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Diffstat (limited to '')
| -rw-r--r-- | drivers/iio/potentiometer/mcp4131.c | 493 |
1 files changed, 493 insertions, 0 deletions
diff --git a/drivers/iio/potentiometer/mcp4131.c b/drivers/iio/potentiometer/mcp4131.c new file mode 100644 index 000000000..b3e30db24 --- /dev/null +++ b/drivers/iio/potentiometer/mcp4131.c @@ -0,0 +1,493 @@ +/* + * Industrial I/O driver for Microchip digital potentiometers + * + * Copyright (c) 2016 Slawomir Stepien + * Based on: Peter Rosin's code from mcp4531.c + * + * Datasheet: http://ww1.microchip.com/downloads/en/DeviceDoc/22060b.pdf + * + * DEVID #Wipers #Positions Resistor Opts (kOhm) + * mcp4131 1 129 5, 10, 50, 100 + * mcp4132 1 129 5, 10, 50, 100 + * mcp4141 1 129 5, 10, 50, 100 + * mcp4142 1 129 5, 10, 50, 100 + * mcp4151 1 257 5, 10, 50, 100 + * mcp4152 1 257 5, 10, 50, 100 + * mcp4161 1 257 5, 10, 50, 100 + * mcp4162 1 257 5, 10, 50, 100 + * mcp4231 2 129 5, 10, 50, 100 + * mcp4232 2 129 5, 10, 50, 100 + * mcp4241 2 129 5, 10, 50, 100 + * mcp4242 2 129 5, 10, 50, 100 + * mcp4251 2 257 5, 10, 50, 100 + * mcp4252 2 257 5, 10, 50, 100 + * mcp4261 2 257 5, 10, 50, 100 + * mcp4262 2 257 5, 10, 50, 100 + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published by + * the Free Software Foundation. + */ + +/* + * TODO: + * 1. Write wiper setting to EEPROM for EEPROM capable models. + */ + +#include <linux/cache.h> +#include <linux/err.h> +#include <linux/export.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/spi/spi.h> + +#define MCP4131_WRITE (0x00 << 2) +#define MCP4131_READ (0x03 << 2) + +#define MCP4131_WIPER_SHIFT 4 +#define MCP4131_CMDERR(r) ((r[0]) & 0x02) +#define MCP4131_RAW(r) ((r[0]) == 0xff ? 0x100 : (r[1])) + +struct mcp4131_cfg { + int wipers; + int max_pos; + int kohms; +}; + +enum mcp4131_type { + MCP413x_502 = 0, + MCP413x_103, + MCP413x_503, + MCP413x_104, + MCP414x_502, + MCP414x_103, + MCP414x_503, + MCP414x_104, + MCP415x_502, + MCP415x_103, + MCP415x_503, + MCP415x_104, + MCP416x_502, + MCP416x_103, + MCP416x_503, + MCP416x_104, + MCP423x_502, + MCP423x_103, + MCP423x_503, + MCP423x_104, + MCP424x_502, + MCP424x_103, + MCP424x_503, + MCP424x_104, + MCP425x_502, + MCP425x_103, + MCP425x_503, + MCP425x_104, + MCP426x_502, + MCP426x_103, + MCP426x_503, + MCP426x_104, +}; + +static const struct mcp4131_cfg mcp4131_cfg[] = { + [MCP413x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, }, + [MCP413x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, }, + [MCP413x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, }, + [MCP413x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, }, + [MCP414x_502] = { .wipers = 1, .max_pos = 128, .kohms = 5, }, + [MCP414x_103] = { .wipers = 1, .max_pos = 128, .kohms = 10, }, + [MCP414x_503] = { .wipers = 1, .max_pos = 128, .kohms = 50, }, + [MCP414x_104] = { .wipers = 1, .max_pos = 128, .kohms = 