diff options
Diffstat (limited to 'drivers/iio/dac/mcp47a1.c')
| -rw-r--r-- | drivers/iio/dac/mcp47a1.c | 166 |
1 files changed, 166 insertions, 0 deletions
diff --git a/drivers/iio/dac/mcp47a1.c b/drivers/iio/dac/mcp47a1.c new file mode 100644 index 000000000000..0bf994aa0e4f --- /dev/null +++ b/drivers/iio/dac/mcp47a1.c @@ -0,0 +1,166 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Microchip MCP47A1 DAC driver + * + * Copyright (c) 2026 Joshua Crofts <joshua.crofts1@gmail.com> + * + * Datasheet: https://ww1.microchip.com/downloads/aemDocuments/documents/OTH/ProductDocuments/DataSheets/25154A.pdf + */ + +#include <linux/delay.h> +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/minmax.h> +#include <linux/module.h> +#include <linux/regulator/consumer.h> +#include <linux/types.h> +#include <linux/units.h> + +#include <linux/iio/iio.h> + +#define MCP47A1_CMD_CODE 0x00 +#define MCP47A1_MAX_STEPS 64 + +struct mcp47a1_data { + struct i2c_client *client; + int vref_mV; +}; + +static const int mcp47a1_raw_avail[] = { 0, 1, MCP47A1_MAX_STEPS - 1 }; + +static const struct iio_chan_spec mcp47a1_channel = { + .type = IIO_VOLTAGE, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_separate_available = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), +}; + +static int mcp47a1_write(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct mcp47a1_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (!in_range(val, 0, MCP47A1_MAX_STEPS)) + return -EINVAL; + + return i2c_smbus_write_byte_data(data->client, MCP47A1_CMD_CODE, + val); + default: + return -EINVAL; + } +} + +static int mcp47a1_read(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mcp47a1_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = i2c_smbus_read_byte_data(data->client, MCP47A1_CMD_CODE); + if (ret < 0) + return ret; + + *val = ret; + + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = data->vref_mV; + *val2 = MCP47A1_MAX_STEPS; + + return IIO_VAL_FRACTIONAL; + default: + return -EINVAL; + } +} + +static int mcp47a1_read_avail(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + const int **vals, int *type, int *length, + long mask) +{ + switch (mask) { + case IIO_CHAN_INFO_RAW: + *vals = mcp47a1_raw_avail; + *type = IIO_VAL_INT; + return IIO_AVAIL_RANGE; + default: + return -EINVAL; + } +} + +static const struct iio_info mcp47a1_info = { + .write_raw = mcp47a1_write, + .read_raw = mcp47a1_read, + .read_avail = mcp47a1_read_avail, +}; + +static int mcp47a1_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct mcp47a1_data *data; + struct iio_dev *indio_dev; + int ret; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + data->client = client; + + ret = devm_regulator_get_enable(dev, "vdd"); + if (ret) + return dev_err_probe(dev, ret, "Failed to enable regulator\n"); + + /* Delay after device exits reset state (see AC/DC characteristics) */ + fsleep(20); + + ret = devm_regulator_get_enable_read_voltage(dev, "vref"); + if (ret < 0) + return dev_err_probe(dev, ret, "Failed to read vref\n"); + + data->vref_mV = ret / (MICRO / MILLI); + + indio_dev->name = "mcp47a1"; + indio_dev->modes = INDIO_DIRECT_MODE; + indio_dev->info = &mcp47a1_info; + indio_dev->channels = &mcp47a1_channel; + indio_dev->num_channels = 1; + + return devm_iio_device_register(dev, indio_dev); +} + +static const struct of_device_id mcp47a1_of_match[] = { + { .compatible = "microchip,mcp47a1" }, + { } +}; +MODULE_DEVICE_TABLE(of, mcp47a1_of_match); + +static const struct i2c_device_id mcp47a1_id[] = { + { .name = "mcp47a1" }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mcp47a1_id); + +static struct i2c_driver mcp47a1_driver = { + .driver = { + .name = "mcp47a1", + .of_match_table = mcp47a1_of_match, + }, + .probe = mcp47a1_probe, + .id_table = mcp47a1_id, +}; +module_i2c_driver(mcp47a1_driver); + +MODULE_AUTHOR("Joshua Crofts <joshua.crofts1@gmail.com>"); +MODULE_DESCRIPTION("Microchip MCP47A1 DAC Driver"); +MODULE_LICENSE("GPL"); |