542 lines
12 KiB
C
542 lines
12 KiB
C
/*
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* mcp4725.c - Support for Microchip MCP4725/6
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*
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* Copyright (C) 2012 Peter Meerwald <pmeerw@pmeerw.net>
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*
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* Based on max517 by Roland Stigge <stigge@antcom.de>
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*
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* This file is subject to the terms and conditions of version 2 of
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* the GNU General Public License. See the file COPYING in the main
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* directory of this archive for more details.
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*
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* driver for the Microchip I2C 12-bit digital-to-analog converter (DAC)
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* (7-bit I2C slave address 0x60, the three LSBs can be configured in
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* hardware)
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*/
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#include <linux/module.h>
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#include <linux/i2c.h>
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#include <linux/err.h>
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#include <linux/delay.h>
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#include <linux/regulator/consumer.h>
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#include <linux/of.h>
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#include <linux/iio/iio.h>
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#include <linux/iio/sysfs.h>
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#include <linux/iio/dac/mcp4725.h>
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#define MCP4725_DRV_NAME "mcp4725"
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#define MCP472X_REF_VDD 0x00
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#define MCP472X_REF_VREF_UNBUFFERED 0x02
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#define MCP472X_REF_VREF_BUFFERED 0x03
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struct mcp4725_data {
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struct i2c_client *client;
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int id;
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unsigned ref_mode;
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bool vref_buffered;
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u16 dac_value;
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bool powerdown;
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unsigned powerdown_mode;
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struct regulator *vdd_reg;
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struct regulator *vref_reg;
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};
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static int mcp4725_suspend(struct device *dev)
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{
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struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
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to_i2c_client(dev)));
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u8 outbuf[2];
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outbuf[0] = (data->powerdown_mode + 1) << 4;
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outbuf[1] = 0;
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data->powerdown = true;
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return i2c_master_send(data->client, outbuf, 2);
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}
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static int mcp4725_resume(struct device *dev)
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{
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struct mcp4725_data *data = iio_priv(i2c_get_clientdata(
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to_i2c_client(dev)));
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u8 outbuf[2];
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/* restore previous DAC value */
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outbuf[0] = (data->dac_value >> 8) & 0xf;
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outbuf[1] = data->dac_value & 0xff;
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data->powerdown = false;
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return i2c_master_send(data->client, outbuf, 2);
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}
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#ifdef CONFIG_PM_SLEEP
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static SIMPLE_DEV_PM_OPS(mcp4725_pm_ops, mcp4725_suspend, mcp4725_resume);
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#define MCP4725_PM_OPS (&mcp4725_pm_ops)
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#else
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#define MCP4725_PM_OPS NULL
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#endif
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static ssize_t mcp4725_store_eeprom(struct device *dev,
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struct device_attribute *attr, const char *buf, size_t len)
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{
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struct iio_dev *indio_dev = dev_to_iio_dev(dev);
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struct mcp4725_data *data = iio_priv(indio_dev);
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int tries = 20;
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u8 inoutbuf[3];
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bool state;
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int ret;
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ret = strtobool(buf, &state);
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if (ret < 0)
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return ret;
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if (!state)
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return 0;
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inoutbuf[0] = 0x60; /* write EEPROM */
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inoutbuf[0] |= data->ref_mode << 3;
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inoutbuf[1] = data->dac_value >> 4;
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inoutbuf[2] = (data->dac_value & 0xf) << 4;
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ret = i2c_master_send(data->client, inoutbuf, 3);
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if (ret < 0)
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return ret;
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else if (ret != 3)
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return -EIO;
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/* wait for write complete, takes up to 50ms */
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while (tries--) {
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msleep(20);
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ret = i2c_master_recv(data->client, inoutbuf, 3);
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if (ret < 0)
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return ret;
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else if (ret != 3)
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return -EIO;
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if (inoutbuf[0] & 0x80)
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break;
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}
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if (tries < 0) {
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dev_err(&data->client->dev,
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"mcp4725_store_eeprom() failed, incomplete\n");
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return -EIO;
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}
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return len;
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}
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static IIO_DEVICE_ATTR(store_eeprom, S_IWUSR, NULL, mcp4725_store_eeprom, 0);
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static struct attribute *mcp4725_attributes[] = {
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&iio_dev_attr_store_eeprom.dev_attr.attr,
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NULL,
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};
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static const struct attribute_group mcp4725_attribute_group = {
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.attrs = mcp4725_attributes,
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};