100, }, + [MCP415x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, }, + [MCP415x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, }, + [MCP415x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, }, + [MCP415x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, }, + [MCP416x_502] = { .wipers = 1, .max_pos = 256, .kohms = 5, }, + [MCP416x_103] = { .wipers = 1, .max_pos = 256, .kohms = 10, }, + [MCP416x_503] = { .wipers = 1, .max_pos = 256, .kohms = 50, }, + [MCP416x_104] = { .wipers = 1, .max_pos = 256, .kohms = 100, }, + [MCP423x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, }, + [MCP423x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, }, + [MCP423x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, }, + [MCP423x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, }, + [MCP424x_502] = { .wipers = 2, .max_pos = 128, .kohms = 5, }, + [MCP424x_103] = { .wipers = 2, .max_pos = 128, .kohms = 10, }, + [MCP424x_503] = { .wipers = 2, .max_pos = 128, .kohms = 50, }, + [MCP424x_104] = { .wipers = 2, .max_pos = 128, .kohms = 100, }, + [MCP425x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, }, + [MCP425x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, }, + [MCP425x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, }, + [MCP425x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, }, + [MCP426x_502] = { .wipers = 2, .max_pos = 256, .kohms = 5, }, + [MCP426x_103] = { .wipers = 2, .max_pos = 256, .kohms = 10, }, + [MCP426x_503] = { .wipers = 2, .max_pos = 256, .kohms = 50, }, + [MCP426x_104] = { .wipers = 2, .max_pos = 256, .kohms = 100, }, +}; + +struct mcp4131_data { + struct spi_device *spi; + const struct mcp4131_cfg *cfg; + struct mutex lock; + u8 buf[2] ____cacheline_aligned; +}; + +#define MCP4131_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 mcp4131_channels[] = { + MCP4131_CHANNEL(0), + MCP4131_CHANNEL(1), +}; + +static int mcp4131_read(struct spi_device *spi, void *buf, size_t len) +{ + struct spi_transfer t = { + .tx_buf = buf, /* We need to send addr, cmd and 12 bits */ + .rx_buf = buf, + .len = len, + }; + struct spi_message m; + + spi_message_init(&m); + spi_message_add_tail(&t, &m); + + return spi_sync(spi, &m); +} + +static int mcp4131_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + int err; + struct mcp4131_data *data = iio_priv(indio_dev); + int address = chan->channel; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + mutex_lock(&data->lock); + + data->buf[0] = (address << MCP4131_WIPER_SHIFT) | MCP4131_READ; + data->buf[1] = 0; + + err = mcp4131_read(data->spi, data->buf, 2); + if (err) { + mutex_unlock(&data->lock); + return err; + } + + /* Error, bad address/command combination */ + if (!MCP4131_CMDERR(data->buf)) { + mutex_unlock(&data->lock); + return -EIO; + } + + *val = MCP4131_RAW(data->buf); + mutex_unlock(&data->lock); + + return IIO_VAL_INT; + + case IIO_CHAN_INFO_SCALE: + *val = 1000 * data->cfg->kohms; + *val2 = data->cfg->max_pos; + return IIO_VAL_FRACTIONAL; + } + + return -EINVAL; +} + +static int mcp4131_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + int err; + struct mcp4131_data *data = iio_priv(indio_dev); + int address = chan->channel << MCP4131_WIPER_SHIFT; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + if (val > data->cfg->max_pos || val < 0) + return -EINVAL; + break; + + default: + return -EINVAL; + } + + mutex_lock(&data->lock); + + data->buf[0] = address << MCP4131_WIPER_SHIFT; + data->buf[0] |= MCP4131_WRITE | (val >> 8); + data->buf[1] = val & 0xFF; /* 8 bits here */ + + err = spi_write(data->spi, data->buf, 2); + mutex_unlock(&data->lock); + + return err; +} + +static const struct iio_info mcp4131_info = { + .read_raw = mcp4131_read_raw, + .write_raw = mcp4131_write_raw, +}; + +static int mcp4131_probe(struct spi_device *spi) +{ + int err; + struct device *dev = &spi->dev; + unsigned long devid = spi_get_device_id(spi)->driver_data; + struct mcp4131_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 = &mcp4131_cfg[devid]; + + mutex_init(&data->lock); + + indio_dev->dev.parent = dev; + indio_dev->info = &mcp4131_info; + indio_dev->channels = mcp4131_channels; + indio_dev->num_channels = data->cfg->wipers; + indio_dev->name = spi_get_device_id(spi)->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; + } + + return 0; +} + +#if defined(CONFIG_OF) +static const struct of_device_id mcp4131_dt_ids[] = { + { .compatible = "microchip,mcp4131-502", + .data = &mcp4131_cfg[MCP413x_502] }, + { .compatible = "microchip,mcp4131-103", + .data = &mcp4131_cfg[MCP413x_103] }, + { .compatible = "microchip,mcp4131-503", + .data = &mcp4131_cfg[MCP413x_503] }, + { .compatible = "microchip,mcp4131-104", + .data = &mcp4131_cfg[MCP413x_104] }, + { .compatible = "microchip,mcp4132-502", + .data = &mcp4131_cfg[MCP413x_502] }, + { .compatible = "microchip,mcp4132-103", + .data = &mcp4131_cfg[MCP413x_103] }, + { .compatible = "microchip,mcp4132-503", + .data = &mcp4131_cfg[MCP413x_503] }, + { .compatible = "microchip,mcp4132-104", + .data = &mcp4131_cfg[MCP413x_104] }, + { .compatible = "microchip,mcp4141-502", + .data = &mcp4131_cfg[MCP414x_502] }, + { .compatible = "microchip,mcp4141-103", + .data = &mcp4131_cfg[MCP414x_103] }, + { .compatible = "microchip,mcp4141-503", + .data = &mcp4131_cfg[MCP414x_503] }, + { .compatible = "microchip,mcp4141-104", + .data = &mcp4131_cfg[MCP414x_104] }, + { .compatible = "microchip,mcp4142-502", + .data = &mcp4131_cfg[MCP414x_502] }, + { .compatible = "microchip,mcp4142-103", + .data = &mcp4131_cfg[MCP414x_103] }, + { .compatible = "microchip,mcp4142-503", + .data = &mcp4131_cfg[MCP414x_503] }, + { .compatible = "microchip,mcp4142-104", + .data = &mcp4131_cfg[MCP414x_104] }, + { .compatible = "microchip,mcp4151-502", + .data = &mcp4131_cfg[MCP415x_502] }, + { .compatible = "microchip,mcp4151-103", + .data = &mcp4131_cfg[MCP415x_103] }, + { .compatible = "microchip,mcp4151-503", + .data = &mcp4131_cfg[MCP415x_503] }, + { .compatible = "microchip,mcp4151-104", + .data = &mcp4131_cfg[MCP415x_104] }, + { .compatible = "microchip,mcp4152-502", + .data = &mcp4131_cfg[MCP415x_502] }, + { .compatible = "microchip,mcp4152-103", + .data = &mcp4131_cfg[MCP415x_103] }, + { .compatible = "microchip,mcp4152-503", + .data = &mcp4131_cfg[MCP415x_503] }, + { .compatible = "microchip,mcp4152-104", + .data = &mcp4131_cfg[MCP415x_104] }, + { .compatible = "microchip,mcp4161-502", + .data = &mcp4131_cfg[MCP416x_502] }, + { .compatible = "microchip,mcp4161-103", + .data = &mcp4131_cfg[MCP416x_103] }, + { .compatible = "microchip,mcp4161-503", + .data = &mcp4131_cfg[MCP416x_503] }, + { .compatible = "microchip,mcp4161-104", + .data = &mcp4131_cfg[MCP416x_104] }, + { .compatible = "microchip,mcp4162-502", + .data = &mcp4131_cfg[MCP416x_502] }, + { .compatible = "microchip,mcp4162-103", + .data = &mcp4131_cfg[MCP416x_103] }, + { .compatible = "microchip,mcp4162-503", + .data = &mcp4131_cfg[MCP416x_503] }, + { .compatible = "microchip,mcp4162-104", + .data = &mcp4131_cfg[MCP416x_104] }, + { .compatible = "microchip,mcp4231-502", + .data = &mcp4131_cfg[MCP423x_502] }, + { .compatible = "microchip,mcp4231-103", + .data = &mcp4131_cfg[MCP423x_103] }, + { .compatible = "microchip,mcp4231-503", + .data = &mcp4131_cfg[MCP423x_503] }, + { .compatible = "microchip,mcp4231-104", + .data = &mcp4131_cfg[MCP423x_104] }, + { .compatible = "microchip,mcp4232-502", + .data = &mcp4131_cfg[MCP423x_502] }, + { .compatible = "microchip,mcp4232-103", + .data = &mcp4131_cfg[MCP423x_103] }, + { .compatible = "microchip,mcp4232-503", + .data = &mcp4131_cfg[MCP423x_503] }, + { .compatible = "microchip,mcp4232-104", + .data = &mcp4131_cfg[MCP423x_104] }, + { .compatible = "microchip,mcp4241-502", + .data = &mcp4131_cfg[MCP424x_502] }, + { .compatible = "microchip,mcp4241-103", + .data = &mcp4131_cfg[MCP424x_103] }, + { .compatible = "microchip,mcp4241-503", + .data = &mcp4131_cfg[MCP424x_503] }, + { .compatible = "microchip,mcp4241-104", + .data = &mcp4131_cfg[MCP424x_104] }, + { .compatible = "microchip,mcp4242-502", + .data = &mcp4131_cfg[MCP424x_502] }, + { .compatible = "microchip,mcp4242-103", + .data = &mcp4131_cfg[MCP424x_103] }, + { .compatible = "microchip,mcp4242-503", + .data = &mcp4131_cfg[MCP424x_503] }, + { .compatible = "microchip,mcp4242-104", + .data = &mcp4131_cfg[MCP424x_104] }, + { .compatible = "microchip,mcp4251-502", + .data = &mcp4131_cfg[MCP425x_502] }, + { .compatible = "microchip,mcp4251-103", + .data = &mcp4131_cfg[MCP425x_103] }, + { .compatible = "microchip,mcp4251-503", + .data = &mcp4131_cfg[MCP425x_503] }, + { .compatible = "microchip,mcp4251-104", + .data = &mcp4131_cfg[MCP425x_104] }, + { .compatible = "microchip,mcp4252-502", + .data = &mcp4131_cfg[MCP425x_502] }, + { .compatible = "microchip,mcp4252-103", + .data = &mcp4131_cfg[MCP425x_103] }, + { .compatible = "microchip,mcp4252-503", + .data = &mcp4131_cfg[MCP425x_503] }, + { .compatible = "microchip,mcp4252-104", + .data = &mcp4131_cfg[MCP425x_104] }, + { .compatible = "microchip,mcp4261-502", + .data = &mcp4131_cfg[MCP426x_502] }, + { .compatible = "microchip,mcp4261-103", + .data = &mcp4131_cfg[MCP426x_103] }, + { .compatible = "microchip,mcp4261-503", + .data = &mcp4131_cfg[MCP426x_503] }, + { .compatible = "microchip,mcp4261-104", + .data = &mcp4131_cfg[MCP426x_104] }, + { .compatible = "microchip,mcp4262-502", + .data = &mcp4131_cfg[MCP426x_502] }, + { .compatible = "microchip,mcp4262-103", + .data = &mcp4131_cfg[MCP426x_103] }, + { .compatible = "microchip,mcp4262-503", + .data = &mcp4131_cfg[MCP426x_503] }, + { .compatible = "microchip,mcp4262-104", + .data = &mcp4131_cfg[MCP426x_104] }, + {} +}; +MODULE_DEVICE_TABLE(of, mcp4131_dt_ids); +#endif /* CONFIG_OF */ + +static const struct spi_device_id mcp4131_id[] = { + { "mcp4131-502", MCP413x_502 }, + { "mcp4131-103", MCP413x_103 }, + { "mcp4131-503", MCP413x_503 }, + { "mcp4131-104", MCP413x_104 }, + { "mcp4132-502", MCP413x_502 }, + { "mcp4132-103", MCP413x_103 }, + { "mcp4132-503", MCP413x_503 }, + { "mcp4132-104", MCP413x_104 }, + { "mcp4141-502", MCP414x_502 }, + { "mcp4141-103", MCP414x_103 }, + { "mcp4141-503", MCP414x_503 }, + { "mcp4141-104", MCP414x_104 }, + { "mcp4142-502", MCP414x_502 }, + { "mcp4142-103", MCP414x_103 }, + { "mcp4142-503", MCP414x_503 }, + { "mcp4142-104", MCP414x_104 }, + { "mcp4151-502", MCP415x_502 }, + { "mcp4151-103", MCP415x_103 }, + { "mcp4151-503", MCP415x_503 }, + { "mcp4151-104", MCP415x_104 }, + { "mcp4152-502", MCP415x_502 }, + { "mcp4152-103", MCP415x_103 }, + { "mcp4152-503", MCP415x_503 }, + { "mcp4152-104", MCP415x_104 }, + { "mcp4161-502", MCP416x_502 }, + { "mcp4161-103", MCP416x_103 }, + { "mcp4161-503", MCP416x_503 }, + { "mcp4161-104", MCP416x_104 }, + { "mcp4162-502", MCP416x_502 }, + { "mcp4162-103", MCP416x_103 }, + { "mcp4162-503", MCP416x_503 }, + { "mcp4162-104", MCP416x_104 }, + { "mcp4231-502", MCP423x_502 }, + { "mcp4231-103", MCP423x_103 }, + { "mcp4231-503", MCP423x_503 }, + { "mcp4231-104", MCP423x_104 }, + { "mcp4232-502", MCP423x_502 }, + { "mcp4232-103", MCP423x_103 }, + { "mcp4232-503", MCP423x_503 }, + { "mcp4232-104", MCP423x_104 }, + { "mcp4241-502", MCP424x_502 }, + { "mcp4241-103", MCP424x_103 }, + { "mcp4241-503", MCP424x_503 }, + { "mcp4241-104", MCP424x_104 }, + { "mcp4242-502", MCP424x_502 }, + { "mcp4242-103", MCP424x_103 }, + { "mcp4242-503", MCP424x_503 }, + { "mcp4242-104", MCP424x_104 }, + { "mcp4251-502", MCP425x_502 }, + { "mcp4251-103", MCP425x_103 }, + { "mcp4251-503", MCP425x_503 }, + { "mcp4251-104", MCP425x_104 }, + { "mcp4252-502", MCP425x_502 }, + { "mcp4252-103", MCP425x_103 }, + { "mcp4252-503", MCP425x_503 }, + { "mcp4252-104", MCP425x_104 }, + { "mcp4261-502", MCP426x_502 }, + { "mcp4261-103", MCP426x_103 }, + { "mcp4261-503", MCP426x_503 }, + { "mcp4261-104", MCP426x_104 }, + { "mcp4262-502", MCP426x_502 }, + { "mcp4262-103", MCP426x_103 }, + { "mcp4262-503", MCP426x_503 }, + { "mcp4262-104", MCP426x_104 }, + {} +}; +MODULE_DEVICE_TABLE(spi, mcp4131_id); + +static struct spi_driver mcp4131_driver = { + .driver = { + .name = "mcp4131", + .of_match_table = of_match_ptr(mcp4131_dt_ids), + }, + .probe = mcp4131_probe, + .id_table = mcp4131_id, +}; + +module_spi_driver(mcp4131_driver); + +MODULE_AUTHOR("Slawomir Stepien <sst@poczta.fm>"); +MODULE_DESCRIPTION("MCP4131 digital potentiometer"); +MODULE_LICENSE("GPL v2"); |