diff options
Diffstat (limited to 'drivers/iio/potentiometer/mcp41010.c')
| -rw-r--r-- | drivers/iio/potentiometer/mcp41010.c | 202 |
1 files changed, 202 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/mcp41010.c b/drivers/iio/potentiometer/mcp41010.c new file mode 100644 index 000000000..79ccac6d4 --- /dev/null +++ b/drivers/iio/potentiometer/mcp41010.c @@ -0,0 +1,202 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Industrial I/O driver for Microchip digital potentiometers + * + * Copyright (c) 2018 Chris Coffey <cmc@babblebit.net> + * Based on: Slawomir Stepien's code from mcp4131.c + * + * Datasheet: https://ww1.microchip.com/downloads/en/devicedoc/11195c.pdf + * + * DEVID #Wipers #Positions Resistance (kOhm) + * mcp41010 1 256 10 + * mcp41050 1 256 50 + * mcp41100 1 256 100 + * mcp42010 2 256 10 + * mcp42050 2 256 50 + * mcp42100 2 256 100 + */ + +#include <linux/cache.h> +#include <linux/err.h> +#include <linux/iio/iio.h> +#include <linux/iio/types.h> +#include <linux/module.h> +#include <linux/mutex.h> +#include <linux/of.h> +#include <linux/of_device.h> +#include <linux/spi/spi.h> + +#define MCP41010_MAX_WIPERS 2 +#define MCP41010_WRITE BIT(4) +#define MCP41010_WIPER_MAX 255 +#define MCP41010_WIPER_CHANNEL BIT(0) + +struct mcp41010_cfg { + char name[16]; + int wipers; + int kohms; +}; + +enum mcp41010_type { + MCP41010, + MCP41050, + MCP41100, + MCP42010, + MCP42050, + MCP42100, +}; + +static const struct mcp41010_cfg mcp41010_cfg[] = { + [MCP41010] = { .name = "mcp41010", .wipers = 1, .kohms = 10, }, + [MCP41050] = { .name = "mcp41050", .wipers = 1, .kohms = 50, }, + [MCP41100] = { .name = "mcp41100", .wipers = 1, .kohms = 100, }, + [MCP42010] = { .name = "mcp42010", .wipers = 2, .kohms = 10, }, + [MCP42050] = { .name = "mcp42050", .wipers = 2, .kohms = 50, }, + [MCP42100] = { .name = "mcp42100", .wipers = 2, .kohms = 100, }, +}; + +struct mcp41010_data { + struct spi_device *spi; + const struct mcp41010_cfg *cfg; + struct mutex lock; /* Protect write sequences */ + unsigned int value[MCP41010_MAX_WIPERS]; /* Cache wiper values */ + u8 buf[2] ____cacheline_aligned; +}; + +#define MCP41010_CHANNEL(ch) { \ + .type = IIO_RESISTANCE, \ + .indexed = 1, \ + .output = 1, \ + .channel = (ch), \ + .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), \ + .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), \ +} + +static const struct iio_chan_spec mcp41010_channels[] = { + MCP41010_CHANNEL(0), + MCP41010_CHANNEL(1), +}; + +static int mcp41010_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mcp41010_data *data = iio_priv(indio_dev); + int channel = chan->channel; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val = data->value[channel]; + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + *val = 1000 * data->cfg->kohms; + *val2 = MCP41010_WIPER_MAX; + return IIO_VAL_FRACTIONAL; + } + + return -EINVAL; +} + +static int mcp41010_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + int err; + struct mcp41010_data *data = iio_priv(indio_dev); + int channel = chan->channel; + + if (mask != IIO_CHAN_INFO_RAW) + return -EINVAL; + + if (val > MCP41010_WIPER_MAX || val < 0) + return -EINVAL; + + mutex_lock(&data->lock); + + data->buf[0] = MCP41010_WIPER_CHANNEL << channel; + data->buf[0] |= MCP41010_WRITE; + data->buf[1] = val & 0xff; + + err = spi_write(data->spi, data->buf, sizeof(data->buf)); + if (!err) + data->value[channel] = val; + + mutex_unlock(&data->lock); + + return err; +} + +static const struct iio_info mcp41010_info = { + .read_raw = mcp41010_read_raw, + .write_raw = mcp41010_write_raw, +}; + +static int mcp41010_probe(struct spi_device *spi) +{ + int err; + struct device *dev = &spi->dev; + struct mcp41010_data *data; + struct iio_dev *indio_dev; + + indio_dev = devm_iio_device_alloc(dev, sizeof(*data)); + if (!indio_dev) + return -ENOMEM; + + data = iio_priv(indio_dev); + spi_set_drvdata(spi, indio_dev); + data->spi = spi; + data->cfg = of_device_get_match_data(&spi->dev); + if (!data->cfg) + data->cfg = &mcp41010_cfg[spi_get_device_id(spi)->driver_data]; + + mutex_init(&data->lock); + + indio_dev->info = &mcp41010_info; + indio_dev->channels = mcp41010_channels; + indio_dev->num_channels = data->cfg->wipers; + indio_dev->name = data->cfg->name; + + err = devm_iio_device_register(dev, indio_dev); + if (err) + dev_info(&spi->dev, "Unable to register %s\n", indio_dev->name); + + return err; +} + +static const struct of_device_id mcp41010_match[] = { + { .compatible = "microchip,mcp41010", .data = &mcp41010_cfg[MCP41010] }, + { .compatible = "microchip,mcp41050", .data = &mcp41010_cfg[MCP41050] }, + { .compatible = "microchip,mcp41100", .data = &mcp41010_cfg[MCP41100] }, + { .compatible = "microchip,mcp42010", .data = &mcp41010_cfg[MCP42010] }, + { .compatible = "microchip,mcp42050", .data = &mcp41010_cfg[MCP42050] }, + { .compatible = "microchip,mcp42100", .data = &mcp41010_cfg[MCP42100] }, + {} +}; +MODULE_DEVICE_TABLE(of, mcp41010_match); + +static const struct spi_device_id mcp41010_id[] = { + { "mcp41010", MCP41010 }, + { "mcp41050", MCP41050 }, + { "mcp41100", MCP41100 }, + { "mcp42010", MCP42010 }, + { "mcp42050", MCP42050 }, + { "mcp42100", MCP42100 }, + {} +}; +MODULE_DEVICE_TABLE(spi, mcp41010_id); + +static struct spi_driver mcp41010_driver = { + .driver = { + .name = "mcp41010", + .of_match_table = mcp41010_match, + }, + .probe = mcp41010_probe, + .id_table = mcp41010_id, +}; + +module_spi_driver(mcp41010_driver); + +MODULE_AUTHOR("Chris Coffey <cmc@babblebit.net>"); +MODULE_DESCRIPTION("MCP41010 digital potentiometer"); +MODULE_LICENSE("GPL v2"); |