/* * 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, }; #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");