/* * 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) */ #include <linux/module.h> #include <linux/i2c.h> #include <linux/err.h> #include <linux/delay.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; bool powerdown; unsigned powerdown_mode; }; static int mcp4725_suspend(struct device *dev) { struct mcp4725_data *data = iio_priv(i2c_get_clientdata( to_i2c_client(dev))); u8 outbuf[2]; outbuf[0] = (data->powerdown_mode + 1) << 4; outbuf[1] = 0; data->powerdown = true; return i2c_master_send(data->client, outbuf, 2); } static int mcp4725_resume(struct device *dev) { struct mcp4725_data *data = iio_priv(i2c_get_clientdata( to_i2c_client(dev))); u8 outbuf[2]; /* restore previous DAC value */ outbuf[0] = (data->dac_value >> 8) & 0xf; outbuf[1] = data->dac_value & 0xff; data->powerdown = false; return i2c_master_send(data->client, outbuf, 2); } #ifdef CONFIG_PM_SLEEP 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 ssize_t mcp4725_store_eeprom(struct device *dev, struct device_attribute *attr, const char *buf, size_t len) { struct iio_dev *indio_dev = dev_to_iio_dev(dev); struct mcp4725_data *data = iio_priv(indio_dev); int tries = 20; u8 inoutbuf[3]; bool state; int ret; ret = strtobool(buf, &state); if (ret < 0) return ret; if (!state) return 0; inoutbuf[0] = 0x60; /* write EEPROM */ inoutbuf[1] = data->dac_value >> 4; inoutbuf[2] = (data->dac_value & 0xf) << 4; ret = i2c_master_send(data->client, inoutbuf, 3); if (ret < 0) return ret; else if (ret != 3) return -EIO; /* wait for write complete, takes up to 50ms */ while (tries--) { msleep(20); ret = i2c_master_recv(data->client, inoutbuf, 3); if (ret < 0) return ret; else if (ret != 3) return -EIO; if (inoutbuf[0] & 0x80) break; } if (tries < 0) { dev_err(&data->client->dev, "mcp4725_store_eeprom() failed, incomplete\n"); return -EIO; } return len; } static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0); static struct attribute *mcp4725_attributes[] = { &iio_dev_attr_store_eeprom.dev_attr.attr, NULL, }; static const struct attribute_group mcp4725_attribute_group = { .attrs = mcp4725_attributes, }; static const char * const mcp4725_powerdown_modes[] = { "1kohm_to_gnd", "100kohm_to_gnd", "500kohm_to_gnd" }; static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev, const struct iio_chan_spec *chan) { struct mcp4725_data *data = iio_priv(indio_dev); return data->powerdown_mode; } static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev, const struct iio_chan_spec *chan, unsigned mode) { struct mcp4725_data *data = iio_priv(indio_dev); data->powerdown_mode = mode; return 0; } static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev, uintptr_t private, const struct iio_chan_spec *chan, char *buf) { struct mcp4725_data *data = iio_priv(indio_dev); return sprintf(buf, "%d\n", data->powerdown); } static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev, uintptr_t private, const struct iio_chan_spec *chan, const char *buf, size_t len) { struct mcp4725_data *data = iio_priv(indio_dev); bool state; int ret; ret = strtobool(buf, &state); if (ret) return ret; if (state) ret = mcp4725_suspend(&data->client->dev); else ret = mcp4725_resume(&data->client->dev); if (ret < 0) return ret; return len; } static const struct iio_enum mcp4725_powerdown_mode_enum = { .items = mcp4725_powerdown_modes, .num_items = ARRAY_SIZE(mcp4725_powerdown_modes), .get = mcp4725_get_powerdown_mode, .set = mcp4725_set_powerdown_mode, }; static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = { { .name = "powerdown", .read = mcp4725_read_powerdown, .write = mcp4725_write_powerdown, .shared = IIO_SEPARATE, }, IIO_ENUM("powerdown_mode", IIO_SEPARATE, &mcp4725_powerdown_mode_enum), IIO_ENUM_AVAILABLE("powerdown_mode", &mcp4725_powerdown_mode_enum), { }, }; static const struct iio_chan_spec mcp4725_channel = { .type = IIO_VOLTAGE, .indexed = 1, .output = 1, .channel = 0, .info_mask_separate = BIT(IIO_CHAN_INFO_RAW), .info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE), .ext_info = mcp4725_ext_info, }; 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); switch (mask) { case IIO_CHAN_INFO_RAW: *val = data->dac_value; return IIO_VAL_INT; case IIO_CHAN_INFO_SCALE: *val = data->vref_mv; *val2 = 12; return IIO_VAL_FRACTIONAL_LOG2; } 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, .attrs = &mcp4725_attribute_group, .driver_module = THIS_MODULE, }; static int 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]; u8 pd; int err; if (!platform_data || !platform_data->vref_mv) { dev_err(&client->dev, "invalid platform data"); return -EINVAL; } indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data)); if (indio_dev == NULL) return -ENOMEM; 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"); return err; } pd = (inbuf[0] >> 1) & 0x3; data->powerdown = pd > 0 ? true : false; data->powerdown_mode = pd ? pd-1 : 2; /* 500kohm_to_gnd */ data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4); return iio_device_register(indio_dev); } static int mcp4725_remove(struct i2c_client *client) { iio_device_unregister(i2c_get_clientdata(client)); 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 = 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");