program is distributed in the hope that it will be useful, but
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* WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* General Public License for more details.
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*
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*/
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#include <linux/iio/iio.h>
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#include <linux/module.h>
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#include <linux/regulator/consumer.h>
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#include <linux/spi/spi.h>
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#include <linux/sysfs.h>
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#define AD8801_CFG_ADDR_OFFSET 8
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enum ad8801_device_ids {
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ID_AD8801,
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ID_AD8803,
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};
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struct ad8801_state {
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struct spi_device *spi;
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unsigned char dac_cache[8]; /* Value write on each channel */
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unsigned int vrefh_mv;
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unsigned int vrefl_mv;
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struct regulator *vrefh_reg;
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struct regulator *vrefl_reg;
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__be16 data ____cacheline_aligned;
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};
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static int ad8801_spi_write(struct ad8801_state *state,
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u8 channel, unsigned char value)
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{
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state->data = cpu_to_be16((channel << AD8801_CFG_ADDR_OFFSET) | value);
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return spi_write(state->spi, &state->data, sizeof(state->data));
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}
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static int ad8801_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int val, int val2, long mask)
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{
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struct ad8801_state *state = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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if (val >= 256 || val < 0)
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return -EINVAL;
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ret = ad8801_spi_write(state, chan->channel, val);
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if (ret == 0)
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state->dac_cache[chan->channel] = val;
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break;
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default:
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ret = -EINVAL;
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}
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return ret;
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}
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static int ad8801_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan, int *val, int *val2, long info)
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{
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struct ad8801_state *state = iio_priv(indio_dev);
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switch (info) {
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case IIO_CHAN_INFO_RAW:
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*val = state->dac_cache[chan->channel];
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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*val = state->vrefh_mv - state->vrefl_mv;
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*val2 = 8;
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return IIO_VAL_FRACTIONAL_LOG2;
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case IIO_CHAN_INFO_OFFSET:
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*val = state->vrefl_mv;
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return IIO_VAL_INT;
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default:
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return -EINVAL;
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}
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return -EINVAL;
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}
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static const struct iio_info ad8801_info = {
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.read_raw = ad8801_read_raw,
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.write_raw = ad8801_write_raw,
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.driver_module = THIS_MODULE,
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};
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#define AD8801_CHANNEL(chan) { \
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.type = IIO_VOLTAGE, \
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.indexed = 1, \
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.output = 1, \
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.channel = chan, \
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE) | \
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BIT(IIO_CHAN_INFO_OFFSET), \
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}
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static const struct iio_chan_spec ad8801_channels[] = {
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AD8801_CHANNEL(0),
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AD8801_CHANNEL(1),
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AD8801_CHANNEL(2),
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AD8801_CHANNEL(3),
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AD8801_CHANNEL(4),
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AD8801_CHANNEL(5),
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AD8801_CHANNEL(6),
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AD8801_CHANNEL(7),
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};
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static int ad8801_probe(struct spi_device *spi)
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{
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struct iio_dev *indio_dev;
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struct ad8801_state *state;
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const struct spi_device_id *id;
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int ret;
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indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*state));
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if (indio_dev == NULL)
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return -ENOMEM;
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state = iio_priv(indio_dev);
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state->spi = spi;
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id = spi_get_device_id(spi);
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state->vrefh_reg = devm_regulator_get(&spi->dev, "vrefh");
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if (IS_ERR(state->vrefh_reg)) {
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dev_err(&spi->dev, "Vrefh regulator not specified\n");
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return PTR_ERR(state->vrefh_reg);
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}
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ret = regulator_enable(state->vrefh_reg);
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if (ret) {
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dev_err(&spi->dev, "Failed to enable vrefh regulator: %d\n",
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ret);
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return ret;
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}
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ret = regulator_get_voltage(state->vrefh_reg);
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if (ret < 0) {
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dev_err(&spi->dev, "Failed to read vrefh regulator: %d\n",
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ret);
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goto error_disable_vrefh_reg;
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}
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state->vrefh_mv = ret / 1000;
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if (id->driver_data == ID_AD8803) {
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state->vrefl_reg = devm_regulator_get(&spi->dev, "vrefl");
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if (IS_ERR(state->vrefl_reg)) {
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dev_err(&spi->dev, "Vrefl regulator not specified\n");
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ret = PTR_ERR(state->vrefl_reg);
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goto error_disable_vrefh_reg;
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}
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ret = regulator_enable(state->vrefl_reg);
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if (ret) {
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dev_err(&spi->dev, "Failed to enable vrefl regulator: %d\n",
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ret);
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goto error_disable_vrefh_reg;
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}
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ret = regulator_get_voltage(state->vrefl_reg);
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if (ret < 0) {
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dev_err(&spi->dev, "Failed to read vrefl regulator: %d\n",
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ret);
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goto error_disable_vrefl_reg;
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}
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state->vrefl_mv = ret / 1000;
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} else {
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state->vrefl_mv = 0;
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state->vrefl_reg = NULL;
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}
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spi_set_drvdata(spi, indio_dev);
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indio_dev->dev.parent = &spi->dev;
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indio_dev->info = &ad8801_info;
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indio_dev->modes = INDIO_DIRECT_MODE;
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indio_dev->channels = ad8801_channels;
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indio_dev->num_channels = ARRAY_SIZE(ad8801_channels);
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indio_dev->name = id->name;
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ret = iio_device_register(indio_dev);
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if (ret) {
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dev_err(&spi->dev, "Failed to register iio device: %d\n",
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ret);
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goto error_disable_vrefl_reg;
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}
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return 0;
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error_disable_vrefl_reg:
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if (state->vrefl_reg)
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regulator_disable(state->vrefl_reg);
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error_disable_vrefh_reg:
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regulator_disable(state->vrefh_reg);
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return ret;
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}
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static int ad8801_remove(struct spi_device *spi)
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{
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struct iio_dev *indio_dev = spi_get_drvdata(spi);
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struct ad8801_state *state = iio_priv(indio_dev);
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iio_device_unregister(indio_dev);
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if (state->vrefl_reg)
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regulator_disable(state->vrefl_reg);
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regulator_disable(state->vrefh_reg);
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return 0;
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}
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static const struct spi_device_id ad8801_ids[] = {
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{"ad8801", ID_AD8801},
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{"ad8803", ID_AD8803},
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{}
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};
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MODULE_DEVICE_TABLE(spi, ad8801_ids);
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static struct spi_driver ad8801_driver = {
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.driver = {
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.name = "ad8801",
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},
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.probe = ad8801_probe,
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.remove = ad8801_remove,
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.id_table = ad8801_ids,
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};
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module_spi_driver(ad8801_driver);
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MODULE_AUTHOR("Gwenhael Goavec-Merou <gwenhael.goavec-merou@trabucayre.com>");
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MODULE_DESCRIPTION("Analog Devices AD8801/AD8803 DAC");
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MODULE_LICENSE("GPL v2");
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