diff options
Diffstat (limited to 'drivers/iio/dac/ltc1660.c')
| -rw-r--r-- | drivers/iio/dac/ltc1660.c | 249 |
1 files changed, 249 insertions, 0 deletions
diff --git a/drivers/iio/dac/ltc1660.c b/drivers/iio/dac/ltc1660.c new file mode 100644 index 000000000..dc1018854 --- /dev/null +++ b/drivers/iio/dac/ltc1660.c @@ -0,0 +1,249 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Driver for Linear Technology LTC1665/LTC1660, 8 channels DAC + * + * Copyright (C) 2018 Marcus Folkesson <marcus.folkesson@gmail.com> + */ +#include <linux/bitops.h> +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> +#include <linux/init.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/regmap.h> +#include <linux/spi/spi.h> + +#define LTC1660_REG_WAKE 0x0 +#define LTC1660_REG_DAC_A 0x1 +#define LTC1660_REG_DAC_B 0x2 +#define LTC1660_REG_DAC_C 0x3 +#define LTC1660_REG_DAC_D 0x4 +#define LTC1660_REG_DAC_E 0x5 +#define LTC1660_REG_DAC_F 0x6 +#define LTC1660_REG_DAC_G 0x7 +#define LTC1660_REG_DAC_H 0x8 +#define LTC1660_REG_SLEEP 0xe + +#define LTC1660_NUM_CHANNELS 8 + +static const struct regmap_config ltc1660_regmap_config = { + .reg_bits = 4, + .val_bits = 12, +}; + +enum ltc1660_supported_device_ids { + ID_LTC1660, + ID_LTC1665, +}; + +struct ltc1660_priv { + struct spi_device *spi; + struct regmap *regmap; + struct regulator *vref_reg; + unsigned int value[LTC1660_NUM_CHANNELS]; + unsigned int vref_mv; +}; + +static int ltc1660_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, + int *val2, + long mask) +{ + struct ltc1660_priv *priv = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val = priv->value[chan->channel]; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = regulator_get_voltage(priv->vref_reg); + if (*val < 0) { + dev_err(&priv->spi->dev, "failed to read vref regulator: %d\n", + *val); + return *val; + } + + /* Convert to mV */ + *val /= 1000; + *val2 = chan->scan_type.realbits; + return IIO_VAL_FRACTIONAL_LOG2; + default: + return -EINVAL; + } +} + +static int ltc1660_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, + int val2, + long mask) +{ + struct ltc1660_priv *priv = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (val2 != 0) + return -EINVAL; + + if (val < 0 || val > GENMASK(chan->scan_type.realbits - 1, 0)) + return -EINVAL; + + ret = regmap_write(priv->regmap, chan->channel, + (val << chan->scan_type.shift)); + if (!ret) + priv->value[chan->channel] = val; + + return ret; + default: + return -EINVAL; + } +} + +#define LTC1660_CHAN(chan, bits) { \ + .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), \ + .scan_type = { \ + .sign = 'u', \ + .realbits = (bits), \ + .storagebits = 16, \ + .shift = 12 - (bits), \ + }, \ +} + +#define LTC1660_OCTAL_CHANNELS(bits) { \ + LTC1660_CHAN(LTC1660_REG_DAC_A, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_B, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_C, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_D, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_E, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_F, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_G, bits), \ + LTC1660_CHAN(LTC1660_REG_DAC_H, bits), \ +} + +static const struct iio_chan_spec ltc1660_channels[][LTC1660_NUM_CHANNELS] = { + [ID_LTC1660] = LTC1660_OCTAL_CHANNELS(10), + [ID_LTC1665] = LTC1660_OCTAL_CHANNELS(8), +}; + +static const struct iio_info ltc1660_info = { + .read_raw = <c1660_read_raw, + .write_raw = <c1660_write_raw, +}; + +static int __maybe_unused ltc1660_suspend(struct device *dev) +{ + struct ltc1660_priv *priv = iio_priv(spi_get_drvdata( + to_spi_device(dev))); + return regmap_write(priv->regmap, LTC1660_REG_SLEEP, 0x00); +} + +static int __maybe_unused ltc1660_resume(struct device *dev) +{ + struct ltc1660_priv *priv = iio_priv(spi_get_drvdata( + to_spi_device(dev))); + return regmap_write(priv->regmap, LTC1660_REG_WAKE, 0x00); +} +static SIMPLE_DEV_PM_OPS(ltc1660_pm_ops, ltc1660_suspend, ltc1660_resume); + +static int ltc1660_probe(struct spi_device *spi) +{ + struct iio_dev *indio_dev; + struct ltc1660_priv *priv; + const struct spi_device_id *id = spi_get_device_id(spi); + int ret; + + indio_dev = devm_iio_device_alloc(&spi->dev, sizeof(*priv)); + if (indio_dev == NULL) + return -ENOMEM; + + priv = iio_priv(indio_dev); + priv->regmap = devm_regmap_init_spi(spi, <c1660_regmap_config); + if (IS_ERR(priv->regmap)) { + dev_err(&spi->dev, "failed to register spi regmap %ld\n", + PTR_ERR(priv->regmap)); + return PTR_ERR(priv->regmap); + } + + priv->vref_reg = devm_regulator_get(&spi->dev, "vref"); + if (IS_ERR(priv->vref_reg)) { + dev_err(&spi->dev, "vref regulator not specified\n"); + return PTR_ERR(priv->vref_reg); + } + + ret = regulator_enable(priv->vref_reg); + if (ret) { + dev_err(&spi->dev, "failed to enable vref regulator: %d\n", + ret); + return ret; + } + + priv->spi = spi; + spi_set_drvdata(spi, indio_dev); + indio_dev->info = <c1660_info; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->channels = ltc1660_channels[id->driver_data]; + indio_dev->num_channels = LTC1660_NUM_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_reg; + } + + return 0; + +error_disable_reg: + regulator_disable(priv->vref_reg); + + return ret; +} + +static int ltc1660_remove(struct spi_device *spi) +{ + struct iio_dev *indio_dev = spi_get_drvdata(spi); + struct ltc1660_priv *priv = iio_priv(indio_dev); + + iio_device_unregister(indio_dev); + regulator_disable(priv->vref_reg); + + return 0; +} + +static const struct of_device_id ltc1660_dt_ids[] = { + { .compatible = "lltc,ltc1660", .data = (void *)ID_LTC1660 }, + { .compatible = "lltc,ltc1665", .data = (void *)ID_LTC1665 }, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, ltc1660_dt_ids); + +static const struct spi_device_id ltc1660_id[] = { + {"ltc1660", ID_LTC1660}, + {"ltc1665", ID_LTC1665}, + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(spi, ltc1660_id); + +static struct spi_driver ltc1660_driver = { + .driver = { + .name = "ltc1660", + .of_match_table = ltc1660_dt_ids, + .pm = <c1660_pm_ops, + }, + .probe = ltc1660_probe, + .remove = ltc1660_remove, + .id_table = ltc1660_id, +}; +module_spi_driver(ltc1660_driver); + +MODULE_AUTHOR("Marcus Folkesson <marcus.folkesson@gmail.com>"); +MODULE_DESCRIPTION("Linear Technology LTC1660/LTC1665 DAC"); +MODULE_LICENSE("GPL v2"); |