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static const char * const mcp4725_powerdown_modes[] = {
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"1kohm_to_gnd",
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"100kohm_to_gnd",
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"500kohm_to_gnd"
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};
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static const char * const mcp4726_powerdown_modes[] = {
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"1kohm_to_gnd",
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"125kohm_to_gnd",
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"640kohm_to_gnd"
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};
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static int mcp4725_get_powerdown_mode(struct iio_dev *indio_dev,
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const struct iio_chan_spec *chan)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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return data->powerdown_mode;
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}
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static int mcp4725_set_powerdown_mode(struct iio_dev *indio_dev,
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const struct iio_chan_spec *chan, unsigned mode)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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data->powerdown_mode = mode;
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return 0;
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}
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static ssize_t mcp4725_read_powerdown(struct iio_dev *indio_dev,
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uintptr_t private, const struct iio_chan_spec *chan, char *buf)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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return sprintf(buf, "%d\n", data->powerdown);
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}
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static ssize_t mcp4725_write_powerdown(struct iio_dev *indio_dev,
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uintptr_t private, const struct iio_chan_spec *chan,
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const char *buf, size_t len)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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bool state;
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int ret;
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ret = strtobool(buf, &state);
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if (ret)
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return ret;
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if (state)
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ret = mcp4725_suspend(&data->client->dev);
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else
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ret = mcp4725_resume(&data->client->dev);
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if (ret < 0)
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return ret;
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return len;
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}
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enum {
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MCP4725,
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MCP4726,
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};
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static const struct iio_enum mcp472x_powerdown_mode_enum[] = {
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[MCP4725] = {
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.items = mcp4725_powerdown_modes,
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.num_items = ARRAY_SIZE(mcp4725_powerdown_modes),
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.get = mcp4725_get_powerdown_mode,
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.set = mcp4725_set_powerdown_mode,
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},
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[MCP4726] = {
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.items = mcp4726_powerdown_modes,
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.num_items = ARRAY_SIZE(mcp4726_powerdown_modes),
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.get = mcp4725_get_powerdown_mode,
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.set = mcp4725_set_powerdown_mode,
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},
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};
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static const struct iio_chan_spec_ext_info mcp4725_ext_info[] = {
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{
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.name = "powerdown",
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.read = mcp4725_read_powerdown,
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.write = mcp4725_write_powerdown,
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.shared = IIO_SEPARATE,
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},
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IIO_ENUM("powerdown_mode", IIO_SEPARATE,
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&mcp472x_powerdown_mode_enum[MCP4725]),
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IIO_ENUM_AVAILABLE("powerdown_mode",
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&mcp472x_powerdown_mode_enum[MCP4725]),
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{ },
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};
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static const struct iio_chan_spec_ext_info mcp4726_ext_info[] = {
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{
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.name = "powerdown",
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.read = mcp4725_read_powerdown,
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.write = mcp4725_write_powerdown,
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.shared = IIO_SEPARATE,
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},
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IIO_ENUM("powerdown_mode", IIO_SEPARATE,
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&mcp472x_powerdown_mode_enum[MCP4726]),
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IIO_ENUM_AVAILABLE("powerdown_mode",
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&mcp472x_powerdown_mode_enum[MCP4726]),
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{ },
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};
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static const struct iio_chan_spec mcp472x_channel[] = {
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[MCP4725] = {
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.type = IIO_VOLTAGE,
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.indexed = 1,
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.output = 1,
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.channel = 0,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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.ext_info = mcp4725_ext_info,
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},
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[MCP4726] = {
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.type = IIO_VOLTAGE,
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.indexed = 1,
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.output = 1,
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.channel = 0,
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.info_mask_separate = BIT(IIO_CHAN_INFO_RAW),
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.info_mask_shared_by_type = BIT(IIO_CHAN_INFO_SCALE),
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.ext_info = mcp4726_ext_info,
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},
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};
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static int mcp4725_set_value(struct iio_dev *indio_dev, int val)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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u8 outbuf[2];
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int ret;
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if (val >= (1 << 12) || val < 0)
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return -EINVAL;
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outbuf[0] = (val >> 8) & 0xf;
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outbuf[1] = val & 0xff;
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ret = i2c_master_send(data->client, outbuf, 2);
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if (ret < 0)
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return ret;
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else if (ret != 2)
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return -EIO;
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else
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return 0;
