diff options
Diffstat (limited to 'drivers/iio/dac/rohm-bd79703.c')
| -rw-r--r-- | drivers/iio/dac/rohm-bd79703.c | 162 |
1 files changed, 162 insertions, 0 deletions
diff --git a/drivers/iio/dac/rohm-bd79703.c b/drivers/iio/dac/rohm-bd79703.c new file mode 100644 index 000000000000..e998ab51052e --- /dev/null +++ b/drivers/iio/dac/rohm-bd79703.c @@ -0,0 +1,162 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * BD79703 ROHM Digital to Analog converter + * + * Copyright (c) 2024, ROHM Semiconductor. + */ + +#include <linux/bits.h> +#include <linux/device.h> +#include <linux/module.h> +#include <linux/regmap.h> +#include <linux/regulator/consumer.h> +#include <linux/spi/spi.h> +#include <linux/iio/iio.h> + +#define BD79703_MAX_REGISTER 0xf +#define BD79703_DAC_BITS 8 +#define BD79703_REG_OUT_ALL GENMASK(2, 0) + +/* + * The BD79703 uses 12-bit SPI commands. First four bits (high bits) define + * channel(s) which are operated on, and also the mode. The mode can be to set + * a DAC word only, or set DAC word and output. The data-sheet is not very + * specific on how a previously set DAC word can be 'taken in to use'. Thus + * this driver only uses the 'set DAC and output it' -mode. + * + * The BD79703 latches last 12-bits when the chip-select is toggled. Thus we + * can use 16-bit transfers which should be widely supported. To simplify this + * further, we treat the last 8 bits as a value, and first 8 bits as an + * address. This allows us to separate channels/mode by address and treat the + * 8-bit register value as DAC word. The highest 4 bits of address will be + * discarded when the transfer is latched. + */ +static const struct regmap_config bd79703_regmap_config = { + .reg_bits = 8, + .val_bits = 8, + .max_register = BD79703_MAX_REGISTER, + .cache_type = REGCACHE_RBTREE, +}; + +struct bd79703_data { + struct regmap *regmap; + int vfs; +}; + +static int bd79703_read_raw(struct iio_dev *idev, + struct iio_chan_spec const *chan, int *val, + int *val2, long mask) +{ + struct bd79703_data *data = iio_priv(idev); + + if (mask != IIO_CHAN_INFO_SCALE) + return -EINVAL; + + *val = data->vfs / 1000; + *val2 = BD79703_DAC_BITS; + + return IIO_VAL_FRACTIONAL_LOG2; +} + +static int bd79703_write_raw(struct iio_dev *idev, + struct iio_chan_spec const *chan, int val, + int val2, long mask) +{ + struct bd79703_data *data = iio_priv(idev); + + if (val < 0 || val >= 1 << BD79703_DAC_BITS) + return -EINVAL; + + return regmap_write(data->regmap, chan->channel + 1, val); +}; + +static const struct iio_info bd79703_info = { + .read_raw = bd79703_read_raw, + .write_raw = bd79703_write_raw, +}; + +#define BD79703_CHAN(_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), \ + .address = (_chan), \ +} + +static const struct iio_chan_spec bd79703_channels[] = { + BD79703_CHAN(0), + BD79703_CHAN(1), + BD79703_CHAN(2), + BD79703_CHAN(3), + BD79703_CHAN(4), + BD79703_CHAN(5), +}; + +static int bd79703_probe(struct spi_device *spi) +{ + struct device *dev = &spi->dev; + struct bd79703_data *data; + struct iio_dev *idev; + int ret; + + idev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!idev) + return -ENOMEM; + + data = iio_priv(idev); + + data->regmap = devm_regmap_init_spi(spi, &bd79703_regmap_config); + if (IS_ERR(data->regmap)) + return dev_err_probe(dev, PTR_ERR(data->regmap), + "Failed to initialize Regmap\n"); + + ret = devm_regulator_get_enable(dev, "vcc"); + if (ret) + return dev_err_probe(dev, ret, "Failed to enable VCC\n"); + + ret = devm_regulator_get_enable_read_voltage(dev, "vfs"); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to get Vfs\n"); + + data->vfs = ret; + idev->channels = bd79703_channels; + idev->num_channels = ARRAY_SIZE(bd79703_channels); + idev->modes = INDIO_DIRECT_MODE; + idev->info = &bd79703_info; + idev->name = "bd79703"; + + /* Initialize all to output zero */ + ret = regmap_write(data->regmap, BD79703_REG_OUT_ALL, 0); + if (ret) + return ret; + + return devm_iio_device_register(dev, idev); +} + +static const struct spi_device_id bd79703_id[] = { + { "bd79703", }, + { } +}; +MODULE_DEVICE_TABLE(spi, bd79703_id); + +static const struct of_device_id bd79703_of_match[] = { + { .compatible = "rohm,bd79703", }, + { } +}; +MODULE_DEVICE_TABLE(of, bd79703_of_match); + +static struct spi_driver bd79703_driver = { + .driver = { + .name = "bd79703", + .of_match_table = bd79703_of_match, + }, + .probe = bd79703_probe, + .id_table = bd79703_id, +}; +module_spi_driver(bd79703_driver); + +MODULE_AUTHOR("Matti Vaittinen <mazziesaccount@gmail.com>"); +MODULE_DESCRIPTION("ROHM BD79703 DAC driver"); +MODULE_LICENSE("GPL"); |