diff options
Diffstat (limited to 'drivers/iio/dac/ad8801.c')
| -rw-r--r-- | drivers/iio/dac/ad8801.c | 239 |
1 files changed, 239 insertions, 0 deletions
diff --git a/drivers/iio/dac/ad8801.c b/drivers/iio/dac/ad8801.c new file mode 100644 index 000000000000..f06faa1aec09 --- /dev/null +++ b/drivers/iio/dac/ad8801.c @@ -0,0 +1,239 @@ +/* + * 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"); |