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}
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static int mcp4726_set_cfg(struct iio_dev *indio_dev)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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u8 outbuf[3];
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int ret;
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outbuf[0] = 0x40;
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outbuf[0] |= data->ref_mode << 3;
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if (data->powerdown)
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outbuf[0] |= data->powerdown << 1;
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outbuf[1] = data->dac_value >> 4;
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outbuf[2] = (data->dac_value & 0xf) << 4;
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ret = i2c_master_send(data->client, outbuf, 3);
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if (ret < 0)
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return ret;
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else if (ret != 3)
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return -EIO;
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else
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return 0;
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}
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static int mcp4725_read_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int *val, int *val2, long mask)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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*val = data->dac_value;
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return IIO_VAL_INT;
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case IIO_CHAN_INFO_SCALE:
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if (data->ref_mode == MCP472X_REF_VDD)
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ret = regulator_get_voltage(data->vdd_reg);
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else
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ret = regulator_get_voltage(data->vref_reg);
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if (ret < 0)
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return ret;
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*val = ret / 1000;
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*val2 = 12;
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return IIO_VAL_FRACTIONAL_LOG2;
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}
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return -EINVAL;
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}
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static int mcp4725_write_raw(struct iio_dev *indio_dev,
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struct iio_chan_spec const *chan,
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int val, int val2, long mask)
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{
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struct mcp4725_data *data = iio_priv(indio_dev);
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int ret;
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switch (mask) {
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case IIO_CHAN_INFO_RAW:
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ret = mcp4725_set_value(indio_dev, val);
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data->dac_value = val;
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break;
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default:
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ret = -EINVAL;
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break;
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}
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return ret;
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}
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static const struct iio_info mcp4725_info = {
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.read_raw = mcp4725_read_raw,
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.write_raw = mcp4725_write_raw,
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.attrs = &mcp4725_attribute_group,
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.driver_module = THIS_MODULE,
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};
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#ifdef CONFIG_OF
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static int mcp4725_probe_dt(struct device *dev,
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struct mcp4725_platform_data *pdata)
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{
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struct device_node *np = dev->of_node;
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if (!np)
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return -ENODEV;
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/* check if is the vref-supply defined */
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pdata->use_vref = of_property_read_bool(np, "vref-supply");
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pdata->vref_buffered =
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of_property_read_bool(np, "microchip,vref-buffered");
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return 0;
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}
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#else
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static int mcp4725_probe_dt(struct device *dev,
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struct mcp4725_platform_data *platform_data)
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{
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return -ENODEV;
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}
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#endif
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static int mcp4725_probe(struct i2c_client *client,
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const struct i2c_device_id *id)
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{
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struct mcp4725_data *data;
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struct iio_dev *indio_dev;
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struct mcp4725_platform_data *pdata, pdata_dt;
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u8 inbuf[4];
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u8 pd;
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u8 ref;
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int err;
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indio_dev = devm_iio_device_alloc(&client->dev, sizeof(*data));
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if (indio_dev == NULL)
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return -ENOMEM;
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data = iio_priv(indio_dev);
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i2c_set_clientdata(client, indio_dev);
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data->client = client;
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data->id = id->driver_data;
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pdata = dev_get_platdata(&client->dev);
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if (!pdata) {
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err = mcp4725_probe_dt(&client->dev, &pdata_dt);
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if (err) {
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dev_err(&client->dev,
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"invalid platform or devicetree data");
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return err;
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}
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pdata = &pdata_dt;
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}
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if (data->id == MCP4725 && pdata->use_vref) {
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dev_err(&client->dev,
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"external reference is unavailable on MCP4725");
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return -EINVAL;
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}
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if (!pdata->use_vref && pdata->vref_buffered) {
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dev_err(&client->dev,
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"buffering is unavailable on the internal reference");
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return -EINVAL;
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}
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if (!pdata->use_vref)
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data->ref_mode = MCP472X_REF_VDD;
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else
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data->ref_mode = pdata->vref_buffered ?
