diff options
Diffstat (limited to 'drivers/iio/dac/mcp4725.c')
| -rw-r--r-- | drivers/iio/dac/mcp4725.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/drivers/iio/dac/mcp4725.c b/drivers/iio/dac/mcp4725.c new file mode 100644 index 000000000000..e0e168bd5b45 --- /dev/null +++ b/drivers/iio/dac/mcp4725.c @@ -0,0 +1,227 @@ +/* + * mcp4725.c - Support for Microchip MCP4725 + * + * Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net> + * + * Based on max517 by Roland Stigge <stigge@antcom.de> + * + * This file is subject to the terms and conditions of version 2 of + * the GNU General Public License. See the file COPYING in the main + * directory of this archive for more details. + * + * driver for the Microchip I2C 12-bit digital-to-analog converter (DAC) + * (7-bit I2C slave address 0x60, the three LSBs can be configured in + * hardware) + * + * writing the DAC value to EEPROM is not supported + */ + +#include <linux/module.h> +#include <linux/init.h> +#include <linux/i2c.h> +#include <linux/err.h> + +#include <linux/iio/iio.h> +#include <linux/iio/sysfs.h> + +#include <linux/iio/dac/mcp4725.h> + +#define MCP4725_DRV_NAME "mcp4725" + +struct mcp4725_data { + struct i2c_client *client; + u16 vref_mv; + u16 dac_value; +}; + +#ifdef CONFIG_PM_SLEEP +static int mcp4725_suspend(struct device *dev) +{ + u8 outbuf[2]; + + outbuf[0] = 0x3 << 4; /* power-down bits, 500 kOhm resistor */ + outbuf[1] = 0; + + return i2c_master_send(to_i2c_client(dev), outbuf, 2); +} + +static int mcp4725_resume(struct device *dev) +{ + struct iio_dev *indio_dev = dev_to_iio_dev(dev); + struct mcp4725_data *data = iio_priv(indio_dev); + u8 outbuf[2]; + + /* restore previous DAC value */ + outbuf[0] = (data->dac_value >> 8) & 0xf; + outbuf[1] = data->dac_value & 0xff; + + return i2c_master_send(to_i2c_client(dev), outbuf, 2); +} + +static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume); +#define MCP4725_PM_OPS (&mcp4725_pm_ops) +#else +#define MCP4725_PM_OPS NULL +#endif + +static const struct iio_chan_spec mcp4725_channel = { + .type = IIO_VOLTAGE, + .indexed = 1, + .output = 1, + .channel = 0, + .info_mask = IIO_CHAN_INFO_RAW_SEPARATE_BIT | + IIO_CHAN_INFO_SCALE_SHARED_BIT, + .scan_type = IIO_ST('u', 12, 16, 0), +}; + +static int mcp4725_set_value(struct iio_dev *indio_dev, int val) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + u8 outbuf[2]; + int ret; + + if (val >= (1 << 12) || val < 0) + return -EINVAL; + + outbuf[0] = (val >> 8) & 0xf; + outbuf[1] = val & 0xff; + + ret = i2c_master_send(data->client, outbuf, 2); + if (ret < 0) + return ret; + else if (ret != 2) + return -EIO; + else + return 0; +} + +static int mcp4725_read_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int *val, int *val2, long mask) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + unsigned long scale_uv; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + *val = data->dac_value; + return IIO_VAL_INT; + case IIO_CHAN_INFO_SCALE: + scale_uv = (data->vref_mv * 1000) >> 12; + *val = scale_uv / 1000000; + *val2 = scale_uv % 1000000; + return IIO_VAL_INT_PLUS_MICRO; + } + return -EINVAL; +} + +static int mcp4725_write_raw(struct iio_dev *indio_dev, + struct iio_chan_spec const *chan, + int val, int val2, long mask) +{ + struct mcp4725_data *data = iio_priv(indio_dev); + int ret; + + switch (mask) { + case IIO_CHAN_INFO_RAW: + ret = mcp4725_set_value(indio_dev, val); + data->dac_value = val; + break; + default: + ret = -EINVAL; + break; + } + + return ret; +} + +static const struct iio_info mcp4725_info = { + .read_raw = mcp4725_read_raw, + .write_raw = mcp4725_write_raw, + .driver_module = THIS_MODULE, +}; + +static int __devinit mcp4725_probe(struct i2c_client *client, + const struct i2c_device_id *id) +{ + struct mcp4725_data *data; + struct iio_dev *indio_dev; + struct mcp4725_platform_data *platform_data = client->dev.platform_data; + u8 inbuf[3]; + int err; + + if (!platform_data || !platform_data->vref_mv) { + dev_err(&client->dev, "invalid platform data"); + err = -EINVAL; + goto exit; + } + + indio_dev = iio_device_alloc(sizeof(*data)); + if (indio_dev == NULL) { + err = -ENOMEM; + goto exit; + } + data = iio_priv(indio_dev); + i2c_set_clientdata(client, indio_dev); + data->client = client; + + indio_dev->dev.parent = &client->dev; + indio_dev->info = &mcp4725_info; + indio_dev->channels = &mcp4725_channel; + indio_dev->num_channels = 1; + indio_dev->modes = INDIO_DIRECT_MODE; + + data->vref_mv = platform_data->vref_mv; + + /* read current DAC value */ + err = i2c_master_recv(client, inbuf, 3); + if (err < 0) { + dev_err(&client->dev, "failed to read DAC value"); + goto exit_free_device; + } + data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); + + err = iio_device_register(indio_dev); + if (err) + goto exit_free_device; + + dev_info(&client->dev, "MCP4725 DAC registered\n"); + + return 0; + +exit_free_device: + iio_device_free(indio_dev); +exit: + return err; +} + +static int __devexit mcp4725_remove(struct i2c_client *client) +{ + struct iio_dev *indio_dev = i2c_get_clientdata(client); + + iio_device_unregister(indio_dev); + iio_device_free(indio_dev); + + return 0; +} + +static const struct i2c_device_id mcp4725_id[] = { + { "mcp4725", 0 }, + { } +}; +MODULE_DEVICE_TABLE(i2c, mcp4725_id); + +static struct i2c_driver mcp4725_driver = { + .driver = { + .name = MCP4725_DRV_NAME, + .pm = MCP4725_PM_OPS, + }, + .probe = mcp4725_probe, + .remove = __devexit_p(mcp4725_remove), + .id_table = mcp4725_id, +}; +module_i2c_driver(mcp4725_driver); + +MODULE_AUTHOR("Peter Meerwald <pmeerw@pmeerw.net>"); +MODULE_DESCRIPTION("MCP4725 12-bit DAC"); +MODULE_LICENSE("GPL"); |