diff options
Diffstat (limited to 'drivers/iio/potentiometer/mcp4018.c')
| -rw-r--r-- | drivers/iio/potentiometer/mcp4018.c | 188 |
1 files changed, 188 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/mcp4018.c b/drivers/iio/potentiometer/mcp4018.c new file mode 100644 index 0000000000..44678d3721 --- /dev/null +++ b/drivers/iio/potentiometer/mcp4018.c @@ -0,0 +1,188 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Industrial I/O driver for Microchip digital potentiometers + * Copyright (c) 2018 Axentia Technologies AB + * Author: Peter Rosin <peda@axentia.se> + * + * Datasheet: http://www.microchip.com/downloads/en/DeviceDoc/22147a.pdf + * + * DEVID #Wipers #Positions Resistor Opts (kOhm) + * mcp4017 1 128 5, 10, 50, 100 + * mcp4018 1 128 5, 10, 50, 100 + * mcp4019 1 128 5, 10, 50, 100 + */ + +#include <linux/err.h> +#include <linux/i2c.h> +#include <linux/iio/iio.h> +#include <linux/module.h> +#include <linux/mod_devicetable.h> +#include <linux/property.h> + +#define MCP4018_WIPER_MAX 127 + +struct mcp4018_cfg { + int kohms; +}; + +enum mcp4018_type { + MCP4018_502, + MCP4018_103, + MCP4018_503, + MCP4018_104, +}; + +static const struct mcp4018_cfg mcp4018_cfg[] = { + [MCP4018_502] = { .kohms = 5, }, + [MCP4018_103] = { .kohms = 10, }, + [MCP4018_503] = { .kohms = 50, }, + [MCP4018_104] = { .kohms = 100, }, +}; + +struct mcp4018_data { + struct i2c_client *client; + const struct mcp4018_cfg *cfg; +}; + +static const struct iio_chan_spec mcp4018_channel = { + .type = IIO_RESISTANCE, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), +}; + +static int mcp4018_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mcp4018_data *data = iio_priv(indio_dev); + s32 ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = i2c_smbus_read_byte(data->client); + if (ret < 0) + return ret; + *val = ret; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + *val = 1000 * data->cfg->kohms; + *val2 = MCP4018_WIPER_MAX; + return IIO_VAL_FRACTIONAL; + } + + return -EINVAL; +} + +static int mcp4018_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct mcp4018_data *data = iio_priv(indio_dev); + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (val > MCP4018_WIPER_MAX || val < 0) + return -EINVAL; + break; + default: + return -EINVAL; + } + + return i2c_smbus_write_byte(data->client, val); +} + +static const struct iio_info mcp4018_info = { + .read_raw = mcp4018_read_raw, + .write_raw = mcp4018_write_raw, +}; + +#define MCP4018_ID_TABLE(_name, cfg) { \ + .name = _name, \ + .driver_data = (kernel_ulong_t)&mcp4018_cfg[cfg], \ +} + +static const struct i2c_device_id mcp4018_id[] = { + MCP4018_ID_TABLE("mcp4017-502", MCP4018_502), + MCP4018_ID_TABLE("mcp4017-103", MCP4018_103), + MCP4018_ID_TABLE("mcp4017-503", MCP4018_503), + MCP4018_ID_TABLE("mcp4017-104", MCP4018_104), + MCP4018_ID_TABLE("mcp4018-502", MCP4018_502), + MCP4018_ID_TABLE("mcp4018-103", MCP4018_103), + MCP4018_ID_TABLE("mcp4018-503", MCP4018_503), + MCP4018_ID_TABLE("mcp4018-104", MCP4018_104), + MCP4018_ID_TABLE("mcp4019-502", MCP4018_502), + MCP4018_ID_TABLE("mcp4019-103", MCP4018_103), + MCP4018_ID_TABLE("mcp4019-503", MCP4018_503), + MCP4018_ID_TABLE("mcp4019-104", MCP4018_104), + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(i2c, mcp4018_id); + +#define MCP4018_COMPATIBLE(of_compatible, cfg) { \ + .compatible = of_compatible, \ + .data = &mcp4018_cfg[cfg], \ +} + +static const struct of_device_id mcp4018_of_match[] = { + MCP4018_COMPATIBLE("microchip,mcp4017-502", MCP4018_502), + MCP4018_COMPATIBLE("microchip,mcp4017-103", MCP4018_103), + MCP4018_COMPATIBLE("microchip,mcp4017-503", MCP4018_503), + MCP4018_COMPATIBLE("microchip,mcp4017-104", MCP4018_104), + MCP4018_COMPATIBLE("microchip,mcp4018-502", MCP4018_502), + MCP4018_COMPATIBLE("microchip,mcp4018-103", MCP4018_103), + MCP4018_COMPATIBLE("microchip,mcp4018-503", MCP4018_503), + MCP4018_COMPATIBLE("microchip,mcp4018-104", MCP4018_104), + MCP4018_COMPATIBLE("microchip,mcp4019-502", MCP4018_502), + MCP4018_COMPATIBLE("microchip,mcp4019-103", MCP4018_103), + MCP4018_COMPATIBLE("microchip,mcp4019-503", MCP4018_503), + MCP4018_COMPATIBLE("microchip,mcp4019-104", MCP4018_104), + { /* sentinel */ } +}; +MODULE_DEVICE_TABLE(of, mcp4018_of_match); + +static int mcp4018_probe(struct i2c_client *client) +{ + struct device *dev = &client->dev; + struct mcp4018_data *data; + struct iio_dev *indio_dev; + + if (!i2c_check_functionality(client->adapter, + I2C_FUNC_SMBUS_BYTE)) { + dev_err(dev, "SMBUS Byte transfers not supported\n"); + return -EOPNOTSUPP; + } + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + + data->cfg = i2c_get_match_data(client); + + indio_dev->info = &mcp4018_info; + indio_dev->channels = &mcp4018_channel; + indio_dev->num_channels = 1; + indio_dev->name = client->name; + + return devm_iio_device_register(dev, indio_dev); +} + +static struct i2c_driver mcp4018_driver = { + .driver = { + .name = "mcp4018", + .of_match_table = mcp4018_of_match, + }, + .probe = mcp4018_probe, + .id_table = mcp4018_id, +}; + +module_i2c_driver(mcp4018_driver); + +MODULE_AUTHOR("Peter Rosin <peda@axentia.se>"); +MODULE_DESCRIPTION("MCP4018 digital potentiometer"); +MODULE_LICENSE("GPL v2"); |