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MCP472X_REF_VREF_BUFFERED :
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MCP472X_REF_VREF_UNBUFFERED;
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data->vdd_reg = devm_regulator_get(&client->dev, "vdd");
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if (IS_ERR(data->vdd_reg))
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return PTR_ERR(data->vdd_reg);
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err = regulator_enable(data->vdd_reg);
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if (err)
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return err;
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if (pdata->use_vref) {
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data->vref_reg = devm_regulator_get(&client->dev, "vref");
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if (IS_ERR(data->vref_reg)) {
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err = PTR_ERR(data->vref_reg);
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goto err_disable_vdd_reg;
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}
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err = regulator_enable(data->vref_reg);
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if (err)
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goto err_disable_vdd_reg;
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}
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indio_dev->dev.parent = &client->dev;
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indio_dev->name = id->name;
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indio_dev->info = &mcp4725_info;
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indio_dev->channels = &mcp472x_channel[id->driver_data];
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indio_dev->num_channels = 1;
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indio_dev->modes = INDIO_DIRECT_MODE;
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/* read current DAC value and settings */
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err = i2c_master_recv(client, inbuf, data->id == MCP4725 ? 3 : 4);
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if (err < 0) {
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dev_err(&client->dev, "failed to read DAC value");
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goto err_disable_vref_reg;
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}
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pd = (inbuf[0] >> 1) & 0x3;
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data->powerdown = pd > 0 ? true : false;
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data->powerdown_mode = pd ? pd - 1 : 2; /* largest resistor to gnd */
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data->dac_value = (inbuf[1] << 4) | (inbuf[2] >> 4);
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if (data->id == MCP4726)
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ref = (inbuf[3] >> 3) & 0x3;
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if (data->id == MCP4726 && ref != data->ref_mode) {
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dev_info(&client->dev,
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"voltage reference mode differs (conf: %u, eeprom: %u), setting %u",
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data->ref_mode, ref, data->ref_mode);
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err = mcp4726_set_cfg(indio_dev);
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if (err < 0)
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goto err_disable_vref_reg;
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}
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err = iio_device_register(indio_dev);
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if (err)
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goto err_disable_vref_reg;
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return 0;
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err_disable_vref_reg:
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if (data->vref_reg)
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regulator_disable(data->vref_reg);
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err_disable_vdd_reg:
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regulator_disable(data->vdd_reg);
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return err;
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}
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static int mcp4725_remove(struct i2c_client *client)
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{
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struct iio_dev *indio_dev = i2c_get_clientdata(client);
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struct mcp4725_data *data = iio_priv(indio_dev);
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|
|
iio_device_unregister(indio_dev);
|
|
|
|
if (data->vref_reg)
|
|
regulator_disable(data->vref_reg);
|
|
regulator_disable(data->vdd_reg);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static const struct i2c_device_id mcp4725_id[] = {
|
|
{ "mcp4725", MCP4725 },
|
|
{ "mcp4726", MCP4726 },
|
|
{ }
|
|
};
|
|
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("MCP4725/6 12-bit DAC");
|
|
MODULE_LICENSE("GPL");
|