| /* |
| * 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/init.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 iio_dev *indio_dev = dev_to_iio_dev(dev); |
| struct mcp4725_data *data = iio_priv(indio_dev); |
| u8 outbuf[2]; |
| |
| outbuf[0] = (data->powerdown_mode + 1) << 4; |
| outbuf[1] = 0; |
| data->powerdown = true; |
| |
| 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; |
| data->powerdown = false; |
| |
| return i2c_master_send(to_i2c_client(dev), 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 int 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, |
| }, |
| IIO_ENUM("powerdown_mode", false, &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), |
| .scan_type = IIO_ST('u', 12, 16, 0), |
| .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); |
| 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, |
| .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"); |
| 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; |
| } |
| 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); |
| |
| 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 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 = 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"); |